How do I reduce the speed of a 12v childrens car

[surreyman]

Hi all , i would be so grateful for any help- i have bought a half scale electric willys jeep for my 5 year old son. It currently runs on three car batteries wired in series which are connected via a progressive accelator unit to an 1100 Wat motor. The problem is that it does over 20mph and he could badly hurt himself as the car is heavy. I would like some advise as to how to put in some speed regulator. preferably something that i can turn up/down depending on who is using it. Will happily post pics if someone tells me how on this site! Any help appreciated

 

[BobK]

In order of increasing difficulty:

1. Run it from two or one batteries. Simply move the + cable to do that.

2. Mechanically limit the accelerator.

3. Modify the electronic controller. We would need a lot more info for that. A start would be a picture of it.

Bob

 

[Minder]

Presumably a DC brushed motor,
Depending on the type of controller you have, you could first try reducing the supply by removing a battery (or maybe two).
More on the type of controller would help, but it should not do any damage by trying the battery reduction first.
If there is a built in charger, it may want to see 4 batteries at this point though.
M.

 

[Tha fios agaibh]

I'd rewire the 3 batteries from series to parallel connections.
The battery runtime will increase and speed will go down to probably about 6 mph.

 

[Harald Kapp]

I'd rewire the 43 batteries from series to parallel connections.

I say it will depend on the speed controller whether this will work or not.
If the speed controller is a simple rheostat type, there should be no problem.
If it is an electronic speed controller, it will possibly not work with too low a battery voltage.
We'll need to know more about the controller, as Minder requested.

 

[Harald Kapp]

Duplicate thread?

Yup. Threads merged, thanks for noticing.

 

[Harald Kapp]

Change the gear ratio? Requires no modification of the electrics/electronics at all.

 

[Tha fios agaibh]

I agree that more needs to be known to say for sure.
A few years ago I modified a hotwheels type car and there was no controller or reostat only switches to control speed. I assumed it was a similar design.

 

[BobK]

If the speed controller is a simple rheostat type, there should be no problem.

A rheostat for an 1100 Watt motor would be something to see!

Bob

 

[Tha fios agaibh]

@surryman, To upload picture, click upload a file button below, then click browse to locate the location of your picture.

 

[surreyman]

I say it will depend on the speed controller whether this will work or not.
If the speed controller is a simple rheostat type, there should be no problem.
If it is an electronic speed controller, it will possibly not work with too low a battery voltage.
We'll need to know more about the controller, as Minder requested.

hi, i disconnected one battery and the car simply did not run

 

[Tha fios agaibh]

hi, i disconnected one battery and the car simply did not run

We need to know more info about this circuit. Sketch or pictures of components.

You can't simply disconnect one battery.

 

[Minder]

Sort of an obvious question, but did you connect the remaining three properly?
M.

 

[surreyman]

Sort of an obvious question, but did you connect the remaining three properly?
M.

Yes I think so !

 

[surreyman]

Yes I think so !

I one of the pictures you can see the speed regulator that's attached to the end of the accelerator

 

[surreyman]

I one of the pictures you can see the speed regulator that's attached to the end of the accelerator

So I disconnected completely /removed the live to neutral on the bottom battery and removed the cable . I then moved the negative on the bottom battery and moved it to the negative on the one above . Thereby the bottom battery had no connection to it at all. The jeep would not run

 

[Minder]

I just see batteries. I don't see any controller, Is that an accelerator linkage or ?
Is that it at the top of the picture?
Not the best solution, but is there any means of limiting the stroke of the rod?
M.

 

[surreyman]

I just see batteries. I don't see any controller, Is that an accelerator linkage or ?
Is that it at the top of the picture?
M.

yes the middle pic is the top accelerator linkage that slides the plastic speed regulator in an out- there are two wires that come from this and dissapear towards the rear. idealy what i need is another adjustable speed regulator after this first one

 

[Minder]

I don't see why the present one could not be limited somehow, too bad there is not more detail on it.
M.

 

[surreyman]

I don't see why the present one could not be limited somehow, too bad there is not more detail on it.
M.

i will ask the manufactures for its specification