Back on the road

It's been awhile but I have been working on the car as often as possible and I'm finally back on the road.

The original BMS didn't have any wire protection, if for some reason a wire got shorted out and burned up, you'd have to rerun that wire. I added small inline fuses to each cell at the battery. It's a little more cost and time, but something that's worth it in my opinion.

Here is a picture of the completed front end. Six batteries were removed from the original design to all for the AC compressor and pulley assembly. The good news is I finally have AC, but the news is it's winter time and I have to wait awhile to use it. However, part of this was to add the heater and on the cold mornings it really heats up the small cab space of this car quickly.

The motor controller was modified in multiple ways. First the Curtis "whine" was removed and the car is now completely silent, as an electric car should be. The maximum voltage was increased to allow for my fully charged voltage on 54 cells (I charge up to about 184v). Finally the amps was increased from 500 to 750. This made a huge difference in acceleration and overall power. My 0-30 went from (I think it was 7 seconds) down to less than 4 seconds. Overall the total power of the controller went from 72kW to just over 130kW.

I removed that large, and unreliable BMS screen from the dash and replaced it with the E-xpert Pro. This has turned out to be a great little display. On top of showing pack voltage, amps, Ah, and remaining runtime, it has some other extras and is highly configurable. You can customize this meter to your battery, driving needs and how hard you want to push your battery by setting what is considered full, empty, when to raise alarms, etc. So for example I setup mine to alert me when the pack is 30% SOC and to consider 20% SOC empty. This affects how the "fuel" gauge displays its bars. I also turned on a feature that will automatically add the back light as long as >1 amp is going through the shunt. As I drive the back light is on, and 10 seconds or so after stopping it turns off. I also configured the meter to consider the battery full when 184v is reached and the charger is at about 2 amps for at least 1 minute. This then resets the Ah counters and gauge and avoids any calibration errors that might allow the meter to slowly drift over time.



Here is the trunk now. I wouldn't call it finished because things are still a little messy and I'd like to get carpet back in there. Trunk space is still reduce, but I can at least fit something in there now if needed. The little black things on top of the charger are the new Cell Log 8 modules that I'm using to monitor high and low voltage conditions. These are about $13 a piece and will monitor 8 cells each. I build a little circuit board for each to simplify the wiring. They have an internal relay that allows you to provide signalling to the charger, a buzzer, light, etc. They are not isolated, however, so expect to use an additional relay on each module to isolate it. These modules will turn on when the charger is connected to AC power or the key is on.


Another thing I modified this round was the suspension. I added another 9 cells (over 100 lbs) and with so much additional weight in the rear I knew I couldn't avoid it this time. Online I found the spring rates saw that the rear springs were much stiffer than the front. The front springs were 245 lbs/in while the rear springs were 311 lbs/in. I moved the rear springs to the front of the car and replaced the rear with 10" (original springs are 11" unbound) 400 lbs/in springs. The put the rear exactly back to stock ride height and my front is still 1/4" lower but I think within range for alignment. I still need to take the car back down for an alignment to see if this will do.

It's great finally being back on the road. The gas to drive my truck 70 miles to work each day was really adding up. That and I just missed my car, too much fun to drive. I'll keep you posted on miles. I think around 16-17k miles total at this point.

Trunk Ventilation

One issue I frequently dealt with was the charger shutting down due to over heating. I would finish work and come out to find a car with less than full charge. Luckily most of the time it had charged enough to still get my home, but I found myself a couple of times sticking around work another hour or more. The temporary solution was to leave the trunk slightly cracked during non winter months and this did the trick.

I plan to ensure adequate ventilation this time and have installed two 120mm fans. They will connect directly to the 240v charger source and run continuously during the charge cycle. The fans are quiet (30 dB), low speed (1900 RPM), move up to 67 CFM and take 7.5 watts of power each.

Here is a shot of the mounted fan. The trunk is big ugly at the moment but I plan to reinstall the carpeting after the modifications are complete.


Here is a shot from the bottom of the trunk. I've installed a vent which will deflect water spray while driving. They are angled to take the incoming air which should close the vents as well during speed.

Motor Cooling

One area I found that needed improvement was the motor cooling. There is an internal fan which does a decent job, but on longer commutes like mine the temperature of the motor just continues to rise. On really hot days I found the motor would cut out a little from time-to-time. My theory is this is the springs that hold the brushes down becoming too hot and allowing the brushes to float briefly.

My plan is to install four small fans directly above each set of brushes that turn on when the motor heats up using a thermostat. The thermostat is basically a temperature driven switch that will trigger a relay to turn on the fans. I selected 40C or 105F as the turn on. This will keep it from turning on during short trips but will ensure it starts cooling as soon as possible.

Here are the fans I used. They are 2" fans that do 20 CFM and draw .25 amps.


Here is one of the mounted fans and the thermostat. I made a bracket that attaches to the old temperature sensor and the thermostat bolts to the bracket.


When I manually enable the system I can feel a good breeze coming out the back the motor so that's a good sign. We'll see what happens after I get it back on the road.

More battery testing

I ordered 12 new cells for the upgrade. The plan was to replace the two cells that have had bad sag since day one and 10 new cells. I decided this would be a great time to do another capacity test for comparison against my original cells.

When I got the original cells I was told the factory capacity tests were all above 160, if I recall they were mostly around 165Ah. I charged a group of four new cells the same way I did the old cells. That is, not long after switching from CC stage into CV stage I remove charge and begin testing. The old cells were drained at ~130 amps until 2.5v and the worst cells yielded 145Ah, most around 150Ah. The new cells I only drained down to 2.8v and the reason is that at 2.8v they had produced 183.5Ah!

This raised a few thoughts of course and along with the fact they have improved the cells, I'm lead to believe that Sky Energy (CALB) who sells an equal size and weight 180Ah cell for more money is most likely selling the exact same battery. Unfortunately I don't have the 180Ah cells to test, perhaps they are getting 190-200Ah. I believe the batteries might be coming with more capacity also so that after time, they are still considered to be at their rated capacity or higher.

Trunk Mods Part II

Not much to show here. I've installed 15 additional cells in the area the old fuel tank use to be. This is directly above the rear sub frame. This is too much weight for the original shocks so I'll be modifying the suspension all around. Even though the sag isn't much, the suspension doesn't allow for much correction and the alignment was never back in spec causing inside tire wear. I plan to resolve that this time around.

Too Cool

After completing the trunk modifications I needed to modify the front racks to reduce the number cells and provide space for the air conditioning. Unfortunately during the first stages of the conversion I focused on getting batteries in and soon found I didn't have room for the AC. Wanting to make sure this didn't happen again, I decided to get the AC in and then see how many cells I could fit afterwards.

