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kiko asked

How to wire 3 360Wp Panels to ca SmartSolar MPPT 100/50


I have the following setup for my expedition vehicle:

The 3 panels in parallel will produce a max. current of 30A to my understanding. With a cable length of roughly 10m (5m one way), I would have to use a 16mm2. This is also the maximum the clamps on the device can handle.

My first question is how to connect the MC4 ports of the panels to the controller. Using those 3to1 MC4 bundlers and going on with a MC4 cable will not work, as I can only find solar cables up to 6mm2. Should I use 3 cable pairs in paralell right to the MPPT or bundle near the panels? Which type of string box etc. would you use? Would it be correct to use a 10A fuses on the single connections / 30A fuses on the bundled connection?

My second question is: Is it ok to als use two 1m 16mm2 with a 60A fuse to connect the MPPT to the + and - distributions?


For reference, last row:

MPPT ControllersSolar Panelwiringfuses
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1 Answer
wkirby avatar image
wkirby answered ·

I like to use a 15A 1000V PV rated fuse for each string. In your case, each panel is a string as you have all three in parallel. A 15A fuse would be fine in your case. If one panel fails and the other two try to dump 20A into it, a 15A PV fuse would protect it.
10A fuse should do the job in theory, but it could fail in a cloud edge event when your panels could make 400W each.
Use a combiner box, buy or build one. Feed all of your PV cables in, connect to the fuse holders and then a bus bar after that to have the 16mm cables come out to the MPPT.
I once built a combiner box with panel mounted MC4 connectors underneath to make the PV connections easier.

A 60A fuse for the MPPT to DC bus cables will be about the maximum to go. Probably a good choice sine the controller can output 50A continuously on a good day.

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Related Resources

MPPT Product Page

MPPT Error codes

MPPT 150/60 up to 250/70 Manual

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