I was gifted LIFEPO4 packs never used. Stored for 3 years. Cell voltage is 1.7V
- Thread starter pullin_gs
- Start date
400bird
Solar Wizard
Yup, stick a fork in them, done. I'll come pick them up and recycle them for you. ?
Damage was done, charge them slow, monitoring voltage and temperature. They'll probably survive with a significant portion of their capacity remaining.
Wait, cell volts is 1.7 or pack voltage is 1.7, big difference.
Damage was done, charge them slow, monitoring voltage and temperature. They'll probably survive with a significant portion of their capacity remaining.
Wait, cell volts is 1.7 or pack voltage is 1.7, big difference.
Pierre
Somewhere down South
- Joined
- Dec 21, 2019
- Messages
- 1,143
I have successfully revived and still using today some 3,2v LFP cells that had low voltages between 0,7 and 1,4 after sitting for a long time.Charge / discharge them slowly a few times and then do a charge / discharge capacity test before you discard . You may be able to save some.
yabert
Solar Enthusiast
Same thing for me. I revived many cells who hit 0.1V nine years ago and some are still used today.
So 1.7V / cell is not a huge problem. Charge them slowly.
Kenny_
Solar Addict
Seek Resurrection. May you be blessed by the Sun God.
chrisski
Solar Boondocker
- Joined
- Aug 14, 2020
- Messages
- 5,410
If I had a bit of free time, I’d work on reviving them.
If I was to busy, I send to the recycle bin.
Steve_S
Offgrid Cabineer, N.E. Ontario, Canada
I provided this in another post a while back but could not find it, so I'm reposting this from my lib of docs.
Recovery Instructions:
Charge each LOW cell, one at a time, starting at 3.000V and around 10A and let it slowly take the charge till it cuts off. Rinse repeat for each cell. They should all take it BUT BE GENTLE & POLITE ! Once they all get to 3.000 then parallel the cells and top them in INCREMENTS, I would suggest 0.100V increments. Yes slow, painful, TEDIOUS but if you want to recover them....
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They technically can recover IF they were not frozen or cooked while in a state of discharge, if they have, then do one cell at a time and in a safe box in case it pops & leaks. IF you are lucky, they will recover and maybe you've only lost a percentage of capacity. IF they recover to at least 3.400Vpc, I would run at least 3 good cycles through them (charge/discharge) and then capacity test each cell to ensure the packs integrity, because even if One Cell goes wonky, it will affect the whole pack, as the lowest common denominator rules.
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Once you get the cells up to 3.650 (I would stick to 3.600 myself) and fully saturated (meaning taking <2A) and stop charge current. The cells WILL SETTLE which is perfectly normal & expected behaviour. They will likely drop to about 3.500 from 3.600 within 1 hour or so, give or take a bit. They will usually continue to settle till around the 3.400-3.450 mark where it will slow considerably as the LFP Working Voltage range is 3.000-3.400.
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Once this is done, I would setup the pack temporarily with the BMS and discharge the battery pack to cutoff, then recharge through the BMS till it reaches full at a respectable Amperage. 100AH Cell can typically take a Max of 0.5C or 50A charge rate. 20-40A Charge rate would be as high as I would go "for now" while determining their condition.
-
When charging at a higher amperage the cells heat up (normal & expected) and the higher the amps the warmer they get. With ESS cells @ 0.5C it's never crazy ! EV Grade Cells @ 5C Charge Rate = another matter ok. We are dealing with ESS cells here, so staying "in context". You will want to check the cells during Higher Amp charging feel the sides etc, they should be consistent / constant... a Hot Spot = Warning Flag ! You WILL NOT GET THAT with Lo Amp Charging, it has to be at least 0.25C and the temps should be notable within 1/2 hour or so. Be diligent & watchful !
Additionally, I am adding these two graphics for your reference.
Recovery Instructions:
Charge each LOW cell, one at a time, starting at 3.000V and around 10A and let it slowly take the charge till it cuts off. Rinse repeat for each cell. They should all take it BUT BE GENTLE & POLITE ! Once they all get to 3.000 then parallel the cells and top them in INCREMENTS, I would suggest 0.100V increments. Yes slow, painful, TEDIOUS but if you want to recover them....
-
They technically can recover IF they were not frozen or cooked while in a state of discharge, if they have, then do one cell at a time and in a safe box in case it pops & leaks. IF you are lucky, they will recover and maybe you've only lost a percentage of capacity. IF they recover to at least 3.400Vpc, I would run at least 3 good cycles through them (charge/discharge) and then capacity test each cell to ensure the packs integrity, because even if One Cell goes wonky, it will affect the whole pack, as the lowest common denominator rules.
