Old RV - New PV's With Strut-Channel Mounting

[Browneye]

I'm new here, starting a new thread on my 430W installation, so I can ask questions when they come up. This forum has been a wealth of information.
I have also been scouring the 'net for, and learning about, LiFePo4 batteries as well.

I'm not sure where I first saw strut channel mounting for panels, maybe it was youtube. There was some good info on another thread here as well. Anyway, after scrutinizing what I had room for on my motorhome roof, and what might be viable options, I settled on the cheap stuff from home depot. 3 ten foot lengths gave me two channels each for my 58" solar panels - and crossbars to bolt the panels to. These are the 1-5/8" X 13/16" electro-galvanized strut channel. Funny, I had never heard of strut channel before this project. There it was, in stock at good ol' home depot. They had the 1/4-20 channel nuts in stock too, they are really slick. The rest of the fasteners are stainless. I used blue locktite for all of the mounting screws to make sure they didn't come loose.

I cut and painted the rails, and the channel nuts, then glued the rails down with VHB 5952, plus three #14 self-tapping screws in each rail. I tried picking one rail up to re-position it a smidge after just setting it down, and it was going to be a battle so I left it. Now I know that stuff sticks like you know what.

This is a 16yo Winnebago/Itasca - it has a fiberglass roof, which is very thin, and bonded to very thin luan plywood. It's in good shape though, and cleaned up well with acetone and a scotchbrite pad, then alcohol. Then stuck the rails.

The panels are 215W 36-cell, brand Nature Power - HD sells them now, and had a one-day sale recently for $154 each. I couldn't pass that up at 71cents a watt. I also got a Tracer Xtra 30A controller, and all the ancillary cables and fuses and connecting hardware. Wiring and SCC installation is next.

I found some wind loading calculations here in wiki - could be up to 250lbs of lift for these size panels, and elsewhere some tensile strength for glazing with 3M VHB. With those estimates I have about a ten-times margin of strength. For glazing they use 18psi on the VHB, and I have 180square inches of adhesion area, so I figure I'm good. Ran some screws in there to make sure.

Cut to size and painted with automotive acrylic enamel. Painted the nuts too:

I covered up the slots in the channel with eternabond, and sealed the outer edges and screw heads with Sika urethane sealant. I froze the eternabond and then cut the 2" roll into 1" strips. Worked out really well. 1" tape is backordered 'till next year.

Sealed and mounted. Happy with the way this turned out:

Here's a pic of our 2005 Itasca Sunrise 31W motorhome, off grid with the solar-suitcase I got a few years ago. It was time to upgrade:

 

[chrisski]

I cut and painted the rails, and the channel nuts, then glued the rails down with VHB 5952, plus three #14 self-tapping screws in each rail. I tried picking one rail up to re-position it a smidge after just setting it down, and it was going to be a battle so I left it. Now I know that stuff sticks like you know what.

I think that's a good installation. Becoming in style to only use tape, which may not be the best idea.

off grid with the solar-suitcase I got a few years ago. It was time to upgrade:

Those suitcase panels

My suitcase can make more energy than the roof panels capturing early in the morning, moving to the noon sun, and then again to the setting sun. Also some places have parking constraints, like marked parking under a tree.

 

[Browneye]

I like your install - went and took a look.

I started a thread here on the portable ones: https://diysolarforum.com/threads/rv-solar-suitcase-how-much-will-mppt-improve-output.30918/

While I did move the SCC to the inside of the coach, I've since ordered another Tracer AN mppt to go with it - a 10A for the two 80w panels. I can change the portable ones to series - will be better for the 25' cables, and with the same specs the charge controllers should work better together - one for the roof top and one for the portables.

Seems the cheapo pwm that came with the portable setup doesn't play well with the newer mppt controllers - too much pulsing to get a good read on battery voltage. Victron solves this by linking them together in a comm setup. I'm going to try EP tracers without - they're less than half the price. Hope I'm not sorry.

