I am setting up a robot with 2 dc motors and 3 SR04 sensors. When I have all of them running off the 5v from my pro mini there is not enough power to turn the wheels and run the sensors. I have a 11.1 3Cell LiOn battery that I would like to power the motors with. Is is possible I can attach that to the HBridge directly to get more power or do I need to step it down to 5V?
Yes, the battery should always go direct to the H-Bridge. You are lucky you have not released the magic smoke from the Mini's voltage regulator.
If the motors are nominally 5V or some other voltage which is not 11V, then do not worry. Just be careful not to give them too much juice with the analogWrite() command. They will run fine on little bursts of 11v.
Hi,
What H-Bridge motor controller are you using?
Tom.... 
MorganS:
Yes, the battery should always go direct to the H-Bridge. You are lucky you have not released the magic smoke from the Mini's voltage regulator.If the motors are nominally 5V or some other voltage which is not 11V, then do not worry. Just be careful not to give them too much juice with the analogWrite() command. They will run fine on little bursts of 11v.
I don't like that idea at all. The phrase "halt and catch fire" comes to mind.
Why not just use a stepdown converter to power the motors off of whatever voltage they like? Be sure to monitor battery voltage and turn it off when the batteries are dead (you can damage lipo batteries by overdischarging).
Then, if you powered the board through the regulator straight off the 11v (and make sure you don't have the two power rails connected, and that the motor power was coming from the other supply) you've solved the next problem you'll have (noise on the power supply from the motors resetting the Arduino) too.
MorganS:
Yes, the battery should always go direct to the H-Bridge. You are lucky you have not released the magic smoke from the Mini's voltage regulator.If the motors are nominally 5V or some other voltage which is not 11V, then do not worry. Just be careful not to give them too much juice with the analogWrite() command. They will run fine on little bursts of 11v.
Well I have not connected the battery to the mini its self. I was running it off a AA battery pack had the LiPo for other reasons
I am using the Ti L293D driver, I should be able to hook it to the +Vmotor pin(pin 8), I think. Need to charge the battery some and test later.
Now I have a pro mini, can I hook the battery back directly to the board? VCC to Vbus and Ground to GRD?