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Lipo lost capacity?

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Old 05-09-2008, 10:50 AM
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grayle
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Default Lipo lost capacity?

Hi I purchased a 2100 mah 11.1 volt maxamps battery about a year ago and it will only accept about 900 mah of capacity on the charge. I use a triton jr. charger and a blinky balancer. I have less then 20 charges on this battery, Is there anything I can do to regain the lost capacity? I don't believe its my triron jr. because my plane doesn't fly as long as it used to. What causes such a drop in capacity? I have never let it get below three volts per cell, and the voltage when fully charged reads 12.4 volts. When my plane won' t fly anymore, I check the voltage and it's at 11.25. My plane is a GP Reactor 3D, Rimfire 30-35-1250, Electrifly 35 amp ESC and a 11x5.5E APC prop. I checked the amp draw when everthing was new and at full throttle it was pulling 25 amps. Thanks, Grayle
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Old 05-09-2008, 10:57 AM
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Default RE: Lipo lost capacity?

Take the pack once and discharge it to 9.0 volts once. Then charge it back up and se what it takes back. Also what is the LVC point set at on the ESC? One other thing when you store the pack during the winter are you storing it fully charged? Or Empty?

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Old 05-09-2008, 11:14 AM
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Default RE: Lipo lost capacity?

Hi, thats how I found out the battery was only taking in 900 milliamps, I used the triton jr. to discharge down to 9.0 volts, at about .4 amps, Charged it back up at 2.1 amps, and left the blinky on to balance it out. When I stored it, it was full. The electrifly LVC is determined off the initial voltage of the pack x .67. WOW, I just took 12.6 x .67 and it comes to 8.442 volts. That seems really low. I have never run it down below 9 volts because I check it with my blinky everytime. Thanks, Grayle
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Old 05-09-2008, 11:20 AM
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Default RE: Lipo lost capacity?

So it sat all winter long with a full charge in it? Or at least it was full when you started.

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Old 05-09-2008, 11:28 AM
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Default RE: Lipo lost capacity?

Yeah it sat all winter with a full charge. I 've read that lipos are to be store at about 50% charge, but does storing them at 100% make them lose capacity? I'm basically trying to figure out if its my battery or my esc or my charger. I s there a way to tell if its undeniably my battery? I had a coworker charge my battery on his thunder power charger ad he thinks its just fine. But his charger doesn't tell him capacity numders like the triton. Should I discharge the battery to see how much it pulls out?
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Old 05-09-2008, 11:38 AM
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Default RE: Lipo lost capacity?

Yes storing them at full all winter is a bad Idea. You should do 50% of capacity and then cycle the packs every 30 days then put them back to 50%. The result of storing at a full charge can be what you are seeing. Try a dischareg and see what you can pull out of it then see what you can put back in. On a side note I get to Otsego a couple of times a summer, The mother-in -law lives in the RV park on the river during the summer months. Actually this weekend I will be at the Father-in-laws in Big Lake. I was hoping for a little golf but it looks like rain is on tap for Saturday. See what you get for numbers on the pack. Did you happen to purchase the Extended warranty on the pack when you bought it?

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Old 05-09-2008, 11:44 AM
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Default RE: Lipo lost capacity?

Nope, I didn't buy the warranty, But I guess I'll have to be more careful next time. Thanks for your help. Otsego is nice, just far away enough from the cities without having to deal with traffic and noise. I live on the west end, It's nice quiet and peacefull. Grayle
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Old 05-09-2008, 11:47 AM
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Default RE: Lipo lost capacity?

Let me know what happens after you discharge it and charge it back up.

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Old 05-09-2008, 12:34 PM
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Default RE: Lipo lost capacity?

I'll check it out tonight and report as soon as I can. Grayle
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Old 05-10-2008, 07:52 AM
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Default RE: Lipo lost capacity?

ok I discharged the battery last night and was only able to pull just under 800 milliamps. I checked the voltages with my blinky and one cell was below 3 volts, so I charged the battery at .1 amps until the voltage on the low cell came above 3.2 volts, then went to bed. I woke up and check the battery again with the blinky and that same cell didn't light up. I put a meter on the low cell and didn't get any voltage reading. I am now in the process of charging again at .1 amp to bring that low cell above 3.2 volts, which did accept voltage. After two minutes, the voltage was at 2.87. Basically I think that cell can't be saved, and it probably why the capacity has gone down so low.
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Old 05-12-2008, 07:34 AM
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Default RE: Lipo lost capacity?

Yes you have a weak cell. Now you know why storing them at 50% is recommended. It sounds like a hassle to have to do this but it works. I always tell people to only buy the amount of packs that they will use also so that they don't have stuff laying around that will not get used and will only make the storing and cycling process harder to do.

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Old 05-17-2008, 03:12 PM
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Default RE: Lipo lost capacity?

I have a 7.4 6000 about 2 years old and it is starting to buldge and lose power should I junk it and where do I take it to get rid of it.
I have heard these batteries can cause fires and that is not what I want!
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Old 05-19-2008, 02:04 PM
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Default RE: Lipo lost capacity?

Discharge it with a 12 volt automotive light bulb cut off the leads and then tossin the trash. Once dead they are physically and chemically harmless.

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