Joe1199

I am using 2 5s 5000mah in series and have recently been getting an error alarm on my checker saying the packs are unbalanced, i charge the packs individually and I do balance charge and the figures are usually roughly

4.15
4.17
4.14
4.14
4.14

this doesn't suggest a bad cell but what could be causing this, I was always under the impression balance charging wasn't advisable every time? Is it just my checker being over cautious?

can I safely run the packs at these levels?

thanks
joe

Rob2160

Hi Joe,

Personally I would have no issue running that pack.

Your numbers show less than 1% variation between cells and most of my Lipos are the same.

Do you follow the 20% rule? i.e. Don't discharge more than 80% of the pack's capacity in normal use.

What type of charger are you using? Does it also show individual cell voltages. Can you measure them with a proper multimeter also?

Another thing to check is the cell voltages after use, are they still within 1%

e.g. 3.71, 3.70, 3.69 etc.

If you have a larger difference at this point then it might indicate a failing cell.

Do do the packs get hot or puffy after use?

I balance charge every time - it takes a bit longer but won't hurt the battery at all.

RustyUs

I was always under the impression balance charging should be done every charge unless your cells are known to be discharging at different levels everytime, or really out of whack when LVC kicks in. For me, keeping track of all my 2S/3S/4S packs, and which cells play well with others, I just storage charge a LiPo pack almost every time after use, and balance charge the pack before almost every use.

Those numbers that are shown in OP are well within "usable" voltages. Those numbers can't be after a charge. Are they?

chuckk2

It may be time to clean all the connectors. Dirt you cannot see can cause much of the differences.

RustyUs

I still would like to know if those numbers ^^^ are after a balance charge. 'Cause at the end of a balance charge your cells should be showing 4.19v ~ 4.20v per cell.

What is the safety timer set at on the charger?

Possibly someone is mistakenly thinking a "safety timer" alarm is the end of a balance charge. I know my three chargers all have a default safety timer setting of 90 minutes and sometimes that is not enough time to fully balance charge a pack. Depending on what charger you have, and how much wattage is harnessed through it; will determine how many amps and how long it will take to you (OP) to charge them 5S packs.