Super Basic Solar Upgrade

[Ranger_Tim]

All I want is to install two solar panels with a charge controller to provide charging capability to my existing flooded lead acid batteries. I intend to use these Centennial group 27's until they are done (probably another year or so). I will upgrade then.

I want to use the factory wiring that exists in the camper. The controller location is prewired with access behind a cabinet panel. I know the wiring is going to be minimal and won't carry the current efficiently. The plug on the roof is like the type you see on battery chargers. One step at a time.

The current power management device charges, converts and protects the circuitry in the camper. I do not intend to replace it until I have to.

Here are my questions:

Can I add a solar controller and panels that will charge my batts without worrying about any ill effects to the converter being affected? Does the solar back-feeding the converter cause problems?

What type of panels are the best to get for a camper roof? What do people use to install them through the membrane and prevent leaks? Any particular concerns about drilling through the membrane?

Where is the best site to learn more without getting into a full-blown solar zealot approach to state of the art solar power generation involving thousands of dollars? I start talking about this and my wife's eyes begin to glaze over almost immediately. All she imagines is a mountain of cash going out the door.

Maybe I should just slog it out with the Honda 2200 until I win the lottery? I just envy those that can charge all day. It would totally top us off. We don't use much power at all. Bought the genny to run the A/C once in a blue moon. Haven't done it once yet.

[RambleOnNW]

I use a 100 watt Renogy suitcase solar panel with integrated PWM waterproof controller. They also sell controller less panels if you perhaps want to mount a more efficient MPPT controller in your rig. Also have 2 40 foot WindyNation 8 awg MC4 extension cable sets. With that setup we can park in the trees for shade and position the panels in the sun. That is sufficient to provide the 25-35 Ah we need for our low daily use and has significantly cut down our generator use.

[ajriding]

No worries on the two chargers playing together. They will be fine.

Use bigger gauge wire if you can, this will be well worth the time it takes to route new wire from the panel to the controller to the batt. 10 gauge, 12 would be the smallest I would ever run.

Run the two panels in "series" not parallel. They will be more efficient running down the wires, and the MPPT controller can take the 37 volts and convert to the lower 12-14.7 volts needed to charge the batts.

Glass Mono panels are what you want. Any of the ones on ebay are fine, but do not get the flexible ones. Many people prefer two panels instead of one big one. If one goes bad then you are out half..
The Poly panels are fine, but te mono are better for RVing.

You can sometimes run the wires down the fridge chimney, or use a "gland" to get in into the roof. Use "gland" for your search term on ebay. or "entry gland".

Use Dicor Lap sealant, never silicone (hard/impossible to remove) or caulk (cracks).

For a charge controller get an MPPT one. Do not get the $20 ones. IF you find a great deal then they will be $50 range. At least 30 amps. PWM would be OK if you already have it, but MPPT is the most science...

You can make aluminum L-brackets and use VHB (very high bond) tape to tape them to a metal or fiberglass roof, but not to a rubber roof or on top of a rubber coating. You can use self-tapping screws to go through the L-bracket and into the panel (careful to not screw into the actual solar cells or wires or glass) or you can pre-drill / use existing holes and use bolts (stainless steel).
You can screw into the roof also, but use Lap sealant liberally.

The panels on the roof will not see highway speed wind when you are driving highway speeds, there is turbulence on the roof so the forces are not that great so close to the roof. Some RVers use four 3-inch wide L-brackets and adhere them to the roof and the panel. I use 24 inch long angle irons (same shape as L-bracket just longer) and screw to the panel. I have metal roof so used VHB tape to secure to the roof. Leave room under the panel for air flow and for the wires to exit. Cool panels work better.

This is really all you need to know...

[AnEv942]

Really sounds to me like you have a handle on it- it's not that complicated and what you plan will work, well.
Basic kits most will use poly-crystalline panels which will charge your batteries. Basic kits will use an PWM controller which will charge your batteries correctly.
Many vendors for simple basic 2 panel kits under $250. Complete; panels (2)100 watt panels, mounts, wiring, connectors and controller.

(only as example)
(amazon) other listings
Better Mono-crystalline panels generate more power, but at additional cost. Better efficiency in delivery using MPPT controllers (desirable) but again adds cost. Buying 'top shelf' unfortunately, price increase is a lot more than the 10-15% efficiency gain. Does offer better efficiency/charging- but price reflects. Buying basic does not require doing again though room to 'upgrade' should you want.

Ranger Tim wrote:
Snipped... All I want is to install two solar panels with a charge controller to provide charging capability to my existing flooded lead acid batteries...

I want to use the factory wiring that exists in the camper. The controller location is prewired with access behind a cabinet panel. I know the wiring is going to be minimal and won't carry the current efficiently. The plug on the roof is like the type you see on battery chargers. One step at a time...That obviously will work with adding SAE plug to panel wires, however most of the kits include 10ga wire to get from panels to controller.

