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Planning 1994 Honda Acty conversion!

13K views 58 replies 11 participants last post by  Acty DCty 
#1 · (Edited)
Hey, friends! My buddy and I recently decided to try an electric conversion.

We found a working base-model 1994 Honda Acty in a used car lot, and it seemed to be a good fit. Manual transmission, manual steering, manual windows. Light, small frame. Plenty of room for batteries in the pickup bed. Rear wheel drive, right under the batteries.

Neither of us has much experience working with cars, but we used to kit-bash old computer parts together to get them to run operating systems they were never meant to run. We once turned a 1991 Mac LC into a web server. We were looking for a more 21st century engineering challenge, and settled on this. I am quite sure we will screw something up horribly, but that's part of the fun!

For me, the goal is not to make the World's Greatest EV, but to make an EV that starts and stops and does not catch fire.

As far as components we have so far - just the Acty. Everything in it seems to work great. We are researching parts, but thought it was smart to post here before we spent more money.

So, if this were your conversion project - where would you begin? :D

Please don't judge us for being beginners! We're committed to doing the research, and we don't mind if we fall short. We figure the worst thing that can happen is we ruin a 1994 Honda Acty.

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#2 · (Edited)
Plenty of room for batteries in the pickup bed.
It would be nice if the battery would fit under the bed rather than in it. The mid-engine configuration isn't bad for that: if you put the motor where the engine was it takes some of the space in the middle that should be battery, but at least it doesn't have a shaft running down the middle like a front-end one truck would.
 
#3 ·
It would be nice if the battery would fit under the bed rather than in it.
Yeah, I saw a YouTube video where a guy did this. It makes sense if we're trying to keep it from getting top-heavy. But it does seem more involved, since we'd probably have to make our own battery boxes for mounting them that way.

What budget batteries and motor would you recommend for a tiny car like this? (I'm pretty sure it runs off a motorcycle engine right now.)
 
#4 ·
I would say the cheapest would be to use a wreck Nissan Leaf. However, assuming you want to keep the manual transmission, there is a far amount of effort involved in matching a Leaf motor to a different manual transmission, and a learning curve on how to control the Leaf systems. On the other hand, depending on the dimensions, you might be able to make the Acty a front-wheel drive using the Leaf front-end, depending on how much you are willing to cut and weld to the Acty. Looks like a fun project for sure.
 
#12 ·
I apparently missed this when it was originally posted...
I would say the cheapest would be to use a wreck Nissan Leaf. However, assuming you want to keep the manual transmission, there is a far amount of effort involved in matching a Leaf motor to a different manual transmission, and a learning curve on how to control the Leaf systems. On the other hand, depending on the dimensions, you might be able to make the Acty a front-wheel drive using the Leaf front-end, depending on how much you are willing to cut and weld to the Acty.
Although the Leaf drive unit (motor and transaxle) is in the front of the Leaf, there's no need to use it in the front. The Acty has the engine just ahead of the axle which it drives (the rear), just as the Leaf motor is just ahead of the axle which it drives (the front). Since the Acty is rear-wheel-drive, and doesn't use a live beam axle, it would probably be easier to use a Leaf unit in the rear than in the front.

Since this came up a motor has apparently been chosen, but I haven't seen any indication of what it is.

Edit: apparently a new thread has been started, for no apparent reason, so this one is now pointless.
 
#9 ·
We've started making videos about this project. We're still really early in the planning phase, but we're having a lot of fun. Big news is we've bought a motor and tested it, and are picking up batteries we bought from a warehouse in a couple weeks.

Thought folks might want an update! 🚙⚡

 
#14 ·
The other thread was created just to share the videos. This thread is the one we're using to seek advice and input. If the video thread is in the wrong subforum, apologies, but we weren't aware there was a better place to put it.
If the videos are about your build, why not just put links to them in this thread? Otherwise, you'll have two threads, and people trying to help with any of your questions in this thread will be frustrated by only part of the information being available here.

The motor is a used GE forklift motor that previously was used in a Toyota conversion. We have a video where we describe and test it.
I saw that, which is why I made my comment. There's no point in running a thread "to seek advice and input" then sharing information such as your motor choice only in a different thread. If you have questions later about the motor, in which thread would you ask them? If it's in this thread, how would we know what you had chosen or done, since that's all in a video only mentioned in the other thread? One thread works.

I'll spare you my usual rant about videos instead of useful communication. ;)
 
#16 ·
Hey folks!

As we progress with our conversion (full update coming soon), we're having a discussion about heating the cabin. Considering that heating the cabin is usually the biggest energy hog in an EV, we're thinking about how - or even whether - to do it. We are in Pittsburgh, which can get quite cold.

We do need a defogger so it's street legal, but we're split on whether to include any heating mechanisms for driver comfort. I know some EVs get around this by heating the seats, but I'm curious if we have the skills to realistically achieve that without setting something on fire.

If we included no heating mechanisms, it would basically just be a non-winter vehicle, which is OK with us. But I think we could still extend its months of operations a bit by insulating the cabin. Right now, there is basically no insulation: just two layers of metal between you and the cold.

My collaborators think insulating the cabin wouldn't achieve much, since most of it is windows (which we're obviously not spraying insulation on). But I think that adding a layer to the roof and back of the cab, plus a layer inside the door panel, plus a layer under the dash, would be worth the slight weight added.

