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Voltage cutoff on 3cell li-poly?

681 Views 10 Replies 6 Participants Last post by  buildflycrash
What should the voltage cutoff be on a 3cell li-poly?
I'm using a etec 1200 mah with cc 25 sc and himax 2015-4100 motor.
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If you aren't real familiar with the discharge characteristics of Lipos, Use 9V soft cut. If you can tell when your cells are starting to drop off, you can use 7.2V, but you risk screwing the pooch if you can't tell when they are going flat. You can easily ruin your pack if you press it.

Best advice: If you aren't sure, use 9V and soft cut.
Hey chuck what did you program mine for?
Though I had ruined 1 already, it wouldn't take a charge on the apache charger. The light just flashed red, got a tritron this week and was able to chagre it. Used it today and didn't have any problems. Didn't run any of the packs as long as I did the one that would charge before. Believe I run it near 21 or 22 minutes.
Gator help setup this up an I believe it is at 7.2 v.
Thanks Chuck
dhooks said:
Hey chuck what did you program mine for?
Yours is 9V, soft cut. That's what they are really supposed to be set at. Castle Creations has had a self-admitted typo in their instructions forever, saying 7.2V cut off. So many people use this, and report no ill effects, that lots of people still use it even after they know 9V is correct.

But it was decided that if you ran 7.2V, you best not run soft cut as it can really, really drain the cells, but use hard cut. Trouble is, hard cut sucks for 3D.

So you'll be fine. If you want to reprogram later, it's not all that hard and you'll be better prepared to judge the pack life by then.
Thanks the way my life goes Id be in a 3 ft hover an the hardcut kicks in....but wait its just a foamy.....who cares. :D
have also in mind that some chargers won't charge the lipoly packs i voltage is too low. You will have to slooow charge them to bring them back up to a certain voltage, and then you can hook them up to the regular chargers again.
Chuck, what do you think of this

when my lipo charger would not put a charge to my 3cell 1300 pack I gave them a dose of charge (5min.) on my Mimh setting at .5 amp. I then switched back to the lipo setting and all is well (I think).

Scott B

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Man, I don't know. When they get drawn down below 2.85V/cell or something, some chargers won't detect them, or might detect them as a lower cell count pack. But I think the 1/10th C charge rate with a NiMh or Nicd charger until they reach 3V/cell is what I've heard use.

I've never personally had to do this, so it's all a guess on my part. Please don't burn anything up over what I've written here!
Best thing is NOT to run the packs too low.. but if it happens, you can recover most of the time... by slow charging using about a tenth of the normal charge rate.. but on a NIMH charger.. til the voltage reaches about 2.5 volts per cell.. then put on Lipo charger and should be ok.. although.. this does shorten the life of the lipo.. and maybe some of the strength.
Dave ,Chuck-- thanks for the reply, I have not noticed any differance in the pac and have not had to do it for about 20 cycles. It did seem to save the pack when it would not take a charge and I did try with two different chargers to get it back up.

Scott B
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