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?
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.
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.
My 38v pack only reaches an indicated 41.6v max charge and drops to 41.4 when unplugged. However when tested each cell has been 4.2v. I believe the Gouache indicating low is if zero significance. I have been using mine for a year now with Samsung 35E cells and whilst I wasn’t impressed with their cold weather performance their warm weather performance is phenomenal. I road 35 miles on pretty flat terrain two days ago and only used 16% of a full charge. That’s a very real range of about 280 miles under the same condition. I use my assistance in a very specific way in that I just use ECO to overcome inertia and get up to about 9/10mph then turn the motor off as my Bosch powered Raleigh Motus is a doddle to ride without assistance. I ride for exercise but I have heart and spinal damage issues and the assistance is simply to prevent severe stress therefore any high assistance is out of sheer physical necessity NOT for casual easy riding. If you want to ride at Turbo full time you can except just under 50 miles in warm weather and about 35 in cold conditions with Samsung 35E cells. They simply are not the best choice of cell for a cold climate as I have found to my cost. Just don’t worry about INDICATED power levels as the battery really performs exactly as it should. Cell choice though is so important.