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So what do I need to know about adding Solar to an RV

welndmn

welndmn

Well Done Man
Joined
May 21, 2020
Member Number
1008
Messages
712
Loc
Concord, CA
I know, there are Youtube videos out there for beginners, but I think most of those people have no idea what they are doing.

Should I just buy a kit?
I see Renogy ahs simple 100w kits, but you can expand to 400w if needed with a controller for $300.
Good enough?
cheaper to buy a controller and then panels separate?

This is for an RV, I'm really not trying to power everything in the world, just want to put a charge back in the battery as my batteriers die down after about 4-5 days.
I really don't use much power.
I only have 2 batteries.
 
All I've done with mine is adding a battery monitor, solar charge controller, and portable panels. It seems to work fine, but I honestly haven't really put it to a major test. I think my portable setup will get me covered, and allows me to park in the shade. But of course, requires setup each time.

The battery monitor thing was kind of a pain to install, just because you have to find a spot to wire in a shunt with some large cabling, make your own cables, all that. But it's the only good way to figure out the state of charge of the batteries. And, if you guess wrong, it's the only good way to figure out how long to run the generator to charge back up.

I'd like to have a rooftop setup just so I could swap my traditional cooler for a powered one. If I was going to do all that, I don't have much faith in myself that I'd do it the right way with rigid panels standing off the roof. I'd probably just go the super easy route of glue-down semiflexible panels, even knowing that their efficiency is crap and they provide zero shade. Don't be like me!

My portable panels are pure chinesium semi-flexible. The best I've seen is 170 watts, and I don't know how many watt-hours in a day. That's in full sun. You'll probably want to park in the shade as often as possible, so you will REALLY want the ability to upgrade after you do some trial runs.
 
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I'm assuming the camper is 12v.

just get a 12v 40amp charge controller and a few panels. Renogy makes good stuff, but so do others.

don't overload the charge controller with too many panels. that is why I suggested a 40amp controller because it will be able to handle 6-8 100w panels or so.
 
400w of 100w compact Renogy or HQST panels. in series parallel on 10 ga wire or parallel them all up on 4ga wire.
I used 1/4" - 2"x2" aluminum angle for racking, bolting short pieces with three 5/16" lag screws through the roof, trusses with dicor self leveling sealant under and over the feet.
100W Watt 12 Volt Mono Solar Panel Compact Design 100W 12V Power 607052794439 | eBay
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Use the Victron 100/30 Smart Solar charge controller and the smart battery sense for temperature compensation. That will give you the Bluetooth voltage monitoring saving the extra cost of battery monitor, there are cheap solutions for that too depending on how nerdy you want to get.
www.solar-electric.com

Victron Energy SmartSolar MPPT 100/30 Solar Charge Controller 12/24VDC at 30 Amps

Part Number: SCC110030210
www.solar-electric.com www.solar-electric.com

That will get you a bad ass system for basic 12v loads and moderate inverter use, I make 1.2kw to 1.6kwh depending on usage and sun.
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You can save money by using a Epever MPPT controller or a whole lot by using a PWM controller.
I wanted to pretty kick ass controller with smart app for monitoring out in my chair looking at the mountains and while driving to the site.
PWM will require parallel wiring only using larger wire. If you are in CA where you are gonna get good sun the PWM/parallel advantage doesn't matter as much as in clouds or shade.
As long as you don't over volt the controller you will be fine as they can handle more current than they are rated but not voltage.
IT's common in the cloudy areas to grossly over panel by amperage but never voltage. Cold panels have higher than rated voltage so you don't really want to be super close to the voltage limit either.



 
welndmn said:
I know, there are Youtube videos out there for beginners, but I think most of those people have no idea what they are doing.

Should I just buy a kit?
I see Renogy ahs simple 100w kits, but you can expand to 400w if needed with a controller for $300.
Good enough?
cheaper to buy a controller and then panels separate?

This is for an RV, I'm really not trying to power everything in the world, just want to put a charge back in the battery as my batteriers die down after about 4-5 days.
I really don't use much power.
I only have 2 batteries.
Click to expand...
Renogy is an easy button, but IMO the larger commercial panels are better. More efficient, more diodes, high voltage (good wiht MPPT controller). I have a single LG 365W panel, victron 100/50.

Dont do flexible panels, you want air gap under them.

The ABS corners/mounts dont actually stick to sika 252.....
 