 

[chrisski]

Thanks on the compliment.

I’ve expanded the suitcase panels to be 2S4P for a total of 800 watts of outputs for a 24 volt upgrade I’m working on. By putting the panel in series I’ve voided that warranty. I’ve found that cloudy conditions do on the voltage the panels put out so being in series helps with that. So far I’ve only tested this panel system 6 at a time on smaller solar generator.

Currently the RV is in the shop with the tire fenders shredded from a blowout. Taking forever for the parts to come in.

 

[Loadtoad]

Don't want to hijack your thread, but I was going to use the unistrut also for my installation, but instead used 6" mini rails from signature solar. Lot cheaper, lighter, and mated with the brackets made for a lightweight inexpensive install.

 

[Browneye]

Ah bummer. I've seen that happen - it can really tear up a unit.
The front michelin XRV's on ours were 9 years old...I figured I better just scrap them and count my blessings. They were showing a few tiny weather cracks, but overall good. Just 45K miles on this coach.
Got new Sumitomo's for the rear about five years ago and they've been great, so got them for the front. So far I like - they ride just as good if not better than the michi's, for nearly half the price. Sumitomos come from Japan. They put the semi-truck balance bead-bags in them which seems to work well. You get some wobble at first, then it smooths out.

I almost went for some more portable panels, but dragging them out and setting them up is a pain. Besides, I don't have a lot of deep bays for storage, so that's a problem as well. So now I have both, can deploy as needed. That you can adjust the portables to where the direct sun is, is a big plus.

 

[Browneye]

Don't want to hijack your thread, but I was going to use the unistrut also for my installation, but instead used 6" mini rails from signature solar. Lot cheaper, lighter, and mated with the brackets made for a lightweight inexpensive install.
View attachment 72378View attachment 72377

I like. I was looking for an easy way to remove them if necessary. As long as you can get to the mounting bolts you're golden!

 

[Loadtoad]

I like. I was looking for an easy way to remove them if necessary. As long as you can get to the mounting bolts you're golden!

The mini rails will be permanent, but the solar panels can be removed very easily and swapped out for a new.

 

[jwelter99]

I'm new here, starting a new thread on my 430W installation, so I can ask questions when they come up. This forum has been a wealth of information.
I have also been scouring the 'net for, and learning about, LiFePo4 batteries as well.

I'm not sure where I first saw strut channel mounting for panels, maybe it was youtube. There was some good info on another thread here as well. Anyway, after scrutinizing what I had room for on my motorhome roof, and what might be viable options, I settled on the cheap stuff from home depot. 3 ten foot lengths gave me two channels each for my 58" solar panels - and crossbars to bolt the panels to. These are the 1-5/8" X 13/16" electro-galvanized strut channel. Funny, I had never heard of strut channel before this project. There it was, in stock at good ol' home depot. They had the 1/4-20 channel nuts in stock too, they are really slick. The rest of the fasteners are stainless. I used blue locktite for all of the mounting screws to make sure they didn't come loose.

I cut and painted the rails, and the channel nuts, then glued the rails down with VHB 5952, plus three #14 self-tapping screws in each rail. I tried picking one rail up to re-position it a smidge after just setting it down, and it was going to be a battle so I left it. Now I know that stuff sticks like you know what.

This is a 16yo Winnebago/Itasca - it has a fiberglass roof, which is very thin, and bonded to very thin luan plywood. It's in good shape though, and cleaned up well with acetone and a scotchbrite pad, then alcohol. Then stuck the rails.

The panels are 215W 36-cell, brand Nature Power - HD sells them now, and had a one-day sale recently for $154 each. I couldn't pass that up at 71cents a watt. I also got a Tracer Xtra 30A controller, and all the ancillary cables and fuses and connecting hardware. Wiring and SCC installation is next.

