DC motor speed control/ Electric wheelchair

[Prawo Jazdy]

Hello,

I am trying to work out if I can use geared 12V motors from an electric wheelchair to drive a child’s car (homemade).

It’s a Toylander build, and the stock motors are two 12V 180W items from Parvalux. Since these are quite pricey, I had hoped to use used wheelchair motors instead, but it seems hard to find data on their power, current, RPM. Does anyone have any experience with such things? Are they gutsy enough to accelerate and push a plywood 1/2 scale Land Rover and an adult along at 4mph?

I’m also wondering if I can make my own speed controller using a pedal such as this:
https://www.amazon.co.uk/Brake-Vehicle-Accelerator...
...as an input.
Is this fanciful or achievable? I’ve done some electronics stuff in the past (school and university) - not for a while but I’m not a complete beginner. Is there any way I can use something light duty like this to control two 180W motors, or am I just going to wish I’d spent ~£650 on new motors and speed controllers?

Any suggestions or guides for electronics welcome.

[Prawo Jazdy]

Thanks for the replies. It is decades since I watched Robot Wars, but I didn’t know that.

Curly, thanks very much. I can’t believe of all the things I’ve searched, I didn’t put in “wheelchair motor speed controller”. I had got as far as watching people rig up MOSFETs and potentiometers on YouTube, but hadn’t searched for the most obvious thing. I’ve only started looking at wheelchairs recently - I was originally looking at mobility scooters, but a local repair shop sent me down the wheelchair route, so separate motors instead of a transaxle.

I hadn’t expressed myself very well, as I knew you couldn’t just connect the pedal to the motors, but I wasn’t really sure how to work out what you could plug in to the ‘magic box’ of the speed controller, and what you couldn’t. Looking at the different controllers available, it suddenly seems more reasonable that TL are charging what they are for a speed control unit, as some of the ones on your links are big money, presumably for a higher specification that I haven’t yet understood the need for.

I had to google what PWM was, and it instantly brought a lot of long-unused physics/engineering flooding back! I’ll look through the guides from people who’ve done it - they look really useful. Thanks again!

[Prawo Jazdy]

Sorry for the delay in replying to you. That’s really useful feedback HardDrive, thanks. I am concerned a bit about the weight - how heavy would you estimate the finished vehicle is? I don’t have a garage but we have an outbuilding in the garden for storing it, however the door is slightly too narrow for it to go in on it’s wheels, hence the weight being an issue for moving it around. I considered routing some material away from the reverse of some of the parts which don’t seem structurally important, but I don’t imagine the weight reduction would be very noticeable.

I’ve seen your finished car on the build thread, but I’ll take a more thorough look. Yours looks brilliant! I doubt I’ll be able to achieve that level of detail though - it has taken me long enough to get all the plywood cut and tidied up.

Edited by Prawo Jazdy on Thursday 19th November 17:29

[Prawo Jazdy]

Thanks. It definitely won’t fit through the door frame on its wheels, and I don’t think storing it in the kitchen will be popular with anyone except my son

I may have to create some sort of trolley that it can go on on its side to go through the door. It’s either that or build a kennel for it in the (rather small) garden