Join Date: Jun 2013
Location: Newfoundland, Canada
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Solar Panel Confusion
I have four panels on my Spirit 28, installed by the previous owner. Now that the boat is on the hard, it's time to take a look and see what the heck it's all about.
I have four batteries, tied together in two groups. Each group was two batteries, positive to positive, negative to negative.
one set are "car size" marine batteries marked 110ah. The other pair are "double size", with no indication of amp-hours.
The "car size" don't hold a charge, when I pulled them yesterday I discovered they are VERY low on fluid .
I never looked at the panels much, and wasn't even sure if they were putting anything out. I was busy enjoying my boat when I could, and fixing the big stuff (i.e. engine, sails, etc).
Here is my confusion, the four panels are paired. Each pair is connected to a small control box. Each control box connects in turn to one set of batteries. Those two control boxes are putting out 20v with 6.5-7 amps...... that seems like a lot. And, from what I have read 20v is way more than you want to use to charge a battery.
I would like to replace the control boxes with MPPT units. Do I need an MPPT unit for EACH panel/battery combination? Can I use one MPPT to run all four panels to all four batteries?
1979 Glastron Spirit 28, Hull #28.
Twenty years from now you will be more disappointed by the things you didn't do than by the ones you did. So throw off your bowlines. Sail away from safe harbor. Catch the trade winds in your sails. Explore, Dream, Discover.