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Got a bit more work done yesterday. The enclosure housing the BMS system was way too big to fit in the compartment so I took everything out of it and mounted just the control board in a small plastic enclosure. The contactor which shuts off the batteries if they reach a high voltage of about 15 volts or low voltage of 11.2 I mounted on the wall so the positive wire from the batteries will connect to that. Then I mounted a piece of aluminum angle to the floor of the compartment to mount the BMS switch, reset button, and alarm buzzer. The buzzer will alarm at about 1/2 volt before the BMS shuts down the battery. I also ordered a Victron BMV-600S battery monitor to mount on the panel above the microwave. This will give me a state of charge of the batteries and I'll have an alarm beeper on it set a couple tenths of a volt higher than the BMS buzzer. My plans are to charge the batteries then leave the charger off. Then monitor the Victron and charge when that beeper comes on only charging until it switches to float the shut it off. This is the preferred usage profile that the live aboard boat guys are using and seems to work good for them. I figure my battery usage will be similar. It seems there is no need to float charge lithiums. And there is no need to fully charge them. You can partially charge them with no problem. So it'll take a bit of an adjustment but should be easier to maintain these.
I mounted 2x2" heavy aluminum angle to the floor and the batteries will sit in this square. I also have 2 pieces of 1/8" aluminum sheet cut out for the battery sides. I'll use 5/16" threaded rods to attach these. This will hold the 4 cells securely. 400# of batteries should not move. Considering Newell doesn't use tie-downs for the 8D's this should work.
I got the aluminum at a small shop that builds crawfishing boats. He had some drop-offs that I got for $20. Yeah, yeah, I know Tom would have only paid $18. I'm cheap but don't squeak quite as much as him
I am also balancing the cells. I need to get each cell voltage as close to each other as possible. They range from 3.446 to 3.481 so my choices are to either buy a voltage adjustable charger to bring the low cells up to 3.481 or use a resistor to bring the high cells down to 3.446. So being cheap, I took an old spotlight and connected it to each cell while I monitor the voltage. It's working great.
That's all for today, and probably this week. Got a few other things planned.