DIM (did it myself) battery

TacomaJoe

Solar Enthusiast
Joined
Dec 8, 2021
Messages
68
After a recent purchase of a pile of parts from a fellow DIY'r I started the battery building process. The 8 Ganfeng 277Ah cells were grouped into two sets of 4. I did an initial 4S set with me as the BMS charging at 14.2V (caution if you are a BMS, pay attention). When the pack approached a full charge, I switched it to 4P and hit it with 3.65V (5A supply takes a while). After days of monitoring and sneaking the cell voltage up to 3.65V, I left them 4P and put a headlamp load to slowly drain the charge down.

Very pleased with the results so far. Set them up to 4S, wired in the JBD BMS, dragged them into my trailer for a discharge test on my 600W inverter. They went from 277Ah to 2Ah and the cell delta stayed within 10mV. I need some cables to complete the install into the boxes from Solar Supply House and looking forward to upgrading the trailer battery capacity.

For the thrill seekers, I'm sad to report that this process has gone smoothly (nothing better than following instructions) didn't hook anything backwards or drop any tools on the pack.
 

toms

Photon Sorcerer
Joined
Jul 24, 2020
Messages
1,111
We need pictures - how is the internet supposed to point out all the trivial errors in your setup if you don’t give us pictures 🤣
 

TacomaJoe

Solar Enthusiast
Joined
Dec 8, 2021
Messages
68
Here's my cell.IMG_0735.JPG

The charge/drain setup. The jumpers are long enough to make diagonal jumps so I could make a 4P out of a 4S without moving cells. In this case I have one 4P charging and one 4P with a headlight load on it.IMG_0766.JPG

My jury rig wire job to discharge during the last trailer trip. Threw everything in a box for 4S. The leads were different lengths tying the two 4S together and to my trailer inverter. I noted that charge and discharge rates were affected by the wire difference but it was temporary.IMG_0698.JPG

My bloat test is to lay a cell on a flat surface and give a finger poke to the four corners and look for movement. I had two cells with a small amount of wiggle.IMG_0764.JPG

Setting another cell on top would eliminate the wiggle so I don't think I would call that bloat.IMG_0765.JPG

My original battery, put together a year ago didn't have a case. I just had the BMS taped to one side and a panel with the shunt and ANL fuse taped to the other. I dropped the old FLA onto the trailer and am putting the pieces in a case to give me 3 matched batteries when done.IMG_0767.JPG

Heading out again tomorrow so I won't make much progress. Need to get some wire connections made up for inside the case.
 
Top