Our battery pack has the 6-pack cells in plastic trays, and there is a plastic strap around each 6-pack holding it to the tray, does that mean I have a proto-type pack?
I finally got a lithium iron phosphate charger (from PowerStream Technologies:
http://www.powerstream.com/lifepo4-chargers-1-cell-wallmount.htm) and began charging today.
The bad 6-pack was below the BMS module. I took out the eight screws that hold the BMS module plate to the battery tray and had to clip two plastic wire ties (installed for wire management) to allow me to raise they entire tray and give me access to the cells below. I did not have to disconnect any of the connectors to the BMS modules.
This is what my trouble tray cells looked like:
6-pack #1 - between yellow wire and lug (blue BMS wire) - 3.34V
6-pack #2 - between yellow wire and and green wire - 3.34V
6-pack #3 - between orange wire and and yellow wire - 3.34V
6-pack #4 - between red wire and orange wire - .11V (now up to 1.47V, woo-hoo!!!!)
6-pack #5 - between lug (brown BMS wire) and red wire - 3.34V
total = 13.47V (now up to 14.83v)
I am pondering just soldering a wire into the orange and red BMS wires (basically the wires on end of the 6 pack) and running them to the outside of the battery. It also look like I may be able to simply additional another wire via a connector already in each 6-pack, but not used.... will post a picture if I can do this as I prefer not cutting and soldering any wires used by the BMS. I am thinking this will allow me to manually monitor the one questionable 6-pack, and if it looks to be dropping, I'll pull the battery disconnect and charge that one cell without having to drop the battery. Any reason I SHOULD NOT do this?
I checked all the 6-packs I could access (77), only one other was slightly low at 2.91 V (will charge that one after doing the one that was really low), all the others were 3.34V
The trays all read either 16.7V (smaller trays made up of 5 groups of 6-packs, 5 x 3.34V=16.7V), or 19.9 - 20.0V (larger trays made up of 6 groups of 6-packs, 6 x 3.34V = 20.04V).
The two low trays were low by exactly the amount of the two low 6-packs. One read 19.6V (should have been 20V), the other 13.4V (should have been 16.7V) This indicates to me I only have two 6-pack issues.
So for me at least, it looks like a couple of trouble 6-packs, all others look good.