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To answer your first question, @otr_320, these LiFePo4 batteries do charge just the same way as all other LiFePo4 batteries.  They accept a constant current up to 200A as the cell voltage steadily increases.  When the battery voltage rises above about 14.1 Volts, the charge current drops to zero over about a 90 second period as the battery voltage rises to the charging voltage of 14.6V.

    

Correct me if I am wrong, but isn't this rather fast?

It seems to me that what is different is that these batteries have a novel BMS.  It seemed weird initially, but now I believe that it is just a new and different way of managing batteries.  It seems that these are, maybe, 450Ah batteries and LiTime restricts the full charge (as well as full discharge) in order to extend the battery life.  That explains why they charge so fast:  Almost all the charge cycle is done in Bulk mode, once they enter absorption mode, the BMS relatively quickly shuts down further charging.  This charging shut down has an unfortunate consequence in that the batteries do not show their full voltage until you discharge them a bit and disable the full-charge detection.

I think the 3rd paragraph of my original post explains why the batteries might function in a previously-unexpected manner when paralleled.

I no longer consider the operation of these batteries weird, now that I think I understand them.  Let's start calling the behavior novel.

2nd battery came in at 228.4Ah.  Both batteries exhibited weird voltage readings at one time or another.

I suspect I might get somewhat higher Ah output if I charged the batteries sufficiently slowly.  LiTime says they only have 35mA of balancing current, so when charging at 120A that won't correct much of an imbalance.  When topping up with solar panels at a few Amps, the batteries would stand a better chance of getting fully balanced.

In conclusion, the LiTime 230Ah batteries seem to be a pretty good choice in the bargain Lithium market.

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