Jeffpro

My Feedback: (1)

I just built Great Planes' new DC-3 electric. I installed a NiMH battery in it but am interested in replacing it with a Li-Poly battery for longer flight times. Can I just remove the NiMH and put in a Li-Poly, or is there more to it than that?

NMPhi767

That is pretty much it. Just make sure that your ESC has a cutoff that will keep your batteries above or at the recommended cutoff voltage for li-pos. IF you drop a li-po's voltage too low, bad things can happen.

Jeffpro

My Feedback: (1)

Do ESCs typically have a cutoff voltage, or do most allow the voltage to drop to 0? Is there a recommended cutoff value for li-pos, or does it vary from battery to battery?

Greg Covey

Jeff,

Your normal ESC should work just fine with Lithium cells. All my Lithium setups (and they are numerous) use standard brushed and brushless ESCs. The built-in BEC has a Low-Voltage (LV) disconnect circuit that shuts off the motor while leaving power to the receiver and servos.

Good luck!

Jason Beach

My Feedback: (4)

Most ESC's have a cutoff. The problem is that generally they are around 5v which is fine for nicad or nimh. Li-poly batts shouldn't be ran below 3v per cell, which is 6v for a 2cell pack, and 9v for a 3cell pack. Some ESC's have a programable cut-off so you can fit it to your needs, but this is not required. If you are using a regular ESC without a programable Low voltage cut-off (it'll tell you in the instructions if it's programable) and Li-poly batts, you'll want to check the voltage of the pack every few minutes throughout the flight to make sure you're still above 3v per cell. After a few flights you'll know how long those batteries will fly in that application and you can use a timer.