Hello,
I’ve read the manual carefully and I couldn’t find answer to this question:
If the MAX amps send to battery are 20, can the load output provide 5 additional amps from the solar array during the day? Reason I think this might be possible is it says the PV can be higher output:
“1a) The solar charger will limit input power if more PV power is connected.”
If I am reading this correctly for 24v sustem, solar array can be 100Vocc and 20Isc, so that is north of 1500watt. But at the same time, it says for 24v nominal PV power is 580w
The measuring I did with clamp current meter also don’t seem to match what the VC BT app reports for battery current and load.
Note: I can’t reach the 20amp limit yet, but I am looking into adding more PV and load. My current loads are about 3 amps.
So how is this Load output internally connected and controlled?
The load output is fed from either the battery or the MPPT converter. The MPPT converter is limited to the device rating, in your case 20A. If the MPPT is charging the battery with 20A with no load, then you turn on a 5A load, the battery will now charge with 15A because the MPPT can deliver a max of 20A TOTAL to load and battery.
Thanks.
Any idea about the overpowering? Manual says PV voltage open circuit not to exceed 100v, Isc not to exceed 20amp. So if I have 48v panels with says 18amp Isc, that is close to 900watts. Will the controller be ok with the extra power (volts)? I know I will be wasting some solar energy, but issues is with cloudy and winter days.
The controller will just limit the throughput if there is too much solar power by forcing the panel voltage higher than Vmp to reduce current below Imp. Typically over panelling is around 30% but that is an economic rule of thumb, higher is allowed as long as you do not exceed max Voc or Isc. Your max 900W example will be OK.