The cabin is very small, which leads me to believe that, with more insulation, body heat might make a meaningful contribution to keeping it warm.

Thoughts on insulation?
 
#17 ·
In my old 1996 OEM Renault Clio Electrique it was a gasoline heater. Very efficient way of using the liquid energy. It was perfect during cold Swedish winters. It consumed something like 0.3 l/h at full power and did not use any of the battery’s energy (same range as in summer).
 
#18 ·
As promised, here is a text update on our progress!
  • We bought a used GE forklift motor. The motor has a SEPEX field and is capable of regen. I am not sure of the exact model number. It is capable of taking up to 120 vdc. We tested it, and it still works. Next step here is to disassemble and clean it. For those who like videos, we made a video about the motor here.
  • We bought a small quantity of 100 Ah 3.2vdc LiFePo4 batteries so that we can build a very basic circuit and start running tests. Wired in series, the batteries will total about 64vdc, which is about half what we expect to use, and we also roughly guess we will want 2 banks of them in parallel for 200 Ah. So, this is probably about a quarter of our final total of batteries. The batteries have a low charge and discharge rate: just 100 amps. But considering I can push the Acty uphill with one arm while there’s a passenger inside it, I think it will probably be fine. The calculation I did suggested that, even with the low discharge rate, 120vdc of these batteries would give us around 35 horsepower - almost exactly what the current engine offers. Anyway, if they don’t work for this, we’ll just sell them. Video about the batteries here.
  • We’ve built and installed an AM radio transmitter so that you can get phone audio over the car’s speaker. We’ve also installed a second speaker. (The car only came with one!) Videos about the transmitter are here: 1 2 3
  • We bought LED lights to replace the current lights in the car, and have been replacing them as the shipments arrive.
  • We’ve ordered spray insulation, which we’ll use to help the cab retain heat better in winters. Video about energy efficiency here.
  • We ordered this controller, which should also be capable of regen. I hope it works with our other systems. We don’t know much about how these things work. I’ll be coming back here for advice once it arrives. (If it doesn’t play nice with our batteries and motor, I’ll just hock it on eBay again.)
  • We ordered a cheap potentiometer pedal that I believe should work with the controller.
Next up, we need a battery management system, and we’re not sure where to begin on that. Any suggestions?
 
#19 ·
Is that controller designed for Sepex motors? Sepex motors need a special controller that can adjust the field strength. Or I guess you can also run a fixed voltage field with a reduction in performance.

For BMS check out Daly. They have some good quality BMS with lots of features and nearly any voltage or cell combination you can think of.
 
#21 ·
Sepex motors can regen, but it's not the same thing. Sepex motors do not have permanent magnets in them they require a separate field voltage applied. It's really hard if not impossible to find Sepex controllers that work over 60-70 volts or so which is why it piqued my attention.

I'm sure you guys could figure out how to make it work. You could use a separate controller with modified Arduino code possibly.

Here's a good explanation: Sepex Motors explained for dummies (like me) by JohnnieB

Sepex motors are like the modern induction motor of their time but now obsolete except in golf carts. But still quite a few good reasons to use it if you've got it!
 
#23 ·
I had been under the impression that SEPEX and regen were the same - that one was necessary to get the other.
Regeneration, which is just running the motor as a generator, is possible with almost every type of electric motor, but the big exceptions are series-wound brushed DC motors: in series motors, the field winding is in series with the stator winding, so it's not possible to separately control the field - you can't "turn on" (excite) the field to make it generate. The controller linked earlier can only handle regen if there is no field winding, specifically in a brushed DC motor with permanents instead of a field winding. A SepEx motor (also called a shunt wired motor) allows separate control of the rotor (armature) and stator (field) current, so it can do regen... if you have a controller with separate armature and field sections, or two controllers which are coordinated as Electric Land Cruiser suggested.

You're off into obscure territory here, which is fine if you want to explore and learn. The vast majority of DIY conversion projects either use brushed DC series-wound motors (so they can't do regen), or use three-phase AC motors (which can all do regen). A few use permanent magnet DC motors (in small sizes); almost none use SepEx motors and it would be hard to find a single example of anyone using a SepEx motor with a custom set of coordinated by separate controllers.

Hopefully that round-up will help in interpreting what you find in your reading.
 
#25 ·
We also have the option of just ignoring the SEPEX field and not doing regen, right?
Earlier you said that the "has a SEPEX field". Unless it has both a series field and a shunt (SepEx) field... no, you can't just ignore the SepEx field. You need a magnetic field, created by current in some field winding (or by induction which this motor doesn't do, or by permanent magnets which this motor doesn't have).
 
#27 ·
#29 ·
Albeit off topic a Nissan Leaf motor has a 7/8” 20 count slip fit spline, Many Honda’s including the ACTY (depends on age can be 18 or 19 as well)
can have this same spline count on the transmission meaning you just need an adapter for the mounting face of the Nissan to mount up when the spline matches
 
#34 ·
Adhesives work poorly on polymers in general, but exactly which polymer is very important. For instance, even the Permatex Permapoxy Black Plastic Weld suggested above works for many polymers, but Permatex says that it "will not bond polyethylene and polypropylene plastics". For some polymers, solvent bonding is the practical solution - that's how ABS and PVC pipes are joined.
 
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