Solar battery charger for my CD25,

[Will J]

Hello all,
What do recommend as far as size, amps, where to buy a solar charging mat to plug into the battery to keep it changed while at my mooring? Is there a good place to get this solar mat that’s reasonably priced? I’m new to this as my old boat required no battery.

Thank you for your help.
Will

[mgphl52]

Will,
You can find a lot of info here using the search feature.
Another great location is https://marinehowto.com/
which used to be on Pbase.com as "mainecruising"

[Carl Thunberg]

I have little expertise in solar battery charging systems, but I know there are no simple answers. It all starts with an inventory of your power consumption needs, and battery type. The stock CD25 is a simple boat with interior lights and navigation lights. Do you have an electronic bilge pump? Do you have a chartplotter? Do you have sailing instruments, sound system, or other power requirements?

For what it's worth, my boat is very similar to a stock CD25. I have interior and navigation lights, and a small chartplotter with depth sounder. I almost never use the interior lights, opting instead for a battery-powered lantern. I have the smallest AGM battery I could find, and a 0.5 amp solar charger with no controller. On a typical day sail, the only electronic device is the chartplotter. I check the voltage on the battery regularly, and it reads 13V every time. If I go out for several days, the solar charger doesn't quite keep up. This system works for me because I know how I use my boat, and I check it regularly with a multi-meter. If I kill my battery prematurely, that's a price I'm willing to pay for the trade-off in simplicity. I'm not advocating this approach for everyone, but it works for me. I would never have taken this approach on my former CD30. It only works because it's a small, uncomplicated boat.

[barfwinkle]

Hello Will J

I had a solar panel onboard Rhapsody. Using the boat on the weekends I used a 5 watt panel and a Morningstar SunSaver 10 Charge Controller. I had lights, VHF, Garmin 441S, & Autohelm TP-2000. That little panel never failed to have a fully charged battery when I arrived at the boat for the weekend and I anchored out a lot (anchor light was an LED light with very low draw).

A fairly simple setup. I used a "RAM" mount on the stearn rail for the panel and the controller was in the port locker. The SunSaver finally gave up the ghost (this spring) but it worked fine for 15 or so years. I still use the panel at my off grid cabin with great success.

Fair winds

[Will J]

Very good information regarding the solar battery charger. As for now, all I have are running lights and interior cabin lights. I will look into my solar panel options. Thank you all!

[sloopjohnl]

i have been using a 5 watt panel from Northern tools to maintain a group 27 automotive battery in my Typhoon for five years now with same battery. running lights, anchor light, interior light and bilge pump are the boats only draws. i believe they are about $50 with alligator clips included. it rests in the corner of the port cockpit seat when i am absent and although not the best location for sun exposure it is relatively out of sight and still does the job.

[mgphl52]

Very good information regarding the solar battery charger. As for now, all I have are running lights and interior cabin lights. I will look into my solar panel options. Thank you all!

Using LEDs every where possible/affordable will also greatly lessen battery draw, but I'm sure you already know that!

[Will J]

Ok, great! Northern tool! I’ll look at that. That’s what I was hoping. Something that works well and is not in the way. I just have one car battery(?) in the port sail locker to keep charged. I’m glad to know the alligator clips come with it. I’ll look at getting one today. I’m guessing Northern tool has a website. Thank you much for your information! -Will

[Steve Laume]

So if you are using alligator clips, then the battery terminals are exposed all of the time?

Those might be fine for a cabin in the woods but I would cut them off and crimp on a proper terminal for a boat. Wing nuts are not even recommended for battery terminals but would be a major step up and you could put a cover on the battery.

There is a lot of energy stored in your battery, that you don't want getting loose on you, Steve.

[sloopjohnl]

i agree Steve on a more permanent secure hookup to the terminals if the panel is in a permanent location. However being on the cockpit seat exposes it to damage so when i arrive at the boat the first thing i do is remove the panel and place it in a secure location in the cabin. the alligator clips make this a fast and simple task. My battery is in a permanent secure location under the companionway and the wires leading from the panel travel from the cockpit seat, under the bottom drop board to the terminals of the battery.

[Steve Laume]

It would only take a few seconds to spin off a couple of wing nuts. My batteries are down in the bottom of a cockpit locker and I would never trust them to play nice down there with exposed terminals when things got moving around.

Your situation might be perfectly safe but I would not recommend using alligator clips for most battery installations.

If you are looking for a quick disconnect, you could connect proper terminals to the battery and then install a plug in the line to the solar panels. The connection would stay securely in place on the battery terminals and the plug could terminate wherever it was convenient.

For a small panel there are plugs with an insulated female end that would go on the battery side and the female ground on the panel side. You definitely don't want to have an exposed terminals on the battery side.

You also need to make sure that the positive and negative on the panel never touch. These things are always hot when light is hitting the panel. I once learned this lesson, never to be forgotten, when I touched the output on a solar electric fence charger inside a feed store show room, Steve.

[Terry]

In the FWIW department:

I wouldn't hesitate to use a roll-up panel with gator clips, rolled and stowed during sails. Cheap and easy.

For me, though:
The 5 watt panel on the engine cover worked well from the time it was originally installed--probably in the late 1980s--until recently. It was hardwired direct, with no need for any controller. And it kept the battery up nicely. Depth finder, radio, nav and interior lights, but rarely used for any long periods at night.

For quick disconnects, check out Anderson Power Poles. They're not terribly difficult to install even with a regular crimp tool, and are pretty much GI proof. I use them on my amateur radio gear. There are a variety of power distribution boxes available for the connectors, too, many with fuses.

I decided to install a couple new batteries a few years ago, and put in AGMs. I like them as they don't gas, can be turned any which way one needs to make them fit. Cassandra --CD25-- has room for two on each side, though not installed that way at this time.

I like fuses at the batteries, myself. I use standard auto fuses in a water-proof holder.

The type of AGM battery I have has a lip on the bottom that accommodates a hold-down bracket. Cleaner, I think, than the strap method.

I don't have a battery box. Don't like them. They are not required for AGMs, either. However, I don't sail in storms. . . yet. At some point I'll put a piece of 1/4 in. plexiglass over the batteries, maybe with a hinge for access. I do think about shorting out if something landed on top and just happened to touch each terminal. Maybe the bail to a bucket, or something.

I don't use thumb screws on batteries, either. SS nuts and washers. Wrench and socket is best, but cresent wrench works fine. Small one. Probably should have a line attached.

Y'all enjoy the 4th.

L-RD Bless, Keep, Shine. . .