The first and probably hardest step determining how power the compressor. My first option was to modify the compressor to use a standard V belt. In this case it was easy to create a main pulley to attach to the motor. However I determined, after dismantling the compressor, it was going to be very difficult. My second option was to find/make a pulley that could use the same style of serpentine belt the compressor used. I opted for this method. I used the original pulley which accepted a spline shaft. The ADC 9" motor has a much smaller, round keyed shaft. I bought a 3/4" hub from tractor supply. I was able to get my uncle to turn down the hub and we then pressed it inside the original pulley with a hydraulic press. We ran a weld around one end to make sure it could turn inside. With this done it was just a matter of fabricating a frame that mounted the compressor and tensioner to the motor frame.

Here you can see completed setup. Reusing the tensioner instead of trying to make the compressor adjustable is the best route. The tensioner keeps the belt at the ideal tension as it stretches with age. This setup should be maintenance free for years.


Here is a shot from the other side.


I ordered from Jegs and got a Gates belt K060345. This is actually a bit over 35" and is the six v serpentine style belt used originally, just much shorter. This was stocked and I got a "free" hat. Considering their "free" shipping had a $5 handling fee, I'm not sure which one of the two I actually got free.

Here is a 12v functional test video. It's not nearly as noisy as this little camera picks up.

After everything was functional I needed to charge the AC system. The system had been opened for months, and even if it had only been opened for a day or so you need to do a lengthy evac process. An oil based vacuum pump is required which I bought one from Harbor Freight. You'll also need an AC manifold set which I also got from Harbor Freight.

The process is fairly simple. First connect the high(red) and low(blue) side hoses to the A/C system. The sizes are different so you can't accidentally connect the wrong one. This manifold set has a yellow hose and two spots where the yellow hose can connect, one is open and the other is a pressure fitting. Connect the yellow hose to the open side and then to the vacuum pump. Turn on the vacuum pump and then open the high and low valves. Let this run for several hours, the longer the better. The pump will get the system down fairly quickly, but it won't remove all the moisture this fast. You must leave it running to remove the moisture (3-5 hrs will do it). Once complete, first close the high and low valves, then turn off the vacuum pump.

You'll need to check the service manual to determine how much refrigerant should go into the system. You'll also need to replace any oil that was lost. There are refrigerants that contain oil, but it's not enough for a complete recharge so you'll need to do the math and figure out what you need.

The recharge process is simple. Read and follow the directions on the can first and foremost. Disconnect the vacuum pump and connect your refrigerant. The can should be shaken during the entire process. Open the valve on the can, then open the LOW side ONLY. Never open the high side valve while recharging. You'll hold the can upright and rotate 90 degrees every few seconds again given the can a good shake frequently. You'll want to make sure there is enough refrigerant and oil in the system before turning on the A/C system (again consult your service manual). Most systems should have a low pressure safety switch to prevent this. With the A/C system on max you'll notice the low side gauge drop as it compresses the gas to the high side. As it pulls from the low side more refrigerant from the can will pass into the system. As the can empties it slows down so be patient 5-15 minutes per can. Repeat this process to add oil and more refrigerant as needed. When complete close the low side valve, then close the refrigerant valve. The high and low side connectors can be popped off easily at this point, but when you disassemble the manifold some gases will escape so do this in a well ventilated area so you don't breath it in.

That was it, now I have some really cold air coming out of my EV!

Trunk Modifications Part I

I've been working on modifications to the car over the past couple weeks. In order to get the AC back into the car some of the cells needed be shifted from the front of the car to back. Additionally, I want to add a more cells. The only solution was to make better use of the trunk. The number of new cells I'll add is still not firm but I'm looking to add as many as possible for multiple reasons.

1. Greater range. More cells means I have more energy and can travel further before recharging.
2. Distributed load. The more cells I have, the less they have to work for my daily commute which will increase the life of the cells.
3. Performance. Currently the 144v system allows the motor to hit about 4k RPM before the controller switches to VMax. Any additional increase in RPM greatly reduces torque requiring you to shift to a higher gear. Increasing the voltage will allow the torque to remain steady for higher RPM meaning the motor will want to rev out higher.

Here is a shot of the original trunk space. You can see there isn't much usable space currently above the fuel tank, about 3" and it opens up to only about 8-10" on the far right.

The old spot I use to have the charger has a curve to it and greatly reduces the usable space.

A couple of minutes with my plasma cutter and the rear most area is opened up and ready for a new battery rack.

This area now allows for storage of all 15 cells that used to take up the remaining trunk space (including charger). The rack is lined with a thin plastic and sealed to keep out water, etc. I used an expanding foam on the outside underneath the car to also fill in any open areas. The sides use a 1/4" thick steel for strength since the rack is also binding the cells together. If you use a thin metal it will bend as the cells begin to swell which is very bad on the cell life. It's amazing how much pressure is needed to contain them properly. The top (black) metal is much more light weight and designed to simply keep the cells from being able to shift upwards on bumpy roads or a rollover.

Next I will be working on the area where the gas tank use to sit. It looks like I can fit another 18 cells here if it all works out. I will need to make some suspension modifications for the extra weight I'm adding with these additional batteries.

Battery testing

I have removed everything from the car to complete that to do list I created a long time ago and have been putting off (more on this later). While I had the batteries out I wanted to do a test to determine how much capacity is remaining now that the cells are about 1.5 years old and have over 15k miles. I've also calculated it takes me roughly 120Ah to get to work and 80Ah to return home (2k foot elevation climb to get to work). Using 15k miles, and the 70 mile commute that gives me about 214 trips I've made to work so far. Each round trip (120Ah + 80Ah) / 160Ah batteries = 1.25 charge cycles. Therefore, 214 x 1.25 is 267 charge cycles I've used.

Below is my battery testing solution.

• Costco a 2300 watt power inverter. This allows me to test four batteries at a time to get my 12v source.
• 1500 watt space heater. This gives me just over 130 amp load on the batteries which is close to 1C and will give a decent enough load to test.
• E-Xpert pro battery monitor from TBS Electronics with a 500 amp shunt. This will track the Ah used for me and give accurate results compared to trying to calculate this myself based off of ever changing voltage/amperage as the batteries drain.
• CellLog8 allowed me to easily monitor each cells voltage to determine when a cell was too low during the load test or too high during recharge.
• For charging I used my original battery charger, a 12v charger I had, and my bench power supply. This allowed me to charge up to 45 amps and helped speed up the testing greatly. I only did quick charges and once the amperage needed was between 5-10 amps I stopped charging and begin the test. This means the cells were NOT fully charged (probably 90 - 95% is my guesstimate) which is important when reviewing the results below.

