Greetings everyone,

I am new to RV'ing and just recently purchased a tent trailer. I live in Northern CA and there are so many places to camp, but most of them are "dry." My battery is good for about a day and then I need to charge it back up.

In this area, we get sun just about every day from May to October and I'd really rather go solar than buy a generator.

Does any one have any insight or experience with trickle charge solar panels?

Thanks,
Jenn

Hi Jenn,

How many amp hours is your battery? If you wish to go solar a "trickle" charger isn't going to do much for you. The solar panel needs to be large enough to run *all* the drains from your camper--and have some juice left over for charging the battery so it can be used at night. A 100 watt panel might do the trick if you are very conservative about using lights at night. One of the biggest electrical "hogs" is lighting. I suggest looking at the new technology Sensibulb.

http://www.sailorssolutions.com/index.asp?...amp;Item=SEN10W

A regular incandescent 12 volt bulb draws 2 amps. The led's draw about 0.146 of one amp.

The other thing to do is to replace your existing battery with the two biggest meanest ones you can find (if they will fit). (Try Walmart).

Sadly generators are still far cheaper than solar panels.

Hi PianoTuna.

Have you personally tried any of these SensiBulbs? I'm especially interested in how they do with light dispersement -- would want them to be more of a flood rather than directional light.

Although initially pricey, they look great from an electrical draw standpoint. Power is typically not a problem for us, but it might be nice to have a few of these low-power LED lights strategically placed throughout the coach for those times we are dry camping and are restricted in the use of the generator.

Thanks for your input.

- Kevin

Hi Jenn.

I agree with PianoTuna that solar is still more expensive than a generator, however, for a tent trailer, your electrical needs may be very low so it's possible that solar could make sense for you.

There's a handy little calculator you might want to check out at http://www.carmanah.com/content/products/g...calculatordist/. When you get to the second screen, select "Solar Charging Kit". You can enter the number of electrical items you typically use, the amount of use per day for each item, and the calculator will suggest one of their solar products to meet your electrical requirements. From there, you can determine the basic "size" of the solar system you are needing and then do your shopping.

A more comprehensive list of typical "Appliance Energy Use for RV's" can be found at http://www.rvsolar.com/. From their homepage, choose "Systems/Sizings" and scroll down for the list of typical energy draw for specific appliances. This is not an online calculator, but can give you some good additional information.

Hope those links help out!

Happy trails!

- Kevin

Hi Kevin,

Yes I have one that I am "trying out" before I take the plunge and buy a whole bunch. It seems to produce nearly as much light of the same color and character as a standard 1156 12 volt 2 amp bulb. It does have good light dispersement in the ceiling fixture I put it in. The best part is the much lower heat production.

Thanks for your responses!

My power requirements are:
1. Minimal light usage, less than an hour a day
2. The water pump
3. The propane furnace which according to the manual draws 3.4amps We have to run the heat at night. Last week we were camping at 5000 ft and it dropped to 45F at night.
4. The propane alarm.

The refrigerator and hot water heater are propane.

As far as the battery is concerned. I have no idea what the amp hour rating is. There is no designation anywhere on the battery. It is a Bond deep cycle battery distributed by BBI, Sacramento. I don't think it is the same Bond Battery Company in Australia that I found on Google. I'll run a battery depletion test to find out the amp hours.

The battery is also 5 years old and I don't know how well it was treated before. It might just be time to replace it.

However, using several different calculators I've figured that I am using less than 30-35 amp hours/day.

Here's one more article that may help in your search for solar power answers: http://home.iprimus.com.au/rfh/solar.html.

Wish I had some first-hand knowledge to impart...

- Kevin

Hi Jenn,

35 amp hours @ 12 volts = 420 watt hours. Assuming 50% efficiency a 100 watt panel may meet your needs.

I think most propane fridge draws some power. They have a control board that is on 24/7.

You can cut down on your furnace use by running a burner or more than one burner on your stove at a low setting. Another option is to get a propane catalytic heater. They use no power.

If the battery is 5 years old and has been discharged completely several many times it is likely toast.

Oops, I calculated the amp/hours wrong. It's only 20-25 per day.

So according to the watt hours formula above that would be 300 watt hours at 25 amp hours? Please explain how you figured the size of the panel

Hi Jenn,

The makers of panels tend to maximize the figures they list. I.E. Full Sun at Noon with panel at 90 degrees to the sun. No clouds. I do have an older solar system on my RV rated at 60 watts--so it in theory should be able to charge at 5 amps. The best I've seen is 3. Your need is 25 amps...so I'd have to have my "best output" for about 9 hours. (i.e. I need more solar panels).

Also, you need to charge up the battery for night use! Better to error on the larger side than to go too small. The battery charging is less than 80% efficient too. And 25 amp hours will take you below 80% of the capacity of most deep cycle batteries. If you go below 50% of capacity life of battery is shortened.