Java230 said:
Renogy is an easy button, but IMO the larger commercial panels are better. More efficient, more diodes, high voltage (good wiht MPPT controller). I have a single LG 365W panel, victron 100/50.

Dont do flexible panels, you want air gap under them.

The ABS corners/mounts dont actually stick to sika 252.....
Click to expand...

Ditto, the big panels are awesome but depending on the specific RV can be problematic with shading from AC units vents etc.
For the same money I could have 600+watts but at increased mounting complexity, in my case it would have been fine.
 
FWIW as I'm adding solar to my slide in camper I'm finding some real world constraints affecting my decisions that often get overlooked or are just situation specific.

dimensions of the panel and space available on the roof. Don't just look at the number of watts and cost, make sure the panel/panels will actually fit amongst all the protrusions and stuff up on the roof.

charging needs of your batteries. I have a single deep cycle battery I'm looking to keep charged under moderate use (inverter running a laptop, water pump, furnace occasionally, LED lights in the camper) and topped up when not in use. A 20A charger seems sized about right for a single battery. while a 40 or 60A charger might be a better bang for the buck, the excess capacity would be wasted in my setup.
 
With my setup of two GC2 6v's I try and make sure all the charging and heavy use is during the daylight hours so I can enter the night time with everything fully charged, it sounds obvious but I see people miss that detail often on forums.

I will also fire the generator for 10-15 minutes to super high load stuff instead of sapping the batteries even more.
My experience has been in good summer sun 3x to 4x of panel wattage per day.

Obviously if you don't pull any amps besides battery charging during the day your usage will be much lower only drawing what is needed to recharge/maintain, often folks misunderstand this as low solar output but it is actually low demand.

I am probably preaching to the choir but I thought I would just go ahead and add that info for anyone else that has not ever had solar.
My goal is to go to bed every night with the battery just off float voltage so the furnace has a full battery bank to work with and I don't draw below 40-50% of capacity.
 
Derp said:
FWIW as I'm adding solar to my slide in camper I'm finding some real world constraints affecting my decisions that often get overlooked or are just situation specific.

dimensions of the panel and space available on the roof. Don't just look at the number of watts and cost, make sure the panel/panels will actually fit amongst all the protrusions and stuff up on the roof.

charging needs of your batteries. I have a single deep cycle battery I'm looking to keep charged under moderate use (inverter running a laptop, water pump, furnace occasionally, LED lights in the camper) and topped up when not in use. A 20A charger seems sized about right for a single battery. while a 40 or 60A charger might be a better bang for the buck, the excess capacity would be wasted in my setup.
Click to expand...
Your uses parallel mine exactly. I have a single 100W Renogy panel on top of my slide-in, and a 20A (I think) MPPT controller. It has done everything I've wanted it to do, and I love having it. I rarely ever even bother to charge the camper while driving, since it's already fully charged all the time anyway. :D And I've used it to charge another car's battery via jumper cables, when that battery was failing. I think I've seen a maximum of about 5A out of it, which has been plenty since I don't use much power when camping.
 
my advice would be a victron inverter / solar charge controller (one unit)

110 is nice, can have a fridge running, or battery charging, etc
 
montrose818 said:
my advice would be a victron inverter / solar charge controller (one unit)

110 is nice, can have a fridge running, or battery charging, etc
Click to expand...
that is the bad assest setup for sure, load sharing off a 20amp circuit would be bad ass for a small inverter generator supplementing big loads like AC etc.

I didn't have the funds so I just used a chi-com 2000w pure sine inverter and my RV's built in generator transfer switch.
 
duluth.craigslist.org

345 Watt Solar panels $130 to 160 - farm & garden - by owner - sale

1 to 5 panels $160 each 6 to 19 panels $150 each 20+ $140 each 32+ $130 each (32 per pallet) ***Remember that you still get 26% of your money back as tax credit in 2021!!! The panels are 345 watt...
duluth.craigslist.org

Craigslist for cheap commercial panels. There's tons of listings like this in my area, I'm sure you could get someone to ship some.

I've actually got a solar panel manufacturer 20mi from me.
 
My trailer is wired with a Renogy solar controller but no panels. We are thinking about adding panels. We are mixed on either mounting to the roof or carrying portable panels. How we see it:
  • leave portable panels at home if we are going to have power available
  • put portables in the sun if we are parked under trees/shade
  • mounted panels aren’t in the way for packing or when camp is set
  • portables are easy to clean
  • portables could get blown around in wind
  • mounted panels will keep the house battery charged when stored or while driving
  • portables don’t need holes drilled in the roof

Is it dumb to not just mount panels to the roof?
 
