How I Used an Automatic Transmission in an EV

I have been lots of questions on how exactly I used the automatic transmission in my EV. So this insanely long post is a summary of how I did the whole transmission setup.


The first thing I did was design a motor coupling and plates that mimicked the old ICE. I kept the torque converter and flywheel setup, and since it mimics the original engine, the adapter plates and motor coupling can be used with the automatic or a manual transmission. I used the transmission's Flex Plate to design the motor coupler, which is a taper locking coupling. The aluminum plates were created using a second transmission I bought off Craiglist because at the time the car was still driving and I wanted to have as little down time as possible, so I bought the second transmission (which was skipping gears) as a EV sacrifice so I could use it as a template for the coupling and for the bolt hole pattern on the plates.Next, I left the Automatic transmission installed with the existing radiator/transmission cooler. I also left the PCM and ECU installed as they are needed to operate the transmission and the dash board. I also used the old engine mount to hold up the rear side of the 9" ADC FB1-4001A series wound motor. The motor has a rear shaft that will connect to the Power Steering pump and A/C compressor.
After all the mechanical is done, comes "fooling" the PCM. I Do not idle the motor at all. It does take about 6 seconds to build up pressure for the clutches to operate, but that only happens when the EV is first started before a trip. During driving the pressure stays up while at stop lights and such, and getting going again is no slower than with using a manual with a clutch.

Now comes the big question: How did I change the shift points on the transmission? Did I reprogram the PCM? Modify the transmission soleniods? I did nothing of the sort! The key to using to changing the shift points: replace the TPS with a 5 k potentiometer!

In and ICE he TPS tells the transmission when to shift, depending on how hard the pedal is pressed, when accelerating or cruising or coasting. By replacing the TPS with a 5K potentiometer I now can manually tell the PCM when to shift. The higher I set it, the longer it stays in each gear. After 1,000 miles of driving like this, I have had no problems and I have found a few settings that work well depending on which terrain I drive on. Higher RPMS mean better efficiency while lower RPMS allow for better acceleration.

I usually leave it at about 1/4 turn, however it needs to be set to 0 every time I start up the EV because if the TPS (5k pot) is higher than 0, the transmission thinks you are stepping on the gas and will lock the Shifter into place so you cant move it from Park. Annoying, but effective safety measure. And I will not be bypassing that protocol, but if I do the transmission can easily be shifted into Neutral with the EV off, and that is a safety issue that is checked during the yearly Inspection.

The Plan, Civic EV 2.0

I am developing a plan for installing the newly acquired EV parts. For the time being, I am going to continue to use the motor I have and get that blower installed, which I now have all the parts for. I have done some range tests, and will do some more to gather data.

My plan is to install the new motor, but in order to do that I need new adapter plates and motor mounts. I am going to put the motor on the bench and clean it up, adjust the brush timing and get the commutator cleaned up. It has been sitting for 7 years, but spins up just fine. This is the list of things I want to do:

• Remove Transmission and have new plates made for the FB1-4001A
• Upgrade to a stiffer Coilover system
• Rewire EV with the better 2/0 gauge cable and proper lugs
• Mount PakTrakr and AMP meter to dash
• Build metal frame for the battery racks
• Rebuild front control tray
  
• Setup K&W BC-20 Charger
  

This is pretty much Civic EV 2.0 because of all the upgrades/changes.

I am saving up the money required for the new plates, and hope to have the new Coilovers ordered soon. My plan is to get the motor/transmission to the machine shop, and while they work on it I will work on the rest of the EV. My time is limited due to classes, and I spent two weeks on the plates before, probably 40+ hours of cutting work, and just don't have the time. Everything else is small, probably a weekend's woth of work and a few people already have shown an interest in helping out.

The Motor is In!

It took most of the afternoon, but the motor is finally in! Everything appears to be aligned and I can spin the motor, so I think it is looking good. I have also bought 2 more batteries and hope to do a quick test spin up this afternoon after classes.

