Batteries ordered

After months of debating which batteries to buy the deed is done and there is no going back. I originally started this build with the idea of using the typical LA(Lead Acid) battery as the power source. After doing the math and seeing what other EVs range seemed to be it didn't seem LA could really get the range I was looking for, at least not without making my car weigh in a 4,000 lbs. I ordered 45 of the ThunderSky LFP-160Ah modules at $264 a pop, not cheap. On top of that the charger and BMS system added another $3,000. The full setup was ordered from Elite Power Solutions.

The amount of money up front for this setup is scary but after doing the math the investment should be well worth it in the long run. First off I can get about four times the capacity out of them as LA pound for pound. The setup I ordered will add 550 lbs. of lithium to the car which should keep the overall weight of the build at or maybe slightly below the original weight. This compared to most EV conversions needing the suspension beefed up to support the extra weight. Lighter will also mean faster acceleration than with the LA and also less power required to accelerate.

A standard LA battery last around 200 charges. Some of the higher end cells can go as much as 400 cycles. Cycle life of the lithium cells start at 1000 and go as high as 3000 cycles for 70% DOD. If I used flooded LA and got 200 cycles out of them I would still break even if I only got 800 cycles out of the lithium cells so I shouldn't have any trouble getting my moneys worth if the cells hold up....we'll see.

Hurry up and wait. So now that I finally committed to this purchase I get to wait for 5 to 9 weeks for them to arrive. UGH. I'll take this time to work on the electric systems of the car and hopefully have things ready to go when the cells arrive.

12v Test Video

It's just too cool to see the car moving that words can't describe. I got my neighbor to video as I backed it out of my driveway up the street a bit and then back in. I edited the video to shorten it up since at 12volts it wasn't moving very fast if there was much of an incline.

Installing the motor

After taking a nice vacation to Oregon for some quad riding in the dunes and getting over a nasty cold I was finally able to get back to the project. First I needed to hoist the motor and transmission down into the car so I could start measuring things and figuring out how to build the motor mount. I knew this would be a two man job even with the hoist so I grabbed my neighbor again for some help. The top center bolt of the adapter plate to transmission turned out to be perfectly balanced for the setup.

Here is another closer shot to show what we have to work with. You can see the original two motor mounts that we need to eventually tie into. Still plenty of room in here for other things later such as batteries.

Here is a top down view just to show another angle. My neighbor had a good idea of using this strap to support the motor weight so the car could easily be moved around if needed.

A quick note about the rotation of the motor. It turns out that all Honda engines do not rotate counter clockwise like I read. At least the S2000 rotates clockwise. This effects where the front motor mount holes need to be so make sure your motor is setup correctly before making your motor mount.

Let the work begin. Here I am making my first cut of the project.

Here is one of the brackets made to set against the adapter plate and utilize those bolts to build a frame around the motor. A plasma cutter makes these custom corners a breeze. The metal used here was 3/16" x 3" flat bar.

That same mount shown in place.

Next I welded 1/4" x 1 1/2" angle to the plate.

I made another plate for the other side of the motor. These couldn't set at the same level on this side and are slightly higher overall because the closest bolt to the center is below the angle iron in this shot and can't be seen.

Here is the finished support frame. The front bracket was also 3/16" x 3" flat. The center was notched out for the secondary output shaft of the motor. The two ears were added to bolt to the front of the motor. We'll see how all this fits a bit later.

Finally on the frame assembly two holes have been drilled on each side to mount the brackets that attach to the old motor mounts. These must be bolted on and NOT welded because the motor mount bolts are at an angle and the motor will not drop in properly if it's all welded together.

Here is one of the two motor mount adapters. It's hard to see here but there is a bend to metal to transmission from the angle of the motor mounts to the level frame support. The larger center hole on the left is a 1/2" hole and existing motor mount bolt goes here. The slightly offset hole from there is an alignment hole where the motor mount has a tab sticking up. The two smaller holes are for the mounting to the frame support. I used 3/8" bolts here and drilled the holes one size up from there. The most important feature of these adapters is the small strips of metal on each side. They create a triangular shape and add a great amount of support against the weight that will be pushing down on them.

Here is a quick shot of the whole assembly before we take it out for paint. It's much easier to the angle of the mount adapters in this shot. At this point I've probably installed and removed pieces of this a dozen times as the measurements were made and it was all built.

