Battery died, time for big conversion solar, fridge, etc

Shawn S

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Aug 27, 2021
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First of all, I don't really know what I am doing. I have read some of the big threads, but a lot of stuff is going right over my head. I can fix things, but I don't have a great understanding of solar and what I may or may not need.

My deep cycle battery died. I want to get more robust with my electricity storage, and add solar to extend our usable time. Are there kits out there that I can buy? Renogy?
I have a 2000 10' Alaskan CO. It is sitting on a 2018 Silverado 3500 duramax.
I have a year 2000 3 way fridge, I would like to buy a new fridge and go 2 way and eliminate the propane.
I have room for multiple batteries (truck camper on flatbed).
I have room for multiple solar panels (no AC, single max fan).
I drive relatively long distances to camp, 6-8 hours is common, and sometimes longer than that.
I plan to keep my propane furnace and propane water heater, unless someone convinces me otherwise.
I like to backpack. I will leave the camper for several days at a time and live out of my tent. But, there will be some times when we are in the camper for an extended run of days.
I will be in a lot of situations where the solar panels will not work at a great efficiency, driving, backpacking for a couple days, etc.
If it matters, my camper is stored inside when I am not using it.

My first question is whether there are kits out there that I can buy that will give me a head start. Renogy had a 400w kit with 2 100 amp batteries, would this be a good start? They also have a 3 battery kit for $100 more.
 
Depending on where you are, you may want to consult with KP in Reno. He does installs. If you want to do the work yourself, you are in the right place. :)

The Renogy stuff is OK; I prefer Victron gear to Renogy, but the Renogy stuff has worked well for a lot of folks. On a related note, I'd rather have ONE big solar panel than 4 small ones. And in general, kits are compromises. If you are ok with that, it might be a good starting place. Here are some things to consider:

Do you need a 2000W inverter? I have a 3000W inverter in mine, but run an induction cooktop on it. Most folks can get away with a much smaller inverter.

Do you need heated batteries? The unheated ones work for most folks. We're in Calgary and unheated has been fine for us.

It sounds like with 6+ hours of driving to get to your camp spots, charging while driving is important. I'd get a DCDC charger and upgrade the wiring from the (nice!) truck to 6 AWG or more to facilitate that.

At a trailhead, parked in shade/dappled shade with a two way (DC/110V) fridge, you will need about 40AH of capacity in your battery bank for every day that you will be away from the camper. So, 200AH of LiFePo4 battery gives you 4 days away. Good enough? If not, you need even more battery.

Parked inside, you can get away with a normal decent battery charger (NOCO) with an extension cord hanging out an open door/window. If you want, you could add a ACDC charger too, but your camper likely came with an iOTA battery charger/converter that will continue working for you, although replacing that is an option as well.

I hope that helps. Ask lots more questions!
 
Thank you for your help. I am in eastern South Dakota, so a long ways from Reno. From what I have gathered reading the various threads, piecing my own system together is the way to go, but I have a lot to learn before I will fell comfortable pulling the trigger on that. But maybe that's where I start, and worst-case I make changes/upgrades as I go. I guess that isn't any different than buying a kit and upgrading that ad I go. I will do some digging into some more threads and try to learn more.

Is there a starting point to a build? I think that is one thing I am struggling with. We want 40ah a day, gone for 4 days, so let's start with 200 ah of batteries and figure out how to keep them charged. Is that where I need to start?
 
I have a 2021 FWC Grandby with 130 liter compressor fridge on a 2021 3500 hd gas truck. I went through this same process 3 years ago after deciding to do the power system myself. I ended up with 200 ah of lithium battery, 400 watts of solar panels on the roof with a 30 amp mppt charger, and a 30 amp dc to dc charger.

The sizing of all those system elements is adequate for my use in the Pacific Northwest, mostly in Western Washington. I can go at least four nights on a full battery charge with zero charging. Even on cloudy summer days the solar tops off the battery each day. In winter it can’t keep up, and in full shade in the forest it can’t keep up. 90 minutes of driving replaces a day’s worth of electrical consumption.

