What's your top voltage?

General
1

I have recently completed assembly/setup of my Gouach battery pack using Samsung INR18650-35E cells configured as a 13S (48V nominal) pack.

I have noticed that when charging, the pack only reaches approximately 53.4V at full charge. Based on a 13S lithium-ion configuration, I would normally expect a full charge voltage closer to 54.6V (4.2V per cell).

The battery otherwise appears to function correctly, however I wanted to check whether:

  • This reduced maximum voltage is intentional as part of the BMS or charger configuration
  • The charger may be configured conservatively for cell longevity
  • Or whether there could be an issue with the charger, BMS, or pack configuration

can any one advise whether 53.4V is the expected full-charge voltage for this setup, or if I should be investigating this further?

For reference:

  • Cells: Samsung INR18650-35E
  • Configuration: 13S
  • Measured full voltage: ~53.4V
  • Expected full voltage 54.6V
2

I get around the same. In percentage terms I’ve never reached 100%, it typically stops at around 95%. Today was the highest charge I’ve seen yet at 98% or 53.76v. Cell voltages are 4.14 - 4.16.

Also, sometimes it stops charging due to a cell over voltage (err 16). That happened a few days ago at 90% (53.35v). One cell hit 4.21v.

3

Same here. BMS seems to be conservatively set up. The temperature limitations are also very conservative. It makes things safer but also means you can’t really charge to 100%. Good news, your cells will last longer this way.