I found some wind loading calculations here in wiki - could be up to 250lbs of lift for these size panels, and elsewhere some tensile strength for glazing with 3M VHB. With those estimates I have about a ten-times margin of strength. For glazing they use 18psi on the VHB, and I have 180square inches of adhesion area, so I figure I'm good. Ran some screws in there to make sure.

Cut to size and painted with automotive acrylic enamel. Painted the nuts too:

I covered up the slots in the channel with eternabond, and sealed the outer edges and screw heads with Sika urethane sealant. I froze the eternabond and then cut the 2" roll into 1" strips. Worked out really well. 1" tape is backordered 'till next year.

Sealed and mounted. Happy with the way this turned out:

Here's a pic of our 2005 Itasca Sunrise 31W motorhome, off grid with the solar-suitcase I got a few years ago. It was time to upgrade:

Thanks for using some mechanical fasteners and being aware that people might be driving behind you

 

[jimcalf]

I'm new here, starting a new thread on my 430W installation, so I can ask questions when they come up. This forum has been a wealth of information.
I have also been scouring the 'net for, and learning about, LiFePo4 batteries as well.

I'm not sure where I first saw strut channel mounting for panels, maybe it was youtube. There was some good info on another thread here as well. Anyway, after scrutinizing what I had room for on my motorhome roof, and what might be viable options, I settled on the cheap stuff from home depot. 3 ten foot lengths gave me two channels each for my 58" solar panels - and crossbars to bolt the panels to. These are the 1-5/8" X 13/16" electro-galvanized strut channel. Funny, I had never heard of strut channel before this project. There it was, in stock at good ol' home depot. They had the 1/4-20 channel nuts in stock too, they are really slick. The rest of the fasteners are stainless. I used blue locktite for all of the mounting screws to make sure they didn't come loose.

I cut and painted the rails, and the channel nuts, then glued the rails down with VHB 5952, plus three #14 self-tapping screws in each rail. I tried picking one rail up to re-position it a smidge after just setting it down, and it was going to be a battle so I left it. Now I know that stuff sticks like you know what.

This is a 16yo Winnebago/Itasca - it has a fiberglass roof, which is very thin, and bonded to very thin luan plywood. It's in good shape though, and cleaned up well with acetone and a scotchbrite pad, then alcohol. Then stuck the rails.

The panels are 215W 36-cell, brand Nature Power - HD sells them now, and had a one-day sale recently for $154 each. I couldn't pass that up at 71cents a watt. I also got a Tracer Xtra 30A controller, and all the ancillary cables and fuses and connecting hardware. Wiring and SCC installation is next.

I found some wind loading calculations here in wiki - could be up to 250lbs of lift for these size panels, and elsewhere some tensile strength for glazing with 3M VHB. With those estimates I have about a ten-times margin of strength. For glazing they use 18psi on the VHB, and I have 180square inches of adhesion area, so I figure I'm good. Ran some screws in there to make sure.

Cut to size and painted with automotive acrylic enamel. Painted the nuts too:

I covered up the slots in the channel with eternabond, and sealed the outer edges and screw heads with Sika urethane sealant. I froze the eternabond and then cut the 2" roll into 1" strips. Worked out really well. 1" tape is backordered 'till next year.

Sealed and mounted. Happy with the way this turned out:

Here's a pic of our 2005 Itasca Sunrise 31W motorhome, off grid with the solar-suitcase I got a few years ago. It was time to upgrade:

I just bought four of the 215W Nature Power panels for $154.00 each from HD too. I was looking at Rich solar 200W panels, but at $1.10 per watt vs. $0.71, I couldn't pass these up. That is 35% cheaper, and they come with Z brackets, which I'll need since I have a small trailer with a Plywood / TPO roof. I guess if I build my own batteries with cheap EVE cells and JBD BMS, some cheepo panels from Vietnam will fit right in. I sure hope they work!

 

[Browneye]

Thanks for using some mechanical fasteners and being aware that people might be driving behind you

The stories were bone-chilling. I wanted to make damn sure mine weren't coming off unless I TOOK them off.

