Solar chargers for Two 12 volt batts

[Rockinfigs]

Hi im in the market for a solar panel trickle charger for two 12 volt batteries on my hauler. I have an attitude 27 cbg and it came with the option of getting a 10 watt solar panel which i didnt get..i decided to get an aftermarket one so i can take it off n only use it when desert camping for (2) 12 volt batteries connected parallel. two quesiotns

1) should i get the 10 or 15 watt solar from Deltran offered by campingworld

2) since i have 2 batteries and they r connected parallel does it matter which battery i connect the charger to?

thks

[pianotuna]

This is what is balanced and best for twin twelve volt batteries.



As it often doesn't cost a dime more to do this, I think it is worth the trouble.

If you wish to understand the "why" surf here:

correctly interconnecting multiple twelve volt batteries

Others may say it doesn't matter--but unless there is a compelling reason to not optimize charging and discharging why not do it the best possible way?

[pianotuna]

Hi,

30 watts per 100 amp-hours will recharge the bank when the rv is in storage. In use it would not even keep up to parasitic loads, such as the gas valve on the fridge.

Here is a simple flow chart.

Budget-->Energy Audit-->Battery bank size-->number of watts-->PWM or MPPT.

Here is a link to the rather special spreadsheet that N8GS has created to help size solar battery charging systems!
Solar Spread Sheet N8GS

[time2roll]

How much is that 15w panel at CW? $150?

80w panel $116

Controller $30

80 mile drive to Norco saves shipping. Call first to verify in stock.

This will charge and maintain your two batteries far better than the CW panel. If you want power while camping I would go a bit larger but this will provide some limited power.

[Rockinfigs]

I'm looking more for battery maintenance..I'm sorry.. What's a static load? Thks

[BFL13]

Not clear if you want the solar for camping or just for battery maintenance at home or storage.

In either case, beware. Usually at hardware stores, they want vast amounts of dollars for tiny amounts of watts for solar, where you can get way more watts per dollar at real solar places. AND you need lots of watts when camping to make any difference.

Think more like 100w for a pair of batts to make any real difference while camping. So add a controller for under $50 and some wire etc, the whole thing is under $200 for something that will actually work while camping----and the beauty of that is, it will also do just fine as your maintainer.

Meanwhile, the average hardware store wants $300 for a 60w joke of a solar set-up!!!! Buyer beware! 😞

[doughere]

You understand that neither of these panels will recharge your batteries; they will just keep a charged battery from loosing its charge! For that I'd get the 15 watt panel. Make sure you remove any static loads from the batteries.

Hook to either battery.

Doug

[Golden_HVAC]

Hi,

I would not suggest getting anything as small as a 15 watt solar panel. The cost has come down a lot on the larger solar panels, you can get a 100 - 150 watt panel for a little over $1 per rated watt. You can get a China 10 amp controller for about $15. Then you will have a "real" solar system, that will recharge your battery, not just keep it from going dead in a few days.

Your RV has some loads on it, such as the CO meter and propane detector that will consume 35 amp hours per day, or about what a 120 watt solar panel will put out in one day.

SolaronSale.com is one place, SunElec.com is another.

Good luck!

Fred.