Here is the whole assembly again after a primer, two coats of semi flat black and one coat of clear.

Here is a shot from the back side of the assembly.

Here are those two ears I was talking about earlier. These are the only two spots on the motor. Depending on how you build your plate and fasten it to the motor these two bolts could end up anywhere. You do have the option of rotating them in 90 degree increments though by rotating the motor on the adapter plate. I didn't feel like taking everything back apart and didn't see much benefit from a rotation so I worked with what I had.

Here we have the completed and installed motor mount from the right side of the car. The largest bolt on the plate connecting to the adapter plate originally called for 47 foot pounds and that was reused here. The motor mount nuts were torqued to original spec of 40 lb/ft and the newly added 3/8" bolts were torqued to 35 lb/ft.

Here is a shot from the right side of the car. You can see here that bolt is just below the angle iron and a tight fit. Make sure you give yourself enough clearance to get a socket in there. Also I mentioned earlier this side had to set slightly higher. You can't really see it here but I crafted two 1/4" x 1" x 3" spacers to set between the frame and the mount adapters to make up the 1/2" difference.

Here is a shot of the entire assembly installed.

With this done I finished installing a few last things on the transmission (shifter, console, etc). Next I jacked up the rear of the car and put the transmission into 1st gear. I then tried the old 12 volt test again and the back wheels started spinning forward. Make sure to keep an ear out for any strange noises or vibrations. Things should be fairly quiet or something is wrong.

So then I couldn't resist. I lowered the rear of the car and ran the motor again. I was amazed at the torque from only 12v. The car immediately lunged forward and begin moving fairly quickly. I'm pretty excited at this point as things are slowly falling into place.

12 volt test

I started off by removing the bolt that holds the coupler and putting a drop of loctite to make sure it doesn't come out. Even if it did the coupler had to be pressed on and I can't imagine it will ever move again, at least not without using a puller.

Then I attached the spacers and adapter plate to the motor. Again using some loctite and torqued these bolts to 40 ft lbs. With these bolts, and despite them being recessed were still very close the flywheel so I shortened the heads by .07" each using a bench grinder. I didn't want to risk them rubbing after perhaps the motor and transmission warmed up.

Next the flywheel was bolted on. The original specs called for 90 ft lbs of torque but I dropped this down to 70 with a small drop of loctite. The original crankshaft this was on was a hardened steel. The steel we are using is considered soft and I didn't want to risk pushing the material too hard and strip out a hole on something that took so long to make.

We can now attach the clutch and clutch housing. This part can be tricky if you've never changed out a clutch. You'd think they'd design these different to avoid the problem but they don't. The problem is the clutch itself needs to be centered with the housing, and therefore the transmission input shaft. If you simply tighten all the bolts the clutch will probably be too low (gravity) and you'll never be able to push the transmission and motor together. Usually you can just buy an alignment tool that you slide in while you torque the bolts. I didn't have one so made one out of a 17mm socket and some electric tape. It wasn't perfect but allowed me to slightly move the socket on an extension until I could see it was aligned before tightening the bolts. These bolts called for 19 ft lbs and again I used just a small drop of loctite.

Next came the hard part. The two guide pin holes we drilled are very slightly off and it requires some elbow grease to get them started each time. After I finally got it together I realized the clutch arm had fallen out and I had to start over. This is a reverse clutch and it actually pulls on the clutch instead of pushing into it to release. It makes hooking the clutch arm into place tricky and has to be done at just the right time while you're mating the motor and transmission.

Now the grand finale! I was so nervous to apply the 12v to the motor afraid I'd hear some rubbing, clanking, or just see the whole unit vibrating badly. All of this of course unfounded since I witnessed all the machining work. So I wired everything up and then touch the final wire to the battery. Luckily the transmission cross brace was still attached because that's what kept the whole unit from falling over as the initial torque kicked in. The motor always instantly reached its top speed for 12v and output shaft of the transmission was spinning happily along. Very quiet, very smooth...woohoo it works!

Of course the initial test wasn't enough as I was just too excited. I had to go get my wife, bang on my neighbors doors (he helped me strip the car down originally), call my uncle, try out a few of the gears just to see the output shaft spin at different speeds.

Here is a quick shot of the completed assembly after the 12v test.


Another shot so you can see another angle.


