LFP LiFePo4 BMS, Batteries, etc Links

[senormechanico]

John is slippery, isn't he ?
I caught that bit of word smithing right off.

[CatNewBee]

Originally Posted by strongmonty

I was planning on making a 400AH bank using 8x200AH cells. One of the main reasons that I wanted to do this was so that I could, if there were ever a need (and as CatNewBee had suggested in one of their threads), remove half of the bank if something went wrong and still have a 12v system albeit with half of the available AH.
I was putting the order in with REC (side note: They haven't been great at answering my specific questions), and was planning on purchasing the REQ Q BMS 16s. They then told me that "this was suitable for 48V systems." This makes a lot of sense since it is called the "16S" duh! Still though, it seems insane that the unit would not be able to be wired for a 2P4S bank! Again, I feel like the person that I am dealing with over there is sort of "phoning it in" and not really answering my questions.

They suggested that I use the REC ACTIVE but of course that is made for only 4 cells.
Does anyone know if there is another way around this that could use a REC device (I really like what I do know about them) and still be able to do a 2P4S bank?

You will technically have only 4 cells, because you parallel them pairwise. The REC ABMS is the way to go...
You cannot monitor paralleled cells individually, it's the law of electricity, that the voltage is equal on all circuits on a parallel connection.

IF you want redundancy, you can built 2 strings of 4 cells each with its own ABMS and then parallel them with solenoids. Than you have 2 independent manageged LFP batteries. One drawback is, you cannot separate the charge bus and the load bus any more.

[rgleason]

SoggyPaws, Dave and Sherry installed LiFePo see their Electrical System for a very detailed and complete writeup of their system
S/V Soggy Paws - St. Francis 44 - Onboard Electrical Systems

Which uses

1. Battery Charging Philosophy
2. Electrodacus SBMS0 SoggyPaws Details ElectroDacus
3. RJ Lithium Batteries (8) 3.2v 271ah cells https://www.rj-lithium.com/sale-1154...ne-yachts.html
4. Trickle Charging Start Battery
5. Solar System

Their writeup has some excellent links and good explanations.