Here are my questions:

Can I add a solar controller and panels that will charge my batts without worrying about any ill effects to the converter being affected? YES- Does the solar back-feeding the converter cause problems? NO. Both questions- solar charge controller (& other charge source) read and react to battery not other charge source.

Where is the best site....? Well not the best but CA Travelers compiled list of threads/installs within forum and what others have done (not all TC)

Just my 2¢

[towpro]

I saw this nice mount on a sprinter where they had 2 panels stacked, and when you deploy them one slides out like a tray from under the other one. it even blocked ran at the door.

But your idea of angle has merit, but affect the further south you get.
hear in FL I am running Flat during the summer.

[Ranger_Tim]

This does give me a few new ideas on mounting them to the roof rails...

[Bert_the_Welder]

Just to through a thought that occurred to me, watching hipsters convert Sprinter's into Eco-Glamper Virtue Vans..... and thinking as a person that likes camping in the woods rather then the de-forested flat lands of private or KOA "camp" grounds.... Why mount on the roof?
Yes, they are up and out of the way, no messing around with once installed. I completely get that. It's a vacation= do your best to do the lest.

But.... why not have the panels free to roam? Have them on adjustable legs to prop them up at needed angle. A long enough cord that they can be moved around to follow the one sunny spot shining through the trees. I know I avoid parking in the sunny spot so I don't cook in the camper, so roof mount would be kinda dumb in my case. Make a light storage case or sleeve. Stow them under the mattress for travel. In the back seat. Under the dinette.
IMHO, flat on the roof isn't the best when the sun isn't directly overhead.

Have a pigtail in a exterior storage cabinet or even in the battery box to plug the panels into. As a bonus, easy to keep them clean and avoids adding more holes in the roof, which is A+ on my list of don't do's if possible. Also, if they die, your next ones might not fit your old brackets. So now you've got pointless holes and some new holes to go with them. No thanks!

If the roof is the best place for them, either for sun exposure or theft deterrent, make a base (Plywood or ?) with rubber feet or silicone sheet thanks roof friendly. Mount the panels to this. You can still rotate then and you a cable lock to secure to a roof rail, ladder or wrap snug around a AC unit, etc. (Razor wire around the perimeter of the roof, while effective, might be unsightly and limiting in meeting new people. Unless you want to attract the weekend Rambo types....)

Just thought I'd toss that idea at you, in case it hadn't crossed your mind.

[naturist]

http://mobile-solarpower.com

[Freep]

Ranger Tim wrote:

Where is the best site to learn more without getting into a full-blown solar zealot approach to state of the art solar power generation involving thousands of dollars? I start talking about this and my wife's eyes begin to glaze over almost immediately. All she imagines is a mountain of cash going out the door.

https://diysolarforum.com

[pianotuna]

My solar "plays well" with all other charging methods.

Use between 60 and 160 watts per 100 amp-hours of storage.

The series of plain articles here may help

https://freecampsites.net/adding-solar/

[Lwiddis]

Not "super basic," Tim. Do it once and do it right. Other than wire, here's a complete system from WindyNation nearly identical to mine:

https://www.windynation.com/MPPT-Polycrystalline-Solar-Kits/Windy-Nation-Inc/WindyNation-WNI-300-Watt-3pcs-100W-Solar-Panel-Kit-Trakmax-MPPT-40-A-Solar-Charge-Controller/-/343?p=YzE9NDc=

[srschang]

I have four solar panels on the roof of my TC. They do a great job charging the batteries every day. To answer your questions:

Can I add a solar controller and panels that will charge my batts without worrying about any ill effects to the converter being affected? Does the solar back-feeding the converter cause problems? No, your converter will just sense a higher voltage for the battery/solar controller combination.

What type of panels are the best to get for a camper roof? What do people use to install them through the membrane and prevent leaks? Any particular concerns about drilling through the membrane? I installed basic Renogy 100W hard panels. When I began installation on the roof of my new Northstar, I contacted the factory for advice. They use Eternabond tape between the solar panel foot and the TPO roof material, screw it down, then apply Dicor self leveling sealant over the screw, solar panel foot, and Eternabond. I used double sided Eternabond tape, it sticks to the roof and to the foot.

Where is the best site to learn more without getting into a full-blown solar zealot approach to state of the art solar power generation involving thousands of dollars? The best I found is DIY RV Solar Systems Facebook Group. Lots of great ideas and examples of small to immense RV installations.

I start talking about this and my wife's eyes begin to glaze over almost immediately. All she imagines is a mountain of cash going out the door. Yeah, just wait. You will have anyone you ever talk to glazing over and walking away. "Hey Joe, you should have seen yesterday my batteries were pretty low, and I was getting 22 amps from the solar panels!!! Never saw it that high!!! Wait, let me check it right now. A little lower today, must be because the batteries have more charge in them. As I was saying, yesterday... Wait, where'd he go?"