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.

Charging issues

I made another long trip 26+ miles but it hasn't been all fun. I'm still working on a good cell balancing solution and now I've realized I have some charging issues.

I noticed that when I try to crank up my charging amps (above 6 or 7 amps) the BMS starts freaking out and misreporting cell voltages. Many just go to zero and the BMS triggers for the charger to shutdown.Two things will fix this. First, remove the serial cable from the charger to the BMS. I can turn my amps up to max and the BMS happily reports all cell voltages but of course I now have no protection from over voltage and other alerts. The charger will only charge based off full voltage. The second thing that got it working was completely removing the charger from the trunk and setting it on the garage floor. Now I can leave the serial cable plugged in and it all works fine. Put it all back in the trunk and it's crazytown. It seems I'm getting some kind of EMI going through the serial cable to the BMS which is causing problems but not sure why only in the car.

I didn't notice any of this before because I wanted to start out charging the pack at low levels. I need to be able to charge at much higher rates when making long trips (like going to work) or I might have to sleep over. Oh well all part of being the the few first to do something like this.

UPDATE:
This is now fixed. I had to completely isolate the charger from the car ground. I used some foam stripping that is sticky on one side and placed that between the charger feet and the rack it mounts to. I then placed rubber grommets in the holes on the charger feet so the bolts couldn't touch metal on the charger. Last I used rubber washers between the charger feet and the metal washers. Basically just make sure no metal on the charger touched the car metal. I'm now able to charge at 24 amps!

Inside Drive

I went out for another drive and this time with my neighbor so he could film while driving. The drive was 22.1 miles round trip. The fastest I took the car was ~70 mph but there was more available so we'll have to see what top speed is one of these days. I did a lot of driving at 65-70 when possible and 45-55 when traffic was slow. Overall I consumed a bit over 7000 Wh for an average of 316.74 Wh/mile. I really need to test this while trying to average 55 mph and taking it easy to see what the best is.

Things still look good even driving at these speeds though. My total pack capacity is 23040 Wh. If I try not to go below 80 DOD that gives me 18432 Wh. If we divide that by 7500Wh to play it safe we get 2.4576. Then multiply that by the 22.1 miles we got gives us a range of 54.3 miles driving at 65 in the hills.

My next long test I believe will be out to my Uncle Duane's house. It's about 30-35 miles away and completely flat ground. Maybe 6 to 10 stop signs along the way so I plan to drive it at 55 mph the whole way and see how the efficiency looks.

Three, four and more

The days at work have been long when all you want to do is get home and take the EV out for a spin. A couple days ago I went out and drove the car around a bit to get the pack drained down slightly. When I got it home I reset the watt hours remaining and capacity numbers of the BMS. I charged up and it showed about 6kwh. Last night I then took the car again and sure enough both those numbers drop when driving so this will, for now, be my fuel gauge. Eventually I'll take this data and convert it so that my original fuel gauge works as well but that's low on the priority list right now.

The drive last night was by far the best. I got the front bumper back on and what a difference a little wind resistance makes. I went for a total of 16.2 miles of mixed city and hwy type driving. I got the car to 65 mph and there was plenty of power to spare. One day I'll test out the top speed when I get time and I'm on a nice open stretch.

I was also pretty hard on the throttle last night trying to get a good feel of what the car can do. I ended up using about 6kWh. So if I drive really bad I'm still looking at a 60 mile range. I also calculated 375 Wh/mile. Considering the lead foot this is really good. I'll be trying a conservative drive over the weekend hopefully and try to estimate my best range as well.

Things are really going well! So that was drives three and four. The more is another video of the walk through. Still plan on getting the inside car ride and again hopefully this weekend I can get my neighbor to film that so I can focus on driving.

Have something else you want video of or explained better? Just add a comment and I'll see what I can do.

Second drive

Sorry no video or pictures this time but they are coming! I actually had a few errands to run last night when I got home from work so I took the EV out to put some time on the batteries and get those broke in but mostly just to learn more about the nature of the car. I was surprised when I returned home and had put 6.5 miles on just driving around my little town.

I'm learning the torque curves a lot better now and this thing can really accelerate if you shift right. I'm becoming more impressed with the performance as the driver gets better.

