Solar battery charger

I just ran by the camper and checked mine. It has worked very well for me over the last 10 years on single batteries at a time.

Voltage on the Marine group 24 Interstate that came new on the camper:13.71v in sunshine mid day.
Watts-peak:5
Voc: 24
Isc: .350
Vspec(presumably mpp): 15.0v
Nighttime blocking diode: internal

No watt meter or controller on it, but it helped a number of batteries in midlife life get to 10 years of service for me, with very minimal water usage.

For grins I will run it against a few different health batteries in a few different conditions with the amp hour meter attached.

I have found with the stronger sun in Texas I do not need to tilt it as I did in Michigan, and even with a shadow across it full time it will get a charged battery to or above float voltage at mid day. In Michigan it was strong enough at winter solstice (tilted) to get a battery to or over 13v on a sunny day, with better performance the rest of the year.

Battery tended to be anything from a single group 24 to a single group 31.

Jim

http://batterytender.com/10-watt-solar-charger.html

My Son in law uses his to keep his travel trailer battery charged between tyrips. Does a fantastic job.

Shop around for best price

Most individual panels of that size don't have any diode. You can get a diode at Radio Shack for $3 or so.

This one has a diode.

Oh yeah, and Amazon customers - those most "advanced" - complain that this device has no charge control and therefore can overcharge the battery. None have actually witnessed such a disaster, and at this current I don't think this is going to happen.

I was looking at that one. Sears sells it for $58. Does it have a blocking diode?

Jim

If you only need 5W, I recommend this panel especially if you have Amazon Prime. It's monocrystalline, $15 shipped. I just bought 3 of them.

http://www.amazon.com/gp/product/B0046HE62G

Not enough info.
"To keep charged" - with what loads? Do you physically disconnect the battery, or just turn the lights off and call it a day? Is it a single battery, and if so, what size?

Assuming the easiest scenario, - a single battery under 100 Ah (this is what dealers normally push to sell), AND if you physically disconnect the loads, then to compensate for self-discharge that goes inside the battery and never stops no matter what, you need 3W-10W solar charger. Get one from Amazon, where it says "charger" - not "panel", and that comes with cable and clips - those usually have a blocking diode built-in. Costs around $20.

If any loads are present, then you need a charger/panel with more watts. How much more - depends on how much loads.

If there is more than 100 Ah of batteries, then again you need more watts.

If you need more than just "keep it charged", i.e. you want to add some or all of the charge that you drew out of the battery during the last trip, then again you need more watts.

As long as you are drilling holes, pulling wire etc I recommend closer to 60 to 120 watts and a simple controller.

http://www.solarblvd.com Solar-Cynergy-80-Watt-12-Volt $116

http://www.solarblvd.com//Sunsaver-SS-6-6A,-12V-PWM-Charge-Controller $38

Shop around.

Hi,

How big is the battery in amp-hours?

yep, agree with Jim. 10 Watts or so per battery and no controller needed will work as a maintainer but isn't going to charge your batterys from any state of real discharge

If you looking for something to be able to maintain the RV with battery connected to parasitic loads and keep the battery full charged as well as provide recharge capability during storage so that it is fully charged and ready to go anytime then a 100Watt panel with a 6amp Morningstar Sunsaver would work great. HiTech and someothers also use the Landstar brand controller which seems to be very similiar to operating characteristics of the sunsaver but is a lot cheaper. Your talking about around $200 for the 100Watt system self installed (its easy)

afinepoint wrote:
Looking for one to keep the battery charged between trips.

One battery with no loads on it, or parasitic loads from the RV too?

No loads 5w-15w is a pretty simple solution for a wide variety of single batteries. No controller needed.

Potentially something like this would work, but only if it comes with a blocking diode to prevent discharging the battery at night. 5w solar square

Jim