12 volt electric car speed

[Butchy007]

Hi there I have bought a 12volt Audi an have realised it is far too fast for my daughter. The battery runs motors on both wheels. Have tried 6volt battery but not enough power for motors.The person I bought from is not very helpful. Is there any way you can instal a high/low function like other cars have to reduce the speed.not really electrical minded but any help would be appreciated thanks

 

[timothy48342]

Is this one of those ride-in toys?

I tried to do a search for it, but it was hard to tell if I was finding it. If you have the exact product name and brand, that would help to make sure were talking about the same thing.

A link to the pdf of the manual or a wiring diagram would be even better!

Without any of that, I think it seems like a variable potentiometer in series with the battery might work, or even just a resistor. (Hard to guess at the size, though.)

--tim

 

[duke37]

If it has proportional control i.e. goes faster with more pressure then a resistor in series with the comtrol should do the job. If it is just a simple on/off switch, it will be much more difficult.

 

[Butchy007]

Thanks for all replys. This is link to car but it is 6volt mine is 12volt.http://www.amazon.co.uk/Cabriolet-E...f=sr_1_4?s=kids&ie=UTF8&qid=1333803259&sr=1-4

I gave it to someone who tried to fix problem but could not come up wit solution. He tried few tings like changing battery from 12 to 6 but not enough power to run motors. I bought board of eBay which worked ok until u put car in reverse then it changed all + to - an broke the board. There no books or manual came with.

 

[timothy48342]

This is going to difficult without knowing how the thing is wired, since we can't physically look at it. So, can you provide a lot more information about it?

Product numbers.
Not just the product number of the toy, but of all the components you can.
Any numbers printed anywhere: the controler, the motors.
(Hopefull one of those has been used in some other device and will show in a search engine.)

How about a photo of the wiring. I'm not sure what information we would get from that, but maybe it would help up to raise the right questions. A photo of the plate on one of the motors showing all the manufacturers info about those might help, too.
If it easy to take photos and post them to tinypic.com or facebook or somewhere then take a whole bunch. Every component (and the burnt out board from eBay.)

Also, about that board from eBay. How did you know that it would work with you model? How did you hook it up? Do you have that eBay auction id number?

I know... Lots of questions. Some may be useless, but some might help.

-tim

 

[(*steve*)]

What you could do is create a variable duty cycle oscillator from a 555, and have that drive a solid state relay. The relay is placed in series with the motor, effectively providing PWM control.

You set the oscillator to give an appropriate maximum speed.

SSR is important (you can't use a regular relay) and you will need a snubber network across the motor to absorb voltage spikes -- a diode can't be used because the voltage gets reversed.

Tjis would require a minimum of changes to the wiring of the car, and probably changes to wiring to which you have access.