20w coleman solar panel

If I may ask, how much do they get for a 20w panel and controller? I've thought of getting one to keep the batteries from discharging over the winter. It wont be a issue once I install the real system but I'm still curious.

Agree with Westend. Good advice.

Here is a simple flow chart.

Budget-->Energy Audit-->Battery bank size-->number of watts-->PWM or MPPT. What ever type of controller is chosen, make sure it has adjustable set points and a temperature probe that is on the battery.

One rule of thumb is between 60 and 150 watts of panels per 100 amp-hours of storage. The smaller the battery bank the higher the wattage needed (per 100 amp-hours). Here is a link to the rather special spreadsheet which includes an energy audit, that N8GS has created to help size solar battery charging systems!

Solar Spread Sheet N8GS

For a nice explanation of solar, try this link:

Golden rules of solar

Eyetattoo wrote:

Zacvv wrote:
Thats a good thing to hear i was starting to feel like i may have made a bad purchase. How much do you use your 12v system and for what things?
eye tattoo

We power our sound system during the day and usually a 21 inch LED TV. At night the TV and lights get used. I used to run the generator for 6-8 hours a day, now roughly 4 hours. I do plan on adding 1 more 20w panel so it can keep up a little better.

There is no possible way that a 20W solar module will equate with two hours of generator run time even with the smallest RV converter. You are either running the generator too long or have misjudged the amount of charge the module can deliver.

If can you state how many AH's you are using in a day, I'll retract my previous statement.

Zacvv wrote:
Thats a good thing to hear i was starting to feel like i may have made a bad purchase. How much do you use your 12v system and for what things?
eye tattoo

We power our sound system during the day and usually a 21 inch LED TV. At night the TV and lights get used. I used to run the generator for 6-8 hours a day, now roughly 4 hours. I do plan on adding 1 more 20w panel so it can keep up a little better.

Consider this: a 20w module harvesting power in the best light conditions for 5 hrs/day will put 100w back into a battery. An 1156 bulb (typical for 1975) is rated to 26W. The solar harvest will run one light bulb for less than 4 hrs. A water pump is 3-4 amps. A fan is 3 amps=36watts.

I would just carry the little module out and hook it up to the battery. When you get home, charge the battery and leave the module hooked up to the battery. Check the module when connected to battery so that it has an output diode and isn't discharging the battery.

Thats a good thing to hear i was starting to feel like i may have made a bad purchase. How much do you use your 12v system and for what things?
eye tattoo

We have a 20w panel that keeps our two 6volt batteries topped off when not in use. Its not a lot of power but with it our generator use has dropped by 50%.

the roof is made of aluminium. We only use the 12v for our water pump, lights and tiny little fan, Maybe the fridge if we get the thing working.
Is it easy to change over a fridge with another used one?

Silicone acts like plastic. At first, it seems to stick, but then it just fills the gap, and lets in anything around it on all sides that it wants.

RV sealants, on the other hand, stick to the stuff nearby, and remain stuck and sealing in flexible conditions.

Most important, in all situations, is proper cleaning. If the surface is dirty, there is nothing that will properly stick. You really have to clean the surface you want to adhere to before you apply.