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cadams avatar image
cadams asked

Low solar wattage..Batteries not charging.

Just installed my solar system for my electric boat.

(4) 100w panels in series.

(4) 12v 100a gel batteries in series. 48v system.

Victron mppt 100/20 48v controller.

Having trouble getting significant wattage from the panels to my controller according to the phone app. Sunny sky all day long today. The little bridge pin was in for awhile but I took it out a few hours ago.

The highest wattage was like 12w, Most of the time it’s been 2-3 watts.

Minnkota display says batteries are 1/2 charged. No change all day.

Everything is connected properly, including ground.

Looking for answers on why this is happening.


smart solar set-up help
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5 Answers
Matthias Lange - DE avatar image
Matthias Lange - DE answered ·

Did you checked the fuses between the MPPT and the battery?
Also the fuse directly at the MPPT next to the connection terminals?

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cadams avatar image
cadams answered ·

The fuse in the controller was blown. Tried to put a new one in and it almost blew out of my hand. Big spark!

Does that mean my connections are wrong or do I need to disengage part of the system before putting in a new fuse?

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cadams answered ·

I think I know now when the fuses blow. When I turn on the battery on/off switch (see pic) which is part of this minnkota 48v system I heard a pop. I had this on previously when I tried to put the first new fuse in the controller.

So something is making the system overload when I introduce the batteries to the system.

The battery system works just fine otherwise without the solar components.

Any thoughts?

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cadams avatar image
cadams answered ·

Forgot to show the battery of/of controller.


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cadams answered ·

This may sound like a silly question but I’m out of options. On my controller there are 6 ports.
battery, pv and load. I put the battery terminals on battery 1 (pos) and 4 (neg) in the positive and neg battery ports. Should I put them in the load ports instead?
Im just wanting to recharge my batteries using the solar panels.

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