Twin electric motors instead of diff ?

[CompoSimmonite]

I've recently bought another Class III (the biggest size) mobility scooter to use as a basis for an off road version but have now decided that it'd need too much adaption. No problems as I'm sure the complete with all electrics rolling chassis will easy sell on eBay as a basis for a Toyland or similar so am now having to go back to the planning stage.
In "stock" I'd got a pair of quality EMD motors with gearboxes that I salvaged off a golf buggy I scrapped that I'm considering using.
Mental query I can't answer myself is do they work together like a diff on turns or will they act like a locked axle ?
Any opinions ?

 

[normspanners]

if connected in series they work as a diff, but in parallel they are just full steam ahead, whilst mechanically separate

 

[rich r]

On more sophisticated electric vehicles with hub motors a yaw sensor is used to reduce the drive to the inner wheels during turns. But I suspect on your project you might just get away with driving them with the same current and allowing the fact that the wheels are independently powered (though by the same torque) to allow them to travel at slightly different speeds due to the turn.

 

[CompoSimmonite]

I've got the original golf buggy controller but have no idea how the motors are wired. They are 24v each on the body and 24v of batteries so probably parallel. Last night was looking at 4QD controllers http://www.4qd.co.uk/ so suppose I could get one suitable for series and run on 48v of batteries.

 

[normspanners]

The problem of connecting them in series would be if one wheel is stuck, the free motor would receive twice its rated voltage.

On some fork lifts they are connected in series up to a certain speed then change to parallel for high speed and on tight turns one wheel goes into reverse !

 

[CompoSimmonite]

The problem of connecting them in series would be if one wheel is stuck, the free motor would receive twice its rated voltage.

On some fork lifts they are connected in series up to a certain speed then change to parallel for high speed and on tight turns one wheel goes into reverse !

What I like about the 4QD controllers is they detect that and limit power.

 

[bigegg]

I don't know whether this helps, but on the old"big trak" toys, the motors had a pair of magnets mounted inboard, facing each other (with a small gap) so that they turned at the same rate, yet could still turn at different speeds if necessary.

 

[Tinbasherdan]

How about a motor each side driving rear wheels, front steering axle with micro switches to reduce power to a motor when steering is locked over, similar steering style as the kettenkrad

 

[CompoSimmonite]

How about a motor each side driving rear wheels, front steering axle with micro switches to reduce power to a motor when steering is locked over, similar steering style as the kettenkrad

Didn't know that is how Kettenkrad worked. Got me thinking some more

 

[normspanners]

interesting

 

[Wedg1e]

I've recently bought another Class III (the biggest size) mobility scooter to use as a basis for an off road version but have now decided that it'd need too much adaption. No problems as I'm sure the complete with all electrics rolling chassis will easy sell on eBay as a basis for a Toyland or similar so am now having to go back to the planning stage.
In "stock" I'd got a pair of quality EMD motors with gearboxes that I salvaged off a golf buggy I scrapped that I'm considering using.
Mental query I can't answer myself is do they work together like a diff on turns or will they act like a locked axle ?
Any opinions ?

How did they work on the golf buggy?

 

[CompoSimmonite]

How did they work on the golf buggy?

No idea how the twin motors worked on golf buggy other than separate wiring from each to the controller. If possible I'd like to reuse the controller but the buggy was bought without batteries just for the components so never tested. Batteries are the weak point in any electric powered vehicle - expensive and make up most of the weight for small projects like bikes and scooters. Whilst there are alternatives that are lighter the cost rises substantially along with the need for more specialised controller and chargers. With proper mobility scooter and the 4QD controllers you have the ability to alter the way power is sent to the motors so can "dial in" torque, max speed etc. Never played with such ability but useful option to learn how to use.

 

[normspanners]

How about no need for a diff just one drive track and you sit on a trailer ?

 

[wookie]

Batteries are the weak point in any electric powered vehicle - expensive and make up most of the weight for small projects like bikes and scooters.

I've just had a really mad idea... could you have a solar panel roof on your buggy (1m x 1.5m panel produces 250watts), in sun it would provide you with shade as well as constantly topping up your batteries so you could go further...?

 

[mfletch]

I built my own mobility scooter its one wheel drive on the road but I can lock the back axle to make it two wheel drive if needed

 

[Farside]

Have a butchers over at www.endless-sphere.com and you'll find somebody's done it. Whether they got it to work or not is another thing entirely.