Lipo storage?
11-16-2011, 06:59 PM
#2
Not sure I understand your ques...but you don't keep lipo fully charged, at least I don't - they last longer and have less probs that way.
After running, I used to recharge, but now all I do is check voltage. If between 3.7 - 3.85v/cell, I leave them until just before running again and then they are fully charged right before using them.
If the voltage is lower than I like to see, I put them on charger and storage charge them.
After running, I used to recharge, but now all I do is check voltage. If between 3.7 - 3.85v/cell, I leave them until just before running again and then they are fully charged right before using them.
If the voltage is lower than I like to see, I put them on charger and storage charge them.
11-16-2011, 09:46 PM
#5
Tech Adept
iTrader: (1)
It's never a good idea to leave them in a fully charged state for a long period of time. I've had first hand accounts of friends lipos getting puffy just sitting on a shelf fully charged. While there may be other factors involved this practice seemed to be common between them.
I myself have always put them in storage mode after a race. They'll stay that way and get charged up the night before the next race. So far so good!
I myself have always put them in storage mode after a race. They'll stay that way and get charged up the night before the next race. So far so good!
11-16-2011, 11:52 PM
#8
Tech Adept
iTrader: (1)
Storage mode is just another function found on just about any lipo charger that can do the standard charging, balancing and discharging. The storage option would be found in the same place. Basically if you choose this the charger will automatically charge OR discharge your battery to a preset (user changeable) value per cell. The default is usually around 3.4v per cell. Once completed this should leave your pack with about a 60% charge and can safely be left this way for extended periods.
11-17-2011, 03:04 AM
#11
Tech Master
iTrader: (3)
Any time a lipo cell sits fully charged it will start to degrade
The effect is cumulative and the cell resistance will rise over time
Most dont hold onto their packs long enough to worry about it (or they die early)
3.85v is an arbitrary value based on a table similar to this
Resting voltage vs capacity
4.2v - 100%
4.13v - 90%
4.06v - 80%
3.99v - 70%
3.92v - 60%
3.85v - 50%
3.78v - 40%
3.71v - 30%
3.64v - 20%
3.57v - 10%
3.5v - 0%
Hence why an LVC of around 3.4v is often suggested to ensure a resting voltage of 3.7v (20% capacity remaining in the pack)
And why people suggest you should only use 80% of a packs measured capacity
Cheers
The effect is cumulative and the cell resistance will rise over time
Most dont hold onto their packs long enough to worry about it (or they die early)
3.85v is an arbitrary value based on a table similar to this
Resting voltage vs capacity
4.2v - 100%
4.13v - 90%
4.06v - 80%
3.99v - 70%
3.92v - 60%
3.85v - 50%
3.78v - 40%
3.71v - 30%
3.64v - 20%
3.57v - 10%
3.5v - 0%
Hence why an LVC of around 3.4v is often suggested to ensure a resting voltage of 3.7v (20% capacity remaining in the pack)
And why people suggest you should only use 80% of a packs measured capacity
Cheers
11-17-2011, 06:58 PM
#13
[QUOTE=TOM MAR;9921504]The Rev-Tech batteries I have came with a recommendation paper, they say not to leave a (their) battery fully charged state for more than 2 hours as this could cause cells to swell.[/QUOTE
Nice of them to warn you. Wonder if there is any science behind the 2hr figure?
Sitting at full voltage is recognized as one of the things you don't want to do with your lipos.
Nice of them to warn you. Wonder if there is any science behind the 2hr figure?
Sitting at full voltage is recognized as one of the things you don't want to do with your lipos.
11-17-2011, 08:08 PM
#14
[QUOTE=Duster_360;9925611]
+1 It was nice of them, 2 pages of do's & dont's.
We run 1 cell in both oval & World GT on road, & voltage is everything lol.
I got 2 packs in April & they still are within a lap of new. (Following their directions)
I don't know if they are right, just the slightest indication of swelling.
But it makes me feel better.
Next time I talk with them I will ask how they came up with 2 hours.
But I have a first run 5000 Thunder power 2 cell (3 or 4 years old) kept at 7.4 volts for long periods at a time (3 months between uses) for off-road. Ran them last week in SCT Stock ran 3rd in the A main.
Noticeable but slight swelling.
Tom
The Rev-Tech batteries I have came with a recommendation paper, they say not to leave a (their) battery fully charged state for more than 2 hours as this could cause cells to swell.[/QUOTE
Nice of them to warn you. Wonder if there is any science behind the 2hr figure?
Sitting at full voltage is recognized as one of the things you don't want to do with your lipos.
Nice of them to warn you. Wonder if there is any science behind the 2hr figure?
Sitting at full voltage is recognized as one of the things you don't want to do with your lipos.
We run 1 cell in both oval & World GT on road, & voltage is everything lol.
I got 2 packs in April & they still are within a lap of new. (Following their directions)
I don't know if they are right, just the slightest indication of swelling.
But it makes me feel better.
Next time I talk with them I will ask how they came up with 2 hours.
But I have a first run 5000 Thunder power 2 cell (3 or 4 years old) kept at 7.4 volts for long periods at a time (3 months between uses) for off-road. Ran them last week in SCT Stock ran 3rd in the A main.
Noticeable but slight swelling.
Tom
11-19-2011, 05:16 PM
#15
If you routinely do that, may want to consider putting the lipos in a ziploc bag and in the refrigerator - like the veg crisper and let them sit at 38-40F. You need to pull hem out ~24hrs before needing them to let them come back to room temp - leave them in ziploc so any condensation will be on outside of bag, not inside the lipos.
I've been away due to work and mine are sitting in a frig atm. The colder temps seems to suspend lipo aging process. Typically, 3yrs is about the age where lipo media begins to show signs of degrading.
I've been away due to work and mine are sitting in a frig atm. The colder temps seems to suspend lipo aging process. Typically, 3yrs is about the age where lipo media begins to show signs of degrading.