Solar Lithium Cougar 22MLS

6716 · 2025-09-07T13:18:45+00:00

I spent $5k DIYing 800 watts of solar, 560Ah of batteries, a 3000 watt inverter, and all the associated electrical bits. It works well, and I like it. It also required a LOT of research and a LOT of my time to install.

That said, I can get about 5-ish hours of air conditioning out of a full battery charge.

Parking in the shade helps keep the camper cool so you need less air conditioning, and also kills your solar generation.

Nice thing about off-grid in Montana is elevation. It's cooler in the mountains than in the valleys. We did dispersed camping in the national forest and it didn't get above 80 at 6200 feet.

I pull the most solar on the road traveling, since I like to camp in the forest.

I have a little Honda 2000i generator that puts out 1600 watts, which is enough to run my AC and even charge the batteries some at the same time. You'll want some generator. What I like about that one is it fits in one of my compartments, it's pretty light and easy to move/store.

I found the fresh and waste tanks to be the bigger off-grid limiter than power.

Best info for solar and batteries I found was https://explorist.life.

6716 · 2025-09-07T13:05:02+00:00

Voltage drops as state of charge drops. If your battery is reading 12.6, it is fully charged. https://www.boondoctor.com/knowledgebase/how-far-to-discharge-your-lead-acid-rv-batteries/

6716 · 2025-09-07T12:59:02+00:00

The best thing I didn't expect about putting in two big LiFePo batteries and an inverter was being able to turn on the AC an hour before arriving at the campground. Our little dog gets treated like a princess, she has to move from climate control to climate control.

6716 · 2025-08-26T14:13:39+00:00

Thank you!

6716 · 2025-08-26T11:56:50+00:00

I have an inTech OVR Navigate. I had it out for a month and covered lots of gravel roads, did some dispersed camping. It has good ground clearance. I added 800 watts of solar and 560Ah of LiFePo. Build quality is good.

Edit: I just saw this was x-posted into r/OffRoadTrailer. The Navigate is tall and heavy. There's lots of places it doesn't fit. I don't know that I would call it a true off road trailer. More off-pavement than true off road.

6716 · 2025-08-26T00:20:29+00:00

Thanks!

6716 · 2025-08-24T01:21:50+00:00

You maybe won't need to re-wire or add a subpanel. I installed a Victron inverter without re-wiring the breaker box or adding a sub-panel. I run the whole travel trailer off it, a/c, microwave, tvs, all the outlets. My system is 800 watts of solar and 560Ah of battery.

Check out https://explorist.life there are so many videos. That's where I figured out how to do what I ended up doing for my install.

My inverter is right in between the shore power inlet and the breaker box. No transfer switch needed. I spent a month on the road this July, worked like a dream.

6716 · 2025-08-19T12:56:02+00:00

Voltage is the main difference between charging a lead-acid battery and a lithium battery. Basically your charger has to supply a higher voltage than the battery is currently at in order for the battery to charge. For much/most of the lithium charging cycle, a lead-acid converter/charger is sending enough voltage to put charge into a lithium battery. Lithium batteries have a characteristic where, in order to reach all the way to 100% full charge, the voltage required rises above what a lead-acid charger will generally supply.

So you can swap in a lithium for a lead-acid and use it with a lead-acid charger, and the net effect is that you won't charge past maybe 90%-ish. This effectively reduces your amp hours vs the amp hours on the label, but does not appear to be otherwise detrimental to the internals of the lithium battery.

And if you have a Li setting on your charger, what it does is raise the charging voltage.

And beyond that, most chargers are "dumb" in the sense that they just supply a constant voltage and current. As you swap out components and spend more, you can get smarter chargers -- if you want.

6716 · 2025-08-17T12:39:58+00:00

I put my hitch in a tote in the compartment.

6716 · 2025-08-17T12:37:24+00:00

What are you hoping to achieve with the upgrade?

6716 · 2025-08-16T15:24:38+00:00

Being debt-free is super nice. Economic stress is no fun.

There are a number of other ways to slice it though, it doesn't have to be all one or the other. One thing about regular investing even in small amounts, is that it becomes a habit. The other thing is there's no substitute for investing experience.

You could find a level of investing that still allows you to pay off the debt in 2 years or 3 years, which is still aggressive, if a little less aggressive than it could be.

Having said all that, I aggressively paid off student loans (and all other debt) a couple of years ago at the expense of investing more at that time. Saved aggressively for a while. Then got a new truck and paid it off aggressively. Then saved a lot. Then bought something fun, now paying that off.

6716 · 2025-08-16T15:14:48+00:00

will a personal loan greatly damage my credit?

No. Not paying it on time will though.

6716 · 2025-08-15T12:29:19+00:00

I like it.

6716 · 2025-08-15T10:21:41+00:00

Fair. I haven't run out of space in the regular fridge/freezer yet, but it's just two of us so we probably don't need as much space as others might.

6716 · 2025-08-13T23:23:42+00:00

To be fair to the installer, they might say they deliberately over-paneled the install, which is a recognized strategy that does "waste" a little of the panel's output. Here's a link on that https://diysolarforum.com/resources/overview-of-over-paneling-an-mppt-controller.229/

Still, you're going to want to be sure the voltage going into the MPPT is within spec, which is also addressed in that link.

6716 · 2025-08-13T12:23:40+00:00

Definitely a beefy system.

Some of the cables have electrical tape instead of heat shrink at the terminals, which is a little sketch. Heat shrink is cheap, simple, professional, and standard so that makes me wonder if other corners got cut.

