Four-wheel-drive badger

[Mobstuart]

Hi I'm hoping to get some help a power chair for a friend badger Power chair unfortunately it had problems with the way that it was wired only having one controller had problems with traction 4 motors And now two controllers my problem is how do I wire up the joystick to run two controllers

[Burgerman]

it had problems with the way that it was wired only having one controller had problems with traction 4 motors

What does this mean exactly?

Is this thing skid steer?
Are both your controllers programmed identically and with identically correct motor compensation?
As for connecting a standard pod to two power modules you really cant. You would need two joystick pods, with the actual output from the joystick unit feeding both.

But if its skid steer it wont work with any mobility controller or lead batteries in any sensible way.

[Mobstuart]

Thank you for your reply yes it's a skid steer with four motors both controllers are the same and program with the same settings on them

Joystick I plugged into one controller and another cable from the other end of the controller into the next controller that didn't work

[Burgerman]

Nope it wont.

Each controller talks and handshakes to the joystick. You cant have two... Its like talking to two women at once.

Skid steer takes far more amps to turn, than any lead battery or mobility controller can give. So the thing wont steer and will get hot and shut down power.

[Mobstuart]

Okay what would be the best way to get this working properly

[Burgerman]

Now theres a question.

Problem one. Batteries are not capable. Voltage collapses under load with one controller so you will need to change to lithium ion phosphate and about double the capacity.

Problem two. Theres no mobility controller that can do more than about 30 to 35A continuously. At best 120A for a second or so, and gradually decreases from 100 downwards as they warm up... So those are only any good in straight lines or turning while driving forwards or backwards. On a grippy surface a zero speed turn on the spot wont happen! That takes 100A on a powerchair with casters that they were designed for which turns relatively easily. Imagine how much more force is needed to rotate a 300kg mass by sliding its tyres... So you need to reduce current. You can do that by using motors that are HALF the speed. Gearing.

Problem 3. Its now very slow. So you need to increase voltage. That means you keep the added torque from lower gearing, and lower average current, and so you get the extra torque, and you get the speed back for free... So your lithium battery needs to be maybe 36V.

Problem 4. No tank steer controller can accept 36 or 48V. With 1 exception made by Bounder. And robotics solutions such as I use on my BM3 project chair.

Can you see that theres no easy fix here?

Lithium thread read viewtopic.php?f=2&t=1813
Robotics controller (Roboteq) thread as used on my own chair here viewtopic.php?f=2&t=2436
My lithium roboteq chair about 5 pages. http://www.wheelchairdriver.com/BM-MK3- ... rchair.htm

I suggest you read and absorb for a few days because non of this is simple or cheap. And thats why it didnt work to begin with.

[mingu]

oh dear i am the guilty party here ,, yes it was wired on a single controller and it was not always happy turning on tarmac ,,,but show it some mud as lubrication it was happy enough once you get used to a new driving style and covered many miles in horrid mud ,,it never overheated in use on a single controller to be fair ,,

[Burgerman]

Take it on a grass field or car park, or anywhere grippy, and turn left right on the spot for 10 mins. If it will...
Or try using a leaf blower around your garden where you need to be in many different spots or positions/angles for 10 mins. It will definitely overheat and reduce power further.

Traveling forwards as you turn reduces load hugely. And makes it possible to get it to turn. When you say different style of driving, you really mean learning what it will do, and learning what it hasn't the power to do and avoiding these situations. The problem exists in tank chairs, 4x4 skid steer etc. Because no adequately powerful mobility controller exists for skid steer. Something the manufacturers of such devices initially never understand, then after it becomes obvious, choose to pretend its not a problem and lower the gearing (speed) to try and gain back enough torque to get it to work. Which simply doesn't adequately address the issues...

Another example. SAME problem... Watch the first two vids. They have lots of people complaining, and so now they blame the user for expecting to be able to steer by turning on the spot. As it SHOULD be able to do. https://www.tankchair.com/instuctional-videos/

These DO work http://www.ziesel-adventures.com/welcome/
To make that happen, they use big brushless motors, a controller thats 10x as powerful as a mobility controller, and a lithium battery that is higher voltage and much bigger than the ones used in mobility devices. TJAT is what it really takes to make skid steer work.