What is the normal voltage for 24v LIFEPO4

[dazzassj6]

Hi guys, i want to sell this 24v10ah lifepo4 battery. It is the cylinder cells one, its the same one from Cyclone motor kits company.

I charged it up yesterday, havnt used it, and i just measured the voltage and it is 24.3v, also it has no BMS when i got this pack, however i got a BMS from cyclone but dont know how to put it on. I have used this pack a couple of times without the BMS when i first got it, and it ran out of power really quickly, like 5 minutes of riding.

what should be the normal voltage for a fully charged lifepo4 cylinder pack like this?

if it is under, how many possible cells would be dead?? because iw ant to get rid of this pack, but if its stuffed up i dont know what to do, maybe sell the individual cells?

 

[EVnewbie]

LiFePO4 cells are nominally 3.2V each cell.
When fully charged they are 3.6 to 3.7V per cell although not under load. A 24V pack should be 8 cells in series for a 25.6V reading under load. When fully charged should be at around 28V or so. Sounds like you have a bad cell which is predictable considering lack of a BMS board.

 

[rkosiorek]

also there is a good chance that the pack is way out of balance and just needs to be balanced to work properly.

i thought that was the big purpose to LiFePO4 BMS. keep the cells balanced.

maybe you should first get someone to assemble your pack right for you first. before you write it off.

SARCASM STARTING NOW

Of course if you want to safely dispose of that WORTHLESS PACK, BMS and CHARGER. just send them to me and i'll take care of it for you....

SARCASM OFF

these PSI cells are quite reliable. they can only be damaged by serious overcharge or over discharge. to check if the cells are okay and usable or if any have been overdischarged just measure the voltage across each cell individually. cells that measure less than 1.9V are overdischarged and possibly damaged. they possibly will not hold a full charge. those that are less than 1.5V are probably not worth using. less than 1V and you should toss them.

depending on how long you had them on the charger and the charger design, if you have a couple of cells that were overdischarged you may also have damaged a couple of cells by overcharging.

these are good high discharge rate cells. definitetly worth the time and effort to find out how many are salvageble. but you realy need to either figure out how to get that BMS hooked up or find someone to help you with that. likely that only one or two cells are overdischarged and they can replaced.

the Australian importer for those same cells is a member on this site, he goes by the name BMI. he may be able to help you, especially since he is also in Sydney. PM him.

rick

(I hope i just didn't make Armin angry by disclosing his "secret identity"

 

[barneys34]

go here http://visforvoltage.org/forum/5500-cyclone-bms-wiring-issues-lifepo4 it will show u how to wire in the bms never use a lifepo4 without one as u can destroy it if u run the voltage to low it will also help keep your cells all in balance and keep your pack healthy

 

[dazzassj6]

thanks barney