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Finnster · 06.24.2009, 10:31 PM

I've done this myself to speed up lipo charging if the V is too low, but how on Earth are you getting 18V when charging in 4S mode? 4.2V*4= 16.8V

Usually my charger will take it upto 16.8V in CV mode, so the amps slow down, and its not worth charging @ .2A.

I would not ever charge in NIMH mode. Yes you can cheat the charger to force a high amp charge into the lipos, but the charger will not stop running, and will raise the voltage to keep a high amp rate going. It never sees a V drop (like Nimh batts do when full) so it keeps steaming along even if the lipos go way over the 4.2V/cell limit.
This is a recipe to burn your house down. Do not do it.

FYI.. I did this once with an A123 pack before I got a usb adapter to update the charger for a LiFe mode. I got distracted for a sec, walked away, came back to late and my now 5S A123 pack was at 25V/5A and still going (should have stopped at 18V.) Destroyed the whole pack, but fort the A123s are inherently safe and did not burn. Lipos would have caused a fire.

You should just be able to select a 5S batt in the charger and go from there. In certain V ranges it could be a 5S or 4S batt, and chargers default to the lower count for safety. Just confirm its a 5S and go.

At the very worse if you can't, if your charger has a A123/LiFe mode, you may be able to use that mode as a halfway step for a little faster kick. Ie, for a 5S lipo pack, charge as 5S A123 to 18V (full charge is 3.65V/cell), then change to lipo mode.

Otherwise, don't let your batts go so low V. 3.2V/cell is a sfer cutoff, else, as soon as you fell the power start to drop, stop the truck immediately and change the batt. The last few mah kills the voltage and can ruin the batt.

	(#19)
Finnster KillaHurtz Offline Posts: 2,958 Join Date: Apr 2006 Location: Bucks Co, PA	06.24.2009, 10:31 PM I've done this myself to speed up lipo charging if the V is too low, but how on Earth are you getting 18V when charging in 4S mode? 4.2V*4= 16.8V Usually my charger will take it upto 16.8V in CV mode, so the amps slow down, and its not worth charging @ .2A. I would not ever charge in NIMH mode. Yes you can cheat the charger to force a high amp charge into the lipos, but the charger will not stop running, and will raise the voltage to keep a high amp rate going. It never sees a V drop (like Nimh batts do when full) so it keeps steaming along even if the lipos go way over the 4.2V/cell limit. This is a recipe to burn your house down. Do not do it. FYI.. I did this once with an A123 pack before I got a usb adapter to update the charger for a LiFe mode. I got distracted for a sec, walked away, came back to late and my now 5S A123 pack was at 25V/5A and still going (should have stopped at 18V.) Destroyed the whole pack, but fort the A123s are inherently safe and did not burn. Lipos would have caused a fire. You should just be able to select a 5S batt in the charger and go from there. In certain V ranges it could be a 5S or 4S batt, and chargers default to the lower count for safety. Just confirm its a 5S and go. At the very worse if you can't, if your charger has a A123/LiFe mode, you may be able to use that mode as a halfway step for a little faster kick. Ie, for a 5S lipo pack, charge as 5S A123 to 18V (full charge is 3.65V/cell), then change to lipo mode. Otherwise, don't let your batts go so low V. 3.2V/cell is a sfer cutoff, else, as soon as you fell the power start to drop, stop the truck immediately and change the batt. The last few mah kills the voltage and can ruin the batt.