Next comes hoisting the motor/transmission into place in the car and taking measurements for the motor mount that needs to be built next.

Adapter plate and coupler complete

I finally got some time from my uncle to machine the parts and it took longer than we anticipated. Engineering as you go and a lot of measuring twice before you cut really added to the time but I think we'll end up with a reliable setup.

I loaded up the truck with everything I could think I needed and headed to my Uncle's house.


First was to create the coupler. The coupler needed to be 3.125" OD with a 1.125" ID with a .25" key. Here is a picture of the raw metal before we began to work with it.



A shot of the metal slowly getting turned down to the diameter we need.


It's starting to take shape. You can see the end is a little less than 2" wide and about .200" deep if I recall. We did this so the coupler could sit flush against the motor bearing and wouldn't be able to work its way in.


Here we are cutting the coupler slightly longer than we want it. This was the only step of the lathing process that had enough friction to require a lubricant.


Now we are slowly shaving off the end to bring it down to the exact length we need.

After the basic coupler was shaped out we broached out the key way using a 40 ton press. This was so cool to watch I forgot to take pictures.

Next we needed to drill and tap the holes. We used the flywheel as the template and a drill bit that was the same size as the hole to make an initial mark before moving down to the correct bit. To use the existing bolts you'll need an 11mm drill bit and a 12mm - 1mm pitch tap. This is not at all easy to find. My Uncle had to order it from a supplier he uses. You won't find this at Napa or Ace as it's a very uncommon pitch for that diameter.


Here is a picture of the final coupler installed on the motor. A couple things I didn't capture on film was the recessed washer and bolt which screws in from the front. We had to recess these to give clearance for the transmission input shaft. We also are using a beveled hex bolt and we beveled the washer on the lathe to match and recess the bolt further. A quick coat of paint to help with rust and we are done. Notice the black garbage bag duct tapped around the motor. This is quick and cheap to do and will prevent anything getting in the motor during the build.


Here is the simple yet invaluable alignment tool. Basically the adapter plate has an existing 4" ID and the coupler is 3.125" OD. So we machine this tool to slide over the coupler and then the adapter plate slides over that allowing us to perfectly align the plate with the center of the transmission.


Here is the shot making sure the alignment tool works. It's a tight fit, just like we want. The outer darker metal ring is the steel alignment tool.


There were quite a few steps again here that I couldn't take pictures of. We needed more hands than we had.

The first thing you'll do is use any alignment pins on the transmission and mark those across first. Simply slide your plate onto the alignment tool and find a good position that will make sure no part of the transmission is sticking out past the edges. Then using a rubber mallet give the plate a whack over the pins to mark out their location.

In order to start marking your holes you'll need a couple of things. First is a good set of transfer punches. This can be placed in different sized holes and mark the center where we'll need to drill. There were four holes on the tranny that were threaded and we couldn't use a transfer punch. We bought extra bolts and cut the heads off and turned a perfectly centered point in the lathe. We could then use our mallet again to mark these locations and drill them all out.

After we had all of our holes drilled out we butted the transmision to the adapter plate and secured it with a few bolts and marked the outline which you can barely see as a scratch in the metal.

Now comes the cutting. In our case the most precision cutting tool we had was a plasma cutter.

It's not a perfect cut but only took about two minutes. I later took a grinder to the sides to clean it up a little bit but it doesn't need to be perfect as this edge is only cosmetic.

So next we realized the flywheel didn't have enough clearance and was rubbing on the plate. We then had to bevel the inside ring of the plate and recess the four motor bolts. I believe we put those in about .150".

Here we finally have the transmission mounted to the motor! The clutch and flywheel at this point were not actually attached to the coupler. My uncle and cousin held the assembly in place while I snapped a quick picture.

The next step will be to tear this back down and reassemble it with proper torques specs, locking compound, etc and then finally give it the 12v test!

I also had about 80k miles on this setup so I'm going to spend the money and replace the pilot and throw out bearings while I'm here. I'm thinking of just replacing the clutch too as it does show some decent wear.

Adapter plate update

Well I haven't updated the blog lately because there hasn't been any progress lately. I'm really stuck waiting to install the motor and tranny now and that means this adapter plate and coupler need to get finished. After some incorrect parts came in I finally got some pre machined parts I've been waiting on.

Here is the main adapter plate. The pre drilled holes you see are ready to fit the ADC FB1-4001A motor.


