Greetings,Hopefully some of you solar mavens lend some sage advice here. My current set up is:26' TT, one 12v marine Costco battery. 2 solar panels: a 32watt and a 43 watt that aren't roof mounted, I move them around as needed. This setup has met our needs just fine during winter desert camping trips for 2+ weeks. Until this year that is. This year, we had 5 straight days of cloudy weather where the sun couldn't be seen at all. My solar couldn't keep up with our power usage. We do use all LED lights inside. Our power consumption consists of lights, water pump, and charging the iphone or camera batteries.So after that I want to be able to keep the battery charged up in cloudy weather. I'm considering either upgrading my solar to a much higher wattage or getting a portable generator.I prefer the solar solution if I can harvest enough power in the clouds to charge my battery. I have found a 12v, 155 AH golf cart battery that would be a good start, but I want to use up the current battery first, as it's only 2 y/o.Do you think 200 watts of panel with an MPPT controller would be sufficient? Or do I need 300+ watts for charging in clouds? Or am I better off just keeping what I have and getting a little Honda EU2000 for cloudy weather boondocking?Thanks a ton and happy travels.David

Whangler wrote:am I better off just keeping what I have and getting a little Honda EU2000 for cloudy weather boondocking?Yes. You'll get 10, maybe 20% of power on cloudy days, depending on how thick it is.I like to have a way to continue to enjoy using my inverter/batteries even in bad weather, not let my life be dictated by it.

I think a batter bank like mine would be a better idea and cheaper. I have the same as you do so far as voltage. I have a 1200 watt $123 portable Chinese generator that is as quiet as a Honda for back up. 100 watt solar panel with controller. 2/6 volt 1 year old AGM batteries the produce (255 AH @ 20 HR Rate) that I got off Craigslist for $100.

352 wrote: I have a 1200 watt $123 portable Chinese generator that is as quiet as a Honda Wow.. where can I find such a product?

352 wrote:I think a better battery bank like mine would be a better idea and cheaper. I have the sbatter ame as you do so far as voltage. I have a 1200 watt $123 portable Chinese generator that is as quiet as a Honda for back up. 100 watt solar panel with controller. 2/6 volt 1 year old AGM batteries the produce (255 AH @ 20 HR Rate) that I got off Craigslist for $100.

How much solar for cloudy weather | Good Sam Community

16 Replies

napadan
Explorer
Feb 10, 2015
My suggestion is to install 2 6v. golf cart batteries. You might need more solar, but I think that the batteries will do the trick. On a recent camping trip (in the rain!) we used a 135 watt, installed on the roof, solar panel and it kept up with our moderate use for a week. The batteries never got below 75% of charge.
time2roll
Nomad
Feb 10, 2015
My trailer idles right at 500 milliamps (1/2 amp) with the fridge on and gas valve open.

4 amps of 12v seems high. They do draw 3 to 4 amps of 120vac when plugged in.
webwrangler
Explorer
Feb 10, 2015
One more thing--the electronic controller for your propane fridge is a constant draw on your battery(ies). I think a friend told me 4 amps for most of the modern ones.
webwrangler
Explorer
Feb 07, 2015
You definitely need more storage. Two batteries (which it appears you already own) are a good start. I started with solar by trial and error--a little here, a little there, and not really knowing what I was doing. I had one battery; added a second by having a friend weld a rack that would hold the two (12v) and I wired them in parallel. I haven't really been able to put it to the test, but during one week boondocking in a sunny location last fall my batteries didn't appear to run down at all. Of course, that doesn't help with the cloudy week scenario. Your power usage sounds about the same as mine.

"Handy Bob" has a blog on going solar for RVs, which is kind of long-winded but there's a lot of good information, too. After reading his blog a couple of times, I concluded that my next step was to install a Trimetric battery monitor and find out exactly how much power I use and then decide how much more panel I need (if any). I've bought it, but haven't been able to install it yet. Here's a link to Handy Bob's blog

I recommend his "RV Battery Charging Puzzle."

He does not think that MPPT controllers are necessary for most RV setups.

I personally refuse to own a generator and get cranky when I'm camped near someone who uses one.
pianotuna
Nomad III
Feb 07, 2015
Hi,

Welcome to the forums.

Assuming you get 1/6 of the power due to poor conditions 450 watts of panels would be needed.

A more balanced approach might be doubling or tripling the storage and getting 180 watts of panels.
352
Explorer
Feb 06, 2015
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Dakota98
Explorer
Feb 06, 2015
Two things about that little 1200 watt is, >> it's max power is 1200 watts & it's a 2-stroke.

I own a small Champion 1500 / 1200 watt, It's a super little gen & quiet. $225 + free shipping

CHAMPION

Customer service is great & parts are easy to find.

Shop around, you may find it cheaper yet.
christopherglen
Explorer
Feb 06, 2015
My 10kw of solar on the stick and brick is generating less then 600 AC watts (per the grid tie inverter). I would assume a slightly higher percentage on battery charging.
352
Explorer
Feb 06, 2015
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time2roll
Nomad
Feb 06, 2015
You need more battery. Think 300 to 450 amp/hours. A 250 watt 24v panel on the roof and MPPT will also help but they are a bit large, heavy and awkward for portable.

Hard to count on more than 10% production with clouds. More wattage will certainly help if you get just one or two hours of sun.

245w $145 @ solarblvd

Morningstar MPPT $240