I would pass on them. They require cooling and heating management. Using 18650 NCO cells is dangerous and require rigid thermal; management. EV guys will not even use them. As for discharge, AGM can go to 80% DOD. However you would never ever discharge lithium that deeply.
The other thing is Tesla uses NCO cells which only have 300 to 500 cycles. The reason Tesla warrants them the way they do is because they would never allow the customer to ever fully charge them up. That is how you can get greater cycle life.
Last is economics. You claim 24 volts @ 250 wh which is 6 Kwh of storage. In a solar application 2 Kwh usable per day, 5 Kwh total usable for 2 day run time without charging. $1400 / 6 Kwh = $230 per Kwh of storage. You can get a top of the line FLA Pb battery for $175/Kwh with a 10 year warranty. Same top of the line FLA Pb battery with 6 Kwh storage is going to cost $1100. The economics do not work and with used batteries you get squat for warranty.
The best and easiest EV batteries to work with is Nissan Leaf cells. Easy to disassemble and reconfigure using simple BMS techniques top the point you do not need a BMS. .
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Tesla battery pack?
I was poking around looking at different used/surplus batteries and came across listings for Tesla Model S battery modules, 24V, 250Ah. Since Li can be discharged a lot further than SLA/AGM would something like this be a good replacement for a 600 Ah AGM bank or could they be ran in parallel? Pricing was in the $1300 - $1400 neighborhood.
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