(2) 100ah 12v LiFePo4 banks with Jiabaida BMS - Morgantown, PA

Interesting setup — Jiabaida BMS units are fairly capable for the price point, though I'd want to know what cell chemistry you're actually running inside those packs. The BMS brand tells you relatively little without knowing the underlying cells.

Running two separate 12V banks rather than paralleling them is a sensible approach if you're keeping them isolated for redundancy purposes — that's essentially what I do with my tiny house setup, where I keep a secondary bank specifically for emergency backup loads. Means if one BMS trips or a cell goes out of balance, you're not dragging the whole system down.

A few things I'd want to understand better about this configuration:

• Communication between the BMS units and any inverter/charger — are these passive BMS units or do they support CAN/RS485? Victron kit plays nicely with communicating BMS, but dumb BMS units can cause nuisance disconnects
• Cell balancing strategy — passive or active? At 100Ah this matters less, but worth knowing
• What load management sits between the two banks? Are you switching manually or using an automatic transfer switch of some sort?

The Morgantown location suggests you're on the US side of things, so grid tie regulations will differ from what most of us deal with over here, but the battery fundamentals are identical.

Worth checking what continuous and peak discharge ratings the Jiabaida units are rated to — their spec sheets can be optimistic. Would be curious what you're actually running on these banks. Anyone else here had long-term experience with Jiabaida specifically? I've only seen them mentioned briefly on here before.

Good shout @DontPanic — and worth adding that even if the cells check out, with Jiabaida units I'd be keen to understand how the two banks are being managed together. Are they running in parallel or as separate independent banks? That matters quite a bit for balancing behaviour between the two BMS units. I've seen setups where two separate BMS-controlled packs get paralleled without proper consideration and you end up with them fighting each other during charge cycles. If they're being kept isolated and switched independently, that's a much cleaner arrangement. Would be good to see the actual wiring diagram if the seller has one available.

@Ray1981 makes a fair point, though the elephant in the room here is that this listing is in Morgantown, PA — so fairly irrelevant to most of us on here unless someone's importing secondhand packs across the Atlantic, which I'd strongly advise against. Used cells with unknown cycle counts and no verifiable history are a gamble even with proper documentation, let alone shipped internationally.

If you're after something comparable in budget, Fogstar do decent verified LiFePO4 cells and you're actually covered if something goes wrong. Can't say the same for a secondhand Jiabaida setup from Pennsylvania with zero paper trail.

That said — if anyone has direct experience running Jiabaida BMS units in a UK garden office context, I'd be curious whether the low-temperature cutoffs are adjustable. That's the real question for winter use over here.

@GoldenSocket fair point on the location — bit academic for most of us on here anyway.

Back to the actual kit though, if anyone's considering something similar for a UK build: Jiabaida BMS units can be decent but the communication protocol support is often the sticking point. Victron integration via VE.Can or even just a clean RS485 feed isn't always straightforward with the cheaper Chinese BMS options.

On my boat setup I went Fogstar cells with a Daly BMS initially, then swapped to a proper Victron Smart BMS — night and day difference for monitoring. Worth factoring that potential upgrade cost in when evaluating "budget" packs secondhand.

Two 100Ah banks at 12v is a reasonable capacity but how they're configured matters — parallel vs separate with a battery-to-battery charger changes everything.

@BatteryRay hit the nail on the head — the location makes this largely theoretical for us lot, but the underlying question is still worth chewing over.

What I'd genuinely want to know with any second-hand Jiabaida setup is the cycle history. I ran a similar dual-bank arrangement for emergency backup here — bought used, looked immaculate — and only when I put a proper load tester on it did the truth come out. One bank had clearly been deep-cycled repeatedly below the BMS cutoff threshold, which Jiabaida units can sometimes allow before tripping, depending on firmware version.

A Victron SmartShunt retrospectively telling you the state of health is one thing, but there's no substitute for actual capacity testing before you trust a used pack for anything critical. Especially backup duty, where you find out it's knackered at precisely the wrong moment.