Solar panels

[Iceni John]

If any PV panels don't have a 25-year warranty, don't buy them!   Reputable manufacturers stand by their products:  who knows if HF would also do so if their panels' output dropped significantly after a few years?

Panels should be attached well enough that they can withstand 60MPH gusts when raised (if they're tiltable), and obviously well enough to withstand 70-plus MPH wind when stowed down for travel.   If a panel were to hit another vehicle while driving, you're in a very bad legal situation!

My panels charge my house batteries, and they in turn charge my start batteries via 12V-to-12V battery maintainers.   It's really good knowing that the start batteries are always 100% charged regardless of how long since the bus was last driven.

John

[buswarrior]

Headwinds?

Those panels need to be solid beyond 100mph wind speeds.

There's way too many solar panels held on with self drilling screws into sheet metal... if lucky... some think a dab of hardware store caulk will do the job...

It will serve every constructing busnut well to take pictures and document their build methods, not for posting, but for a documentation that your build is not one of the problems out there...

Happy coaching!
Buswarrior

[chessie4905]

I dont consider waranties of 25 years or over 5 to be worth the paper they are printed on. Try and collect in 10 years. luck if company is still in business the way solar is growing and companies being bought out. Fantastic fans had a lifetime warranty, but were bought out and that changed. Had a car battery with lifetime warranty. Replaced once and they discontinued them.

[windtrader]

The PV industry is still growing and evolving and with the political winds howling one really has little idea which manufacturers will stand up over time. SO many of the brands with fine warranties are gone and those warranties serve nicely as @$# wipes in an emergency. Renogy was a big brand that bit the dust - all their remaining inventory is being liquidated all over the place now and left a trail of crying owners who got crap for service as the company slid off the edge.


You can buy LG, Panasonic, etc. and pay double for that paper warranty and commercial builds do to ensure they aren't on the end of a warranty issue themselves, costs passed through anyway.


Panels flying off roofs. AND hitting things. Humm..... I thought this thread was about buying a 100 foldup stored PV system.


Yes, do your math as mounting securely is a very real concern. I heard of some dumbass who failed to get ALL the variables sorted out and some panels went flying off on a maiden voyage.


Here are a couple of thoughts. Do NOT compare residential panel mounting systems with those for a bus traveling 70mph into a 30 mph headwind. The forces are also quite different. A flat panel on a house roof is only going to get side wind forces while a bus can get uplift too.


You can do the paper calculations but that has to translate through the actual construction. For example, if an adhesive is rated at 1000 lb psi but that is a theoretical value based on some laboratory testing done under perfect conditions. In the field, one might grab some brackets, wipe them clean, then glue it up thinking all is well.


But what if the material was galvanized brackets. Great idea since they would not rust. Bad idea because the galvanizing process leaves the surface with a material that is not the same as the raw metal. And guess what - it makes the adhesion much weaker. Doh - well - maybe not unless you really understand materials. Even though the bus skin was sanded to bare metal the bond is only as strong as the weakest material, in this case the galvanized surface is much weaker and then is the failure point.


Bolting through the roof is a solid choice. Welding brackets onto surface is good too. Self-tapping and adhesives can work if done 100% by the books plus a lot of oversizing for safety.


One other idea is straps that run sideways across the bus and attach to reinforced gutters. With fairly thin cabling that is coated, they would hardly be visible and work very well as a secondary system for securing the panel system and a backup safety system if the other brackets were to fail.


Just a few thoughts passed along from some dumbass who seen some of this up close.

[Dave5Cs]

Now back to our regularly schedules program.....LOL

So Richard don't know if that will ever happen because the panels need air flow beneath them to maximize their potential. If they overheat they lose that same wattage somewhat.

[freds]

Now back to our regularly schedules program.....LOL

So Richard don't know if that will ever happen because the panels need air flow beneath them to maximize their potential. If they overheat they lose that same wattage somewhat.

Plus they don't seem to last very long based on a bunch of reviews. Though BattleBorn is selling some now so maybe they are higher quality.

