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Solar system questions

Started by rocu, Aug 01, 2024, 10:05 PM

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rocu

I'm thinking about adding solar to my boat and I need some advice on hardware.

My goals are modest. I want to keep my 12v battery topped off during multi day sails. I use it for nav and cabin lights, an auto tiller and to charge phone and tablet.

At the dock or home on the trailer I want to be able to charge with AC power.

Is there a combo solar controller and AC battery charger? If not, how do I wire up a controller and a charger?

Any recommendations for specific equipment, how-to articles, websites or videos is greatly appreciated.

Spot

I have been running a 50w panel and basic charge controller on a lawn motor battery for a few years.
I am in the process of adding a bigger battery to have more reserve for running a small fishfinder/GPS/chart plotter and a fan for comfort at night.

Calculations show that I am about even between draw and replenish on solar alone. I do not have a shore power setup. I started with this Google sheet for a 'power budget' and customized it locally:

https://www.vanlifeoutfitters.com/sizing-your-electrical-system-load-calculations/

Here is the charging part of my schematic, of note is that the wires to and from the + on the battery are either fused or circuit breaker protected:



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Big dreams, small boats...

JerryC

Choose a solar charge controller that's sized for your PV module and for the battery. And get a separate plug-in charge controller. Connect both to the battery terminals in parallel. I have used Genasun GV-4s for smallish lead-acid batteries. Plug-and-play, and been running for years. The small Victron MPPTs are highly rated. Take a look at Will Prowse's website, https://diysolarforum.com/, you've haven't already found it...

rocu

Thanks Spot and JerryC for the helpful info.

JerryC

Small, lower-power modules for our boats can be hard to find...I needed one that was long and narrow and found it at Rich Solar. I was impressed with the quality build, and the packaging. I've gotten small modules, MPPT charge controllers, OCP devices, and cabling from Alt-E in Massachusetts. They've been around for a very long time, and they have a LOT of DIY information and videos on their website.

Another option to consider: I have "spring clamps" on my AC battery charger cables. Then I can completely disconnect the charger when the battery is charged up, and either stow the charger, or use it on another boat/battery. 

Noemi - Ensenada 20

"solar system" questions....I was thinking, man, he sails MUCH farther than I ever would....

Spot

Pluto is still a planet in my book!
;D
Big dreams, small boats...