Lithium Vs. More Solar

Itinerant1 wrote:

BFL13 wrote:
"If you're thinking of adding 100ah batteries to larger ah capacity batteries your going to run into problems. Yes, they are the same voltages but the lower capacity batteries will shutdown before the larger capacity batteries. The bms's could be setup differently protecting the cells of the different packs. Stay with the same ah capacity battery"

Please explain. I asked about this earlier in this thread, but no answer.

No problem with FLAs so why with Li is the question. (FLAs do not "shut down" eg.) Is it because of BMS? Is the BMS in the same brand 200 different from the BMS in their 100, so they shut down at different times?

If so, why pick the 100 to shut down first? What does capacity have to do with it, when it has no effect with FLAs?

Just like to know and maybe others do too. Thanks.

If using say a 100ah and a 125ah lfp probably no problem.
But...
Using a 250ah and a 100ah the bms's aren't that smart to know to use the 150ah first from the larger bank. So the individual cell voltages with in the dropin battery will diverge from each other as the capacity get sucked from them. As the 100ah drops in capacity so does the cell voltage, which in turn should shut one battery down early. Or charging which obviously the smaller will fill first, once again triggering a shutdown and if for some reason it didn't shutdown good chance there will be some puffy cells at the very least. ;)

You appear not to understand that they rise and fall together per their SOCs. If there is a 100 and 200, and a 60 amp draw, it will be 20 from the 100 and 40 from the 200. (the 200 has half the R compared with the 100 and V=IR, so I is twice with the 200 to keep V the same)

They will each reach 50% SOC at the same time, and when recharged, they will reach full at the same time. They are at the same voltage in parallel, and each has the same voltage/SOC.