25 watt panel for camper, looking for advice on charge controller

[Deb]

We just bought a 25 watt solar panel to use with our camper. The charge colt roller was not included. What do we need?

[sdold]

Hi Deb, welcome to the forum, I moved this to its own topic. I assume you mean "Charge Controller", spell check or something must have got you. Do you already have a battery and do you know what the capacity is in amp hours?

[Deb]

Our battery is a deep cycle marine battery 27DC-2
cold crank amps 600
marine cranking amps 750
reserve capasity 160
i hope this is what you meant

[whazzatt]

Hi Deb. To help others help you, more info is needed.

Like, are you adding to an already existing battery charged by the alternator?

Importantly, what loads are you running? What are your daily insolation figures?

If it's a stand alone battery, then starting here would help you a lot: https://www.solarpaneltalk.com/forum...battery-design

I don't know the ins and outs of combing the panel via charge controller to the a battery already charged by the alternator, but there is already a lot of info about this online, and probably on this forum already.

If stand alone, your 25W panel is pretty useless. A google search suggested your battery is 12V, around 85-90Ah capacity. With a MPPT charge controller your 25W panel will produce 2.08A of current max, so the smallest charge controller will do. But one has to wonder, what's the point? Unless your load consists of one small watt 12V light, anything else you run will drain the battery a lot quicker than your little panel will put back in.

If tied in with the alternator, maybe you could hook the panel via a small charge controller, like a Steca 10.10F, and put a switch in line between the battery and CC, and between the panel and CC. Everything is off when you drive. When you stop, put the battery switch on so your CC detects the 12V battery, then switch the panel switch on, and you'd be able to put a few drops of power back in the battery, but not much. But let others give you better advice or google the best way to connect to a battery already connected to the alternator.

[Deb]

Thanks for your thoughts. I have to tell you, I know nothing about what you just said. And I don't understand it. We go camping for a week at a time and hoped the solar panel would keep our camper battery charged. We go where there are no hookups. Again, thanks for your time.

[littleharbor]

Deb, welcome to the forum.

We all started at square one. You need to read and try to understand as much as you can through this forum, including the stickies in the appropriate categories. There are RV forums that contain a lot of good info for using solar also.

I will say, in a nut shell, you will need no less than 150 watts of solar to do any meaningful battery charging on your RV. You will need a charge controller between the panel and battery. If dry camping for up to a week at a time you would be better off with at least a pair of 6 volt batteries and closer to 300 watts of solar. You need to keep in mind, your RV needs to be spotted in a full sun location. Shadows all but kill solar panel output.

Your 25 watt panel would only be useful for maintaining your RV battery when not in use, but parked with a fully recharged battery.

[Sunking]

25 watt panel?. Why on earth do you want a cell phone charger while camping? Leave the cell phone at home.

[J.P.M.]

25 watt panel?. Why on earth do you want a cell phone charger while camping? Leave the cell phone at home.

Camping ain't what it used to be. It's a changing world pardner.

[SunEagle]

Camping ain't what it used to be. It's a changing world pardner.

A 25 watt would work on a small battery or trickle charge a larger one.

But as you indicate concerning this "changing world", people now use way too many electrical items to pass the time when I use to just read a book or listen to the wildlife when I camped.

[sdold]

I could see using it with a small PWM charger to keep an already-charged battery "topped off" in storage. Anything wrong with doing that?

[whazzatt]

...people now use way too many electrical items to pass the time when I use to just read a book or listen to the wildlife when I camped.

But sometimes you need to blast the tunes to irritate the other campers, so a little more juice helps

[J.P.M.]

I could see using it with a small PWM charger to keep an already-charged battery "topped off" in storage. Anything wrong with doing that?

Nothing. But assuming (perhaps incorrectly) if the purpose of "camping" is to get away, why take it along in the first place ?

[J.P.M.]

But sometimes you need to blast the tunes to irritate the other campers, so a little more juice helps

Assuming the idea of "camping" is also to get some solitude and privacy, why would other campers be close enough to me to be irritated by noise I might generate ?

Like I wrote, camping ain't what it use to be. Now it seems that communing with nature needs 1500 W and 250 lbm of electrical storage and an RV that gets 10 MPG. Sure sounds like progress to me. But, opinions vary I suppose.

[whazzatt]

Assuming the idea of "camping" is also to get some solitude and privacy, why would other campers be close enough to me to be irritated by noise I might generate ?

You just don'y have enough power. Enough juice and campers at the top of the mountain will hear your tunes. An extra 25W might mean the campers at the top of the next mountain will hear them too

[Sunking]

I could see using it with a small PWM charger to keep an already-charged battery "topped off" in storage. Anything wrong with doing that?

No nothing wrong with that at all, or charging a cell phone which was my point. The 25 watt panel is useless as a charger for the Marine Battery he bought, but makes a good cell phone charger which is not needed while camping.