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Old 02-13-2011, 06:47 AM   #1
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Default Lipo Voltage Low

While I was charging my 7.4 lipo's for racing yesterday, I decide to charge up my 1/8th scale Thunder power 3cell 11.1
While I was Doing balanced charged, the charger said no balance connector. Then tried to do a standard lipo charge. said voltage too low. Took a reading, and it was down to just 3 volts. Now knowing it is a 3 cell, there should be at least 9 volts. So question is, is the battery shot now? Someone mentioned that I can try doing this outside! And yes, unfortunately last time I ran it in NOvember, i did not charge it before putting it away for the winter. My bad.

Try charging it with the nickle-metal charger at very low voltage, checking to see if it gets to 9 volts. Then try doing a balanced lipo charge again.

Any thoughts?
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Old 02-13-2011, 06:55 AM   #2
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I concur, absolutely!!!!!!!!!!!!!!!!!!!!!! Have done it many times and you should be good, just charge it low amp's like 1amp. till its gets to 3.2volts per cell. And next time store it before you forget about it, always good to cycle your batt's at least every month and a half to keep them fresh for spring
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Old 02-13-2011, 07:28 AM   #3
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Thanks for the quick reply. Got it outside doing a 1 amp NM charge, checking the voltage every 2 minutes. its slowing going up. At 6.5 volts now.
Cool! hope this works. Dont want to spend another $130 for a new battery thats only 6 months old...
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Old 02-13-2011, 10:25 AM   #4
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How long would you think this would take to get the cells up to 3 volts? Im asking because its been about 1.5 hours, peak volt is now at about 9.33
Only way to see volts per cell is to switch to lipo charge. I see 1 at 3.87, other 2 below 1 volt.
NOrmally, for a balanced charged on this 11.v pack, it took about an hour using 5amp charge. Guess charging it now using NM at 1 amp may take several hours?
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Old 02-13-2011, 10:30 AM   #5
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yes, it should take while.
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Old 02-14-2011, 02:19 PM   #6
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So the update is, I was only able to get 1 cell over 3.5 volts. The other 2 never got above 1 volt. The charger I was using, has the option to to LIPO NM, NC PB etc, but it does not allow me to specify the amount of cells the battery has. Just allows me to adjust the charging amps.
I had read somewhere else that someone used a NM charger, and set the cells to 8, then did the charge.
My NM charger only has 4,5,6,7 cells.
My lipo charger can do NM batts, but cant adjust amount of cells. Would that be the reason I was unable to get all cells up to 3 volts? Should I just try the NM charger and set the cells to 4? 5? 6? 7? Think that would make a differance?
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Old 02-14-2011, 04:17 PM   #7
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have the cells puffed at all?
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Old 02-14-2011, 04:25 PM   #8
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No puffing, batteries never got warm while I was charging
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Old 02-14-2011, 05:34 PM   #9
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Thats not very encouraging assuming you were charging thru the main power leads - everytime I've had to do this the voltage in all cells goes up. I set the NiMh charge rate at 0.5 - 0.7amps and even with a 5000mah, you can see voltage start to climb immed.

That 2 cells didn't change voltage implies they may be damaged. The real trouble with charging as NiMh is you can only charge until the highest cell reaches 4.2v - if you keep going, then that high cell becomes overcharged and thats asking for trouble since it can be dangerous.
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Old 02-14-2011, 05:38 PM   #10
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Quote:
Originally Posted by TeamJammin! View Post
No puffing, batteries never got warm while I was charging
thats good, but unfortunately, i think they may have died. the good thing is that they could have puffed and or exploded (being fully charged). at the worst, you lost a pack, may have to chalk it up to a learning experience and consider yourself kinda lucky! i learned the same lesson but with a 10s flightpower battery!
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