I was having trouble figuring out the remaining capacity on the BMS system and after talking with Elite it turns out I need to do some rewiring. Apparently this system also tracks the current being charged into the cells and my wiring design didn't take this into account so add that to the list of remaining items.

Still to do:
- Put my front bumper back on.

- Finish wiring the BMS system inside the car. It's just sitting there on the console and needs to be mounted. Turns out there is also no way to turn the power off to the BMS computer or the BMS monitor so I will be installing two switches. The monitor only needs to be on if you want to see the output (driving). The computer needs to be on while driving or charging but you could turn it off otherwise.

- Build covers for the cells so they are not completely exposed and a potential hazard.

- Finish the electronics and wiring for the heater.

- Setup DC/DC converter to switch on only when ignition is on.

- Fabricate the serpentine pulley for the AC and get that all mounted up.

- Add a protective shroud under the motor. It's a pretty clear shot between it and the ground right now so preventing anything from bouncing / spraying directly onto or into the motor would be a good idea.

- DMV registration

Probably some other little details I'm forgetting but that's the schedule for the time being.

I'll be trying to do a video with a quick walk through of the car and components with an inside drive this weekend if time permits.

First Test Drive

It's been a long and painful wait getting to the point for the first test drive of my car but the wait is over! This weekend I was able to get the car to the point I could go for the first test drive and I'm still grinning. The video isn't the greatest since it was getting dark. I'll be adding another video in better lighting which also shows under the hood and trunk along with an inside the car test drive later this week.

Wiring it all up.

I've actually been a little behind on the blog. Being so close to the point of a test drive I was putting all my time into the build. Sadly I even forgot to take pictures of all the things I had planned but there are still some good shots.



It's time to wire everything up. To do this you need some form of conduit from the front to the rear of the car in almost all EV builds since usually batteries and components are not all in one location. I used what is known as Smurf tubing because of the Smurf blue color. It's just a 3/4" plastic flex tubing designed high voltage applications in homes. It's light weight, again flexible, and reasonably priced. I think I paid $30 for 100 ft at Home Depot. I also picked up some orange flex for the low voltage wiring. It's technically the same tubing from what I can tell but the color coding is standard (low voltage = orange, high voltage = blue).



In order to connect the rear cells to the BMS system I needed to run 28 wires from the front to the rear of the car. This is to support two BMS voltage modules (11 wires each for cell voltage and 3 for temperature). In addition I ran a 10 gauge solid strand back as well. This gives me a positive 12v line from the DC/DC converter I'll be putting in the trunk to charge the original 12v battery. The DC/DC converter takes the traction pack which in this case is 144v nominal and charges my 12v system essesntially replacing my alternator.



Here is that low voltage run.





Another shot of the uncut wires hanging out of the trunk area.





I installed two runs of the high voltage tubing. Because of the size of the 2/0 traction wiring I could only fit one cable per tubing. I additionlly pulled an 8 guage solid strand wire from the most postive terminal on the front battery pack to connect to the charger. The most negative terminal of the traction pack will be in the rear of the car already so we can attach directly to that terminal later.



The installation of the two other tubings was nothing special but thought I'd show how I closed up the tubing. There are connectors you can get for the tubing to run it into junction boxes etc. These at least reduced the opening diamter some. After crimping on the terminal I added a layer of wire loom to protect the exposed portion of the wire.



Next I wrapped the whole thing with electric tape and finished it off by heat shrinking the ends.

Here is a shot of the three flex tubings coming into the trunk secured by some jumbo sized zip ties. You can also see the DC/DC converter setting in place on the right.

Here is the installed DC/DC converter. I see a lot of people installing this up front in the car. The thing that bothered me was you can easily see in to the electronics of this thing. Maybe it's moisture resistent but I didn't want to take any chances so I decided to place it in the trunk. It made for some extra work but I feel better about having it here where I know things stay dry. These converters actually come with your standard 110v AC outlet cord attached which may scare some. Internally this AC voltage is converted to DC using some sort of bridge rectifier. When sending it direct DC only half of the rectifier is working but the end result is the same. You can simply cut off the 110v plug and wire it to your traction pack. It doesn't matter which wire is positive and which is negative. Next to the big black high voltage power wire you can see the two smaller 12v output wires. The black wire is ground and runs just to the right where there was a convenient bolt to ground to. The white wire as I mentioned before is ran into the low voltage conduit to the front of the car.


