My most recent car project is an EV conversion of an old, inexpensive car.
Why not? :)
This is a question I get often. It's not about having an electric car; I already own one for the every day journeys.
It's hardly going to be "profitable" from a strict economic point of view but that's not the point. Rather, it's a personal challenge, a way to learn more about mechanics, tools and EVs in general.
There are a lot of challenges to be tackled: technical, logistics, legal, etc.
I don't have a strict dead line and, since this is done on some of my scarce free time, I anticipate it will take a while. But the idea is to learn as we go.
There are several steps needed for the conversion: selecting the new bits (motor, controller, batteries, accessories), mechanical work to remove the old, oily pieces and adapting the new ones, electrical and electronic work to wire the new stuff together, and legal paperwork if we want to be able to use public roads.
I choose the Suzuki Samurai (also called Suzuki Santana in Spain, where I guess this one was built) for a number of reasons:
- Light car - Although range is not a primary goal right now, we all know how weight negatively affects range, performance, etc.
- Relatively cheap - I bought mine for just over 2.000€. Parts are also fairly common and really inexpensive. Land Rovers are much more expensive. UMM Alter, an offroad once designed and produced in Portugal would have been nice but it's also considerable more expensive.
- Reliable - I want to focus on the conversion, not on fixing common parts or rust.
- Easy to work with - Relatively large engine bay and few electronics. The Samurai has an ample, square engine bay, its ride height allows me to work underneath with having to jack stand it, and it's very basic: no power steering, no ECU, no AC. Only an old school carburettor and vacuum brake booster.
- Off-roader - Firstly, I wanted to "diversify" my garage. Having a Leaf as a daily and an MX5 (Miata for the US guys) as a "sports" car, I was missing an off-roader.
Secondly, anticipating the headaches I'll have with paperwork to make it road legal, I wanted a vehicle I could use mostly on non-public "roads". What better than an off-roader? :)
Lastly, electric motors have a great torque advantage over combustion engines at low rpms. Electric is great for low speed rock crawler and hill climbing. That's much more important than range.
So, I ended up buying this 1992 red-ish samurai:
- It has about 120 thousand km and it's mostly stock, except for the steering wheel and raised ride height. It came with five original wheels and tires plus four additional wheels and mud tires. Each mud tire is different and the road handling is disasterous, but it's part of the "charm". Plus, for off-road use they are great!
- It's a 1.0 litre engine with 45 bhp (I guess). It's really week and can barely keep up with 100 kph in the highway. But for off-road, it's more than enough thanks to its low gearing.
- Mechanically, it seems fine and there's no rust. There's some hesitation when flooring it and around 2000 rpms or less. I guess it's the carburettor that needs tuning but I don't know how to do it and I don't care less at the moment.
I enjoy driving it as it is and I almost feel sorry for what I'm about to do to it, since it will render it unworkable for the upcoming months. Oh well, I still have my Mazda MX5 for those periods when I really need to just drive. Oh, and despite being an year older, the Mazda seems to be from a completely different era! Light, nimble, eager to sprint, etc. I was expecting that but I'm always surprised when I drive it!
Bill of materials
On my first contacts with EV conversions I was mostly trying to understand the different types of motors (AC, DC, synchronous, assynchronous, etc.), controllers, batteries/chemistries, suppliers, DIY projects, etc.
I followed some blogs, youtube channels and bought some (e)books. I'm trying to gather everything in the External Resources page.
I've ended up selecting this kit:
- Motor: NetGain's Hyper 9. Pretty powerful and efficient AC, Synchronous Reluctance Internal Permanent Magnet (SRIPM) Motor. In fact, it's much more powerful than the stock engine, so I'm planning to keep the clutch to act as a "fuse" and prevent cooking the transmission. It's better to replace the clutch than the transmission, transfer case or shafts.
- Controller: SME ACX1, the recommended controller for the Hyper 9 motor. Pretty powerful and configurable.
- Batteries: I started with a basic workbench DC power supply for testing. Then, I moved to a pack made of Parkside 20V batteries! Now, I'm building a pack with used Nissan Leaf modules.
- Adapter plate: I'm planning to design my own. This will be a project of its own but I want to learn it. I'm using FreeCAD, which I learned while designing the parts. I started doing some scaled down prototypes using laser cut services from a local shop. Then I fabricated some CNC prototypes in MDF. The most recent build was done in aluminium. I have the contacts for these shops in the resources page in case you live around Lisbon.
- Misc: Throttle pot, power cables, communication interfaces, etc.
The overall schematic will be a simplified version of EV West's:
In my case, I won't be using a built charger, DC converter or coolant system for now. In fact, for my very first version, I will try to avoid the batteries and try to "power" it using a workbench DC supply.
The plan is to:
- test most new parts in a workbench before installing them on the car [DONE]
- remove the existing ICE (internal combustion engine) components in the largest group I can (to make it easier to fit it back again if I want or run it outside the car) [DONE]
- install the new EV components - this will include fabricating some adapters and/or bracket to "glue" the new components [MOSTLY DONE]
- select and install batteries and charger [IN PROGRESS]
- check if it's feasible to make it road legal [AH AH AH]
For news and updates about this project, the best way is to follow its articles here.
At first, I considered some used AGM lead acid 12V batteries for the first version. But the still relatively high cost and really poor performance and weight made me decide against it. I tested the controller and motor without load on a bench using a cheap 300W DC power supply. Then, I used five 20V battery packs from Parkside, which were enough to test the drive train in the actual vehicle and move it some centimeters in the shop.
At the present, I'm building my battery pack with one third of the Nissan Leaf modules, out from an used 24kWh vehicle. I still don't have the BMS or charger.
I'm not holding my breath over this since I know it's a long shot, especially with EU and Portuguese regulations. But laws and regulations will HAVE to change eventually and I would still want to try it out and learn, either directly here or using some loophole in other EU country. I know that in Ireland there are some custom made EVs so it's not impossible.
You can also follow the process through my youtube channel. The videos are only in Portuguese (sorry!) and unfortunately I don't capture the entire procedures due to lack of experience and eagerness to get the hands dirty on the mechanical part rather than the video tasks :P
But I hope it will somehow complement the articles and photos on this site.
Remember, I'm no professional mechanic at all so follow the steps with a grain of salt. Also, all comments and help are very welcome. Feel free to participate.