[richard5933]

I've been watching a YouTube channel for a couple of guys living on a narrow boat. They have a bunch of flex panels mounted directly to the roof of the boat, and they appear to be performing quite nicely for them. They've compared the output to that of more traditional panels mounted on other similar boats and found that it was nearly the same. Unfortunately, the brand they installed doesn't appear to be available in the US.

It really shouldn't be that difficult a nut to crack making flex panels that can mount directly to the roof and still produce a decent output. Using flex panels would make it possible to actually install more panels than with traditional flat panels since they can go further to the edges and still not ruin the look of our buses. Still searching...

[freds]

In the case of my Prevost bus, there is a transition line for the steel exoskeleton where the sides transition to the roof.



In this case it's a square steel channel where I had to drill through aluminum first and the steel. I inserted rivnuts for the mounting...

[Jim Blackwood]

Richard, I'm glad you are watching this, as I feel that a direct mount, adhesive secured flexible solar cell matrix could be an ideal power source for a bus or anything with a lot of roof area. Not only that but it has the potential to provide an additional layer of waterproofing.

Heat is an issue of course. They need to be able to function at elevated temperatures. Or one alternative might be a corrugated plastic material with extra large corrugations or 'cells' that could allow some airflow under the solar cells but still provide a secure mounting surface. This would help to further insulate the roof from direct sunlight.

Jim

[richard5933]

The whole air flow under the panel thing shouldn't be that difficult a nut to crack. Can't they just mold in channels on the underside to provide for air to pass? Or use an insulating layer on the bottom? Seems to me that other than adding a small additional cost it would be the easiest part of the production.

Or, build a flexible panel capable of functioning at higher temps.

Lots of marine applications use direct mount flex panels and they are in the sun constantly.

[luvrbus]

2 different cases flexible panels on boats deal with a milder temperature and a more constant temp,here in the AZ heat the solar panels are affected by the extreme heat and loose efficiency. I am told by my neighbor whom has a roof covered with panels         

[buswarrior]

Flexible direct mount panels, or sheets, in a marine environment are far less likely to be sitting on a hot tin roof.

Big trucking company out of quebec, Robert, has quite a number of trucks running with them on various surfaces, hood, sleeper roof, to supplement batteries for daytime sleeper hvac, and weekend power parasites, like the refrigerator.

They only have to live as long as the first fleet runs 'em, 2 to 4 years, or less, when the truck gets rotated to different duty.

Lifespan in oven temperatures is the trick for these stick on panels, a challenge that is being worked on by many smart people, cuz when they succeed, traditional panels will not be the solution for a lot of installs, and they will sell a lot of them.

Happy coaching!
Buswarrior

[Dave5Cs]

Lots of RV's use them too. It is the heat from what they sit on and they do produce electric but not at optimal wattage. It is more when they are raised so air can flow under them that you have them cooling down as you move along and that creates the higher amperage and watts. Not saying it can't be done just that at present it is not done with those panels on RV's.

On our Bus we not only have them 1-1/2" about the roof but it's the upper roof because of  it being a Saudi Bus with the two roofs. and you still don't really notice them on it. 1500 watts (6, 250 watt panels 2 in series 500 ea and then through the combiner box in parallel)and seems to be enough right now but if I sell these I can take them off and replace them with 340 watt panels for 60.00 each plus delivery from SanTan Solar in Arizona.

[Jim Blackwood]

$60 for 340 watts sounds like an unusually good price, things seem to be moving in the right direction.

So about that corrugation... there's the plastic version of cardboard of course, probably about 3/16" high at the most and probably wouldn't get much airflow through that. There is also a Lexan glazing product made about the same way but about 1/2" thick. That'd be much better but could cost more than the panels. Ideally I'd like to see something with 1" to 2" cells. Anybody seen anything like that anywhere? It's just extruded plastic so it shouldn't be that hard to make for someone who had the machines.

Jim

[Dave5Cs]

Jim they are used home Panels and warranted for 5 years but have had no problems with them at all. They all tested out when I received them and great customer support.