I second the recommendation for Victron chargers and battery monitor.
 
Kits are over priced and often not exactly what is needed imho as Vic was getting at.

"X way" fridge language is wrong, I've mentioned this elsewhere. We're talking about DC compressor fridges and ammonia absorption fridges, both can vary in what amount of power sources they are configured for. Plenty of ammonia absorption fridges are "2 way" in that they are propane and AC only (the 3 way versions on DC are extremely inefficient so its skipped often in other markets). My trailer is a "2 way" ammonia absorption fridge. Ammonia absorption fridges require heat to work, making heat from DC is what is highly inefficient.

Do you even need/want an inverter? If so what size, I run a simple ~400w one in my trailer (a victron pheonix 500) that works just fine for basic needs (not a microwave, coffee maker, etc.) and keeps wiring and costs in check.

Batteries: not knowing a ton about your system a pair of 100ah lithium would be great, check out powerurus as an option, <$600 for the batteries. I just got a pair and they load tested well, my buddies have been using them a while already on my recommendation, I was just waiting for my lead acid to die. You can add external heaters if needed.

Agreed on Victron stuff as much as practical, it works well.

I'd be looking at the newer 200w BIFACIAL solar panels to put on a camper with a reflective roof (they adsorb from the backside too, they have clear backing and light goes around the cells). I'd have absolutely put those on my trailer if they were common a few years ago. As for capacity, I'd imagine you'd do well with 200w but if you wanted margin you could use 300-400w. I plan to start with 200w on my truck camper. I have 400w on my trailer but the trailer has 3 vent fans, the heater draws much more amps, bigger space, etc.
 
I don't think bifacial panels mounted flat on a camper roof would be worth the trouble or the extra cost. Not enough light can get to the side mounted to the camper roof to be useful even if the roof were a mirror, unless the panel is spaced many inches, probably more than a foot above the roof.

They are intended to be mounted in a way the they can be illuminated from either side, that is vertically or well above the surface they are mounted above so that light can get to the back side.

More here:


This is an even better video on bifacial panels (watch it to the end).

 
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I don't think bifacial panels mounted flat on a camper roof would be worth the trouble or the extra cost.
If they were notably extra cost I wouldn't think they would be worth it either but you can get a 200w one for $150 for example, so why not? They have a clear backing so light passes in the gaps around the cells which is better than nothing reflecting up to the underside of the cells for basically no realistic increased cost. The fact they're in the same cost ballpark these days is the only reason I brought it up.

On my backburner of house projects I wanted to build a cover over my deck using bifacial panels as the roof, it'd be a cool look and as noted lets a bit of light through and isn't a stark white or black view.


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I look forward to seeing real world data from a bifacial panel mounted to the roof of a camper.

I strongly suspect that the typical 1" or so air spacing, needed to keep the panels from overheating, between the backside of the panels and the top of the camper roof, is insufficient to allow meaningful reflection. Keep in mind that while the cell backing material is transparent (same as the front) the cells are for all intents opaque as is the framing material. The area of the light space around the cells is pretty small relative to the overall cell area. There is some light that does not get absorbed by the solar cells but it is of a different wavelength and lower energy and not a significant source of additional energy. The majority of the illumination of the backside of the bifacial panels is from light reflecting off of the roof surface that enters the air gap from the outside perimeter of the panels (as demonstrated in the video I posted).

If a much larger then 1 inch air space gap between the roof and the back of the panel is created then it is possible to get meaningful reflection from a smooth white surface.

Now if the cost is the same either way I don't see a downside buying them unless the bifacial panels have a lower reliability/durability. My opinion is that the bifacial panels would not be worth paying more than a very small premium to buy.


My professional background is the design, analysis, assembly and test of airborne and spaceborne optical instruments and associated test equipment. I hope my comments are helpful.

