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Hi!
I have a Victron 150/45 MPPT with a 500w solar panel.
I am using 6mm2 cable as specified in the manual. That's suitable up to 50A.
The MPPT is 45A.
The fuse should be above normal current draw but below cable size - so between 45A and 50A!
What size fuse/breaker should I use? Or should I use bigger wire than the manual specifies so I can use a 50A fuse?
Thanks!
I'd like to put a 15A PV fuse with a disconnect switch between the MPPT and the solar panel. Another option would be a 15A DC rated circuit breaker. Please not the emphasis on DC rated, do not use AC circuit breakers for DC circuits.
Some say that if you only have one panel, or a single string, then you can get away without a fuse between the panel and the MPPT, but I like to think about fault currents running back towards the solar panel.
The fuse will not do much under normal circumstances, but if a fault occurs it's there to prevent a fire.
In the future, if you start paralleling a few strings together then you really need to have a 15A fuse for each string.
I know this is old but what WKirby is referring to here is 15A PV Fuse between the panel and the mppt.
Missy in your question you are referring to the 45A charging ability of the mppt to the battery. You should not be having a 15A fuse there.
@randomwalsh I believe you may have misunderstood the question - the OP was specifically asking about between the panel and the MPPT, not the MPPT and the battery - as evidenced by the title of the question. That the OP referred to the "45A" output of the controller rather than the actual PV input was likely the result of a misunderstanding of the way an MPPT works, as many people mistakenly think that you need to put 45A of current into a controller to get 45A of current out of the controller.
