I love my RV solar system!

[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]

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.

[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

[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.

[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.

[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.

[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.