My original testing plan was going to be to drain the batteries until the first cell reached low voltage, then rotate in another cell and continue testing to get results for each cell. After doing this only once I realized that the capacity of the cells was extremely close and it wasn't worth the extra time. I won't post all the results but basically my lowest cell produced 145Ah. I had other groups producing 148, 150, etc. They were all extremely close. Even the two cells that have terrible voltage sag still produced over 145Ah like the others. Now 145Ah is just over 90% of original capacity, however, remember my charging method was manual and I didn't give it the time to do much constant voltage charging. So to my surprise, I think I'm still near original capacity. The only thing is I didn't do this testing when the cells were new and I'm told they will have at least 160 but usually more, so it's possible I've lost more than I know. Either way this is good news and I'm quite happy with the results.

In the name of science part II

If you recall from the last testing I put two Kelley controllers up against my Curtis 1231C. We did some repeated 0-30mph tests and compared times while monitoring the motor side amp output. The Curtis accelerated my car in second gear to 30mph in 7-8 seconds (nothing official just eye-balling a standard watch).

I've been in touch with a great guy who works at Curtis. This weekend I had the opportunity to test a modified Curtis 1231C. Unfortunately I only had a 500 amp shunt so we weren't able to test the motor side amps. I did see my battery amps peaking somewhere around 650-700 though as the controller reached Vmax. This controller reduced my 0-30 to 5 seconds. I will add the shunt later and get the real output from it soon.

He also has an even higher end modified 1231C, but we were having some issues with it. It should be 200 amps more or so. It would be nice to see a 3 second 0-30 :)

Unfortunately I can't give out any of the secret sauce that is being used to upgrade/modify these controllers since I didn't obtain the information myself and don't want to get anybody in trouble.

We should be doing some more tests with the 2nd upgraded controller later and I'll be sure to have the shunt ready for some numbers. I realize most people won't be able to make these modifications, but it should give you a good idea of expected acceleration for a given amount of continuous amps.

15/100

Things are still looking good on the daily commute. The car itself broke 100k miles a couple weeks ago and I'm now at 15k EV miles!

The increase in temperature has made a little improvement to the increasing voltage sag. I think the bottom line is I'm pushing these cells harder than I should for longevity. I believe my commute to work is using >80% capacity and this is taking a toll on capacity. Some mornings I have cell that is very close to fully discharged. I don't know how many miles I have left before at least one cell can't make it and possibly gets ruined to get me here.

I keep going in circles, but I'm leaning towards not selling it now. I'm thinking of making some modifications though now that I see how reliable the conversion itself is. Nothing official yet but here are some ideas I'm toying around with.

Motor controller: The Curtis 1231C has been reliable but I want to get the acceleration back in this car. I'm leaning towards the Soliton1 again for a few reasons.

• It will increase my motor side amps from 500 to 1000.
• It's much larger and has great cooling with the option of water cooling if needed. In the hot summer days on my long commute doing 70mph the Curtis is kicking down the amps sometimes.
• It has many features that will make protecting the batteries, and motor a breeze. I'd like to add some features, but reduce complexity of the build and I think this will be a good step in that direction.
• I'll have the ability to run a pack voltage that is much higher than the voltage applied to the motor. This allows you to run more smaller batteries allowing you to still get the capacity you want, but make it easier to fit them. It also will remove volt sag during hard acceleration. The pack itself will sag, but if your pack voltage is high enough the motor will receive a steady voltage increasing performance even on those cold days.

Trunk mod:
I think I'll end up cutting out the current trunk and expanding it. There is a LOT of room that is not being utilized under there. This will allow me to add more batteries and even move some of the front batteries to the back giving me room to finally mount that AC that I've been missing.

Batteries:
Currently I'll just add some more cells (I'd like to add another 15 or so) so I can get as much from the existing cells. This should ease up on them and extend there life some on my commute. This will give me not only more capacity but the ability to crank up the motor voltage a bit also to increase high end performance along side of the low end performance I'll gain from the controller change.

BMS:
I'd like to get the car to a point where I don't have to look at anything and worry about what's going on. I want to simplify this side of things most of all. I want to be able to get in the car, look at my "fuel" gauge and know if I'm good to go. If there are any issues, then be able to connect something and diagnose the problem. I'm looking into some options for a low cost over haul here. The biggest problem with adding more and more cells is the complexity of protecting them.

As always, anything I do I'll document and share with you.

One year

I just realized it's been just over a year now since I started driving the car to work! I have 12k miles on the car and things are still working well.

I decided to do some quick math to see what 12k EV miles really means. The car originally got 26mpg on my commute. 12,000 miles/26 mpg = 461.5 gallons that I didn't burn this year. Gas in my area has been more or less $3 over the last year so that's $1384 dollars I would have spent on gas.

Although it's great to not have given my money to the oil companies or burned the gas, the actual conversion cost vs returns would never pay off before something needs to be replaced (i.e. batteries). EVs of some form are definitely the future, now we just need to wait for all the auto manufactures to get those production models out which will reduce costs. 2011/2012 will be a huge turn for the auto industry...I can't wait!

10k miles and counting

I haven't been on here in awhile. I few weeks ago I finally hit the big 10k EV mile marker! Other than that there really isn't much to report. I'm still driving the car to work and things are great. The cold weather is still taking its toll on the batteries and the volt sag is high. This makes climbing the steep hills hard as I need more amps to account for the lower voltage but they seem to be dealing with it fine.

You may recall I reported two cells which sagged considerably more than the rest. I figured these would have went out by now but they are still working fine. On the down side, I now have two more cells that seem to sag more than before (about 0.4v under 2C load lower than the rest). I don't plan to replace any of them until they go out completely so I can really test them out. Speaking of replacing them, I noticed that Elite Power Solutions has finally dropped their prices to be more competitive with some of the other suppliers. We'll hopefully see a continuing trend making this option more affordable for all.

For Sale

As much as I hate to do it, it's time to sell the S2KEV. I really want to start looking into my next EV and I have to sell this one for the funds. I put up a listing for now at EVTradin for those interested in the details.

After putting 10k miles on this one I feel comfortable selling it since I know it's been a good conversion and is reliable.

So what's next? I'm not sure yet exactly but you can bet I'll be blogging on it!