The motor looks so small in the compartment, but it should be able to move the car around since it's a 10 HP continuous motor and I don't plan on taking it past 55 at all. (30-45 MPH is the desired speed)

So here is what I have left:

-Paint rear battery rack and install it

-Design and build motor mount for extra strength

-Design and build front battery rack

-Wire everything up

I am really hoping for a short street test this week, up and down the road on the 36 volts I have.

Chargers

I bought 8 Schumacher SC-600A chargers on eBay today. They are 6 amp smart chargers, while not the fastest thing in the world, it will get me started. My budget (pocket mulah) is getting low, and I picked these up nice and cheap at $100 for all 8 inlcuding shipping.

Today I also build another controller circuit, this time using a PIC processor and a 16 KHz frequency so it can't be heard. My other controller used a discrete hardware setup, but had an audible 2 KHz frequency. I will keep the old board in the gloved compartment as a backup in case anything goes awry...

Tonight my dad and I drilled a few 1/2 inch holes in the motor adapter plate to see how easy it is, and it was a breeze. Tomorrow I will mark up all the bolt holes on the larger plates and drill those, and also drill the holes in the spacers. It's coming together really fast and I might just have the motor in on Monday since I will be going away this weekend.

Metal Mayhem

I admit, I have been slacking in my updating of this site in the past weeks. I have significant progress tho! The gas tank is out, I have the rear battery rack designed on it's at the welder and I have gotten my coupler and small plate!

Here I have the motor mounted to the small plate and the couper attached to the motor and flex plate. The plate and the spacers are having 1/2 inch holes drilled in them and then I have to work on the larger plates.

And here is the rear battery rack laid out in the driveway. It will be going over the spare tire compartment, as close to the rear wheels as possible for the best weight distrobution. The rack will hold 5 batteries, and I will have three maybe, four in the front depending on what fits once the motor is in. When I get it back from the welder, I am going to paint it so it won't rust and so i t will look decent when I show off the car to people.

Now I am doing the final cleaning out of the car, removing excess small plates/heat shields, gas lines and a basic washing on the interior. I removed the rear seats to get to the gas tank, so I have to put those back in.

I am hoping to have the motor mounted into the car this week, but we will see. Once the motor is in, I can have everything wired in a day. Then all I will need is the batteries, chargers and front battery rack.

Getting Ready!

Ok, so I have the accesories motor, which is a 1.5 HP @96 volt motor that will be used to run the power steering and the air conditioning. I also have my two contactors that will be the main power switch for the EV. I have some 10 gauge wire that will be used to provide the logic power to my controller (24volts) and also to be used for the contactors.

My coupler is almost ready to be machined. I had to go back and make the drawings more detailed, and to make things go quickly the machine shop will only do the coupler and I will drill the plates myself. Tomorrow they should get the new drawings and it shouldn't take them too long to machine it up. If I am lucky, they can do it tomorrow and Friday.

Oh, yes I almost forgot. I have also ordered my last important part, the circuit breaker. I have a 125 volt 250 AMP circuit breaker on the way that will be my main safety feature and will also be my second cut-off switch next to my contactors. I chose a circuit breaker over fuses because my controller is expermiental and I really can't afford to be cooking fuses like crazy if anything goes crazy.

Raw Materials

Now I am making the final measurements before I purchase all the the aluminum and stainless steel for my adapter system. I am figuring out the best way to piece the system together and keep the costs down. Hopefully I will have everything set and I will purchases the metal tonight. I decided to make the plates my self and to get the coupler machined and I should be getting it machined for a good price.

I also have acquired all the heavy gauge cabling! It was great actually, I was mowing the lawn and found a spool of heavy gauge wire behind the shed that my dad put there a few years ago because he had gotten it and had no use for it. There is over 40 Ft of 3/0 gauge equivalent wire and it should be all the wire I need. This is about a $200 savings so I am psyched!

