Solar Charger

[Sweetale]

Anyone use a small solar panel to recharge your trolling batteries (I have 2)? I will often stow my boat after use in a spot with no power, and would obviously prefer to avoid trips home just to plug in. I realize that we're talking a slow recharge with solar, and most times that will suffice. I also don't want to pull the batteries to bring home either. Thoughts?

[Way2slow]

Never tried them myself. I've had two friends that have tried them, one had them on his two jet skies and the other used one on his boat cranking battery to keep them charged over the winter. In both cases, the batteries were door nail dead when they tried them in the spring with they got ready to use them.

I realize there are different quality levels of them and a good one, with a good charger system might work, but these things you find at Harbor Freight, ebay and places like that, I would not put much faith in them.

Besides, you should understand, unless you buy a really large one, they are only good for a maintainer. You would still need to charge the battery to full charge before connecting the solar system to it.

[tomustang]

A solar panel the size of the lake I fish would probably be big enough for my 3 batteries.

The power you get won't come close..

[BadBassWV]

I too have wondered about these.  I fish a pond prowler 8 foot boat.  I run a trolling motor and fish finder, Do you think If I went out with a charged battery and kept a solar charger hooked up to it while fishing that it would help maintain my battery life.  Or is this thought A waste of Time?

[Wayne P.]

You won't have enough room for solar cells on a boat to "charge" batteries. 

They will "maintain" a charged battery if you don't use the battery/s.

[Choporoz]

I've got one (6W, I think) and badly wanted it to work for same reason as OP.  I tested once in the backyard on a (mostly?) drained battery for one week with no noticeable increase in charge.   Not very scientific, but I was disappointed and haven't taken it out since.

[Way2slow]

I guess it just depends on how much you wanna spend. All you have to do is a little basic math.

First, figure you was only to get a bare minimum that would charge a battery, say about 5 amps going into it, and it should be eight to ten amps, but well will go with five. To do even that little bit, you would need 14.2 VDC @ 5 amps, that's 71 watts (per battery), not allowing for any losses that will be in the system from heat/internal resistances.

Just as a maintainer, you will need a 15 watt unit that will give you 13.2 VDC per battery. If it won't give 13.1 to 13.2 VDC with the battery connected it's not suitable even as a maintainer and with many AGM batteries, you need 13.4 VDC.

Now as one mentioned wanting to run a TM or charge a battery while he's running it, all you need is about is enough of those panels to give you 350 to 600 watts.

I guess what I'm saying, if you buy a quality 15+ Watt panel and charger interface box that will regulate to the voltage at 13.2 VDC and fully charged the batteries before connecting the solar charger, it "might" work. However, notice a said a quality unit, and it's very important to have a good charger interface, if not, you WILL ruin the battery. As for who's to buy, I don't have a clue because I've never messed with one. I can't stress enough, the battery charger circuit is going to be the key to if and how good it works, so I would not even try some bargain basement model.

One more thing, even if you try to use one as a charger, a flooded cell battery "MUST" still be charged at a 10% charge rate every couple of charges. It takes that 10% charge rate to make the battery form gas bubbles inside, and these are necessary to keep the electrolyte from stratifying (to keep it from separating into water on top and acid on bottom) because that ruins the battery.