J
janliber
I am developing a prototype garden workshop design that has an off-grid power supply. The current setup is 300Wp PV, MPPT charge controller with 20A rated discharge current, 266Ah (C100) deep cycle battery and a 3000W (6000W peak) modified sine wave DC 12V to AC 220V inverter. This setup happily provides power for all my tools including a 2.4kW chainsaw. However, it fails 2 crucial tests - the boil-a-kettle test and the mow-the-lawn test. The kettle is 3kW and when that is switched on the controller starts screaming and cuts the power off. The mower is a 1.8kW Bosch mower and that only works when the sun is shining brightly, and only if I keep it running. When I switch it off to empty the grass box, it tries to restart (it revs slowly but can't get up to full speed) and I have to leave it for about 30 minutes before it will go again (if the sun is still shining brightly). In overcast weather, it won't go at all. So I think the reason it works when the sun is out is because the panels are supplying the battery at 12V and constant voltage and thus keeping the the whole system voltage fairly steady at 12V. I don't think that the charge controller is switching the circuit off, rather that the inverter is cutting out because of the low voltage.
How do I fix this? A second battery to provide 24V to an uprated inverter? An uprated inverter on its own? What else….?
How do I fix this? A second battery to provide 24V to an uprated inverter? An uprated inverter on its own? What else….?