Power off the grid - Solar?

[Cluck]

Last week I had posted about options for powering a trailer off the grid. I plan of buying a used 20-30 foot camper trailer and would leave a trailer at my hunting camp, with no electric. I’m looking at different options like generator, gas, and battery/solar. I really want to AVOID a generator if possible. Basically, here is how I plan to use the trailer…

2 days a week max. During the day, I won’t need power. During the night, I would want to power up a few lights, water pump for quick shower (hot water would be gas likely ?) Night time I may need heat sometimes . May use the TV a little at night. Would not be ever be using the refig, stove, microwave, etc.

I like the idea of these solar kits. Based on what my usage above, how many watts would I need ? I found this 30 watt kit… http://www.mrsolar.com/page/MSOS/PROD/RV/MSRV-30#.UeRsFI0qYrf

Is there something better? How many batteries and what type would I need? I’m thinking I can get away with just solar/battery and gas since I would use very little. I’m new to all this trailer stuff, appreciate any insight.

[aarond76]

We can easily make a 3 day weekend on our (2) 6V 235 Ah batteries running LED lighting and little concern for conservation. With you being (2) days a week max you should be fine with a battery set-up like this and the solar set-ups recommended by those above. We bought an LED TV from Walmart, many of them actually run off 12V power through a transformer in the cord. We cut off the transformer and hooked directly up to our 12V battery power. Based on your intended usage, I see no need for a generator. You should be good for 2 days even without any solar input while you are there, then you will have a week of solar recharge to top back up again so a few cloudy days should not effect you.

[westend]

You can use this Spreadsheet calculator to see what you'll need for solar power.
If you read up a little, you could fashion your own system rather than paying the premium for a kit.

[Michael_in_MN]

Cluck wrote:
I was thinking that too. I bet a few high quality batteries would late me as few days of light use. What type of battery? like a regular deep cycle?

Start with either a pair of 6v golf cart batteries or a pair of deep cycle 12v batteries. There are a hundred threads on 6v vs 12v that you can read up on if you want. You will not die or end up in purgatory no matter what you choose, so pick one and go with it.

We camp dry with no television, but with a propane fridge, water pump, LED lights, occasional laptop recharges and very rare propane furnace use. If we get a few hours of sun every day, my 65w panel is adequate to charge my batteries. I'm not sure how will keep up on successive cloudy days though. The suggestions for 100-200w solar are probably more in the ballpark for your intended use.

[Cluck]

I was thinking that too. I bet a few high quality batteries would late me as few days of light use. What type of battery? like a regular deep cycle?

[JiminDenver]

smkettner posted a link to a group from a site others have used. Here is one of the 160w kits available.

160w kit

We use a simple 230w portable system. It kept a grp 27 battery up for a week and we use more power than you are thinking. It was also not all that sunny, by 11am or noon the clouds had moved in. That was more than enough to replace our day to day needs. I would check the voltage of the battery when I got up in the morning and the lowest I saw was 12.5v. That's if I caught it before the system woke up and started charging.
We could go like that forever but we have extra battery for when the clouds wont co-operate for a week or so.

Actually for a few days a week and with as little power as you are suggesting, a few batteries should last you. You will just have to take them home in between and charge them.

[Bruce_H_]

The best quality portable solar unit is the Zamp. Completely self-contained, and comes with a nice formed case. We have the 120 watt model and it puts out up to 6.84 amps. It is more than enough for us, and I think it would be perfect for your situation.

The 120 watt unit is available from the RV Solar Store for $596.

There are cheaper units out there, but none better than the Zamp.

Bruce

[PapPappy]

You may also want to consider wind power:) There was a thread a couple of days ago, with a pretty nice wind power generator for about $400, and it was easily attached to the back ladder on the RV.

Solar is good, but only good during the day...and sunny days at that! The wind is only good on windy days, but depending on where you are, that may be fine.

Ideally, you'd make a system of both....

Good luck:)

[Cluck]

ok, so I need at least 140watt kit. Probably 200 + watt would be best. Can you guys post a link to a complete kit? So all I need is the buy the kit and few deep cycle batteries?

[pianotuna]

Hi,

Forget about the 30 watt kit. It is VERY pricey.

How many amp-hours is the battery bank?

[hmknightnc]

Just a guess based on your intended use (2 days/3 nights max per week, couple hours of TV a night, minimal lighting or LED lights) with trailer parked in relatively good sun. I would start with twin 6volt GC2 batteries, 100 to 125 Watt solar panel, a 15 or 30 amp PWM controller and 300 MSW inverter plus necessary wire and materials. See how that goes and could add another 100Watt solar later if not quite enough

less than $500 all in cost with self install.

A 30watt system is not much more than a battery maintainer (in fact 30 watt solar is what I use as a battery maintainer on my boat)

[time2roll]

http://www.mrsolar.com/page/MSOS/PROD/RV/MSRV-30#.UeRsFI0qYrf

$180 for 30 watts = $6 per watt 😞

Here are some kits at $3 per watt or less:

http://www.solarblvd.com/12-Volt-Solar-Kits 🙂

And yes I think you will be far better served with 120 to 240 watts.
Single group 27 might be plenty. Easy to add a second if needed.

[RoyB]

When we camp off the power grid for extended times it looks like we consume around 250-300WATTS per day of battery power..

Our game plane is to run all of the 120VAC items we want to run from an INVERTER and all of the 12VDC items we want to run direct connected to the battery bank. The big drain occurs between 8PM and 11PM and with our 255AH battery bank we will see it drop down to its approximately 50% state of charge around 8AM each morning. This is when we run our 2KW Honda Generator to recharge the battery bank back up to its 90% charge state in a three hour run time using smart-mode charging technology. Once we get them back to 90% then we can do this all over again the next day/night run off the batteries.

We actually run just about everything we do at a regular electric site except no air conditioner or high wattage microwave use.

Using the solar panel during the day would charge the batteries up just fine. I'm thinking for what you are wanting to do 120WATT solar panel setup would probably be enough. Using the small 30Watt solar panels guys is wasting your money... You have to store the solar energy in batteries to be able to use them at night so why not just have a battery bank big enough to do what you want to do and then re-charge your battery bank to their 90% charge state using solar panels all day long. I still would want to have a generator along with me however- You will not always be able to use solar panels - might be cloudy for three or four days in a roll...

I would think getting all setup using batteries is the first priority to be "successful" and then supplement the re-charging of the batteries using solar panels during the times when the sun is out strong. You may eventually get enough re-charge to skip many days of generator use.

Batteries and Generator will always work for you. You don't need a very big generator - just big enough to run your on-board converter unit and let that re-charge your batteries. We are super successful doing this with our setup... Having solar panels is icing on the cake...

Just some of my food for thoughts on this based on our camping off the power grid experiences...

Its all in the planning...
Roy Ken