When to short is two long

So when I put everything back together last, I failed to mention a dummy moment I had. I managed to short out a cell for a couple of seconds. I really wasn't sure if I had done any damaged so thought I'd figure it out one way or the other before posting the results.

The cell was directly shorted out for a good two seconds, maybe a bit more, although it seemed liked a minute as I was jumping around trying to stop it. :)

I gave the cell a separate charge knowing I had discharged it quite a bit and definitely exceeded the maximum discharge amperage. Somewhere during the first or second week of driving to work the cell didn't have enough capacity to make it here and dropped to zero volts. I knew I had done some damage to it now, not from the zero volt, but the fact that it reached zero volts. If you recall, I've taken another cell to zero volts and it's still alive and kicking so no final verdict there yet.

I manually charged this cell up again for about a day at 5 amps, AFTER the pack itself had reached full charge. This one cell, however, would never fully charge. It seemed it internally had a self discharge of a couple amps maybe.

However, it continued to get me to work...until today. The cell reached zero volts again on the way to work and I knew it was time to replace it. This time, the cell would not charge...at all. I could not get the voltage above 0.7v and the cell got very warm when charging.

So although this is the extreme case of discharging at high rates, it may speak slightly to what happens to a cell when exceeding the maximum continuous ratings, just to a lesser degree. In short, it's bad :)

So, I've now lost my first cell. Luckily it was due to my own ignorance and not a failure for general use.

On a side note, I have noticed much greater voltage sag with the colder weather under load. This may be because the cells don't charge as much in this weather as well as the temperature it self during operation. It's about 45-50F when I leave in the morning and the car charges outside. We'll see how bad it gets when winter really kicks in here.

Is it alive?

I realized I hadn't posted on in here in a couple months now! I'm just having too much fun driving and not working on the car.

I did tear it down just a couple weeks ago to look things over, make sure no welds had broke, check the motor brushes, etc. Everything looks great!

Since I had it all apart, I took the time to FINALLY install my version 2.0 of the LiFePO4 Volt Blocher.

I'm normally parked outside the garage these days as my truck sits here, but thought it was a nice shot charging with the solar inverters in the background.

You can definitely tell this is MY kid, just look at that EV GRIN?!?

In the name of science

Today was a fun day with the EV. It's not often you have multiple components laying around to get to really test things. You do your research and buy components, then just hope for the best. Not today!

Today a group of friends brought over two of their Kelley controllers for some head-to-head comparisons against each other and my Curtis 1231C. The two Kelley controllers were a 144v 500 amp model, and a 120v 800 amp model.

We monitored pack side voltage and amps, as well as motor side voltage and amps. Sadly we didn't have a computer tracking the information for a nice graph later but the results were clear enough.

The tests we did, to try and be as accurate as possible, was a 2nd gear take off to 30mph. This requires no shifting and gives the motor a long low RPM scenario so we can measure amps.

We tried to do as little modification as possible to swap controllers so things didn't need to look good. There are a lot duplicate wires, duct tape and bailing wire. Not to mention the cardboard electric isolators and bungee cord hood tie downs.

Please don't let your final EV project look like this! :)

The Kelley 144v 500 amp controller was rather sad in my opinion. The highest recorded motor side output was 320 amps. Even in first gear that car felt like it had no power. We tried the "torque" and "speed" settings of the controller, but it didn't change much. The 0-30 test took 15 seconds on average!

Next the Kelley 120v 800 amp controller. Surprisingly this is in the exact same enclosure as the 500 amp version. We removed seven of my LiFePO4 cells to drop the pack voltage within spec of the controller. I bit of an apples to oranges test, but we had no choice here. Maximum recorded amps was 640 with a 0-30 time of 8 seconds. Much better, but where is the 800 amps this controller is claiming? Perhaps if you could record with enough accuracy you'd see this number for a fraction of a second. Even the 600 amps is gone in less than a second. From the instant you see 600+ amps, they start dropping fast and within seconds you're looking at 400 amps and then a slower drop off rate. I admit though, out of the hole the bottom end torque felt really good, it just didn't last long.

Technically we tested the Curtis first since it was in the car, but afterwards we tested it again to track a few points better after we understood a few things. The Curtis surprised me as we saw 535 amps at peak. The interesting point was this didn't fall down nearly as quick as the two Kelley's. We counted a full 5 seconds before we even fell below 500. Although the Curtis and Kelley 800 had nearly the same 0-30 of 7-8 seconds the main difference was that the Kelley started off very hard but with it quickly dropping amps it was hard to get to 30 mph in the end. The Curtis on the other hand pulled hard and consistently right past 30 mph.

Pack side measurements weren't really worth mentioning as they were consistant and reflected the performance seen on the motor side. None of the controllers were able to push the pack amperage above 500 amps. Even at the lowest RPM to get high motor side amps, the pack was only seeing 250 or around there during that. This opens my mind now to installing a higher end controller knowing I can really increase my low end without jeopardizing the pack.

5000+ miles

I've been meaning to get a post in when I crossed the 5k mark but I've been busy with other things and haven't found the time. I was going to post a picture of me drinking a beer in a lounge chair to demonstrate the work that went into my 5000 mile maintenance, but again, I just haven't had time.

In short, that's pretty much what needed to be done to the car, nothing. I did raise the vehicle and get under there for an inspection. I wanted to make sure no bolts were missing or coming loose. Additionally I wanted to check for stress or crack marks in the motor mounts, batter racks, etc, but everything looked perfect.

I'm actually over 6k miles at this point. Roughly I think I have about 100 cycles on the batteries after the 4 months of driving @ 1.25 cycles per commute round trip. This is a pretty rough number, but good enough for general tracking of the cells life over the months and years to come.

As bad as it gets, or is it?

Preface:

A few weeks I was driving to work and looked down at the TS BMS system for kWh. The reading was FAR lower than normal for being halfway to work. My first though was, "crap it didn't charge and I'm halfway between home and work". I decided to keep going and keep light on the throttle. I made it to work with power to spare. It turned out the pack was completely charged when I left home, but the BMS failed to recognize most of the energy that was charged into the pack.

The Post:
It's been about a week ago, and I was just pulling out from work to head home. I noticed the computer again didn't register that it had charged. I assumed it was an error and headed home. Sadly this time it wasn't a false alarm. I drove about 32 of my 35 mile trip home when the BMS started yelling about a low cell. Even more sadly, this didn't alarm me since the computer is always giving me false positives. Regardless I started watching the cells and noticed all of them were a bit low (2.8v on average) with the lowest one being 2.5v or so. As I continued to drive they all started dropping, but one more so than others. I could see it going 2.5, maybe 5 seconds goes by, 2.4v, etc. It didn't take any time to reach zero volts under load. At this point I figured I've lost a cell, but the other were still in the safe zone.