 

[Browneye]

I just bought four of the 215W Nature Power panels for $154.00 each from HD too. I was looking at Rich solar 200W panels, but at $1.10 per watt vs. $0.71, I couldn't pass these up. That is 35% cheaper, and they come with Z brackets, which I'll need since I have a small trailer with a Plywood / TPO roof. I guess if I build my own batteries with cheap EVE cells and JBD BMS, some cheepo panels from Vietnam will fit right in. I sure hope they work!

I had been shopping for weeks. The good news is then you realize a deal when you see one.

I am headed over to the Phoenix area over the holiday and was going to just pickup some of those Santan Solar ones - but everything I measured wouldn't fit right on my roof. So....

I couldn't believe it when I saw those. I was getting ready to pull the trigger on the Rich Solar ones too. Or HQST. I narrowed it down to larger watt for two panels rather than three or four of the 100w. As you can see they just fit better. And a series connection is easy for any mppt controller.

Then I had to decide if I wanted a Victron SmartController or the Tracer. Price won out. Lots of happy customers for both. I really liked the bluetooth built in to the victron, but it was also more than twice the price. We'll give it a whirl.

I'm trying to decide on some kind of battery monitor. I thought I would install everything and see what I get out of the Tracer Xtra unit. Then get a shunt and display if I really think I need one.

I'm also looking at a lithium battery replacement, but not willing to spend five grand on batteries like my neighbor did on his 6 battleborns. Dear lord. Been reading up on the DIY sagas and the bigbattery and batteryevo trials. SMH.

I was explaining on my other thread that I replaced the panel connect wires on the new panels to 10awg PV grade wires with MP4 ends. Pretty easy to un-solder the 14g SAE wires they had and put new ones on there. Now I'm all set. Pretty cheap date for $10 a panel.

I need to run the panel wires down the fridge chimney - got 20' of 10awg. At the bottom the drain tray is right above the wiring rats nest under the fridge. I'll just tie into what's there.

Check this out...how Winnebago does wiring from the factory. I have since added the Xantrex 600w inverter - moved the IOTA over a bit and it went in next to it. I've cleaned it up some, but not a lot I can do with it without rewiring the whole rig. Yes, that's the shower pan in the back. LOL

 

[chrisski]

I'm also looking at a lithium battery replacement, but not willing to spend five grand on batteries like my neighbor did on his 6 battleborns. Dear lord. Been reading up on the DIY sagas and the bigbattery and batteryevo trials. SMH.

I’m finding the real cost for my upgrade including tools,wiring, battery cases and a couple other things is about half the cost of BattleBorns. I hear it can be done as low as a quarter.

 

[time2roll]

With that clean pro job mounting panels..... you are ready to build a battery

 

[Browneye]

With that clean pro job mounting panels..... you are ready to build a battery

That is kind of you...but I'm much better, in fact very good, with mechanical stuff. That erector set when I was about eight started a lifetime of mechanical aptitude. I would skip out of eighth grade classes and go to the library and read about how to fix cars. I even worked at a car dealership for a number of years as my first real job. I've built two boats, several cars, a slew of vintage motorcycle restorations, learned to paint when I was 18, built two houses, seriously into RC aircraft, even took up flying for awhile and was going to build an airplane. The electronics are all still just like smoke and mirrors to me. Even so, I'm an IT tech by trade for the past twenty years. I run the network and ecommerce for a distribution company. But then...I have consultants.

I did drop out of two classes at the community college...Electrical and electronics - as soon as all the math started I glossed over.

I used to enjoy working on mechanical stuff, now it just seems like work, so I make craft beer and ride electric mountain bikes. I had to give up a fifty year pursuit of offroad racing and adventure touring motorcycles for old age.

Reading about all the problems people have with trying to make their DIY batteries work is exasperating at a minimum. I don't know if I could handle all the futzing around with them. Top charging and bottom charging, puffing and sensors for every silly thing. I think I would rather just buy one that had a warranty, and setup my rig to keep it charged.

