Larger Princeton (Tesla 6S higher AH units encased in steel boxes)

[ramseyjack]

I have come across 32, pretty much dead (below 1.2v, many at .101V) Princeton GTB-30 battery packs. (I know this is training, not any expectation). A couple of them were at 21.39v so I have been very careful at charging them SLOWLY with less than 4 amps and up to only 23.3v. Did get around 2-3KW out of them (SLOWLY discharging at 13amps before the 19V cutoff).

1 produced 250W, 2@ 2KW, and 1 @3KW before the 19.2 cutoffs. (see attached Cerbo GX logs)

Obviously, this is just a training exercise for myself and my technical staff, Have been installing off-grid and all kinds of solar the last 17 yrs, and prismatic cells make so much more sense than these, but I was thinking of using the few good ones for TOU arbitrage (SCE 4-8pm electricity is .56 per KW) example-test bench. Have been doing arbitrage with Solaredege for years, but trying to get everyone on my staff to think batteries.

Been using Hanmatek DC power supply so far, but time-consuming. I know I can use a Victron MPPT DC charge controller to keep the voltages below their dangerous 25V, and my Victron Blue Smart IP67 (AC) won't go below 25.6V (OOPS)

So does anyone know of a reasonable charger that I can program to the 24.4V and 24v float that is AC?

Thanks !!!


Jack Ramsey

 

[ramseyjack]

Well, no replies so I have moved forward. Hopefully, someone can help me on the next phase.

I ordered another Sol-Ark 12K with a DC battery voltage range of 43-63V and will try 2 scenarios:
1. 2 tesla 21.6V (43.2V) packs in series, and then probably 3 of the 2packs in parallel (7.2 volt upper range usable) 50-100 SOC
or:
2. 3 tesla 21.6v (64.8) packs in series and 2 of the 3 packs in parallel. (9v lower range usable) 0-48 SOC

This is for TOU arbitrage to offset 4-8pm expensive SCE electrical usage. (15KW of solar been there since 2008)

The question I have is there a practical BMS for these 2 scenarios we have a 12s or 18S choice or do I do an individual 6S on each Tesla battery and series them up?

Thanks!

Jack