45 Watt Solar Panel

[shark918v]

I have a 2001 FR 1610 pop-up trailer. I'm trying to figure out a way to prolong battery usage when boondocking while conserving space.

Q: Has anyone ever mounted a 45 watt solar panel on the (pop-up) roof, and wired it to charge the deep cycle battery?

My thought was to possibly mount it to the rear area by A/C unit, then run the wiring over and down the side to the battery.

Any and all thoughts and/or input is welcome and greatly appreciated.

[KMP44]

We sold our Coleman popup my brother-in-law and he was all pumped up to add solar. He bought a really inexpensive 45 watt panel from Harbor Freight. I was skeptical, but it put out a lot of power. He had good results keeping the battery charged. He didn't permanently mount his, which gives him the ability to move it around as needed. Keeping it in full sun is the key to getting maximum output.

If you mount it on the roof, you loose the ability to tilt it and you are at the mercy of shadows from trees. Mounting it is certainly more convienient but that panel is fairly small, so you could carry it on one of the beds or someplace and set it up when you get there. If you are camping in full sun, you could even set it on the roof before you crank it up and have it out of the way. A couple velcro strips would hold it in place while camping.

I think you'll be happy with the solar panel - just consider keeping it movable.

[asparky]

I am just wondering if anyone else has used one of these 45 Watt units from Harbor Freight. Typ. put out a MAX of 3.75A @12VDC... Probably less than that, but a battery tender Typ. puts out around 1.0A @12VDC. granted 24/7. As an Electrician I am not a fan of solar, its come a long way but has a long way to go. But for boon docking any amperage is good. just remember 2 921 bulbs draw almost 3A or 3 912 bulbs draw about 3A also. So going LED for lights will help a lot!! Its on sale now for $145 but you can run your truck or gen. to just charge your batteries for a long time for $145. just my 2 cents!

Solar Panel Kit - Save on this 45 Watt Solar Panel Kit

Ron

[camaraderie]

Take wattage...divide by FOUR and that is ON AVERAGE the amp hours you'll get per day from a solar panel. In this case 11-12 amp hours a day from a 45W panelisn't going to do MUCH while camping and using the battery...but it will recharge and keep a single common sized battery between weekends IF the 50% discharge rule is followed.

[cadman99]

I would consider a different single panel without the charge controller - slim chance of overcharging your battery with an approximately a 3 amp charge if you keep an eye on it.

There are a bunch online - Here's a few from Amazon

http://www.amazon.com/s/ref=bl_sr_la...ode=2972638011

[asparky]

Yea, I wasn't going to buy it, but might work for someone on a camping budget and maybe charge a battery for emergency use or winter storage with no electricity available. like I said I'm not a fan of electrical solar.. now non electric solar hot water is a different story.

Ron

[shark918v]

Ok, back to electrical questions....

Q: let's say I plan to do a lot of boon dock camping. And I currently have a deep cycle battery in use. I keep it on a solar trickle charger when parked. A day before we leave I take it off the trickle charger and let it rest to get an accurate charge reading. The day we leave I hook up the trailer to the charging alternator of the tow vehicle and off we go. When arrive at the destination I break out the larger 45 watt HF solar panel with the charge controller and hook it up to keep the deep cell battery charged. Also, I did replace all the interior lights with LEDs.

Can I add a small sized 12v gel cell battery in parallel with the deep cycle in order to further extend the battery usage???????

And if so, in your opinion, how is the HF 45 watt solar charger going to work in this overall system???

[RPAspey]

You could, but mixing battery types is a bad idea. Each battery type has its own charge parameters. If you desire to add capacity, go with identical deep cycles.

You could use a marine style a/b switch. A battery would charge at home, switch to the B battery which charges while traveling.

2000 Cherokee 31BH, "flipped axles and raised",LEDs, solar, inverter, etc..aka "boondock ready". '07 Tundra 5.7L DC-LB, modded as well. C-co, 8/158th, AVN.

[Happy Vibe]

I run a set of 30W suitcase solar panels (60W total) I have them hooked up to a 12 awg cable so I can move them into the sun. I have camped for over a week with this setup and the batteries stay charged. I have a second deep cycle battery that I can hookup if needed but I have yet to need it. I used a 5 pin trailer connector on the trailer and at the end of the cable so I can hook them up easily. I use a BEP battery monitor to keep track of the battery level. Going to add a mppt charge controller this year to see if this will give me better charging.