Here is the 12v + wire coming from the DC/DC converter and guess where I connected it. That's right the original location the alternator use to be connected. This is the small circuit panel under the hood on the driver side of the car.

Here is the high voltage wiring. This isn't as neat as I hoped for but I was really running out of room and had to place these components close together. The two outside, funny, shiney looking things are the contactors. These are basically giant SPST relays that are designed to handle high voltage and high current. I went with two just for the added fail safe. One contactor closes when the igntition is turned on. The second closes as you depress the accelerator. Additionally there is another low current relay which you can barely see right in the middle of it all which tells the controller when it's ok to run. I plan to add an array of safety features later that will turn one or more of these relays off until all the safety requirements are met. These can be things like the car isn't still plugged in to the wall outlet to controlling the RPM limit of the motor. Towards the bottom is the KLK fuse (white round thing). This is rated for 250 volts and 500 Amps. You'll want to use one of these for every group of battery packs you have. This way if a short happens the fuse will blow and you won't loose your batteries. Last on the bottom left is the giant anderson connector. You can disconnect this to guarantee all high voltage is removed from the system. BEWARE, however, the capacitors in the controller will continue to carry a charge after disconnected.

This is a picture on the other side of the controller. The big black box with the 2/0 cable running through the sensor that detects how much current is being used when driving. This is like a MPG gauge and helps you judge how efficiently you're driving. On the far left is the pot box. This is 5k variable resistor which you connect your original throttle cable to. Now the further you press on the original accelerator the faster you go, just like a gas car. The last thing here is a small fuse block. I tapped into the 12v ignition line from under the dash and ran a line up to the front. When you turn on the ignition now it triggers a relay which then supplies voltage to this fuse block. From here I'm running the vacuum pump and the 12v fan that cools the controller.

Here is a final shot of everything wired up and ready to go.

Now it's time to charge it up and have a test drive!

The controller

With the batteries in I knew how much room I had left to work with up front. It was time to build the control board. This board will be nice surface to mount many of the high voltage components to. I ended up using polypropylene (I think 3/8" thick). It's a little more expensive than using some type of wood but is still easy to work with and doesn't have to be sealed and painted later to make it last.

Next I have to wonder how I let so many weeds crop up in my yard. Right! I have done nothing but work on this car for several months. Below I'm setting up a straight guide for cutting the material. I made the mistake of using a metal bit in the jigsaw and ended up with goo. The blade got too hot and polypropylene started melting. You can probably stick with the jigsaw and a wood bit but I didn't confirm that. I ended up switch to the Sawzall with a wood blade. This blade has massively aggressive teeth and was able to cut the material quickly without causing any heat and made for a clean cut. However you cut it, the trick is to do it fast before it gets hot.


I found this heat sink on eBay for $20. What a deal. It wasn't the exact size I needed but very close. You can buy a ready to go heat sink from Curtis but it's like $300+ or something crazy. EV America sent me a flat piece of aluminum for a heat sink which they claim works just fine but I wanted to overdue the cooling on this component since I had the option. I needed to trim off a few of the fins and drill some holes to match the holes already on the controller for a heat sink.


I ended up using the small sheet of aluminum they gave me anyways to provide a mounting surface on the top side of the board. Without this the controller would just fall through since the a hole needed to be cut that was large enough to let the heat sink pass through. You can also see a very thin piece of sheet metal I used to attach the fan(s) too. I current only am using one fan but installed the option for fan two in case I needed to add a second one later.


Did a quick test fit to make sure it all works together nicely before applying the heat compound.

This was like being in kindergarten again. Finger painting is great! I'm applying the heat compound. It needs to go on all pieces of connecting metal. In this case that was actually four sides of metal: The Controller, the metal support plate (both sides), and the heat sink itself.

I started loosely laying components on the board to get an idea of where things might fit. It's gonna be tight.

Finally the control board all installed.

Next we need to wire everything up.