Very cool!thimel wrote:I did the test of running the battery down from full to nearly empty. As I normally only charge to 80%, two nights in a row I charged to 100% and after it was done, told it to start charging again. This presumably balanced the battery cells. I was surprised to find the SOC starts at only 92.08%. I then drove. I got LBW at 21.6% and VLBW at 10.72%. I then drove slowly home.
Here's my analysis at the data.
1. The overall shape of the 92% and 8.75% (or 100% and slightly below VLBW) appear to be very similar, leading me to believe that the relative health of your cells are fairly close to the same.
2. A SOC of 92% is low - that should read about 95% on a 100% charge.
3. At 8.75% you have a very wide spread in cell-pair voltages at 115 mV.
4. The 4 lowest voltage cell-pairs at 8.75% are also some of the lowest at your 100% charge - in particular #s 20, 26 and 35.
It seems fairly evident that more balancing would get you more usable capacity of your pack - and that if the BMS had the capability to shunt energy to lower voltage cells it might be able to do a
I think that when grabbing this data, also grabbing a screenshot when LBW and VLBW might be useful. For people that normally charge to 80%, a screenshot at 80% and a screen shot right after a 100% charge and after sitting at 100% for a couple hours would be interesting.
Can't wait for my BT adapter to get here!