I got home and after turning my charger amps down to 2 began charging. It took a few hours until the cell was up to 2.8v and I cranked it back up to 30 amps and let it charge.

The next day I was hesitant to even try to make it to work, but I figured this is half the fun of owning an EV. I was surprised to find out that not only did I make it to work but that cell was in the top 5 or so under load meaning the internal resistance was not changed and it's still behaving pre-incident.

How much life, if any has been taken away from this cell? No clue and only time will tell if fails before the others. However, and most importantly, this shows these cells are able to take a lot more abuse than I figured.

EV Bling

We'll the car has been up and running since mid February and I've been driving to work for probably a month and a half or so without any issues (other than the BMS glitches). I don't see any reason it won't keep running fine so I figured it was time to make things a little more official and add my EV Bling. OK I had way too much crap bought that I was going to add to the car but the more thought about it and placed items it just seemed a bit too nerded out. I settled on two changes to help announce the EVness of the car.

First I added the "EV" to the S2000 emblems on the side.

Second was the customized license plates. I had to make another DMV trip for these, but luckily this was routine and went smooth.

Solar and PG&E (Pacific Gas & Electric)

I've been getting a few questions about my solar and how it all works in regards to the power company. I'll do my best to explain it.

The solar is directly connected to the grid through the inverter. The inverter is designed to not send power into the grid if the electricty is off. This prevents the power company from getting shocked if they shut down their side and want to be sure no solar systems are now powering those lines.

So the way it works here is the power company keeps track of the excess energy you produce during the day. This is done in the simplest terms by letting your meter run backwards. Then at night, lets say, when you're not generating any power your meter runs forward again and you recover that excess energy you created earlier. It's really a great setup since you don't have to worry about costly batteries that need replacing.

Additionally, and to some what complicate what I just said, we have a couple of options here and I went with a time of day (TOD) metering. Peak is 1pm-7pm, partial peak is 7-9pm and 9am-12pm, off peak is 9pm - 9am. This is Monday through Friday. The weekends don't have peaks and all holidays are also like weekends. For peak the energy rates start at about 30 cents per killawatt. Partial peak is about 14.5 cents, and off peak is 8.5 cents. What this means is while I'm at work and not using much energy not only am I making excess energy, but it's not really counted on the kW basis. It's tracked as credits in the form of currency. Later at night when I get home and start using the power again I'm buying it back at a cheaper rate than I sold it for. This helps out the power company to supply their power needs during the "peak" for all users and allows me to only require a system that generates about 75% of my energy use.

It gets more confusing yet...Each Peak, Partial Peak, and Off Peak have their own seperate tiers. Tiers, for those who don't aleady have to deal with this, is an alloted amount of energy you can use at a set price. Once you use more than this the price of the power increases. I believe for my power company their are 5 tiers. So even with the right sized system you might end up going up in tiers during off peak (night time and weekends) simply because you don't generate much here. However, you've also been getting paid quite a bit during peak to cover multiple tier pricing during off peak.

So that's how it all works for me with my power company. Hope this clears things up, I know it confuses me more. :)

Elite Power Solutions - Not so Elite

I've been waiting some time to post what I feared would be the case from this company, but I think it's time to let as many people know as possible.

As you're aware for those following along I've had a few, to say the least, issues with the BMS system I purchased from Elite Power Solutions. I've emailed them quite a few times along the way but never really got a fix to anything and it always resulted in me figuring out a work around to make the system happy.

Recently, I thought I had two bad cells. It turns out, again, the BMS was misreporting these cell voltages, but only under load (they show fine at standing voltage, but drop quicker in voltage on under load than they really are). Here is the email transaction. It seems to start off fine, but after well over a month, I just feel like I'm getting the run around.

EDIT (Emails Removed):
Turns out the emails sent around clearly stated they were not allowed to be posted anywhere for public view. I was nicely asked to remove these emails from my blog.

This is where it's at now. I'm sure they will not get back to me until I bug them again. They are more than happy to take your order, but don't count on that one year warranty being honored. As far as the TS cells themselves, I'm so far quite pleased. I only ordered them from somebody in the US hoping to get the customer service support if needed.

I'm probably screwed on ever getting this thing fixed and might just design my own or mix and match a few other options out there.

So where should you buy these cells from now? Dave over at EVComponents is offering the cells and a different charger and BMS system. I kick myself, because his cell prices are about 70% of what I paid from EPS. Check out his website at http://www.evcomponents.com/. They are working at keeping these cells in stock! This means no more 2-3 month turn arouund times either. Very promising for the EV world.

Update: Elite is sending yet another module out to replace the defective one. Sadly, I've discovered another issue with another module. This module has a problem with one cell where it will randomly cut the voltage in half (display only, the cell is fine). This in turn is telling the charger, if charging, there is a low voltage condition. To the charger this means terminiate immediately and do not restart. I've been lucky on the timing and so far have not been stranded while I was debugging the issue. I've since reduced my low voltage trigger to just above zero to prevent yet more false alarms. I'll keep you posted on the results of the second module replacement as well.

DMV trip four

I realized when talking to a guy about my DMV experience that I hadn't posted the fourth, and I sure hope final trip to DMV for registration to Electric.

As you recall from trips two and three, I was told to come back when the registration was due. This would allow them to open the smog section in their computers so they could input the DMV ID number on the BAR cert and finally change the MP field from G to E.

Well, as I'm sure you can guess, the smog section still couldn't come up. They tried this and that, talking amongst themselves and about 30 minutes later...nothing. So the lady says, "Well your registration is due, would you like to pay and maybe that will open up the smog section?" What do I have to loose, I'm thinking. I pay and the computer spits out the new registration paperwork. Sure enough, the MP section is already set to E!

So, in hind sight I'm thinking their system has changed a bit. The BAR referee computer must now directly change type to avoid the whole DMV confusion process. I think if I would have waited for the due notice to come in the mail, I could have paid it online and received the updated E registration without any of the headaches I went through.

I have had a few people telling me that E means something else, or doesn't exist, etc. So I'm really not 100% sure if this is done, and won't know for two years when the smog would be due again. I think I'm good, but you never know with DMV. :)

2500 and counting

Today I broke 2500 miles on electric, woohoo! In general things have been really smooth with the build and I'm overall very happy. I'm really pleased with the lithium cells and the balancers I built. Hopefully the cells just keep us moving for many many years :)

OK, so there is one item I'm not completely happy with. The BMS from TS has some really great features all wrapped into one system. Many piece together things like amp meter, fuel gauge, etc. It was nice to find it all in one package, but this thing has been far from reliable.

