backchannel: MPPT max output

I have 2x420w panels [on a 50A Victron MPPT]

I don’t think your MPPT will charge your batteries for 840w because it’s capped at 600 watts.

Close. The 50A cap is at actual bank voltage, not the chemistry’s nominal voltage. OP’s config shows 14.4Vabs so in theory they could see 720W out of the 50A controller. If the bank were pulled down to measured 12.0v then yes the controller would hit 50A at 600w.

But I suspect they are in northern Europe (Ireland) where the insolation is quite low.