Solar recharge

Hello everyone.  I just bought a coleman 15' camper and I have a question.  We are planning a trip out west for over a month in National Parks.  We will be dry camping as National Parks rarley have hookups.  Some places we plan on spending 4-5 days in place.  So, If I were to buy a solar charger to charge during the day, what would I need?  Right now we have one deep cycle battery that came with the camper.  I plan on changing over some of the lights to LED to reduce load.  We don't spend any time in the camper during the day so there would be little load.  I would like to just plug in a solar charger while we are out for the day in hopes it would top off the battery from the night before.  What are your thoughts?  THanks!!

For starters, you will probably need more than a single battery. Next, it will require a very large solar panel(s) to supply all of your electrical needs. You would probably be better off with a small (1000W or 2000W), quiet, inverter generator to keep your batteries charged.

Joel

Welcome to The RV Forum!

A solar system large enough to power everything in a large motorhome is costly, but in a 15' tent trailer you're only talking about a couple of lights, the circuit boards in the refrigerator and water heater and some water pump usage.

Of these, lighting is the biggest user, so you have the right idea by replacing the regular bulbs with LEDs.  With this change, and being conservative in your usage, your single battery will likely last at least 2-3 days on it's own.  You'll get a feel for how long the battery will last as you go.

Then when you tow the trailer to another campground the car's alternator will recharge the battery through the charging wire running to the trailer connector.

So you really don't need much of a boost to take care of the rest.

Harbor Freight Tools has a small system that will likely do what you want.  See here.

Apprciate the info.

Lou, when I click on the link it takes me to the site but not to any system that you indicated.  Do I need to search for something?  Again, Thank You for the info. 

Interesting - the link takes me right to the system.  But try typing "45 watt solar panel" in the site's search box.

At $190 for a 45W kit, the HF solar charger is actually quite expensive for the size and poor quality.

I have a 160W (2x80W) solar array on my M/H with a 20A charge controller.

These are the panels that I have:
http://www.ebay.com/itm/80W-Polycrystalline-Solar-Panel-18V-TUV-RV-Motorhome-Boat-Poly-80-Watt-/380565385638?pt=LH_DefaultDomain_0&hash=item589b76f1a6

I have this inexpensive 20A controller:
http://www.ebay.com/itm/10A-20A-30A-12-24-Auto-Distinguish-Switch-Solar-Light-Panel-Charge-Controller-/110947577747?pt=LH_DefaultDomain_0&var=&hash=item19d4fdaf93

Including wire, I have less that $400 in the system. We just got back from 6 days of dry camping and never gave a thought to the batteries. It was in the low 40s at night and we ran the furnace all night. We have all LED lights:
http://www.amazon.com/gp/product/B007BSG760/ref=oh_details_o00_s00_i00?ie=UTF8&psc=1


If you are going to keep your current battery, I would recommend 1, 80W solar panel but still get the 20A controller and 10g wire, in case you want to upgrade. Then it would just be a matter of adding another 80W panel to your existing set-up.

This is the wire that I bought:
http://www.ebay.com/itm/NEW-A-W-I-Tinned-Marine-Wire-10-2-SAE-FOR-Bilge-MACERATOR-Pump-40-FEET-USA-MADE-/310656217382?pt=Boat_Parts_Accessories_Gear&hash=item48548db126&vxp=mtr

The key is your battery. It's important to match your solar with the amount of battery storage that you have. If you are going to keep your current battery, there's no point in going to a larger solar array that 80W, just to have the battery fully charged by noon (on most days).. 1, 80W Panel @ less than $200 would give you nearly double that output of the HF solar panel kit and these are real solar panels, the ones that HF sell are toys in comparison.

If you do decide to upgrade your battery to 2x 6V golf cart batteries:
http://www.thesolarbiz.com/Trojan-T-105-6V-Battery?gclid=CMLIwqf53rYCFUxxQgodFBgAow#.UXWHIcph5js
then you might want to add another 80W panel and have 2 to 3 times the storage of what you have now and the capacity to keep it charged, even on partially Sunny days.

One very important point........ if you decide to upgrade to dual batteries (of any kind), be sure to buy 2, new matched batteries (same brand/model# and date of manuf). Never try to add a new battery with an older battery.

Tried it again Lou and it worked.  Funny, I tried it 3 times and it didn't.  Anyways, thank You for the info.

Wavery, are those LED bulbs the same as the 12V halogen bulbs for replacement?  I was gonna replace the entire light but this looks like a cheaper option. I had no idea they made those.  Also, I may run with your idea on the solar charger.  I will run with this battery and when done change over to the 2 6V batteries.  I like the idea of how much longer they will last.  I own a golf cart and know that golf cart batteries are pretty stout. Alot of great info, Thank You

Wavery, is your system mounted?  I was figuring to keep it portable to move it with the sun, or place it in the best position for the sun. 

Fyrestorm said:

Tried it again Lou and it worked.  Funny, I tried it 3 times and it didn't.  Anyways, thank You for the info.

Wavery, are those LED bulbs the same as the 12V halogen bulbs for replacement?  I was gonna replace the entire light but this looks like a cheaper option. I had no idea they made those.  Also, I may run with your idea on the solar charger.  I will run with this battery and when done change over to the 2 6V batteries.  I like the idea of how much longer they will last.  I own a golf cart and know that golf cart batteries are pretty stout. Alot of great info, Thank You

Click to expand...

