Probably safe to step down to 8 awg or probably better to rewire from busbar to final mc4 connectors with 8 awg rather than the installed 7 awg ? My panel setup is 4 x 100 watt ... through the separate , independent fuses on each string in the box . to combine on the bus bar ... parallel ?
yes , i understand , but my concern is will using 8 awg from the combiner box to the charge controller ( as per CC makers specs ) will this short run of 8 awg get hot to the point of dangerous as it is smaller than the 7 awg within the box ?
So what's the input voltage range and current rating of your charge controller?
So 100 volt input, 50 amps into 12 volt battery, MPPT range Vbatt+5 thru 100V, panel current under 60 amps. 4P makes me nervous, Isc could exceed 60A, which destroys the SCC. 4S should work unless it gets cold enough to exceed 100Voc. That leaves 2P2S for 40-ish volts and Isc under 34A. 8ga wire is good to at least 40A, and you are only going a few feet, so that shouldn't be a problem.
Now I am even more concerned , I understand the method 2S-2P however if I go that way how should I run the panel cables through my combiner box ? Should I simply run the lot through one of the four fuses ( currently at 15 amp each , as purchased ) and up that fuse to a higher rating , such as ??? ... then onto the charger with 8 awg ....???
How do you know your panels are wrong? What do the stickers on them say? What measurements have you taken in full sun with the panels perpendicular to the incoming sunlight?
the panel info is as above in this thread & yes I bought bits without too much foresight & now trying to get it to work , haven't done a full sun test yet coz of weather etc but hoping to in very near future ... as it is some shade in the morning will affect final output but once this drama is sorted maybe more panels ( & separate system ) elsewhere ... I'm not expecting a million watts to flow but trying to gain something stand-alone that works & is safe ... I appreciate all help provided as I am no rocket scientist and approaching 74 years , so everything is a challenge , but worthy the journey ... We are in southern Australia , it is now 3:30 am ... bed time but back here tomorrow ... top forum ... top members ... thanks ...
That depends on how many amps are running through it.
So your panels are fine.
There’s a circuit breaker AND a fuse (or two) in the combiner box, why would you add more?
Amps times volts is watts. Imp times Vmp is panel power.
