I love my RV solar system!

[chrisski]

Skip tilting the panels, it's a big added hassle and I can't imagine it not being a maintenance issue. You lose about 15% to 20% by flat mounting your panels, just add an extra panel if you're worried about it.

I was up on the roof installing the tilt panels the last couple of days, and my next install I do won’t have them. What I did not take into account was the space it takes to get my hand between the panels, and in some places where 3 panels would fit, two actually went. Also, I doubt many people use the premade tilt brackets without modifications. My roof that I thought was flat was a curved slightly, which caused me to have to cut the brackets, which also meant buying more hardware.

[Wrybread]

I thought I'd post this interesting follow-up: the employees at my campground finally got power (the permitting process can move painfully slowly sometimes, ha). So I have the option of plugging in. But it's been a couple of weeks now and I simply haven't had the need. And I've been living in the camper 24/7 for months.

[Wrybread]

Awesome on the 8 panel system, amazing! My RV is pretty small, a 26 foot class c. What made it all doable for me was putting panels on top of the various roof vent pipes. Cut off the tops of the pipes, that are there to keep the rain out. Now the panels do that. Just a thought for people without enough space.

I'm considering putting a 4th panel over my bathroom popup vent (the kind that hand cranks open). But that would require making an inside cover so I can close it from the inside to keep the heat in. Would still be a functioning vent, but would no longer let light in. No biggie for me and worth the extra solar panel.

[PNW_Steve]

I get that of course, but I don't get why that is. Now that solar is so cheap and easy, there's just no reason not to have all the wattage you need.

I think a lot of it is just misinformation. Saying that the motor charges "more effectively" for example is just factually wrong. There's not a chance my 4 Trojan T-105's would still be healthy after 6 years if I was relying on engine charging for example. They'd have dipped too low too many times years ago.

Some folks may have space issues when it comes to placing panels. I was going to put two 300 watt panels on my 5th wheel trailer. Then I climbed up on the roof with a tape measure and changed my mind. One panel will have to do. I could make room for the second panel but it would require major work on the roof. Not worth it to me.

My other RV is a different story. It's getting eight 300 watt panels on the roof with space to spare.

[Asterix]

If you connect a load from one end to the center tap, you are only discharging half
the batteries. Eventually one half will be charged when the other half is partly
charged, which can damage half and eventually both halves.

Connecting batteries in parallel will never discharge them exactly evenly, since
nothing under the sun is perfect. Eventually the same problem happens, and
as they get more unequal the life is shortened.

What you can do is momentarily connect banks in parallel for a short heavy
load, such as starting an engine. But after that the banks need to be separated
and individually charged up.

The battery experts may say more. Bruce Roe

I didn't see why there would be a problem under the conditions the 12V side is being used, but if you wanted to do it properly, just use a switch to make sure the CC is not connected across the batteries or alternatively use a relay switch to make sure the series connection is broken. You could do this automatically from the starter solenoid. Power to the starter solenoid providing power to a changeover relay which disconnects the series connection of the batteries.

So I just did a double check on this. If you want info go here https://batteryuniversity.com/learn/...configurations
See the paragraph Tapping into a Series String

[chrisski]

I ended up going with the SPREs. Looks like the T-105s may have been a couple hundred cheaper overall.

I went with a different vendor than at first because the $190 was the shipping price, not the price per battery. Don't know why he sent me the shipping price and not the real price for all four batteries I asked for.

I went with a shop in Vegas, but my daughter is in San Fran until the end of the week, so maybe she could have gotten me a set back without shipping costs.

[Wrybread]

Interesting about the Trojan SPRE. For comparison I think the T105's should go for around $135, you might call these guys to see what their store pickup price on both is, just as a price reference, to make sure you're not paying a large premium for shipping. And of course the T105's are sold in stores for golfcarts and forklifts, so you might be able to find a local place that has them, and maybe they can special order the SPRE cheaper than getting it shipped from Amazon.

[chrisski]

Fair Enough.

The T-105 battery seems fairly easy to get, at least several Amazon suppliers, but the a similar Trojan I'm planning on getting is a little harder to find. The Trojan SOLAR SPRE 06 255 is a 6V 229 AH Battery that is almost the same price or marginally cheaper than the T-105. You'll get at least 6 years off those which is awesome. I didn't find a spec sheet off the Trojan website that talks about depth of disharge vs. charge cycles. Appear to be the same battery except the SOLAR SPRE is about 5/8" taller.

I'm waiting on a salesman to call me back about placing an order for that Solar SPRE.

[Wrybread]

I did mention the batteries, and fuses.

Skip tilting the panels, it's a big added hassle and I can't imagine it not being a maintenance issue. You lose about 15% to 20% by flat mounting your panels, just add an extra panel if you're worried about it.

Buy your battery jumpers pre-made.

If you're on a budget and want a battery monitor, it doesn't need to be expensive anymore (link).

I can't think of a single tool I used for the whole project other than a drill and a $20 multimeter. There probably were a couple of other tools, but not many and nothing fancy.

Of course you can spend as much as you want to on the project, but if someone wants to keep it cheap they can make a fantastic, safe system very inexpensively.