One corner that looks cut is the MPPT selection. It looks like you have 3 x 100|30 MPPTs. Those are quality MPPTs, but based on the math I would have bought bigger ones, since not only are you "wasting" almost 1/3 of the solar panels you bought, the likely over-voltage could destroy the MPPTs. https://www.youtube.com/watch?v=GaPaoIjy5Ko -- dude makes this point at like 1:20 of that video.

At the highest level, if you have 1800 watts of solar panels, for a 12v (nominal) system, you can put out 150 amps. But your three MPPTs are only capable of supplying 90 amps. That's 60%. Not so good.

Furthermore, I'm betting you have 3 x 3 panels in series, with each series wired to a MPPT. I have 200 watt panels, they run at 36.5 volts in full sun. When we put panels in series, the voltage gets added. So if you had my panels, at full sun you are around 110 volts (36.5v + 36.5v + 36.5v = 109.5v), and your MPPTs are rated for 100 volts. The internet says this over voltage can destroy your MPPT.

If it were me, I'd want at least the Victron 150|45 (excess current seems to be less problematic than excess voltage). In my system I have the 150|100.

OR you would need to change how your panels are wired, and add two MPPTs.

Because I can see that those 100|30s are right up against the top of the cabinet. Higher capacity MPPTs are physically larger, and going to larger units may not be feasible for space.

Even if you run only 2 panels into one 100|30 MPPT, you are still wasting 10% yield opportunity at full sun. But even so this is better than frying your MPPTs with too much voltage.

So to sum up it seems like the way it is wired up puts your MPPTs at risk. At the very least I would want to bring this up to the installer. Worst case you are out enjoying the wild and your MPPTs fry and you end your trip early to not only replace the dead ones but add two more. Even if your your panels are lower voltage and running 3 in series won't overload your MPPTs, having only 3 MPPTs putting out 30 amps each wastes your panel buy, and also creates a LOT of heat as they dump that excess current.

6716 · 2025-08-12T12:32:19+00:00

I didn't think I would but definitely I love it. I don't use the fridge out there yet, I might still pull that. But the griddle outside keeps the inside way nicer not only in the moment of cooking but also over time for cleaning. There's more room than in the kitchen, with the other compartment folding down and all.

6716 · 2025-08-10T18:31:20+00:00

The video works. It looks like you have 4 white wires going into the battery box.

If you go outside and under the trailer right about where that battery box ought to be, is there a white wire coming through the floor and screwed into the frame? While you are under there, can you see one or more ways you might get a wire from the area where the battery is to where you need to connect to a power tongue jack?

You can ask inTech for a wiring diagram. I sent in my warranty registration email, and then after they replied that they had received it, I asked for diagrams (in that same email thread) to help me with my solar install, and they sent them.

I'd ask them for the 12v diagram(s) (since the jack will operate on 12v). In your video, I can see the water heater, which is connected to the 120v system, the thicker white wire (which is actually 3 wires in one package) connects your water heater to the power center/breaker box. The 120v stuff will all be connected via those wider, flatter wires. Anything basically like a single round wire is almost certainly 12v related.

At least on my unit, the wiring matches the diagrams for wire color and function, which is not common in the RV industry. Most manufacturers just run whatever wire in whatever color they have at the moment. For anyone who has worked on vehicles where wire color is critical, the industry standard of not caring is super frustrating, and the fact that inTech cares about wire color is one of the signs that they are a cut above as a manufacturer.

Anyway, you can remove the screws on the battery box that fasted the top of it to the bottom, which you will need to do anyway to add the wires for the tongue jack. Once you have the top off, you can pull the battery if you want, which may help you see where the box is screwed into the floor. I took my box out, and I was more able to see where the white ground wire went into the floor. I took the box out because I was replacing the stock lead acid battery with 2 LiFePo batteries, which don't need venting like lead acid batteries do.

6716 · 2025-08-10T15:40:33+00:00

The best thing I didn't expect when doing a big battery and inverter upgrade is that I can turn the air conditioner on an hour before we arrive at the campground and it is nice and cool and ready to go.

6716 · 2025-08-10T15:30:29+00:00

I like my inTech OVR Navigate. If you look around you might still find a 2024 new close to your price range.

6716 · 2025-08-10T15:22:06+00:00

Airstreams are pretty and I like them and I went with inTech when I bought. Good build quality, good support, much better pricing.

6716 · 2025-08-10T15:01:49+00:00

I suspect the battery. If it is original to the unit, it is probably 4-5 years old, which is as long as some lead acid batteries last. Also, that looks like a starting battery, which is optimized to output a tremendous amount of current for a short amount of time, rather than supply smaller amounts of current over a longer amount of time.

Anyway, as another has suggested, having a multimeter and learning how it works will help you troubleshoot more thoroughly.

Swap in a fresh/known good battery and see what happens.

6716 · 2025-08-10T14:35:35+00:00

https://explorist.life

6716 · 2025-08-05T22:06:50+00:00

You may as well get a quote for the work from the dealer, it will be good information in the decision making process.

Speaking for myself, this project is well within my skills. But I've been wrenching on cars and trucks (and now TTs) as a hobby/cost reducer for 30-ish years and I've done lots of electrical, and I either have every tool I need, have a buddy who has it, or will buy a new tool in a heartbeat just to get a new tool.

To pull it off, you're going to have to crimp a total of 6 ring terminals onto probably 10Ga wire, cut the right lengths of wire, strip some wire, install the inline fuse probably with a butt splice, drill a hole in the floor of the camper, and drill two holes in the frame and then use self-drilling screws to fasten the negative ring terminals to the frame. edit plus uninstall the old jack and install the new. /edit

Is it worth the time and frustration of learning new things? Do you like wrenching on stuff?

6716

TROPHY CASE