You may recall my initial problems with charging where the BMS would freak out and start reporting cells at low voltages and such if the charger was at high amps.

The next thing I noticed was two cells that seemed to be sagging pretty bad under load. I placed a volt meter on them and they weren't sagging at all like the BMS reported. There are 5 modules, up to 10 cells connect to each. I switched around two of the modules and then I started getting two different cells (same module) that were reporting sag. I'm still waiting on a replacement from Elite Power Solutions. The first "replacement" didn't work at all and I had to send that one back.

I've also had a couple of occurrences where the charger just stops during the charge and I couldn't figure out why. I was at first assuming it was getting a little hot, so I started opening the trunk (until I get time to vent the trunk better). This seemed to fix it for a bit, but it started happening again. While driving the other day, the BMS alarm went off indicating one cell was about one volt lower than it really was (it immediately jumps back up to normal voltage). This has happened a couple of times now. During charging, any low voltage indication will terminate charging, so again the BMS shows its quality.

I have some plans to implement my own high and low voltage protection, and still use this BMS for the rest of it's functionality. This way if it blimps, it doesn't matter except for viewing purposes.

1.21 Gigawatts!

OK, so maybe I'm not harnessing the power of the lighting bolt, but the sun works well too. I've been patiently waiting as Acro Electric has been installing the solar system for the house, and more importantly the power to charge the car as well!

I kept climbing up on the roof when I'd get home from work to see what they had accomplished.

Day1:
Here is a picture of some of the anchor bolts installed for one of the two groups of panels.


Here is a close-up of one. You see all the black caulking that goes into the drilled hole. Additionally the black piece of flashing will be over the bolt and hole with the higher shingle laid over this as well see later. This flashing allows most, if not all, of the water never even get near the hole.


Day2:
Here is the south facing group of rails installed. You can now see how each anchor is covered by the flashing and slide under the higher shingle.

Here is a picture of the west facing group. I didn't have much south facing roof space so half of the panels went here.

Day3:

The panels and inverters are brought in for installation. The panels are from SunPower model SPR-225-BLK-U. They are small and rated for 225 watts a piece, which is quite a bit especially for their size. There are two inverters SPR-3000m and SPR-4000m. As you've probably guessed they are rated for 3k watts and 4k watts respectively. There are 28 panels total for a DC/STC rating of 6.3kW. This is fancy rating they give to "lab conditions" and you won't see these numbers in the real world. Therefore another rating is given (CEC/CSI) which is a "real world" rating of 5.56kW. The physical roof footprint is 393 sq.ft.

Here is the south roof again with the panels installed. They are a nice solid black color, you can't see the PV cells like you can with the other panels.

The west facing group.

Here is the west facing group again with some perspective of how little roof space was needed for half (3.15kW) of panels. I could really add a lot more if I need to.

Day 4 and 5:

The last couple days was doing all the wiring and finishing touches on the system.

Here are the two inverters mounted in my garage. You can also see the new 220v plug I had them install while they were at it for the car charger. I was running a long, and rather big, cable across my garage before.

Today was the first day they got to fully operate over the entire time frame of sun light and they produced 40kW. I'm pretty sure as summer really kicks in we'll get even more out of them.

A trip to my local Honda dealer

I still hadn't aligned the car after the conversion and I knew the weight changed plenty so it needed to get done. I finally made an appointment and took it in yesterday. My biggest concern was having somebody drive it, so I made sure to explain to the guy I was checking in with what needed to be done. It's nothing hard, but a few tricks that your average guy would think the car was broke when it didn't turn over :)

Long story short, Honda didn't get much work done that morning. I had about 15 of their employees looking at the car and asking questions. It was great to hear from all these guys how clean the job was and how much they liked it. There were a ton of questions from them and it was great to be able to show some people that this kind of thing IS possible despite their beliefs. I also found it interesting that they were impressed with a car that could go 80 miles on a charge. The typical reply was, "hey that's all I'd need to get to work and back".

Towards the end of the actual work the mechanic brought me back to explain something on the alignment. He said because of the weight difference in the front the caster couldn't be brought back into specs on the front, but it was very close. I asked if shifting more cells to the rear (which was something I was thinking of doing down the road) would help and he said no. The rear settings were maxed out on camber and adding more weight to the rear would put it outside the range as well so things will just remain as they are. It definitely makes me glad I went the LiFePO4 route, any amount of lead that could get me to work would kill my little car.

The icing on the cake for the day was I got the employee discount rate for the work since I made their day by bringing the car in. They all knew me by name now and kept thanking me. It was a great day but my wife couldn't understand why it took two and half hours until I explained the story. :)

Hitler's Tesla

I found this inside footage of Hitler and his current delays on his Tesla. Enjoy :)

Parts For Sale

On Saturday I put all my gas related parts up for sale on Craigs List. http://modesto.craigslist.org/pts/1151313984.html

Here are the major items up for sale but there are a lot of little pieces I don't need but didn't want to list.

F20 Engine, Converter, Manifold, ECM, Radiator with both fans, Intake box with filter, Alternator, Muffler Set, Heater Core, Fuel tank with Pump.

The muffler set went today. Hopefully the parts keep on selling to help recoup some of the conversion cost.

1000 miles and counting

On the way to work on Friday I hit 1000 miles! It's amazing how quickly the miles are adding up now that I'm driving to work each day.

Charging Station

It's official, the charging station is complete. I now have a reserved spot and don't need to come in early or put cones out when I leave for lunch. Woohoo!

DMV trips two and three

I don't even know how to start this entry I'm so frustrated and humored at the same time. I headed back down to DMV with my BAR cert. First I'm told sorry, we can't change anything without the title. What? Nobody said this last time I was in here. So I just tell them I'll pay for a new one as if though I lost it. After an hour of waiting and paperwork to fill out they tell me they have change my car to Type Q. I couldn't remember off hand what Q was, but I told her it's suppose to be Type E. She tells me she tried E and it didn't work, but Q worked so she used that. WTF? So I asked her what Q meant, and this part tickles me. She says, "I don't know, but my supervisor said to try either E or Q and the computer didn't allow E but allowed Q so it must be correct". UGH

I leave because I don't know off hand what Q is. After getting back to work I find out they made my car a Hybrid! So I headed back down for trip three to the DMV. Now the two ladies that helped me are out to lunch and I'm told they have to help me again....so I wait. After they returned I explained what Q meant. Now they need a manager to unlock my records because only one change per 72 hours is allowed. They spent a fair amount of time digging through menus and trying different options but couldn't get the computer to take Type E.

