I forgot to add, do this measurement on a clear sky day at midday so you are measuring during max energy harvest
While you have these tradesmen on board, maybe ask them to measure the voltage drop between your solar panels & solar controller and controller and battery with a view to adding additional cable to allow you a/c to work during the middle of the day. I would also consider moving the solar controller to beside the battery to minimise voltage drop between the controller and battery ensuring you have the best charging voltage at the battery.
To measure the voltage drop add a loooong lead to one lead of your multimeter, [ thin speaker wire will do ] select DC volts on the meter [ 20v or higher ], connect one end to the battery positive and the other to the solar controller battery positive.
Then do the same on the battery negative and solar controller negative. Say 0.2 volts is ok 0.5v is too high on each lead. This is measuring the drop or loss in the cable and fuse
this is lost energy in the cable as heat and your battery will not be getting a full charge.
You don’t need to replace your existing cable, adding additional cable beside your existing cable is fine. I would ensure the cable is tinned copper for longevity, I smother any connections with vasaline.
Kind Regards Donald
You guys are freakin awesome. We love watching your videos and are soooooo jealous of the challenges you have to face as you live the life!