Electronics 2000

Hi all
A newbie with a very limited knowledge of electrics I have scoured this forum for answers to my problems without any joy so I'm posting in the hope one of you gurus will help.
Basically I am building a powered trolley to transport my fishing box rods etc, along the lines of a golf cart.
I have come across a pair of motors from a kids ride on car ( 6v - 12v P.O 20 - 45 watts ) and designed a chassis to mount them and the box. I have tested them out and they run fine on a 12v battery ( I'm using a spare car battery for the moment ) however when switched on they take off like a bat out of hell. I tried connecting via an electronic 12v drill switch thinking that would give me some speed control, only resulted in a burning smell coming from switch. First question what kind of switch would I need to give me acceleration up to walking speed ?
Second question, which voltage battery would be better for my application, since the motors will run on either 6 or 12 volts.
Any help or advice will be much
Thanks
John

With 12v you may get away with something like this:
http://compare.ebay.co.uk/like/22112048 ... =66&ff19=0#

Thanks for the reply Pauldf.
I think I see how the speed controller would work, but I was thinking of ( hoping to find ) a trigger switch which would allow me to start from a standstill and accelerate up to speed without jerking the motors. One handed operation is a must and since I'm likely to be out in all weathers some rain protection is also necessary.
Thanks again I will consider a speed controller.
John.

Just found this, http://www.ebay.co.uk/itm/271195544065? ... 1438.l2649
the reverse would be handy but I'm not sure about the 6A for the motors, would it be ok ?
Thanks
John.

I have not checked out the links this comp is very slow (voda dongle uk edge) the variable resistor in the drill is designed to run a lower power motor, the idea is spot on... you need a bigger power tool trigger or similar, I am not going to search for one but they are available. To reverse (depending on the type of motor) a comutator motor you just reverse the current, I dont know what it is called off the top of my head but a switch which switches both pos and neg with 3 positions ie fwd, off, and reverse.
If that does not make sense I will explain better, but you sound like you know what you are doing.

Let us know how you get on.

Tar&stuff.

Some motors have a wired comutator and a wired stator such as a car starter motor, to make them go backwards you swop just the polarity of the stator or the comutator. If you reverse both ie by swopping the supply over then the motor doesn't go backwards. Just a warning tho, some motors have angled brushes and are not suitable for running backwards.
I think the switches spoke of before are DPDT on - off - on.

Thanks for the replies.
I've ordered a control with reverse ( the motors are from a kids ride on and will run in reverse by switching polarity ) I've also ordered a 10 ah 12v battery which since the motors are 20 - 40watts should be a maximum of 6.66 amps with 1.5 hrs run time, am I right ?
Thanks
John.