MWeiss
New Member
- Joined
- Apr 22, 2020
- Messages
- 73
MichaelK, yes, some of the numbers don't add up. But I find that's pretty common with web sites and spec sheets as the persons entering the data sometimes make errors.
I've never seen more than about 41% of rated capacity out of these panels so far. I've been watching them since late April and the highest output I've seen is 2.71kW from the east facing array, just a few minutes to noon. South array, 2.41kW. What I'm finding is that I need a LOT more than forty panels to power our baseline loads. I've had to shut down my graphics workstation last night (saves idle 400w) and stop using the AC and day over day, the average battery charge left is decreasing by about 20% a day. I had to fire up the generator for an hour this morning to put some charge back into the batteries.iamrich, the question that bugs me is when you have two arrays, one in shade and the other in sun, connected together into the same MPPT, is there a drastic loss of efficiency? I would think having dedicated MPPT for each array would allow getting the most out of the array that's shaded. But I won't know until I try. I'm not getting anywhere near 9600W out of this system. Not even close. Not even half that. I would expect close to 160 amps combined from both arrays, but I see 30-40 from one and low 30s from the other at noon.
The other oddity is that the three BMS's don't balance the charge across all three battery banks. Always the case is that the bank with the lowest charge (bank 3) is always being discharged, while the high charge banks are receiving charge. So bank 3 always goes toward zero while the other two are charging during the day or less rapidly discharging at night. Even after selectively charging bank 3 to 100% yesterday, it is now down to 53% while the other two are at 72%. If all the banks are in parallel, they should all be the same charge level!