MPPT 75/10 control, 100 W panel, full noon sun, only 8 W in mode. 20.5 panel V ,0.4 panel A, 13.7 bat V. Is that normal?
Getting 50-98W midday other times in Bulk mode.
thanks
asked
Very low W at noon sun in float mode OK?
@Ted Burke, if your vbatt is 13.7 then the bank is full and won't accept any more (significant) charge current, so the controller won't be pulling power from your panels. All looks well from your description.
Thanks for a clear response.
I’m new to this and I just assumed the solar panels were always PUSHING out the maximum power in watts and the controller changed the form of that power that went to the battery appropriate for the charging phase. I can see from your explanation that the controller is PULLING into the controller only what the battery needs from the panel , not its maximum wattage on a full sun noon. Did I get that right?
Hi @Ted Burke, yes that's (basically) correct: as soon as there's light hitting the panels, they're producing voltage, but no real current until the controller puts a load on them, which drags down voltage and pushes up current which it then flips to low-voltage high-current to charge your battery... if your battery is already full though, there's nowhere for the controller to send current so it won't try to load down the panels.
One way to test this is, under similar conditions as you describe above with the controller only pulling a few watts from the panels, try putting a load on the battery bank (inverter, something like that) and watch your panel production jump up because the controller has somewhere to send current now.