-
Once you get the cells up to 3.650 (I would stick to 3.600 myself) and fully saturated (meaning taking <2A) and stop charge current. The cells WILL SETTLE which is perfectly normal & expected behaviour. They will likely drop to about 3.500 from 3.600 within 1 hour or so, give or take a bit. They will usually continue to settle till around the 3.400-3.450 mark where it will slow considerably as the LFP Working Voltage range is 3.000-3.400.
-
Once this is done, I would setup the pack temporarily with the BMS and discharge the battery pack to cutoff, then recharge through the BMS till it reaches full at a respectable Amperage. 100AH Cell can typically take a Max of 0.5C or 50A charge rate. 20-40A Charge rate would be as high as I would go "for now" while determining their condition.
-
When charging at a higher amperage the cells heat up (normal & expected) and the higher the amps the warmer they get. With ESS cells @ 0.5C it's never crazy ! EV Grade Cells @ 5C Charge Rate = another matter ok. We are dealing with ESS cells here, so staying "in context". You will want to check the cells during Higher Amp charging feel the sides etc, they should be consistent / constant... a Hot Spot = Warning Flag ! You WILL NOT GET THAT with Lo Amp Charging, it has to be at least 0.25C and the temps should be notable within 1/2 hour or so. Be diligent & watchful !
Additionally, I am adding these two graphics for your reference.
Pierre
Somewhere down South
- Joined
- Dec 21, 2019
- Messages
- 1,143
Nice work Steve. Trust you are keeping well and the snow is not too bothersome. Best regards.I provided this in another post a while back but could not find it, so I'm reposting this from my lib of docs.
Recovery Instructions:
Charge each LOW cell, one at a time, starting at 3.000V and around 10A and let it slowly take the charge till it cuts off. Rinse repeat for each cell. They should all take it BUT BE GENTLE & POLITE ! Once they all get to 3.000 then parallel the cells and top them in INCREMENTS, I would suggest 0.100V increments. Yes slow, painful, TEDIOUS but if you want to recover them....
-
They technically can recover IF they were not frozen or cooked while in a state of discharge, if they have, then do one cell at a time and in a safe box in case it pops & leaks. IF you are lucky, they will recover and maybe you've only lost a percentage of capacity. IF they recover to at least 3.400Vpc, I would run at least 3 good cycles through them (charge/discharge) and then capacity test each cell to ensure the packs integrity, because even if One Cell goes wonky, it will affect the whole pack, as the lowest common denominator rules.
-
Once you get the cells up to 3.650 (I would stick to 3.600 myself) and fully saturated (meaning taking <2A) and stop charge current. The cells WILL SETTLE which is perfectly normal & expected behaviour. They will likely drop to about 3.500 from 3.600 within 1 hour or so, give or take a bit. They will usually continue to settle till around the 3.400-3.450 mark where it will slow considerably as the LFP Working Voltage range is 3.000-3.400.
-
Once this is done, I would setup the pack temporarily with the BMS and discharge the battery pack to cutoff, then recharge through the BMS till it reaches full at a respectable Amperage. 100AH Cell can typically take a Max of 0.5C or 50A charge rate. 20-40A Charge rate would be as high as I would go "for now" while determining their condition.
-
When charging at a higher amperage the cells heat up (normal & expected) and the higher the amps the warmer they get. With ESS cells @ 0.5C it's never crazy ! EV Grade Cells @ 5C Charge Rate = another matter ok. We are dealing with ESS cells here, so staying "in context". You will want to check the cells during Higher Amp charging feel the sides etc, they should be consistent / constant... a Hot Spot = Warning Flag ! You WILL NOT GET THAT with Lo Amp Charging, it has to be at least 0.25C and the temps should be notable within 1/2 hour or so. Be diligent & watchful !
Additionally, I am adding these two graphics for your reference.
Steve_S
Offgrid Cabineer, N.E. Ontario, Canada
Doin not too bad actually, snow is still just dustings,,, its on the slow path for the moment, I expect it will get seriously nasty later, who knows, the weather patterns are totally messed up, up here.
Thanks all for the detailed replies. It is really helpful especially since I'm new to LIFEPO4 chemistry.
Anyway, I charged the 24V packs (not individual cells) at 1/5C and both packs took in rated AH before BMS (or charger) shut things down at around 29.2V (3.65V/cell)
It's been a few hours and both packs settled down to around 27.15V (3.4V/cell).
Fingers crossed. Will see what happens over next few days.
I'll load (inverter running some 110V stuff) tests on them then and see what happens in regards to capacity and such.
Anyway, I charged the 24V packs (not individual cells) at 1/5C and both packs took in rated AH before BMS (or charger) shut things down at around 29.2V (3.65V/cell)
It's been a few hours and both packs settled down to around 27.15V (3.4V/cell).
Fingers crossed. Will see what happens over next few days.
I'll load (inverter running some 110V stuff) tests on them then and see what happens in regards to capacity and such.
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