I'm asking here in case any of you can offer some insight,
I have 4 x 110AH 12v Leisure deep-cycle lead-acid batteries; wires in series and parallel to bring the array voltage to 24v.
I have 200w PV (2 panels in series), which feed into a 20A MPPT EPVER controller.
The controller is configured for "Flooded" battery type with a total capacity of 220aH The battery array wiring is as follows (pardon the terrible text representation of the wiring), each is 12v, lead-acid, deep-cycle/leisure battery
Key: +'ve |- X -| -'ve
| C -|
Additional details MPPT Solar feed is connected to the A (-'ve) and D (+'ve) Batteries These are matched vendor and model batteries, as such all should perform near identically; PV is two panels wired in series. 3KW Inverter is connected to the same terminals as the MPPT solar feed.
Issues observed For a few weeks, this has operated just fine, though it has been cloudy with little sun where I am; as the array is nearing 95-98% charge (as I've not been using the stored power due to the lack of sunlight) I'm starting to see some odd behaviour.
- When the MPPT feed is pushing ~4.5A the voltage across cells A and D can be read on a multimeter as 15.9v / 16v this appears to be too high.
- Batteries B and C read at 13.4v and 12.8v this too seems odd, as the wiring setup should be self-balancing.
- When MPPT is disconnected from the array by the isolator voltages return to be equal across each battery, as the batteries balance each other (13.2v) My current conclusion is there is that I am not connecting to the right terminals for a balanced charge, so my questions are as follows.
Is my wiring of the battery array the most efficient and correct, and if not what would be your recommendations on the wiring configuration?
Many thanks in advance.