Panels are cheap....

Mount them to the roof and be done, it made a pretty big difference for me.
My wife vacuums off the inverter when we come back from a trip, I can leave the trailer out of storage with the fridge, radio, CO detecors etc. on with no worry about the batteries. Before I would have to get close enough the house to run the extension cord etc.

If you want portables I would build those too, as the offerings I have seen are crazy over priced.
The HQST compact 100w panels are $79 each...
www.ebay.com

NEW HQST 400W 300W 200W 100W Mono Solar Panel 100W 12V 24V Off Grid RV Home | eBay

HQST 100 Watts 12 Volts Monocrystalline Solar Panel. HQST 100 Watt Monocrystalline solar panel contains 33 highly efficient monocrystalline solar cells protected by a thin layer of tempered glass. Each 100W solar panel is perfect for permanent or semi permanent installation.
www.ebay.com
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welp, i've placed my order for one of those HQST $80 100w panels and 1 HQST 20A 12V 24V PWM Solar Charge Controller w/ LCD to run it.

$108 with tax and shipping.

Don't plan on mounting it to the roof, figure i'll start of with just making some plugs and putting them in an easy to reach spot, then it will be "portable" and i can just set them up wherever. I don't park in a particularly sunny spot at the house so hopefully it will function. biggest drawback to the $20 charge controller seems to be that it can only handle a max of 2 or 3 100watt panels, but that isn't really a big deal. If i need more, just parrallel in another controller and still be well under the cost of a "better" one.

we'll see how it goes and for $100 something is better than nothing
 

Using a monitor shunt like this, you can keep track of power pulled from and added to your battery. It just gets wired in between your ground and the negative on your battery. ALL LOADS must be wired to the battery or a battery-tied distribution block this way. But it's handy as hell. This way, when you're camping, you can see that right now you're withdrawing power, adding power back in, whatever. And it estimates how long you have left like that. If you're a sucker like me, you paid much more for the brand name version of this. But $40 and some wiring time seems like a bargain to not have to guess.
 
I had 120w with a PWM controller on a single deep cycle and just a digital volt meter on my slide in. It worked well to keep up with lighting, and water pump loads. If it wasn't too cold, it would handle the heater for a night and get it back the next day. It wasn't a big setup but worked reasonably for the camper it was in.

After we sold the slide in and got a trailer, followed by a creating a midget human I knew I needed more juice as I hate having to run the generator for hours on end. I built a rack to hold 4-100w panels due to the battery location and roof layout. the rack mounts off the corner trim utilizing existing holes. The panels are in parallel (in case half the array is shaded) with a 10' home run of 8awg. Voltage drop was less than 3%. I used a Epever MPPT controller and have a pair of 12v paralleled batteries that came with the trailer. I'll go 6v in series when these die. I have a cheap 2kw inverter off the batteries in the next compartment that turns on and off from a switch inside so it's not burning juice all the time. I have a double gang in the bunk and another double gang outlet in the kitchen off that inverter as it was much easier than trying to tie back into the panel in my trailer. They work great running TV, phones, small appliances, etc.


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I only really run the generator for the microwave or AC. Heater, coffee maker, etc. all work fine and the solar keeps up on medium sun days.
 
OHV Wildcat said:

Using a monitor shunt like this, you can keep track of power pulled from and added to your battery. It just gets wired in between your ground and the negative on your battery. ALL LOADS must be wired to the battery or a battery-tied distribution block this way. But it's handy as hell. This way, when you're camping, you can see that right now you're withdrawing power, adding power back in, whatever. And it estimates how long you have left like that. If you're a sucker like me, you paid much more for the brand name version of this. But $40 and some wiring time seems like a bargain to not have to guess.
Click to expand...
that's a neat unit. I briefly looked at some other 12v LCD displays and then decided i'd just use my voltmeter if i ever cared :laughing: it already having the math programmed in is handy though
 
Provience said:
that's a neat unit. I briefly looked at some other 12v LCD displays and then decided i'd just use my voltmeter if i ever cared :laughing: it already having the math programmed in is handy though
Click to expand...
Just to belabor the point. It doesn’t just have the voltages in there as a table. It measures your second-by-second current draw, multiplies by the voltage at the time, and keeps a constant record of how much energy has been withdrawn. It keeps track of that like a gas gauge. Then when your solar is overpowering your draw, it counts that as adding fuel back to the tank. So, you always have the best read of whether your batteries are 1/2 full, 7/8 full, whatever.
Hope that makes sense. Measuring energy in vs energy out should be more accurate than guessing at the tank volume.
 
