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Adding solar to 03 Class A RV, what would you do?

Freddythunder

I'm lost, please help
Joined
Aug 31, 2024
Messages
14
Location
Arizona
Hello strangers. I think I have somewhat of a grasp on what I want to do, but it may just be Dunning-Kruger. I have been digging into solar stuff in YouTube, here, irv2, etc. for a few months now. I wanted to do more research before posting, but I'd like to get some stuff bought on Black Friday sales so I'm hoping to get some more direct info. I have to do this in phases because I do not have a palette of money in my garage.

Vehicle current stuff:
We have an 03 WB Journey 32 foot Class A. We're new and naive to RVs so bear with me. Currently there are 3 house batteries, 2 engine batteries, all lead acid, from 2022, group 31, 12 volt. There's a Onan 7500 Generator that if you run that or plug in the 50Amp plug, turns the inverter on for A/C, microwave, refrigerator, etc. I have not learned if I can turn on the inverter without doing one of these two things, but I'd like to. The inverter is a Xantrex freedom 15 mounted in a compartment just East of the battery drawers.

Future phases:
In a future phase, I think I want to upgrade the batteries to 24v batteries for the storage but it's too expensive (maybe 48v depending on cost in the future). I want to move to Lithium batteries (which I heard charge at a different voltage level than what my current charger pushes) and I'm not sure if I can change them one at a time or if I have to change all 5 at one very expensive time. Just the words "mixing battery chemistry" makes me feel like it's a bad idea.

This phase:
Okay, so that's the backstory.. Here's the what would you do question. My first phase, I want to put solar panels up and charge the batteries - but planning for the future. Maybe figure out how to turn on the inverter from the batteries. I currently own 2 100W panels and am planning to purchase more. I think I've learned the best thing to do is wire them in serial and deal with a higher voltage - please correct me.

I want to start with 4 200 Watt panels and a charger. Currently Renogy has a deal (possibly, maybe it's like this all the time, I don't know) https://www.renogy.com/renogy-800w-12v-general-off-grid-solar-kit/ that contains 800W panels and an MPPT, but I've been reading to stay away from Chinese and pay the extra money for Victron. I'm going to install 10 to 14 foot rails on the roof to hold panels for now and in the future.

What would you get if you were me to solve your immediate charging needs while keeping in mind your future plans?

Last thing first - I know the first thing I was supposed to do is figure out how much wattage I'm going to use in a day, but I don't have that figure yet so I'm just trying to shoot high and start measuring. I know I'll be using AC, residential refrigerator, 3 laptop chargers, let's say about 30Amps on the 12 volt system (lights and fans and stuff) in the evening).
 
May not be able to have enough solar to run the air conditioning very much. 2000-3000+ watts needed.
Resi fridge can use 600-800 watts of panels. Realistically 1200 watts and skip the air to take care of basic needs. The planned 800w may do the trick considering the generator is right there if needed.
Hopefully propane hot water, cooktop and furnace.

When mounting the panels keep them a bit elevated and away from shade items such as vents, air conditioners, antenna etc. Even one cell with partial shade can mostly disable a whole panel.

Actually may have an inverter/charger that will charge 12v lithium just fine with an adjustment to the settings.
Need to post the actual equipment to get best answers.

Probably best to keep the lead-acid batteries for the chassis as you convert the house to lithium.

How many nights have you spent in the RV? Sounds like more time camping might be needed even if at a KOA etc. Perfectly OK to unplug and see what works and for how long on the existing equipment. If batteries run down... just plug back in.
 
Good point, running the AC on solar/battery probably way in the future if even at all. I think 800w would be good for now just want to make sure I'm heading down the right path.

Luckily I have a all kinds of real estate on the roof. The AC is basement air so there really isn't much on the roof at all. But thanks for that shade info, I didn't think of that.

I want to keep the original Xantrex freedom 15 (can't find much info on it online, the manual is in the RV I think) inverter/charger as long as I can and upgrade later.

Don't laugh. Haven't spent one night in it yet. Total refurbed the inside and now it's getting cold so we winterized and maybe have to wait until spring or camp without using the pluming. But, def what I'll have to do is go camp in it and experiement.
 
A lot depends on your “real” goals. What I mean is what do you want “it” to do???

I full-time in a 36’ diesel pusher and we boondock most of the time.
I have 1500w of solar for house batteries +100w for chassis.
A lithium battery 12v 544ah
I have all Victron (except the batteries).

To add solar or lithiums to your rig you MUST understand exactly what you have now and then figure out where you want to be and understand the constraints you have to live under.

One big constant is your rig’s CCC. Cargo carrying capacity. This is all your water, food, clothes, stuff, and extra stuff you add to your rig - solar, etc.

Another constant is your plan if you do things one at a time.

For example, I started with a Victron smart shunt. This helped me plan how much solar to start with. I then did 800w of solar and a Victron mppt 100/50 Solar charge controller. Then changed out the house batteries- four GC2 AGM Lead batteries. While testing the inverter I discovered it was not behaving correctly and we were getting ready for a summer in Alaska, so I quickly put in a MultiPlus 12/3000 inverter. That worked well on the trip. As we went full-time - put lithium batteries in - because I already had a 12v inverter the battery stayed at 12v.