Here is one of the four spacers I calculated I'll need to get the distance correct between the coupler edge and the adapter plate edge.


You can see six bolt holes total above. The outer four match the bolt holes on the motor. The inner two are designed to be used with the tension pins shown below. Tapping these pins into the holes will hold the whole assembly together.


A shot of the spacers and adatper plate behind held together with the tension pins. Note the final bolts from the adapter plate side into the motor is what will actually hold this together under the strains of operation. These are only to hold it gether during assembly but will remain in place.


Here is a shot of the assembly sitting on the motor. You can see how the spacers push the adapter plate away from the motor. This allows me to build a coupler that is long enough to fit onto the entire shaft and give plenty of threads for holding the flywheel to it. The adapter plate will eventually be cut to match the shape of the transmission.


An inside shot of where the couplter will go. To match the original distance the coupler will actually inset just slightly from the adapter plate. We may need to do some milling on the face of the adapter plate so the flywheel doens't hit.



Sadly that's it for now. I'm now waiting for when is a good time for my uncle to machine the coupler and finish up the adapter plate to match the transmission. Looks like this will be early October. The anticipation of getting to drive this when it's done is killing me! I think I'll spend the next couple weeks working on my AC and heater designs.

Motor RPM sensor

Now we'll build a sensor for detecting the RPM of the motor. This number is important for safety of the motor, efficient when driving, and most importantly my power steering needs this value. Sure I could just spoof a number to make it happy but would much rather have the real value and display it on the original tachometer.

First off the sensor we will be using is a Melexis 90217 Hall-Effect Sensor. This is really a great sensor. It auto calibrates itself depending on the seen variations in magnetic fields and has a built in ADC. The sensor can be used in a few ways but in this case it seems easier to use the gear tooth pickup feature. Basically you can add a magnet to one side of the sensor and then by running metal past the sensor on the other side causes the magnetic field to pass through the sensor. As each tooth passes by it detects the tooth. Take the total count for a given period of time and divide that by your number of teeth and then convert that time frame to minutes for your RPM!

I picked up a few supplies from a local Tractor Supply and of course hardware store. I found a keyed collar that was 3/4" (secondary output shaft). I also found a 3/4" gear which I figured I could use. They also had the 1/4"x1" key I needed to lock the collar to the motor shaft. I also picked up a plastic spacer. I needed something to house the sensor that wasn't a material the magnetic force would be affected by. The long black thing is just some heat shrinking tubing.



I put some heat shrink tubing around the magnet so that the pins of the sensor wouldn't short out across it. Next I hot glued the sensor to the magnet.



The sensor and magnet were then placed inside the plastic collar and hot glued into place. The connector is attached to the sensor.



Here is a top view. You can see the sensor embedded in the spacer and hot glue.



Next I put a layer of heat shrink tubing around the whole thing (blue) followed by a few wraps of electrical tape. The sensor is ready.



Now we needed something to mount the sensor to that could be mounted to the motor. Again to avoid interfering with the magnetic field I choose an aluminum square tubing. It's easy to work with and doesn't need to be strong to only hold the sensor. It also allowed for the sensor and wire to be enclosed even further. I cut an oblong mounting hole so that it could be precisely adjusted above the gear if needed.



Here is the completed sensor assembly. It was a snug fit into the tubing but I added some extra electrical tap anyway.



I welded the gear to the collar and painted them to protect the steel from the elements. Not bad!



Here is the gear and sensor mounted to the motor. When I'm doing the final wiring I will protect the sensor wires in a loom. Right now I have a few extra washers bring the sensor out far enough. Later this will be replaced with the mount for my AC compressor.



Here is a picture of my setup testing the RPM sensor. Make sure you never apply more than 12 volts on this motor unless it's under load. You can seriously hurt the motor and yourself.



Here is the output from my debugger. I'm doing a 250ms sample in this test so my number needs to be multiplied by 240 to get RPM. If I was doing a 1000ms, or 1 second, sample I would multiply by 60. In addition I have 12 teeth on the gear so the number must be divided by 12.
98 * 240 / 12 = 1960.




In the final project a variance of the pulses, not RPM will be sent to the gauge and EPS unit. I think it was something like four pulses / revolution. I'll have to do some testing and compare my debugger numbers to the gauge to calibrate that.