Let's Make Robots!

motors and amps

hay, during building first robot i had some difficulties with my power source , my setup was basicaly a start here robot but with arduino  i used the l239d motor driver , my power supply was a ni-mh 9v rechargeable battery powering arduino, and 3 AA battery pack to the motor driver

THE PROBLEM: 

my problem was my motors runing weakly, or slowly ( they are gm8 solarbotics motors ), this did inprove slightly when i switched to the battery source mentioned above .

THE QUESTION:

well, i picked up a ni-cd 4.8v 400mAh battery and used it as a power supply and replaced the motors with pololu micro geared motors and they worked fine , so  in my next project i want to use 4 of these motors connected to the one motor driver (either l239d, or l238n)  basicaly my question is how to increase amperage/ choose a sutable supply for all these motors? i mean i want rechargeable betterys , at about 4-6v with high amps and at a small size and lowish cost .

 

thanks for any help :)

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oh ok thank you

Even AAA NiMh batteries can put out 5A+ if they are good quality.

 Your problem is than 1x L293D is only good enough for 2 motors @ 600mA maximum each. Changing to an SN754410 would increase your maximum rating to 1A per motor but you should really use at least 2 of them.

For higher currents you need a FET driver. Ditch the L293D.