Best way to connect a solar charger to 2 battery system?

Jul 2, 2018
48
Catalina 22 Acton Lake, OH
I have an '87 Catalina 22 with 2 identical, new deep cycle batteries in parallel (a jumper between the negative terminals), a selector switch with 3 positions (bat 1, bat 2, or both) and an outboard that has no alternator. I want to connect a solar trickle charger so it recharges both batteries simultaneously, but I am unsure how to connect the solar charger. I am also unsure as to whether i need some sort of regulator to monitor the charging.

Since I don't need to reserve power to start an engine, I intend to run both batteries so they will have the same state of charge, making their charging requirements symmetrical.

So, does anyone know how to set this up? Thanks!
 
Mar 26, 2011
3,399
Corsair F-24 MK I Deale, MD
Just leave the switch on "both" (or off when you leave).

You did not give the panel size or battery size and type. I'll guess about 50W and perhaps 2 group 24 LA. You will need a controller (about $25 on Amazon). Make sure the controler input matches up with the charger (amps and OC voltage, which is probably about 19-21V, normal for "12V" panels).

The controller output wires go direct to the battery studs, with a fuse right next to the battery (not at the charger). Very important--panels can short out. Controlers do not wire through the panel or through the switch.

I suggest reading up a good bit on boat wiring. There are many possible safety errors. Get a book and read it cover-to-cover.

This describes a very simple installation. I've done FAR more complex ones.
http://sail-delmarva.blogspot.com/2017/10/super-simple-solar.html
 
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Jul 2, 2018
48
Catalina 22 Acton Lake, OH
I was considering this kit https://www.amazon.com/dp/B00JML98BK/ref=twister_B00ZYD12UA?_encoding=UTF8&psc=1 . My boat will be sitting in its sun-drenched slip for probably 4-5 days for every one that we're out, and the only loads will be a stereo and maybe running or anchor lights occasionally. I may weekend on it once in a while. I have two type 27 deep cycle batteries, so I assume the 30 watt panel should be up to the task of recharging them. So attaching the charging leads to the positive of one battery and the negative of the other will charge both when the switch is set to "both". Is that correct?
 

jviss

.
Feb 5, 2004
6,745
Tartan 3800 20 Westport, MA
Hi there,

First, I think two 27's is overkill for a C22 that isn't "cruising." Do you have a fridge? Lots of electronics? Maybe incandescent bulbs?

Second, a 30W panel will take forever to recharge a 2x27D bank - assuming the batts are 100Ah each. If you get down to 50% somehow, it might take a week or more (just guessing).

What kind of loads do you have?