Solar Off Grid. PV Solar Matched to Heating Element .
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Murphy's friend Guru Joined: 04/10/2019 Location: AustraliaPosts: 671
Posted: 08:31am 14 May 2023
Well, maybe. All thermostats are not created equal. If the contacts are slow to open or/and the opening distance is insufficient, it will create a DC arc when the contacts *open*.
Once the arc is established, 'off' time no longer plays any role as long as there is solar power and a load to feed it.
Hello Davo99, Yes, It was the Arduino board and the caps that I was referring to. I just wanted to get as close to what you used and any other unit you used.
JS.
phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 2620
Posted: 12:39pm 14 May 2023
I worded that poorly. I should have said the 'on' and 'off' times of the MOSFET. The MOSFET 'on' time needs to be short so that if the thermostat opens while it is on you want the MOSFET to switch off before the arc damages the contacts. The MOSFET 'off' time needs to be long enough to ensure the arc has extinguished and prevent the arc re-striking.
Having the thermostat switch the gate or gate power supply is the safer option.
Murphy's friend Guru Joined: 04/10/2019 Location: AustraliaPosts: 671