Later when we put a residential fridge in we added 400w of solar and a mppt 100/30. Later when we got Starlink, we added another 200w of solar with a mppt 100/20 - then expanded that array to 300w.

We still run our generator about 100 to 120 hours a year. We can only run the air conditioning for a little less than an hour (on full battery), then have to decide if we will keep it running and turn on the generator or turn it off for the day.

Is it ideal to have three arrays? Nope. But because I could not do my final system up front - I am fine with it. All that slow expansion of the solar was over 5 years. So do yours in whatever time frame you wish.

For MotorHomes I really recommend Victron equipment! I think it is worth it - even though they are more expensive.

Sorry for the ramblings- hopefully it will help you think long-term for the project.

Also, Don’t buy ANYTHING until you have a plan on paper (or computer) that lists everything you need and you know exactly where it is going. Over the years I have seen many people buy at Black Friday prices and then later when they try installing realize that that equipment does not “fit” in well (and in a few cases was not at all what they needed), thus wasting money.

Post your plan here and several people will look over it. Often times pointing things out that need changed. (Missing fuses, incorrect wire size, wired to a wrong place,etc).

Good Luck!
 
Adding solar now is a good first step. With the right solar charge controller you can charge the batteries you have now as well as your planned LiFePO4 batteries. Implementing a large solar charge controller now that can be dialed down to charge at lower amps is what you want.

The next step would probably be the inverter/charger if it is not capable of being programmed for LiFePO4 batteries.

The interface between the house batteries and the starter batteries is probably going to be the most challenging part of the design. Read threads here on the forum to see what other members have done. There are a lot of examples out there. Your starter batteries are going to remain lead acid, or maybe AGM. LiFePO4 is not going to work for starting a big engine.
 
Step one is to look at your RV roof and see if it is even a good idea to put panels up there.

A lot of them are covered with a rubberized fabric material that gets brittle over time. Some will start to crack if drilled into.

It might even be that the roof needs a new seal before the panels go on.
 
Step one is to look at your RV roof and see if it is even a good idea to put panels up there.

A lot of them are covered with a rubberized fabric material that gets brittle over time. Some will start to crack if drilled into.

It might even be that the roof needs a new seal before the panels go on.

All too true. I had to repair the wood truss frame and the plywood substrate before I could install my panels.
 
Keep LA batts until the end.
If you are going to have a lot of solar then you might find you almost never need to charge any other way. I have never charged my lithium batteries other than being hooked to solar. Dont sweat the charger issue. Get a low-cost charger, 20amp or 40 amp for when you might ever need it.

That Renogy package makes me hurt, there are WAY less expensive routes if money is an issue.

Forget running Air cond on batteries, at least for now, that going to require a lot of battery power and a big inverter.
How much power does your current air cond use?
There are mini-splits out there that likely use less than yours and also ones that run off 12v 24v or 48v DC battery.
For now use your generator for Aircond.

Get bigger panels than 100watt. look at 300 watt ones instead of 3x100. less wires, less to go wrong, easier to mount.

Yes, panels can be wired in series and parallel at the same time, example, two 300 watt 12v panels in series to make 24 volts and another exact set of panels next to it, and both sets of wires can feed into one set of wires and into one charge controller.
The less your panels are in series then the less chance one little shadow will kill the whole system.

You can use multiple charge controllers to feed one battery bank instead of one big controller.

Check eBay. EPever is one Will has tested in the past (this is Will's site), and are a good price. Get the amperage charger you need. Get multiple ones.

You can find panels for 50-60 cents per watt on eBay also. I just bought 3x 100w panels for about $49 each, new.

Do not get the cheapo flexible ones.

Lithium can be charged with a lead acid charger, but you will never get to 100% full bc the voltage is never high enough, so you can use what you got until you get the right charger. Actually, just keep your charger since you prob never need it due to solar panels, and if you do need it then at least you can charge them back to 80% with the lead acid charger, this will be good enough that one time in forever that you ever even need a plug-in charger. The solar will still work a little even in shade, so eventually will charge to 100% when parked for storage.

Get a DC to DC charger so your alternator can be a source of charge. Add this as one of the last things too, but it is going to be more useful than a plug in charger.

Pros and cons to what voltage battery you pick, but nothing wrong with sticking with 12v as everything in your RV is already 12v. The biggie is if you going to run aircond off batteries. Pick batteries for this purpose and make it work for everything else.

Benefit of 120 v aircond is it works straight off your generator or shore power. Downside of 120v is that you need an inverter to make it run off batteries, but this is a minor one as long as inverter works, and eventually it will not work.
Downside of DC aircond is that it does not run off shore power, so will need enough battery and solar to keep running, or when plugged in will need big enough charger to run aircond. It runs off batt/solar so is free to run and is usually sunny on days you need air anyway.
You might need 500-600 amp hours 12v to run air overnight, but need more to run air for long periods/days and need the sun and need lots of solar.
 
As far as the renogy kit, I have worked with that rover solar charge controller.

I normally don't buy anything from renogy, but a guy already had one and asked me to use it in his van.

For some reason I said yes and made it work "ok" after a lot of effort and anguish, but it would have been better if I just threw it in the garbage and helped him for free.

He had 600 watts on his van and there were cloudy days when it used more power to run it than it produced.

They settings don't work the way renogy has in the manual, and it was not just me, I had a pro EE controls engineer over to help me dig out of the mess.
 

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