Crashcourse
New Member
- Joined
- Nov 1, 2020
- Messages
- 31
Hello, I bought 4 of these very cheap* "Elfhub" 12V 100ah LiFeP04 batteries for $480 CAD each delivered. The BMS is very basic (I googled the numbers and found nothing), no Bluetooth or monitoring of any kind. I opened the cases and installed pigtails on the BMS harness run through the outside of the case so I can monitor with a simple external LiFeP04 battery capacity checker.
After charging the first battery to 14.6V and letting rest for 3 days, the voltages are off by what I would consider to be quite a bit - 0.120mV.
"Cell" 1 3.406
"Cell" 2 3.526
"Cell" 3 3.463
"Cell" 4 3.461
When charging I monitored the voltages with my Fluke DVOM at the BMS terminals and Cell 2 hit 3.72V when the others were ~ 3.55ish then the BMS disconnected charging, so I assume it has a 3.75V disconnect. A little high but... yeah.
My DIY 48V 100ah 16 cell battery with an Overkill BMS always rests around 0.010mV.
Is there any way to properly balance these things or I'm I just going to have to charge the batteries to say 13.8 or so I can at least use most of their capacity?
Thanks for any help.
*very cheap - when I opened the cases I found that the "100ah cells" are made of 4, in series, sets of 5 20ah cells in parallel, so yeah.. you get what you pay for..
After charging the first battery to 14.6V and letting rest for 3 days, the voltages are off by what I would consider to be quite a bit - 0.120mV.
"Cell" 1 3.406
"Cell" 2 3.526
"Cell" 3 3.463
"Cell" 4 3.461
When charging I monitored the voltages with my Fluke DVOM at the BMS terminals and Cell 2 hit 3.72V when the others were ~ 3.55ish then the BMS disconnected charging, so I assume it has a 3.75V disconnect. A little high but... yeah.
My DIY 48V 100ah 16 cell battery with an Overkill BMS always rests around 0.010mV.
Is there any way to properly balance these things or I'm I just going to have to charge the batteries to say 13.8 or so I can at least use most of their capacity?
Thanks for any help.
*very cheap - when I opened the cases I found that the "100ah cells" are made of 4, in series, sets of 5 20ah cells in parallel, so yeah.. you get what you pay for..