I'm two years away from retirement, and then we'll really be able to do some RV traveling. We had a blast when the kids were younger - put forty thousand miles on the ol' motorhome with them - this is the third one. Now the kids are all grown and gone, they all moved back to Seattle. All I hear is "So when are you guys moving back up here?" Well, maybe eastern washington where it doesn't rain so much.

I guess I've got one more house to build... 🤩

 

[Browneye]

Finally got a free day yesterday to hook everything up. Did a major cleanup on the wiring mess under the fridge - should have gotten a photo. LOL

Made a positive side bus bar out of copper pipe - had never seen that done before - youtube to the rescue again. The remote post in the 'e-compartment' was getting way overloaded with cables for converter, inverter, distribution breaker panel for the house, and now the two solar controllers. The ground side had a nice bus bar welded to the chassis frame, but a jumbled mess of wires, so I took everything off and re-routed all of the large gauge major system ground wires, and loomed all the 12v homeruns - there are a couple of dozen of those, grouped in about 10 ring terminals. Made a big difference and gave me room for the new plus-side bus bar and SCC breaker and all of those connections.

Pulled PV wire down the refer chimney and routed out the bottom - goes right into my 'e-compartment' and then out for the solar controllers. Mounted the new smaller Tracer MPPT for the portable suitcase, and changed their feed wires to 2S.

All in all a fun project and I really like how it all worked out. Powered everything up and was getting 3.5A with winter sun way low in the afternoon, and the put the portables up on the roof tilted up and got 3.5A from them too. This is going to work out just fine.

The Tracer SCC's are really easy to setup, good info from them, I really like them so far.

8am, sun just up...portables are pulling 3A and the flat roof-top ones 1.4A. Once the sun gets on them they both read the combined rated voltage of the panels. The roof-top 215's are a little higher voltage rating than the poly portables. 2S they show 41 volts on the SCC. Amps output depends on amount of sun they are able to see. I let the house batteries run down to 12.5, so we'll see how quickly they charge up this morning with everything out in full sun.

The newer model Tracer N 'Xtra' 30A MPPT. Later on this morning it showed 2.1A from the panels, 6.2A out to the batteries. MPPT is awesome - and very little voltage drop thru the PV wires this way too.

And for the portable panels, a Tracer AN MPPT 10A. I changed the lead wires on the panels to 2S. They show 35V on the controller - specs on the panels are 18V nominal. Looks like the value shows just a slight voltage drop through the 22' lead cable. 2S really bumps up the voltage, then MPPT outputs max amps at charge voltage.

2 pole circuit breaker for the PV side so I can shut them down without having to go up on the roof to unplug MC4 connectors. And a 50A switchable breaker for the battery side. 10awg PV wire in, 8awg out to the batteries.

Easy access in the entry step well, pretty innocuous:

 

[Browneye]

Batteries charged up in a couple of hours. By late morning I was getting 22A to them, pretty happy with that.

 

[Browneye]

Well, on to the next project in the old RV. @time2roll has convinced me to build a lifepo pack from cells. Middle of November I pre-ordered US delivery of Eve 230 cells from @Amy Zheng and she has been very responsive and now they are ready to ship product from Houston.

I have been gathering all of the tools and materials I need. I'm really excited about it. It's a big challenge for me, uncharted territory. So here goes.