OHV Wildcat said:
Just to belabor the point. It doesn’t just have the voltages in there as a table. It measures your second-by-second current draw, multiplies by the voltage at the time, and keeps a constant record of how much energy has been withdrawn. It keeps track of that like a gas gauge. Then when your solar is overpowering your draw, it counts that as adding fuel back to the tank. So, you always have the best read of whether your batteries are 1/2 full, 7/8 full, whatever.
Hope that makes sense. Measuring energy in vs energy out should be more accurate than guessing at the tank volume.
Click to expand...
I appreciate and understand the use. starting off with just 1 100w panel, i'm still expecting to run the generator for a few hours when being in the hills for more than 1 night, for any system larger than 100w, it makes a whole bunch of sense to have that. I do like that unit better than some of the others i looked at.
 
Provience said:
I appreciate and understand the use. starting off with just 1 100w panel, i'm still expecting to run the generator for a few hours when being in the hills for more than 1 night, for any system larger than 100w, it makes a whole bunch of sense to have that. I do like that unit better than some of the others i looked at.
Click to expand...
Provience said:
welp, i've placed my order for one of those HQST $80 100w panels and 1 HQST 20A 12V 24V PWM Solar Charge Controller w/ LCD to run it.

$108 with tax and shipping.

Don't plan on mounting it to the roof, figure i'll start of with just making some plugs and putting them in an easy to reach spot, then it will be "portable" and i can just set them up wherever. I don't park in a particularly sunny spot at the house so hopefully it will function. biggest drawback to the $20 charge controller seems to be that it can only handle a max of 2 or 3 100watt panels, but that isn't really a big deal. If i need more, just parrallel in another controller and still be well under the cost of a "better" one.

we'll see how it goes and for $100 something is better than nothing
Click to expand...
That's probably going to be a nice simple setup for your use. I have had no issues with my HQST panels and there is a test on YouTube by Will Prowse that compared them and others and the results were identical. The packaging for mine was even Renogy branded.
 
distance/amp/wire gauge on probably 12v system it looks to be


after thinking about it, went ahead and ordered a 10 gauge duplex cable instead of using the wire roles that i have and tieing them together. should be easier to roll up and store, the extra layer of insulation will be nice in the weather and stuff as well. So i'm up to ~$170 or so



amps-10-gauge-wire-36-47929.jpg
 
What is the preference of running one giant panel vs multiple smaller ones? How about in partly cloudy/partial shade environments, does the output remain the similar?

I'm mainly looking at the mounting convenience of one large panel, a 400w panel is nearly width of my shitboxvancamper and would go on real easy.

Just starting down the solar setup rabbit hole.
 
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Ebs said:
What is the preference of running one giant panel vs multiple smaller ones? How about in partly cloudy/partial shade environments, does the output remain the similar?

I'm mainly looking at the mounting convenience of one large panel, a 400w panel is nearly width of my shitboxvancamper and would go on real easy.

Just starting down the solar setup rabbit hole.
Click to expand...

Multiple parallel panels can handle shading easily only dropping the current of the shaded panel. Series panels don't handle shading as well.


For sure purpose one large panel would be fine. You will lose some redundancy obviously but it might be worth it for simplicity/cost.
 
CarterKraft said:
Multiple parallel panels can handle shading easily only dropping the current of the shaded panel. Series panels don't handle shading as well.


For sure purpose one large panel would be fine. You will lose some redundancy obviously but it might be worth it for simplicity/cost.
Click to expand...
The newer larger panels have diodes build in to help with the shading issue also.
 
I have a lot more reading to do. But I'm thinking how you'd put a battery bank together from nothing. Is every charging source just isolated as it's own system (engine alt direct to battery, generator and/or plug-in 'shore power' run battery charger, solar battery controller/charger). Simple as that? No mushroom clouds if everything is running at the same time? Probably how RV's are setup?

Or are there all-in-one 'plug in whatever source you got' battery controller/charger/monitors out there? Is that's what I'm seeing these $1000 controller/inverters are? Run every power source to that and let it figure it out what to do.
 
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