I am curious - the PV is showing -1W - can anyone explain why this would be - or is this nothing to be concerned about ?
You know what curiosity did to the cat? :)
It's likely just an addition error with your 4x mppts. Nothing to be concerned about. 1W isn't much energy anyway.
But you raise a related point, visible on your very screenpic (watch it working for a while). The battery Amps indicate accuracy to 2 decimal points, but the second is always zero. And on a 48V system the result is 5W steps. I can live with that.
The DCPower is a calculated figure, and does much the same. Except instead of a zero it sometimes shows a 1 or a 9, or less frequently a 2 or an 8. So it's actually highlighting it's own calculation errors rather than providing an accurate A.
Pedantic it is, but VRM shouldn't be showing A to 2 dec places here, as it implies an accuracy that doesn't exist. The A in the mppt box might be reporting a best-effort 2-dec-place, but that might be fair enough with the new high V mppts.
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