5s lithium Ion battery charge

Hi,
I have a 5s lithium Ion battery pack and a designated charger. the capacity is 2600mAh.
The voltage of the batteries right now is 18V, and no matter how much I charge them(tried currents between 1A-2.6A) it stays 18V - which doesn’t make sense becuase they should be max 21V.
Where can I go wrong here?
-Another thing is there is an option in the charger BAL-CHG - what is it?
Adding photos of the battery and charger.
Thanks.

Does the battery have a balance lead (i.e. a connector with 6 wires going to it)? If so that's what you use for BALance CHarGing.

If not you need to be careful because charging a pack like that without balancing it is likely to reduce the battery life and possibly cause other damage.

Steve

slipstick:
Does the battery have a balance lead (i.e. a connector with 6 wires going to it)? If so that's what you use for BALance CHarGing.

If not you need to be careful because charging a pack like that without balancing it is likely to reduce the battery life and possibly cause other damage.

Steve

I don't have a balance lead(only 2 output wires, and charge cable). Still don't get why it doesn't charge over 18V, any thought?
Thanks

You seem to have the charger set up to do a balance charge but with no balance lead connected. I don't know if it will even charge when you set it up incorrectly like that. Have you tried it in Fast Charge Mode instead BAL_CHG?

You're right to expect a fully charged 5S Li-ion or Lipoto be 21V.

Are you sure it is actually charging? Was the battery voltage lower than 18V when you first put it on the charger?

Steve

The amicell website makes it look like there is a BMS (battery management system) verity that if you have a BMS you don’t need a balance charger, it is built in.

there are two sets of wires come out, some BMS use a separate charging input. have you tried the other set of wires?

If the battery is plugged into the correct wire, and it has a BMS, check the voltage coming from the charger.