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I have an 11.1v LiPo battery that has be working just fine and it recently dropped to 8.3 volts as it normally does during use. However this time when I plugged it into the charger the charger started to blink meaning either the battery is too low to charger or there is a problem with the battery. When I checked the battery's individual cells I made note of their individual charges

  • Cell1: 4.15v
  • Cell2: 4.15v
  • Cell3: 0.0v

How is this even possible? Is my battery toast? It's new and was working fine until this happened.

NOTES

  • This battery has a balance charging connection w 1 blk & 3 red wires to the connector
  • I only have only ever used balanced charging for this battery
  • This battery has 16 gauge red/back wires connected to a deans connector for use
  • I use this battery with a quad copter uav.
  • This battery was freshly charged and only lasted ~1 minute the last time it was used
  • I was changing pitch/roll/yaw settings on last use and at one point an ESC started causing a motor to be jittery (happens a lot). As I was throttling down/up (4/5 times) to get the motor to spin correctly the low voltage signal kicked in.
  • I was using this batter with my quad copter last night when I got the "low voltage" cut off from my ESCs. Instead of charging this battery I charged another battery and left this one sitting on my counter (room temperature) over night.

Edit

I just ran a multimeter on each of the wires coming out of the balanced charge connection and here's what I found:

  • Wire1(c1): 4.16v
  • Wire2(c1+c2): 8.33v (4.16v from cell1 + 4.17v from cell2)
  • Wire3(c1+c2+c3): 8.43v (4.16v from cell1 + 4.17v from cell2 + 0.1v from cell3)

Edit

Using a suggestion in the comments I was able to get a voltage readout of 41.2mV for cell 3. This extremely low as it close to 3.7V.

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  • \$\begingroup\$ This is unfortunate, but **** happens. \$\endgroup\$ – Ignacio Vazquez-Abrams Mar 22 '15 at 20:42
  • \$\begingroup\$ yeah, **** happens but such a fail without any external cause seems odd to me. I'm betting on a broken contact somewhere... If you measure the 8ish V across the "big" wires nothing is broken though. \$\endgroup\$ – Vladimir Cravero Mar 22 '15 at 21:58
  • \$\begingroup\$ I was going to try to charge cell3 (0.1v) as a 1 cell lipo but the charger will just tell me the cell is too low to charge. I would try to charge cell3 as NIMH to get it up to 3v but I don't have a NIMH charger and I don't know enough about batteries to be comfortable with a hack like that anyway. \$\endgroup\$ – Jacksonkr Mar 22 '15 at 22:24
  • \$\begingroup\$ 4.15 V is pretty high for a cells that you "ran down". Either you didn't get much flight time or you recharged them and didn't tell us. \$\endgroup\$ – gbarry Mar 22 '15 at 22:38
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    \$\begingroup\$ When you charge, do you balance charge or just a simple quick charge? BTW: A simpler way to check cell voltages is to measure pairs instead of pin-to-ground: gnd->c1, c1->c2, c2->c3. That's how they're wired internally, each "pair" soldered to each cell's + and - terminals. \$\endgroup\$ – slebetman Mar 23 '15 at 3:20

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