Hello
I want to be short and need your help
I have Arduino Uno v3
Ardumoto shield the new version
and two pololu micromotors 30:1 HP
I use 6x1.2V rechargeable NiMH bateries of 1000mAh each
Now writing a sketch which start the motor with PWM of 60
Hard start from 0 to 60 it’s ok… but giving 254 for the motors, it simply restarts the arduino.
Can I use 9V in the DC input and 9V on the Ardumoto in?
Or use two 9V in parallel?
Hi.
It sounds like you are having power issues. Powering the Arduino and motor driver separately would probably help, but I do not recommend powering your motors from a 9V battery, and I do not recommend connecting two batteries in parallel unless you really know what you are doing.
-Derrill
Hey Derill
I know, 2 batteries in parallel just means it can give higher amperage… 
I have to take a closer look oever the whole thing and see what will happen
2 in parallel, with a big uF capacitor on your driver voltage inputs, and a smallish cap close to your arduino input, should help you deal with those current needs.
If you’re talking about 6 nimH batteries, then it is more like 8.4v input at FULL voltage. And 7.2v at their nominal 1.2v/ea. I can see that being quite close to the arduino’s lower bound of 7v. So an additional voltage drop from a current spike could reduce your input quite a bit.
If you’re talking about a 9v alkaline battery, those offer terrible current output. Even two in parallel would be useless.
The biggest concern about putting batteries in parralel is
(1) Do not put different chemistry of batteries together in parallel (no lithium/nimh/lead mixes!)
(2) make sure they’re at the same charge/voltage before you put them in parralel!
(3) definetively don’t put say a 3-series batteries in parallel with a 2 series battery, even if they’re the same chemistry
Other than that, it’s typically safe.