The first thing was to replace the old converter/charger - IOTA IQ4 - which was great for lead acid but we can't be equalizing a lifepo pack, and I couldn't modify it, so I got a new PowerMax 55A unit, the first of their new 2-stage line of chargers for lifepo. And since I was moving the battery to inside the coach for heating and AC environment, I wanted to move the converter out from under the fridge as that is where the 600W Xantrex inverter resides. I did install a temperature-controlled computer exhaust fan, but I've blown up two of those little boards now, getting it properly wired and working. I had it working, then when I moved everything the wires got pulled out and when I put them back I got the proverbial 'let the smoke out' LOL

Anyway, the space is ready for the new pack, the new converter is in, and I've made up all the battery cables to hook it all up. It also turns out the 12V feed to the electrical compartment under the fridge where the inverter AND converter were - was just 6awg wire with a 55A circuit breaker to the main connect post under the steps. I didn't want 55-60 watts from either charging or inverting so far from the battery on 6 gauge wire, or that light of a breaker. So I left that in place and installed a dedicated 12V feed in 4awg to the inverter with it's own 80A anl fuse. The inverter can pull as much as 60A.

And once the house batteries are gone then I'll get a second starter battery and a 100w panel to keep those charged for the chassis. Since the isolator came out, all I need is a short 6" link cable and I can replace the lifepo pack with the chassis battery for house power duty. There was one of these linker cables in 1 guage left over from the old install. I no longer have the alternator connected to the house batteries. I'm trying to decide if I need a Victron Orion 18 or 30 dc to dc charger. It might be nice to have at least something charging while we're driving. Trips are usually 3-5 hours, sometimes more.

None of the cables or wires from winnebago had shrink wrap on the terminals, and they are all die-less crimps, so I hammered all the loose copper strands down and made sure everything was clean, and shrink wrapped them. It sure makes a nice upgrade to the whole system.

I removed the carpet under the settee and painted the plywood base floor where the cell-pack will go. The floor is plywood about an inch thick with an aluminum skin on the bottom side. Cut a 2" hole for cables to pass to the basement, and over to the chassis ground bar, and the plus side posts and breakers. There's another floor under that and everything under the floors - the basement storage - is more or less heated on these units. The engine radiator also heats the hot water tank and has a heat exchanger for the floor ducting from the furnace - so engine heat when you're driving.

Anyway, I've been buying tools and parts and wire and stuff, this is a really fun project. I tested out the Temco hammer die-less crimper and made up all the new battery cables for the new lifepo pack. Scored on some King Starboard HDPE and clear polycarbonate remnants for the battery pack box at our local plastics supply house. Got a OverKill 120A BMS, and found blue black and red welding wire to make up all the connections. A benchtop power supply came in with adjustable voltage for top balancing the cells. A shunt and meter, and a current clamping gauge. Not sure what I'm going to do with that.

I installed a new switched outlet for the new Powermax converter. I took the hardwire telephone face plate off, put a 110V light switch in it's place, then fished 14/2 romex thru the wall and connected it to an adjacent existing 110 outlet. It is nice to be able to simply turn off the converter when on shorepower or generator. All systems are now nicely isolated.

The new battery cables are fished up through the floor, connect to the bus bars and connect posts under the steps where the old golf cart batteries live.

The cardboard is the battery profile. This is under the settee in the main salon. The folks at the taproom last night didn't know what a 'settee' was. They thought I was being hoity-toity. LOL Oh well, it's the sofa in the main cabin of the motorhome.

 

[Browneye]

I ordered the Overkill 120A bms with screw posts for the wires. The bonded ones they offer are 3X8awg. I made up some copper pipe bus bars for single 4awg wire on bms, but I have decided to use 2x6AWG cable instead. Found some blue and black wire in 6 guage, and red 2 guage for the plus-side.

This is the battery I'm copying. I like where this forum member @Carson - Vanlife Rentals is going with his pack builds.
Mine have to be positioned on their side in order to fit under the settee, so the configuration will be slightly different:

560ah 12v Battery with Clean, Modern Case

This is my first post here, but I wanted to share my DIY battery bank. This forum and Will's videos were so helpful that I wanted to share a few things I learned, as well as a few things I created that I haven't seen before (specifically the asthetics of the case). I'd also appreciate any...

diysolarforum.com

 

[Rocketman]

I remember reading that having those batteries on their side can be problematic. (I don’t remember which side is ok). That is something to read the spec sheet very carefully.