Craig
 
Now if the cost is the same either way I don't see a downside buying them unless the bifacial panels have a lower reliability/durability. My opinion is that the bifacial panels would not be worth paying more than a very small premium to buy.
Exactly. They're in the same price point and reviews seemed fine on the one I linked (its in my amazon list as a strong consideration when I need a panel for my camper build). Generally speaking most rigid panels today are build similarly, yes some differences on cell arrangements, etc. but that one is a 10 bus bar 12V, I don't readily see any downside even if gains are minimal/negligible on a flat roof install.
 
pods8,

Are they structurally as robust to stand up to the shock and vibration environment of a vehicle? I do not know the answer to that but it should be considered.

Also weight. I think bifacial panels are heavier but that extra weight for a single 200W panel may be less than 10 pounds I'm not sure - I only looked at a Renogy panel.


Regards,

Craig
 
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I believe the only difference is they use a clear backs sheet vs a white or black one, they aren't two layers of glass, just a single top layer of glass like typical panels of this nature. They're the same general weight and one could assume same durability as they're constructed the same but simply use a clear backing.
 
pods8,

Interesting. Renogy in their advantages and disadvantages of the minifacial vs bifacial says the bifacial panels are heavier and more expensive and not worth the extra cost mounted flat on a roof.

 
I'm sure you know what happens when you try and paint with a wide brush stroke... ;) Sure glass/glass bifacial panels are heavier (and probably more expensive), but that isn't what I was recommending. I recommended a glass/clear backer which as I've linked is right in the same realm of cost and weight. If you don't like the idea of them don't use them but now that we've gotten all those caveats out of the way about the panel specifics I don't see a reason to specifically avoid them. Maybe they offer no benefit and aren't worth pursuing, but at $150 for a 12v 200w panel I see no harm either and they might have a minor gain. Personally I am not one to dink with adjustable angle mounts on a camper but I know some folks do, in which case there is very likely a gain in production I would expect. They're an option to consider and newer to the 12V market so I mentioned them.
 
My commentary is not specifically directed toward you so please don't interpret it as criticism. I was trying to have a dialog for those who may be reading that don't know some of these things might and gain additional insight.

If a discussion can help stimulate thinking or digging for information so that a decision is an informed decision, then it is worth having the discussion.

I respect that what you or anyone else decides to spend their money on is their business.

I hope the above discussion is helpful (to someone).

Regards,

Craig
 
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I enjoyed sitting back and reading your "change to solar" experience and remembered mine and Wandering Sagebrush's experience up in the Shelden NWR in NW Nevada, almost 10 years ago and how times, knowledge and experience with things like general solar knowledge, a dying 3 in 1 gas frig and a (forced) speed up of a planned future change to solar, ringing gas buzzers, batteries, hot springs and associated smells and the fear of going boom! I should add here-" all the things that you are told could happen to your rig if you blow it and do the wrong thing" and suddenly here it is happening in the middle of the night out in the back country. Without this site the people who use it, our experiences and wanderings up country have been made more enjoyable and improved by input from all of you, especially when you have a problem.

Since I cannot figure out how to move my story here from where I first posted it on May 19th, 2014 and the resulting commentary and helpful advise [ Hint Steve or Monte-if someone knows how to move it-your help would be greatly appreciated]. My post is called "When things almost went boom." Without retelling the whole story again, we had a propane problem that led to some interesting comments and with help from folks here and at FWC and my local mechanic, I'm pretty much solar now and glad that I did-even if I lost 7 lamb chops first!

Enjoy
Smoke
 
good luck. i think this site, and crew, is your best bet. i wired up my pop up with with a $900 lithium battery, and all the victron components. i also had the help of a wtw member who drew out my wiring diagram - and then i just followed the map, so to speak. worked great for me, with 200w of solar, 100 ah batt. dometic dc fridge/freezer. i never ran wires from truck engine bay, back to the pop up, as for me, the solar kept the batt. maintained - but there is a risk there if u are in shade. i generally powered up the dometic on ac before trips so it was cold - and when u have ice cream while out camping in the boonies - its a nice surprise.
 
Thanks for sharing your experience of only using solar to charge your lithium. I am facing the same decision. Your experience gives me something to consider. Thanks
 
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