The LED bulbs that I listed are a replacement for the single pin, 12V #1156 incandescent bulbs. Don't buy them at the $7.68 price. Check it a few times a week. They often drop the price to $4.99. I bought 35 of them so it made a big difference.

My system is permanently mounted using "L" brackets that I cut out of aluminum door step plate. The brackets are attached to my roof with 3M VHB double sided tape http://www.amazon.com/gp/product/B004V3SKUY/ref=oh_details_o01_s00_i00?ie=UTF8&psc=1. Trust me.... they aren't going anywhere. That's a common way of installing solar panels on RVs now. No need to drill holes. When it comes time to remove the brackets, a razor balde, acetone and patience can do the job with no damage to the roof.

If you leave yours portable, you can get a higher amount of charge in any given day by moving the panels square with the Sun every 2 hours. I actually highly recommend that for beginners because it gives you a lot better understanding of your system. However, it gets old pretty quick and I can almost assure you that you will double the size and permanently mount the system before too long... .

An 80W panel will charge @ 5.8A in full Sun with the panel fairly squared to the Sun. If you can move the panel every few hours for 12 hours, you may get ~60AH in a full day. The same panel permanently mounted will yield approx 30AH in that same full day (assuming there is no shade). So, one could accomplish the same amount of charging capacity by doubling the size of the panels.

When I lived on my sailboat, I had 4x 80W panels and I had them on swivel brackets so that I could move them into the Sun several times a day during long ocean passages. Once I was at anchor, I didn't mess with them because we were off doing other things. It's just a time management issue really.

Thanks again, I'm ordering the panel, controller and lights. Your a big help!  8)

Also if you have any pictures hady of how you mounted it, throw them on.  I would love to get more ideas. 

Thanks!!

These pics are of the installation on my TrailManor folding trailer:

One of our advertisers, rvledbulbs.com, has led replacement bulbs of all types and gives RV Forum members a 10$ discount. See their ad above the these messages.  These guys help us keep the lights on around here, so giving them your business helps us too.

I will be happy to check them out!  Thanks!

We have a large teardrop trailer and have all LED lights but also have TV XM radio, and we power a Waeco refrigerator. We have a 180W high voltage panel feeding into a Morningstar 20A MPPT converter. Why high voltage, even in low light it provides usable current. 

Wavery, I have the panel and controller.  I'm going to get some 10G wire to install it all.  But, there are some wierd connectors on the solar panels.  Did you cut them and just wire it together?  Or is there a adapter set I need to buy to plug the 10G into the solar panel.  Its a male/female plug set on the panel.

Fyrestorm said:

Wavery, I have the panel and controller.  I'm going to get some 10G wire to install it all.  But, there are some wierd connectors on the solar panels.  Did you cut them and just wire it together?  Or is there a adapter set I need to buy to plug the 10G into the solar panel.  Its a male/female plug set on the panel.

Click to expand...

Those are MC4 connectors:
http://www.youtube.com/watch?v=ISZg5nUDyH8

I used them on one camper that I had and found them a royal PITA...... On my current set-up, I cut off the connectors, soldered the wires and used heat shrink. If you plan on having the panels portable, you may want to consider installing the MC4 connectors on your 10G wire.

When you disconnect these connectors, the release tabs are so tiny that they hurt my fingers to press them in to release the connections.

Wavery,

is that install weather safe... Thanks for the links by the way...

bigcitypopo said:

Wavery,

is that install weather safe... Thanks for the links by the way...

Click to expand...

If you are talking about the 3M 4941 double sided tape... it is absolutely weather safe (IMO) if you use at least 4"x1" on each of 4 legs. That tape has a holding power of 1120# per panel. This weekend, I was driving 40MPH into headwinds strong enough that they tore off my TV antenna and dislodged part of my roof. We had steady winds of 30MPH with gusts near 70MPH right on the nose. I heard a loud bang on the roof in one of the gusts and pulled over to find the TV antenna bent in half. I climbed up on the roof (not fun in that wind) to cut it loose and check everything else. I gave a hefty tug on all 4 corners of each solar panel and they were solid as a rock. That tape has a "Dynamic Overlap Shear Strength" of 70# per sq inch:
http://multimedia.3m.com/mws/mediawebserver?yyyyy9n1N30UEazyu1T_6czyLa_XLJ0enazyLazyLyyyyyy--

4sq inches will give you 280# of shear resistance per leg. 1120# for 4 legs.

http://multimedia.3m.com/mws/mediawebserver?mwsId=66666UF6EVsSyXTt58T2o8z6EVtQEVs6EVs6EVs6E666666--&fn=70-0709-3862-9.PDF


On my way down is when I noticed that part of the roof came out of the "J" channel that attaches the roof to the sides. I was able to get it back in but I'm pretty unsettled that it happened. What a shoddy way to build a M/H.

If you are referring to soldering the wires and using heat shrink, that is the best method of insuring a weather tight connection.

Solar is a very real possibility, especially in your situation.  I am working out a system myself, it just makes so much sense.  Once purchased there is no gas to be purchased, maintenance is minimal compared to a generator and you do not have to listen to the drone of even the most quietest of the generators.
Here are a couple very good links with useful and interesting information for you.
http://handybobsolar.wordpress.com/about/

http://www.jackdanmayer.com/rv_electrical_and_solar.htm#Equipment

Great Horned Owl makes a good point about needing more than a single battery.  The better scenario is two 6-volt batteries wired in series which will provide the required 12volts, but will approximately double your amp hours.