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Cutoff voltage for Lithium ESC

Old 02-21-2004, 09:54 AM
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Default Cutoff voltage for Lithium ESC

I bought a couple of lithium ion battery packs for use in my park flyers, and am considering buying a couple of lithium polymer packs as well. Trouble is, I didn't realize until after I had purchased them that you can't discharge these packs below 5 volts (manufacturer recommendation). The esc's I have cut off voltage at 3.7 volts, so it looks like I'm going to have to purchase a new speed control. I have seen recommendations for the Pixie speed controllers, but the programmable one has an adjustable voltage cutoff of 4.8/ 5 volts from what Ive read.
I guess my question is this: Is there a "tolerance" for the low voltage cutoff on esc's when using them with lithium batteries? Is 4.8 volts "safe" or will I risk ruining my batteries? I don't want to spend the time messing with timing my flights, then measuring voltages to establish "safe" flight times for the current esc I have. Or, could someone recommend a speed control that either has a programmable voltage cutoff or is factory set to work with lithium's that won't cost me an arm and a leg?
Thanks, MinotRich
Old 02-21-2004, 10:07 AM
Dr Kiwi
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Default RE: Cutoff voltage for Lithium ESC

Get a Castle Creations Pixie 20P (or 7P if you are only flying small stuff <7A) - for 2s Lipoly set the cutoff at 6v, for 3s at 9v. You could stretch to 2.5v/cell under load, but it is better to play it safe, especially if you have a slow, floaty type aircraft.

Cheers, Phil
Old 02-21-2004, 11:34 PM
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Default RE: Cutoff voltage for Lithium ESC

Dr. Kiwi,

Why does it matter if the aircraft is slow and floaty?

I too am grappling with the Lipoly cutoff.

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