Charging/Discharging current question

[sl33pyriceboi]

hello everyone,

i have tried searching the forum but had no luck. so please go easy on me and dont flame me too bad for my stupidity. lovecpf

the question is about battery charging/ charging rate. and to my understnading so far from what ive read, charging at a low current is best? (i hope my terminology of "current" is correct.)


my charger: TURNIGY ACCUCEL-6
batteries: Tenergy LiFePo4 rcr123 @ "3.0v" (more like 3.3v)



question1:
charging a SINGLE battery - what current should i charge my battery at for BEST/MOST capacity? i want to pack the MOST mAh in my batt as possible. charge at 100mah? 200mah? 300? 500? 1Ah?


question 2:
charging 2 batteries in a SERIES - lets say i am charging 2 of my rcr123 in a series. (so total voltage of the series is 6.6v). IF i charge it @ 1Ah, would it be the same as IF i was charging the individual cells @ 500mAh each?


question3:
its about discharging - what optimal current i should discharge a SINGLE rcr123 (remember its LiFePo4)??? remember i want to recharge it back. and when i recharge it back, i want to pack the most mAh in the battery.

thanks again guys :wave:

james

 

[sl33pyriceboi]

one more question:

question4:

is charging in a series (using those wires in between each cell to balance them) better than charging the cells individually due to the fact that it saves time?

i would hate to charge all 8 of my rcr123 one battery at a time when my charger allows balancing of cells.

bump

 

[jasonck08]

Q1: Generally speaking its advisable to charge at about .5-.8C of the cells actual capacity. So if its rated at 500mA, charge at ~250-400mA.

Q2: It's not advisable to charge cells in series, but with Lifepo4's since they tolerate more, its do-able but I wouldn't recommend it. If you charge at 1A @ 6.6v (2 cells in series) it is similar to charging a single cell @ 1A.

Q3: It should tolerate at least 2C discharge currents (~1A), maybe higher.

Q4: Balanced charging is always recommended.

 

[pae77]

I agree with the previous advice but if you want to pack the most capacity in those cells, charging them at a somewhat lower current than the usually recommended current of .5 to .8 C seems, ime, to pack a little more capacity into the cell (but the difference is pretty slight). For my 18650's, I find about .25 C (1/4 C) i.e., charge rate equal to 1/4 of the cell's actual capacity, to be a good compromise between packing the most capacity in and yet still maintains a reasonable total charging time. For smaller capacity cells I usually charge at .3 to .5 C.

 

[sl33pyriceboi]

so is it better to charge my lifepo4 cell individually or a series (two cells in a series) while balancing them with the charger?

thanks for the help guys. i really really really appreciate it.

 

[zer0ne]

You seldom go wrong with single cell charging unless you choose the wrong current for single cell charging . If you have multiple same cells, then it would be faster charging in series with balancing.

 

[VegasF6]

Yes, one at a time is safest, but time consuming. If you have a balance charger, and balance cable there is no reason not to use it. Probably best if those batteries are the same capacity, approx age and at the same state of discharge. I wouldn't series charge say a 16340 and an 18650 and of course not a lifepo4 and lico cell, but thats common sense?

There is also a discussion taking place here about charging parallel vs series.