BMS charging voltage range

[nthnmchrlly]

Hi, sorry if this is a noob question but dont really have anyone to ask so yeah, I recently built my first Lifepo4 32650 battery pack on a 2s4p configuration coupled with a 10A BMS. When charging at set 7.2v but it only takes 1A off my CV power supply even when I set the current limit higher than that. Upon checking the specs of the BMS it states that the charging voltage is 7.2v-8.4v, so I then decided to increase the charging voltage to 7.6v and now its charging higher amps so I set my current limit to 4A. Is it safe to charge like this? Cause going back to charging at 7.2v at 1A for my 20Ah pack would take a long time.
BMS is:
Model: HX-2S-JH20
Module size: 46.7*23*3.15mm
Upper limit working current: 10A
Upper limit instantaneous current: 20A
Over charge voltage range: 3.65±0.05V
Over discharge voltage range: 2.0-2.5V±0.05V
Static current: <10uA
Charge voltage: 7.2V-8.4V
Short circuit protection: yes. Delay self recovery


Can anyone kindly enlighten me please.
Thanks.

 

[Ampster]

What size are you batteries in Ahrs? Does the manufacturer say what the maximum charging Amps should be?

 

[nthnmchrlly]

What size are you batteries in Ahrs? Does the manufacturer say what the maximum charging Amps should be?

Nominal Capacity: 5Ah
Charging Current: 0.5-1C

 

[Ampster]

Nominal Capacity: 5Ah
Charging Current: 0.5-1C

Okay 1C is a 5 Amp charging current per cell. You have 4 in parallel so in total you have 20 Ahrs of capacity. You could charge them safely at 20 Amps and it would take an hour. Your BMS is limited to 10 Amps but most people suggest only going to 50% of BMS capacity. 5 Amps charging rate would take 4 hours.

 

[nthnmchrlly]

Okay 1C is a 5 Amp charging current per cell. You have 4 in parallel so in total you have 20 Ahrs of capacity. You could charge them safely at 20 Amps and it would take an hour. Your BMS is limited to 10 Amps but most people suggest only going to 50% of BMS capacity. 5 Amps charging rate would take 4 hours.

Thanks for the reply, I already got that part, what I'm not clear on is when I charge at my set 7.2 voltage on my power supply, the pack only charges at 1A. Only when I set it at a higher voltage that it charges at a decent 4A. Is it safe to charge at a higher voltage like stated on the BMS specs? Thanks again

 

[Ampster]

7.2 volts is 3.6 volts per cell. At that point your batteries are probably 95 to 99% full. It is safe to go to 3.65 v per cell but many sources suggest that it will shorten the life of your cells. I charge mine to 3.5 per cell. YMMV