[chrisski]

My costs for the charging part of my system (the solar stuff) are about $530, and that's for 900 watts of solar power. That's a lot:

- $130 for a 300 watt panel (I have 3 of them, but 2 would do)

- $140 for a charge controller (link)

Without the 3rd mostly unnecessary solar panel it would cost $400, plus a bit for the wires. I call that cheap for limitless power that doesn't require any work and drastically extends the life of my batteries by keeping them charged, but as you say that's opinion.

As far as being easy, with the various solar forums on the internet, it's dead simple. There's lots of people who loving helping with this stuff.



Honestly I'd be amazed if anyone's batteries could last 2 years without solar. Unless they're super diligent with charging, but then I couldn't imagine why someone would want to work so hard when there's such a simple alternative.

If someone needs batteries too, the simplest thing to do is add either 2 or 4 Trojan T105's ($135 each). Or I've had great luck with the Costco 6 volt cheapies (about $90 each), just make super sure to keep them topped up with water. Plus about $400 for a good inverter, the wires, fuses, etc. If money is tight you could easily get away with one or two 300-watt solar panels, that charge controller, the 600 watt version of that inverter (or just get a cheapie inverter), and 2 Trojan T-105's or the generic alternative. That would cost well under $600 for a solar system including batteries that would probably be far and away the best one in any RV park.



.

With the $530 you mention, I would put the true cost of a decently constructed solar setup from scratch with no tools to be built by an individual with no labor fees at six times to 8 times that $530. At least that is what it will cost me to get 600 watts of panels, 440 ah battery bank, and a 1000 watt inverter, with no hidden costs.

seems to leave off the cost of the 4 T-105's, which I'm guessing runs a lot closed to $1k. Also, with the real cost I'm getting because my RV is not pre-wired to solar, things are adding up quick. The tilt bracket for to get a better angle during the winter for 6 panels is $240. 2/0 wiring for the batteries is $70, and a crimper for that can be $100. Constructing the thee battery box is even turning out to be pricey, at least $100, but closer to $200 to include a 2" venting system to the outside. Want to fuse the battery and put circuit breakers on the panels and feed lines, could be another $100, to buy a six string combiner box from midnight solar $120. If you want to get power distribution blocks, that could be $100 for 250 amps, but if you're trying to power a 2000 watt inverter on 12 VDC, which is a bad idea, but people will do, that's not strong enough. If I want something to monitor my power, $250. If I want to use a contractor relay to get something to auto shut off my RV's DC shore power converter so I can plug my inverter into the shore power, that's another $100

[inetdog]

Out of curiosity, what would damage them? If you parallel the two 12 volt battery banks in a 24 volt system made of 6 volt batteries, the batteries should (I think, I've never done it, and not recommending it, just wondering) be discharging at the same rate. So what exactly damages them in that configuration?

If you literally parallel the lower 12 V and upper 12/v banks of a 24 V system you are creating a spectacular short circuit. You would have to disconnect the 24v bank from charger and load and then reconfigure the two banks from series to parallel.
They do make power converters that provide a nominal 12V output and draw equal currents from the upper and lower banks. Not cheap, but more efficient than a simple 24V to 12V DC to DC converter.

[Wrybread]

Yeah, solar is tough to fully rely on if you need to power air conditioning off-grid. But I literally can't imagine having an RV or trailer without it.

- $300 to $700 for a modern high powered solar system
- not sounding like a helicopter is taking off for hours every day
- years and years of noise and effort-free power
- extending the life of your batteries by at least 100%

PRICELESS!

[Ho jo]

From the way I see solar is not for everyone.

for the last 3 years 3-4 months in summer.
I camp offgrid in the Virginia mountains in a travel trailer.
I park in the shade with 2 remote systems 400 watts on pwm and 500 on mppt. 50-58 amps charging. More than enough for my
416 ahs batteries @12 volts.

Temperatures get to 88f in the afternoon
I can't run air conditioning on my system so the generator Runs from 1-6.

I've found it's just easier to charge from the generator since its already running.

The generator doesn't care if the sun don't shine for 28 days like last sept.
(edit sept 2018)
So I sold the solar panels and charge controllers.
and bought a more efficient inverter generator

Now I don't have to put up the panels when I get there or take them back down when I leave.
less work and more time to enjoy my stay.
Just my 2 cents.

[NCmountainsOffgrid]

right, a portable generator, or an onboard generator, are simply too valuable to try to 'replace' with solar - they are full 120v power sources, when and where you need them, and can be used for other needs outside of camping, as well. Solar is expensive for the time it takes to ever 'recoup' the financial 'investment' for it - most campers just don't have that 'time', or that patience... or are not 'parked' in the sun to make it work best. Portable options are fine, but if they are portable, chances are they're also not very powerful.

I have some of both - onboard generator and some solar. Both work well for what they 'do', but ultimately, in a 'mobile' setting for camping and traveling, the solar becomes a 'trickle charger' for the battery bank, while the generator is the primary source of deep recharging and for 120v needs for air conditioning, and heavier high-draw appliances and devices, as needed. Of course, on a motorhome, you also generally have the advantage of the Alternator charging your batteries while driving, so the solar tends to take a back seat to both the others, only really being 'used' when parked and the generator is not in play, if not in the shade.

[Keylan]

Solar panel in RVing is an environmentally way to enjoy outdoors. But for now, a portable generator is much convenient for me. Congratulation on your successful solar panel set-up!