Finally I asked if they have entered in the data from the BAR cert since there is a DMV ID# on there and the BAR ref told me they needed to input that information into the computer. Well it turns out this needs to be entered into the smog section which will not show up until smog is due for the car. Yeah, it just kept getting better.

They wrote down everything they had learned on a paper so that when I come back in a month they will know where to start. Luckily the registration is due in a month because the BAR cert is only good for 60 days!

I'm hoping by documenting all of this I can save time for others in California who need to go through this process. I'll keep you posted.

BAR Referee

Today I had the appointment with the BAR referee. DMV required me to get a certificate stating that the car had been converted from gas to pure electric.

They asked me a lot of questions before and after seeing the car. I had to point our the batteries, motor, etc. State which emissions pieces I had removed (which was everything). It almost seemed they were trying to see if I even knew what I was talking about or catch me in some type of lie for why I converted it. They probably get a lot of people trying to pull one over on them to pass smog.

After the vehicle inspection they went to the computer and started going through a bunch menus. Then they showed me a huge list of all the items my car is now exempt from. The information was electronically sent to the DMV, but they also gave me a physical paper to take back when finishing the DMV paperwork.

That was it. No crazy safety inspections or anything like that. Just a quick visual over view of the top side under the hood. Next step, back to DMV.

500 miles!

Today's second trip to work brought my total miles over 500 now. A small milestone, but one none the less.

DMV Registration Started

I think this part scares me the most of the whole process. I just can't find good information on what to expect here.

I went to DMV today and asked what I need to do in order to change the registration from Gas to Electric. After they did some research, they gave me the phone number to BAR (Bureau of Automobile Repair) stating that I need to get an inspection from them first and then come back.

After being on hold for 30 minutes I spoke with a nice gentleman who informed me I called the wrong number and I needed to call the BAR referee instead. I received that number and made another call. It turns out I can go to Modesto Junior College which is within battery range for a round trip! I'm so glad I don't need to tow it, especially if I don't pass and need to return.

I asked the guy on the phone now what was involved so that I could make sure the car was ready, sadly he didn't know. I have an appointment in two days so we'll see what happens.

First drive to work

Yesterday the plug was installed and everything was in place for my first run to work today. I was a bit nervous but everything couldn't have went better.

I left 30 minutes earlier than normal to make sure I got the spot next to the charging station. They haven't marked it off yet and installed the sign so I'll have get there early for a few days or so. It's not an issue with my company as I think everybody knows I've done the conversion but we share the parking with surrounding companies as well and it would be hard to go door to door tracking down the owner of the vehicle to ask them to move it. :)

It looks like I used about 60% of my pack on the 35 mile drive to work. Sounds bad, but considering the 2,000 ft elevation climb over the journey it's about what I expected. It also appears I used about 35% of the pack coming home. I drove a lot faster on the way home since I had the downhill advantage so I could lower than number if I tried. I'll keep tracking the numbers, but it doesn't appear I'd want to risk the round trip without at least a little time on the charger.

Here is the pedestal / charging station that work installed for me. A big thanks to Front Porch and those involved getting this taken care of for me.


Here is another shot of the car charging at work.


I did run into a little issue when I first got there and plugged in. Within a minute or the so the car quit charging. Turns out there was only a 20 amp breaker installed and it wasn't enough. After talking to the electrician he installed a 20 amp breaker because the plug style I requested was only rated for 20 amps. An error on my part, but he came out immediately and upgraded the breaker and plug style to 50 amps. I had to change the plug styles on my side too and then it was up and charging. I still need to keep track of how long it takes charging at work and at home as well as the energy required to start calculating energy costs.

BMS Touchscreen

I've been debating mounting this monitor for the BMS for some time. First I wasn't sure if I'd keep it connected all the time or not. The original plan was to monitor the serial I/O going to it and then take that data and turn things like the capacity into something for my fuel gauge. I also wasn't sure if I'd even stick with this BMS system or replace it with something better. After looking around I'm just not excited about any of the other BMS systems, especially not for the cost of something that does more. Now that I've added my own cell balancers the system I think is going to meet my needs perfectly.

OK, so for the first time I got so caught up in trying to figure out the best way to do this and make it look clean that I forgot to take pictures of the process. Sorry all.

I used 1/4" plywood and created frame about an 1/16" wider on each side, so 1/8" wider/taller total. This is to allow room for the monitor to still fit after wrapping the foam and leather material around the sides. The frame is shorter on one side so the monitor tilts towards the driver and to compensate for the curving dash. The front side is easy since it's all squared up, but the backside took a few attempts to get the curves just right to match the dash.

After the frame was complete I took and wrapped the outside with a very thin foam using a spray adhesive to attach it. Next I wrapped it with a synthetic black leather material to try and somewhat match the natural look of the car.

Finally I screwed some L shape brackets into the frame (two on each side) and finally screwed the frame into the dash. This part killed me and was probably the biggest delay factor. I really didn't want to screw anything into my dash!

The wires are ran behind trim/panels up in behind the dash poke out through a small hole I made just above the radio and below the BMS monitor.

Here is a picture of the final product from the driver seat.


Another shot from the passenger seat. You can see a little better here how the back needed to match the contour of the dash. It's not perfect, but I'm happy with the results.


Of course after completing the install I had to take it for a spin. It was very nice having this information at quick glance and is going to really help my driving to easily see the amp loads. This quick little spin puts me up to about 280 miles so far. I keep checking at work and things are moving along on the plug install. Looks like it was a pretty big job to get power from the main panel out to the parking spots. It's scheduled to be finished this Friday so I might be driving to work finally as soon as next week. If not, it shouldn't be much longer. I can't wait!

40 mile drive

I had some time to spare this weekend waiting for parts to come in and nothing major to get done so thought I'd take it for another drive. I first went down to Prime Shine Express and drove it through the car wash. Poor thing hasn't had a bath in at least 8 months. Next I headed off in the direction to work and drove until I had travelled a total of 20 miles. I pulled over and jotted down my exact miles and energy consumption. Since there is a lot of up hill on the way to work I wanted to break up the two directions for comparison. I headed back home and took a bit of a scenic route, including a stop at the store for milk, to get as close to 40 miles as possible just for a nice round number.

