My brand new 18650 batteries will not charge above 3.7 volts on my Imax B6AC V2 charger…! Set on Li-ion or Lipo setting!! What is happening here? I thought it would take 18650s up to 4.1 or (4.2 lipo) volts. The charger display reads 4.1 when charging and one page reads FUEL: 100%, Cell: 4.1v but when I check it with the chargers own built in Battery meter or a hand held it is always 3.7 volts….? Not a bit more!
Quick description… I am charging, or trying to charge four 18650’s connected in parallel battery pack with my Imax B6AC V2 charger. All the batteries were at 3.6 volts when put on the charger. Charger was set to 1s & 4.0 amps charge/1 amp each. This set-up was going to be an external power supply for time lapse photography with my action cameras. The Cameras stock batteries run from 4.2 or 4.1 down to 3.65 or 6.7 when they shut off for being in a Low Battery condition in the cameras. I thought these 10,000mAh packs I made would be just right for my needs as 4.2v is their nominal/fully charged condition !! But only being able to reach a 3.7 volt charge with them has me confused. I have four Samsung 18650s & four Panasonic 18650s both sets will not charge up above 3.7 volts. Can anyone help me with this…? Much appreciated.
thanks… but no it is on the regular charge setting. I have made sure of that. I just can’t figure it out as the charger shows a cell condition of 4.1v & FUEL: 100% when checking during a charging. But the chargers own meter and a hand held indicate 3.7v…?
Try charging them with a standard 18650 charger by connecting the + and - poles of the charger with the +/- poles of the battery pack.
Also did you ever try the cells separately with a standard li charger? Maybe the cells are bad or you fracked em while creating yhe pack? Have you got a pictutr of the pack? Some bad soldering connection could be the cause.
The most likely cause is your charger is broken, or maybe stuck in a LiFePO4 mode and terminating the charge at 3.6v or 3.7v.
It’s also possible the batteries are bad, but you’d notice the entire pack’s voltage dropping if there was one bad cell with an internal short. I guess it’s possible, since you’re seeing a huge voltage sag from 4.1v down to 3.7v when the charging stops.
If another charger doesn’t work, take the cells apart and test them individually. And make sure they really are all in parallel, though that would probably be obvious.
I would not think my charger would be indicating 4.1v directly during the charging attempts if it were only by some manufacturer program error set for 3.7 volts charge termination. It would only indicate 3.7 during charging if so.
If you don’t think it’s your charger, then it’s probably the batteries. The fact that 4.1v is reading full, might be indicating a problem. It really shouldn’t read full until the batteries are at 4.2v.
The 4.1v reading may be when the charge current is being applied. That is, 4.1v is what the charger is using to try to charge the battery. The real resting-voltage of the battery might be 3.7v, which indicates a huge internal resistance or an internal short of some kind.
I’d measure the actual voltage and amps that the charger is putting out when it’s trying to charge the batteries. That will definitely tell you if the charger is defective or not.
Are you sure you are in the proper mode? Changing between lithium setting is a bit of a pain and can be confusing. Then make sure you are not in [storage] mode.
Try charging something else: NiMh, car battery, etc. just to see if the charger is functioning at all.
figured out what was wrong…the battery pack leads were bad some how…? they were made of surplus tinned wire in 20 ga. As soon as I bypassed them and clipped my charger directly to my battery packs tab wire terminal bus strip the charger started functioning correctly. I charged a 10,000 mAh & 13600 mAh battery pack up in about 4.5 hours @ 1.2 amps and they both fully charged up to the 4.1 volts…! I replaced my leads now with new wire and everything is working good now.