Update: I have ordered all of my aluminum plates, spacers and the stainless steel piece that will be used for my coupler. All I have to do is wait for the pieces to come in and find a machinist for the coupler. I have e-mail a few and they either did not return my e-mail, or are booked until mid July which is too long for me.

First Battery

I have bought my first out of the eight EV batteries. It's a Walmart MAXX29 12 volt 125Ah deep cycle that has shown great promise so far. It was manufacted this month (May 2008) and was fully charged when I bought it. I hooked it up to my controller and motor and it ran great and was still fully charged after 20 minutes of playing with it. My last battery barely lasted 5 mins on testing and completely gave out after 15 mins so this is a great upgrade. 96 volts 125 Ah will give a 12 KWh pack of batteries. I hope to be getting some more in the coming weeks while I am still getting my adapter plate and coupler made. I may order the raw materials this week so I can attempt to lay everything out so the ready for a quick machining.

Progress Update

Ok, so I have some more progress. I have made the modifications to my controller and added the connection panel so I can connect the throttle and power to the controller. I am in need of a new battery to do anymore testing, but using small motors and power sources everything seemed to work. It also has this safety feature that if the current sensing fails, the controller stops the motor. It will probably always be a work in progress, but this should get the car moving. I also bumped it up from 250 amps to the full 500 amps. So now its a 24 to 156 volt 500 AMP controller.

I have also started my templates and hope to bring them to a shop next week and see what they can do. This is really a concept template because I don't have the tools to properly make them, and the shop will use its own equipment and scan in the measurements to a computer and CNC mill out the plate. I do have the designs for the coupling done and will be bringing those along as well. My 7/8 taper hub piece should help make the coupler real simple since last time I went over there we spent about an hour trying to figure out the coupler because they didn't have the machine to make the key way and all the lovejoy couplers out there didn't have enough strength to survive the torque of the motor.

I will not be working on the car this weekend since I will be spending it in the middle of nowhere fishing on a well earned vacation trip.

The Key to It All

I finally got the key piece to making my motor coupling. It's a 7/8 inch hub that has the all important keyway and a taper so I can crimp it to the motor shaft. I now have all the materials I need to have a machine shop build this. I am going to finish up my own AutoCad designs so they can have a baseline on how I want it done. It should also save money since I did the designing.

Gas Prices are Criminal!

Well, I just drove by the gas station today, and the current price of gas is $3.57 a gallon!! I still have a few weeks left of the semester and probably going to need another two or three fills ups at bank-draining prices!

So in the past week or so I have had about a whopping 5 minutes to work on this project, and in that time I changed the wire on the PB5 throttle from a two wire to a three wire cable.

Today I hope to work more on the motor plates and adapter, and I am still waiting for a piece of keyway to come in so I can have a better idea of what needs to be done. I have started to make some plate templates out of plywood I have lying around but I think I am going to have to bring the transmission and motor to a machine shop and let them have at it. The real trick is finding a place that wont cost me an arm and a leg. I got a quick quote from a local shop, but I am still going to look around since the end product would cost me more than I currently have.

I also have been recalulating my battery needs, and the battle between weight, total costs and range is being fought. So far, I think the 12 volt is winning with a 35 mile range, 480 LBs of lead and a $500 price tag for all eight of them. Also, charger 12 volts is easier than 8 volts.

Finally Some Free Time...

I finally had some free time today, so I hooked up the controller again to the motor and did some actual testing. Things went great, I got about a good 15 minutes of testing in before my old crappy battery gave out. I did an earlier test on Sunday which went well, but I fixed a few things to improve it. Now it seems to be working great, and it barely was warm. The only thing left to do if finish up the back end to it with proper connectors and it will be done! It does have a primitive current limiting, but it is set to 250 AMPs, and I will be keeping it much less than that to save the batteries. My guess it that it will be drawing around 50 to 75 AMPs from the pack when cruising at 40 MPH.

I am still tweaking the design for the motor coupler, but since school has been busy I haven't had a lot of time this past week to work on this project. I am making a package of sorts that I will be giving to local machine shops so I can get a qoute on the part.