[cadman99]

The charge controller will see whatever batteries are hooked to it. If you have two different batteries that require different charging rates neither will get fully charged. You would need to switch between the two batteries to get each fully charged.

These three HF panels will actually produce about 2 1/2 to 3 amps maximum if in full sun and aimed at the proper angle. Usually you will get maximum output for about 5 hours per day. Less during morning and afternoon sun. So on average maybe 1 1/2 to 2 amps during the full day.

As I said in an earlier post if you are using a fair sized deep cycle battery the chances of over charging with a direct hookup (no controller) are very minimal. A quick check with a voltmeter or hydrometer will indicate charge condition. I would also use a single 50 watt panel - why mess with three panels. So keep it simple to start. One panel tied directly to the battery - your done.

[camaraderie]

@HappyVibe... 60 watt solar panels are capable of outputting at most 20 amp hours a day in sunny weather. You must be a very frugal user of amps.
****
As to the question raised by Clark...RPAspey has it exactly right +1.
The only thing you might want to do is to bring along a clamp meter that can measure DC amps on your next trip...then at night....measure the amp draw on your positive battery cable with various stuff you typically use turned on. Then by figuring the # of hours a day you will have that draw...you will know your amp hour needs. Obviously...if you have refrigeration you'll need to account for that draw on an intermittent basis....usually 25% of actual draw when on (i.e. 6 hours times actual draw) is sufficient.
Assuming your have a group 27 or 31 battery delivering around 100amp hours of capacity...you have 50 amp hours of use before you need to recharge. (50% rule prevents paying for batteries frequently!) . If your amp hours IN from the sun...don't equal your calculated amp hours OUT from use.. you now know how long those 50 amps will last you. Alternatives are bigger panels...or more batteries or a generator to let you camp longer.

[Happy Vibe]

Yes we are frugal. we don't watch TV or play the radio much, all the interior lights are LED. The main draw is the fridge control panel and Co detector.

[camaraderie]

Originally Posted by Happy Vibe

Yes we are frugal. we don't watch TV or play the radio much, all the interior lights are LED. The main draw is the fridge control panel and Co detector.

Yup...frugal enough to make a Scotsman blush!
Just a thought...an MPPT controller isn't gonna get you too many more amp hours a day off that set up...probably THREE on average. Alternatively...A tripod or similar mount for those panels that you could adjust 3-4 times a day to face perpendicular to the sun could significantly increase your amphours.
Panel output for flat panels is generally quoted as the EQUIVALENT of 6 hours of direct 90 degree angle sunlight per day. In the summer...you can see how much loss of available power this represents. If you're generally around the site ...you can pick up a lot of the missing daylight by making the occasional positioning adjustment.

[Happy Vibe]

MPPT is more for playing with than real gain. The panels I have are on stands and as I said they are on a long wire so I can move them around the site. I plan on running them in series so they will run at 24 volts and see what I get. This is as much a science experiment, not just for keep they battery charged.

[cadman99]

Yeah but .......... Most frig circuit boards draw at least 1 amp and run 24 hours a day. So you need 24 amps per day just to run the frig (on propane). With a 45 watt panel you will be lucky to get that much daily. (2amps avg. X 10hours = 20amps). In addition the CO detector draws another 1 amp 24 hours a day. So the guess-estimate is your 45 watt solar panel will not keep up with the frig and CO detector.

LEDs work fine - I run a string of 18 LEDS that draw 160milliamps. I use a 4amp hour battery and a 5 watt panel no controller. Works good as long as the sun shines.

If you are going to run an inverter for 110VAC then you don't have a chance with a 45 watt panel.

[Happy Vibe]

MY panels do keep up because I have camped a few time for over 1 week and the batteries were still charged. My fridge does not take that much current, my draw is less then half an amp. I do not use an inverter because they are power hogs. Also I have 60w of panels, unless you were referring to the OP's setup. Sorry to the OP I seem to have high jacked your thread.

[blw2]

Jjst from what I've read elsewhere, better panels can be had.....
Appearently these HF panels work but aren't very good (as expected)....
I think I remember maybe something about not putting out well in less than optimal conditions, etc....