I have had an old lifepo4 48v 21ah sitting around in my house for quite a few years now.
I first bought the pack from china in 2011, it worked very well and used it up untill 2013 when the motor started cutting out, taking off the ducttape that the pack was surrounded in, I noticed quite a few cell tabs had corroded or came loose. I realised I had not been running it at its full capacity of 21ah for a while.
I understood then I had not been taking care of this pack very well. I used it in heavy rain quite often with a rack bag that was not 100% waterproof.
Untill recently it had be sitting in my house since 2013 but I could not find anywhere to get it spot welded back together so I went ahead and bought a spot welder. It was either faulty or it just kept tripping the power switches in the house every time I turned it on.
So now I've decided to simply use lots of continuous copper wire scunched above each cell terminal as padding and tightly wrapping it with ducttape. Testing each cell pack as I go along. I found there were quite a few dead or faulty cells and some had also swelled up but were fine. So after casting those cells aside I went with 48v 18ah
Unfortunately back in 2012 I had absent mindedly crossed the BMS charge port with the battery output or blew the charger, I cannot really remember what happened but the battery still worked fine then and I simply charged it cell by cell instead.
When I tested the voltage of each cell pack after wiring and ducttaping it all together, each cell pack read 3.28v and with just 2 packs at 3.25v
I have have just been charging each 18ah cell pack with a 3.6v 10ah lifepo4 cell charger, The cell charger usually stops charging after a while once the cells are fully charged and it will enter the float charge mode but while charging most of these cell packs, the cell charger just keeps charging them for more than 2 hours. There were only a few that entered float charge. If I disconnect the charger the cell voltage will read 3.32v on any of the cell packs and will drop back down to 3.27v - 3.29v
I know these cells have seen better days but I was wondering if anyone knew if that resting voltage is ok? I am going to connect an ammeter to my handlebars to see what it can reach before cutting out, I have a 1000w motor so I know with 48v 18ah its only 864w so the BMS will cut out before I can use full load but the ammeter will show me at what current it will cut out.
The lifepo4 cells are 26650(MP-Fe 2VX09E19)
Sorry for the ramble!
Thanks
I first bought the pack from china in 2011, it worked very well and used it up untill 2013 when the motor started cutting out, taking off the ducttape that the pack was surrounded in, I noticed quite a few cell tabs had corroded or came loose. I realised I had not been running it at its full capacity of 21ah for a while.
I understood then I had not been taking care of this pack very well. I used it in heavy rain quite often with a rack bag that was not 100% waterproof.
Untill recently it had be sitting in my house since 2013 but I could not find anywhere to get it spot welded back together so I went ahead and bought a spot welder. It was either faulty or it just kept tripping the power switches in the house every time I turned it on.
So now I've decided to simply use lots of continuous copper wire scunched above each cell terminal as padding and tightly wrapping it with ducttape. Testing each cell pack as I go along. I found there were quite a few dead or faulty cells and some had also swelled up but were fine. So after casting those cells aside I went with 48v 18ah
Unfortunately back in 2012 I had absent mindedly crossed the BMS charge port with the battery output or blew the charger, I cannot really remember what happened but the battery still worked fine then and I simply charged it cell by cell instead.
When I tested the voltage of each cell pack after wiring and ducttaping it all together, each cell pack read 3.28v and with just 2 packs at 3.25v
I have have just been charging each 18ah cell pack with a 3.6v 10ah lifepo4 cell charger, The cell charger usually stops charging after a while once the cells are fully charged and it will enter the float charge mode but while charging most of these cell packs, the cell charger just keeps charging them for more than 2 hours. There were only a few that entered float charge. If I disconnect the charger the cell voltage will read 3.32v on any of the cell packs and will drop back down to 3.27v - 3.29v
I know these cells have seen better days but I was wondering if anyone knew if that resting voltage is ok? I am going to connect an ammeter to my handlebars to see what it can reach before cutting out, I have a 1000w motor so I know with 48v 18ah its only 864w so the BMS will cut out before I can use full load but the ammeter will show me at what current it will cut out.
The lifepo4 cells are 26650(MP-Fe 2VX09E19)
Sorry for the ramble!
Thanks