Solar battery charger

[wayne anthony]

Don't know if this is the right spot, but couple years ago bought a 15 watt solar panel and control from Harbor Freight. First day of use, fully charged the battery on my Terry 5th wheel (one 12 volt battery and not much power drain from trailer).

Second day battery crapped out (9years old).

Third day the control for the panel crapped out. Got a new one from H. F.

This year finally got to use it for 5 days on Padre Island. With two 12 volt batteries, electric jacks, electric awning, and slide, seemed like it kept up but never reached the full charge state. Wayne

[herk7769]

Originally Posted by wayne anthony

Don't know if this is the right spot, but couple years ago bought a 15 watt solar panel and control from Harbor Freight. First day of use, fully charged the battery on my Terry 5th wheel (one 12 volt battery and not much power drain from trailer).

Second day battery crapped out (9years old).

Third day the control for the panel crapped out. Got a new one from H. F.

This year finally got to use it for 5 days on Padre Island. With two 12 volt batteries, electric jacks, electric awning, and slide, seemed like it kept up but never reached the full charge state. Wayne

You are kidding right? 15 watts?

Dude your batteries did it ALL.
15 watts?

At FULL SUN that's a bit over 1 amp! Your propane detector draws that!

Minimum solar panel size for two 12 volt batteries is 180 watts. Even then you will need to run your generator with a good 20-40 amp battery charger for several hours every few days or so to keep them topped off.

A few more trips like that 5 day trip like Padre Island and you will be buying another pair of batteries I am thinking.

[wayne anthony]

Some of us can get by a couple of day without t. v.s and our electrical junk.

[herk7769]

Originally Posted by wayne anthony

Some of us can get by a couple of day without t. v.s and our electrical junk.

GOT ME!

Still that panel is a trickle charger designed to keep a fully charged battery from freezing due to internal resistance discharging the battery that is not hooked up to anything.

[flyrotor]

Herk,

A couple of weeks ago I bought a 45 watt solar charger set from Harbor Freight, my intentions are just to keep the batteries charged for normal daily use, which mostly consists of the lights and water pump, very seldom do I use the heater and never in the summer. I do realize there is some uncontrolable electrical burn such as the fridge control panel, propane monitor alarms etc.

I do not have any high volume electrical needs such as televisions, radios, fans or other appliances.

Do you think I am behind the 8 ball with this? I usually camp 4-6 days at a time, rare that it ever exceeds that.

[herk7769]

Originally Posted by flyrotor

Do you think I am behind the 8 ball with this? I usually camp 4-6 days at a time, rare that it ever exceeds that.

Well, I guess that depends on what "behind the 8 ball" means to you.

45 watts is a bit over 3 amps at full sun.

"Full Sun" is when the sun angle is exactly 90 degrees to the surface of the panel. Unless you have a motor drive on your panel system; this happens exactly once a day IF you have the azimuth set correctly for your latitude.

If you just flop it down, you will get less than rated output.

Now, back to the 8 ball.

Say you average 2 amps all day. Say 12 hours of sunlight. That will put 24 amps into your battery a day. If all you pull from the battery is 24 amps you will use "none" of the battery capacity that day. Net zero.

If you use more, say 50 amps per day. You will have reduced the battery capacity by 26 amps per day; not 50. This will effectively double your battery life.

Now 50 amps may seem like a lot, but ONE 12 volt incandescent light fixture uses about 3 amps (~1.5 amps per bulb). The water pump running uses about 13 amps. My motor driven slide draws 18 amps when running them in or out. Running both at the same time...
Well I don't want to say but it sure looks cool.
Can you say "Transformers."

I know you don't run the slides every day or the awning up and down either but you get the drift. Some is better than none.

To go "off the grid" without a generator you are going to need to create more power than you use. A minimalist would need a 200 watt panel and a fair sized (500 amp-hour) battery bank.

[flyrotor]

Thanks Herk

[herk7769]

Just got this sale in an email. They are reputable and I and another friend have done business in the past.

Solar Cell, Solar Panel, Solar PV, Solar Products, Charge Controllers, Solar Trackers

Great deal on a 180 watt panel 24 volt 10 charging amp panel!
Make sure you get the correct controller to drop the output to 12 volts.

[toshu]

At 5-15 W, I am assuming that this size/type of system would be suited for maintaining the charge on a battery that is sitting around idle, in storage....

Has anyone used one of these systems for just charge maintenance??

If so, what are pros and cons??

[polkatronron]

All I am looking for is a small solar charger to keep the deep cycles from dropping off over the cold winter. I don't believe in taking batteries out in fact I think cold is better than warm for them as long as there is a trickle of current going into them..any recommendations