hedgehog911
New Member
- Joined
- Oct 5, 2021
- Messages
- 3
My first time building a pack, but after reading here for weeks. I've got a really odd problem....
So this is a 16 cell 48V unit. I top balanced all the cells by connecting all in parallel and charging at 3.65V until current dropped to zero. This looks weeks and weeks! Then I assembled into the pack as shown (sorry for the messy balance leads)…
I connected the Overkill 100A 16S 48V BMS, and then completed the -ve connection to a Victron Multiplus-II GX 48V 5000VA. I got a spark on connecting the -ve, suggesting the capacitors in the Victron were drawing current. However the Victron didn’t appear to switch on.
I then logged into the BMS using the Android software, and found that the 5 cells nearest the -ve end of the pack are showing higher voltages than I’d expect...
Somewhat alarmed, I’ve disconnected the pack by taking out the link between cells 8 and 9 (top of my picture above) which I assume must stop all current flowing.
I’ve checked the voltages with a Fluke multimeter, and this confirms that same as shown on the BMS above.... that the 5 cells nearest the -ve connection of the pack appear to be much higher voltage than I’d expect from a resting battery.
I don’t really want to reconnect anything until I understand what’s going on. Has anyone experienced anything like this?
Dave
PS - I can still connect to the BMS at the moment, even though the battery has that link taken out and so is reading 0V. How can this be?
So this is a 16 cell 48V unit. I top balanced all the cells by connecting all in parallel and charging at 3.65V until current dropped to zero. This looks weeks and weeks! Then I assembled into the pack as shown (sorry for the messy balance leads)…
I connected the Overkill 100A 16S 48V BMS, and then completed the -ve connection to a Victron Multiplus-II GX 48V 5000VA. I got a spark on connecting the -ve, suggesting the capacitors in the Victron were drawing current. However the Victron didn’t appear to switch on.
I then logged into the BMS using the Android software, and found that the 5 cells nearest the -ve end of the pack are showing higher voltages than I’d expect...
Somewhat alarmed, I’ve disconnected the pack by taking out the link between cells 8 and 9 (top of my picture above) which I assume must stop all current flowing.
I’ve checked the voltages with a Fluke multimeter, and this confirms that same as shown on the BMS above.... that the 5 cells nearest the -ve connection of the pack appear to be much higher voltage than I’d expect from a resting battery.
I don’t really want to reconnect anything until I understand what’s going on. Has anyone experienced anything like this?
Dave
PS - I can still connect to the BMS at the moment, even though the battery has that link taken out and so is reading 0V. How can this be?