Solar charging?

[mjeronimo]

I met someone this past weekend who was using a small harbor freight solar panel and he was charging his battery through his cigar lighter he had a MH. Can I do the same thing through my cigar lighter socket next to the television in my TT? Will batteries take a charge through the 12v socket? I figure that I may be able to play the radio without draining batteries, if this works. Any advise would be appreciated. Thanks

[LM3929]

The small solar chargers (1.5 to 1.8 watts) are only good for very small batteries and mostly to cover the parasitic draw (if that).

you would need about a 15 watts output to put 1.1 amps into the battery

Lorne M.

[mjeronimo]

That's what the guy at the cg said that the solar panel put out 1amp. But can I charge through the 12v outlet by the television ?

[JRTJH]

Originally Posted by mjeronimo

That's what the guy at the cg said that the solar panel put out 1amp. But can I charge through the 12v outlet by the television ?

I think this is the charger you're talking about: http://www.harborfreight.com/15-watt...l#.UyQs3jbD-po

You can try, but that "cigarette lighter socket" is actually a 12 VDC feed from the TV amplifier. It does connect to the fuse panel in your power supply center (converter), but it may not be electronically connected to the battery when unplugged from shore power in such a way that it would allow charging to occur.

The way to check is to unplug shore power, disconnect your battery, plug in the "solar charger" in that socket, measure across the battery cables and see if 12 VDC is being applied. If it is, the only available source would be the solar charger., indicating that it is supplying power to the battery. Don't expect much (if any) benefit from a 1.5 watt charger. It's likely rated at 1.5 watts in full sunlight when facing the sun directly. Any off angle or cloudy conditions will reduce the output to much less than the rated output. Your parasitic drain on the battery is probably at least 5 watts and probably more like 10-15 watts, so you'll still be in a negative drain condition even with it operating at full power, and certainly even less on cloudy days and when not pointed directly at the sun.

I'd think that if you're going to get any benefit from this type of solar charger, you'd need to completely remove the battery from the RV circuit by disconnecting it electrically and then apply the charger directly to the battery terminals. If there's any parasitic drain, this small a charger won't keep up.

Let us know how it works if you decide to experiment.

[limey]

JRTJH is correct - but you should be looking for 13 - 14 volts at the battery from the charger. At 12v it will not fully charge the battery.

[Western Traveler]

Staying with this thought, I picked up a 45 watt system from Harbor Freight for a dry camping trip we leave on tomorrow. I thought I could add to it later if it performs decently.
I planned on hooking it directly to the batteries, is that the standard connection?

[JRTJH]

If you mean the HF 45 watt solar kit, yes, just hook the output from the regulator to your battery. Keep in mind that there is no "limiter" on the output and it's possible to overcharge your batteries. That won't happen while you're camping, but you wouldn't want to put your RV in storage, turn off the battery switch and leave the solar kit hooked to the battery. Without a limiting system to control charging, it is possible to overcharge your battery and "boil" the water down to a point where you could damage your battery plates.

While in use, that won't happen, but in storage it's possible.

Let us know how much longer you are able to go before recharging the batteries using this system.... Enjoy your camping trip, many of us will "join you" later in the season <sigh>

[Western Traveler]

Thanks for the quick response John. I won't be leaving this one out when in storage but thanks for the reminder. I am thinking of adding a small flag pole and a small solar topper for dry storage but homework and time before that happens.

[mjeronimo]

Thanks for the info. I don't know how to do the link thing but it's 13watt folding brief case looking panel. Maybe I'll just hook it directly to the battery as you and western traveler were discussing . Thanks for the info!