Driving a small DC motor directly from a LiPo

[prebs]

I remember very vividly a day back in 2008 when a LiPo battery got shorted and exploded. So understandably, im a bit nervous around them. I want to drive a small 5v DC motor, and it would be nice to do this through a 3.7 LiPo battery (motor should work even at 3.7). I am only worried that the motor might draw too much current, and upset the battery. I was thinking of adding a diode between, but would that have any safety effect at all ?

Please advice if I can power a motor from a LiPo battery safely

Thanks

[cowana]

Hi prebs

In 99% of cases you'll be fine - a typical DC motor draws <1A, and a typical lipo can happily supply >5A. However it does depend on exactly what motor an battery you're talking about - can we have some more details?

A diode would help slightly in reducing the voltage available to the motor (thus reducing current) - however this isn't a great way to protect the batter as you'll reduce the torque available.  A fuse (or thermistor or polyfuse) would be a much better solution.

Cheers,
Andy

[digsys]

They're not much different than any other type of battery chemistry. Forget the diode, and use a Polyfuse as suggested.
Depending on chemistry, you can draw between 2C and 20C from the LiPO. If you don't know what type of chemistry it is,
be safe and limit it to 2C. The only other precaution you might add, is not to let it drop below ~2.8 - 3.2V under full power.
It just reduces the #cycles a bit. Can you post a pic of the battery?

[redben]

You should also put a small capacitor in parallel to give more current when the motor is stopped or slowed down. It will help the battery to absorb current spikes and keep everything running with noises as low as possible.
It will also prevent from magnetic and RF issues due to the sparks created at the brushes contacts.