On this trip I tried to keep my average speed closer to 55mph instead of 65mph just to see if I could notice the energy usage difference. I noticed my amp gauge staying around 125 amps instead of the 150 or so I saw at 65mph. After I arrived back at home I plugged it in and did the math. I averaged 345.18 wh/mile for the 20 mile trip up the hill and coming home I averaged 242.57 wh/mile. My overall overall average for the 40 mile trip was 293.23 wh/mile. This is considerably better than the 350 wh/mile average from my "Inside Drive" video doing 65-70mph most of the way. I'll continue to test things to improve this number over time like moving away from the Z rated tires, perhaps a belly pan or anything to improve rolling resistance and aerodynamics.

I used roughly 50% of my pack during the trip in the hills at 55 mph. At least I know even after my pack has aged and lost some capacity I'll still easily make it the 35 mile trip to work where I can recharge.

Speaking of recharging at work I just got word that everything is go on the plug getting installed and the job is suppose to start next week with a two to three week time frame. Most of the time is waiting on some parts, I think the pedestal with all the plugs. I'll get some pictures as the work progresses on that too. Once the plug is in I'll be ready to start commuting with the car. There are of course things left to do but they will be done here and there when I fell like it now, no more rushing!

Volt Blocher

It's been awhile since the last update but I've been busy on the next step in the project which is the cell balancers for the lithium cells. I wasn't sure what I was going to do for balancing as anything on the market is not cheap. Dimitri, a buddy of mine from Florida who is working on his second conversion, ask what my plans were for balancing, but I had none. He had found a few schematics of shunting balancers that people had designed. I messed around with the schematics in prototypes and although a good stepping stone they didn't work the way I wanted so I began designing my own circuit.

The cells are charged in series and viewed to the charger as one large cell. The charger has no way of equalizing the SOC (state of charge) for each individual cell. I've designed a simple cell balancer that takes advantage of the nature of lithium during charging. LiFePo4 cells are 3.2v nominal and like other lithium technology stay right around this nominal voltage until the end of the charging cycle when they climb in voltage very quickly. The cell balancer is designed to start shunting energy at 3.6 volts that would otherwise be going into the cell. The balancer shunts 1.5 amps at 3.6v and goes up from there as the voltage increases. Let's say you are charging your pack at 10 amps, then each cell is receiving 10 amps. If a cell reaches 3.6v 1.5 amps of this energy is shunted and the cell is now only receiving 8.5 amps. The remaining cells which are below 3.6v still receive the full 10 amps which allows them to catch up over time and perhaps multiple charges. The lower the overall charging rate then the higher percentage of the energy can be shunted allowing for a complete cell balance in one charge. For example if you can limit your charge to 1.5 - 2.0 amps you can simply leave the charger on and wait for all balancers to indicate they are shunting and therefore the pack is now balanced.

Here is a picture of a completed cell balancer. They simply need to be connected to each cell only. There is no master unit or mess of wires to tie them all together. I named them Volt Blocher. My my last name Blocher (pronounced Blocker) and the fact they will keep the voltages down by shunting away the energy.


Here is a picture of them installed in the car. I needed to make 45 units for my setup. My wife helped out on the assembly line and really saved me some time.


Here is a picture of the units in action. In the closer four units you can see that three of the four units are shunting energy indicated by the red LED. At this point the picture was taken only about 6 or so of the 45 units were in this state meaning the remaining cells needed to catch up.


This looks much cooler in person but thought I'd add a shot with most of the cells now shunting. Lots of red and green lights. After about three hours of charging I had just four cells remaining that weren't balanced. I'm going to continue to charge at a slow rate and see how long it takes to bring them level with the others.


There will soon be two others using the Volt Blocher units. Dimitri and Jim have ordered their DIY kits and will hopefully have them up and running soon.

For more information and ordering please visit VoltBlocher.com

Fill it up!

Now that the charging is working correctly I was feeling good and decided to finish up the plug. Remember those two circles I cut out for the cooling fans on the controller heat sink? Turns out they are just want I needed. I marked out the three bolt holes. Then I measured the thinner diameter of the plugged and plasma cut that out of the center.


A nice and tight fit. The other side of the plug will come in from the other side and sandwich the plate. I used a 4 prong twist lock 220v 30 amp plug. It's only hooked to the 220 side of the charger. The 110 plug is just laying in the trunk. It won't be used much if at all but is there in case that's all I can get.


A few bolts and the plug was done. Looks pretty cool. When I get time that sticker will be changed or modified just for fun. I think "Premium Electrons Only" will suit this car better now don't you?


Fill it up! Charging will be quick and easy now.

Controller Temperature Sensor

I designed the new computer to monitor the temperature of the motor controller but being in a hurry to drive I didn't make and hookup this sensor until now. After each short drive I keep checking the controller and at least in the winter so far heat is no concern at all. I'm only seeing a few degrees increase in temperature.

Either way it'll be nice to see this temperature while driving so I decided to finish that up.
I used a hobby servo extension cable for the wiring. You can depress the little tabs and remove the connectors from the housing.


Note the position of the wires. It's not the same as the original order on the cable. The LM34 temperature IC from left to right is +, signal, -. Use three small pieces of shrink tubing to protect the terminals and keep them from shorting out on each other.


Next I wrapped all three connection in one larger piece of shrink tubing.


Now to make a housing for this sensor. We want to use something that will conduct and transfer heat quickly so that we can see changes to the temperature quickly. I'm using a small aluminum tubing that I cut a 1" long piece from. The bolt and nut are used to reinforce walls on half of the tube while shaping the other half.

After pounding the unprotected half with a hammer you get a nice flat piece that we can drill into for mounting the sensor somewhere.

A little JB Weld to hold the sensor in place. Shove the sensor to the far end so that it contacts the metal to pick up the heat well although the JB Weld does a fair job at heat transfer from what I've noticed.

Here is the final sensor hooked up and ready to be mounted.

I used a self tapping screw and mounting the sensor on to the heat sink of the controller.

This is temporary as I'm still not sure exactly what I want or need mounted in the car. This little LCD screen is showing the RPM from the computer, the temperature of the motor and the temperature of the controller. The RPM are not needed since the dash has that implemented already. Eventually I'll probably use the microprocessor to determine which of the two is hottest relative to its maximum temperature (which I also am outputting here on the screen for reference) and use the dash temperature gauge to represent that temperature. This way it won't matter which of the two is hot, if you see the gauge getting too high, something is too hot and that's all that matters.

After my first test drive I realized I did something wrong. When driving the temperatures tend to bounce around a little and unless you let off the throttle it's hard to tell the real temp. I didn't run shielded wire from the sensors to the computer. I'll need to pull the front batteries out when I do the AC so I'll rerun those wires at that time.