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In a new project, the client wants to use PV panels that can be heated with "back current"(?) (german: Rückstrom) and actually the PV vendor allows up to 20A - per module.
Has anyone done this in the past, and what needs to be taken care of if the PV panels are on VIctron MPPTs (250/85)?
Yes, the reason is to melt snow. Main problem/issue is to make a circuit that will in such a case automatically detach the MPPT and limit the back current. But there are other issues as well:
What happens when the melting/sliding snow and sunshine cause the panels potentially delivering again while such backcurrent is applied?
A little bit more about the topic - unfortunately it still seems to be an exotic approach (German):
https://photovoltaikbuero.de/pv-know-how-blog/leise-rieselt-der-schnee/
There were some inverter-specific solutions more than 10 years ago like the "de-icing box".
https://photovoltaikbuero.de/wp-content/uploads/2010/01/SOLPLUS_Flyer_DE-ICING_DE.pdf
Seems like there is a reason not to have this anymore.
you could try reversing the connections ie the bat + and - to the Panels and the solar input to the power source + and - .
IMPORTANT limit the mppt current to under 20 amps otherwise you would get too higher a current back into the panels. If it was me i would start at say 5amp limit see how it goes.
I have no idea why you would want to do this unless it was to melt snow or ice off the panels
this may work. but its a total guess
Good Luck
