Solar height? How short can it be?

[Ghaniba]

Curious to those with solar on their roof. How tall is yours? Could you have built it shorter? I'm curious how much height a solar install could be kept to, minimally?

Dave aka Ghan

[JDOnTheGo]

Minimally, about 1/2" - that would be for the flexible/stick on type panels (not ideal, IMO). Otherwise, it all depends.... the residential type panels that I've used 2.25" "thick" - add some mounting hardware and an air gap and I would guess 4". My installations have always been lower than the plumbing vents, air vents, air conditioners, and misc. other stuff on the roof.

[Ghaniba]

Originally Posted by JDOnTheGo

Minimally, about 1/2" - that would be for the flexible/stick on type panels (not ideal, IMO). Otherwise, it all depends.... the residential type panels that I've used 2.25" "thick" - add some mounting hardware and an air gap and I would guess 4". My installations have always been lower than the plumbing vents, air vents, air conditioners, and misc. other stuff on the roof.

Very cool. Thanks! I'm in the middle of my roof raise and contemplating how much room to leave.

Dave aka Ghan

[john61ct]

To maximize square footage for panels, some people raise them high enough to put the opening vent cover for the fan underneath.

Be aware if gets **very** hot under there.

Dunno why we don't see more passive HWS heating coils making use of all that waste heat.

[Ghaniba]

Originally Posted by john61ct

To maximize square footage for panels, some people raise them high enough to put the opening vent cover for the fan underneath.

Be aware if gets **very** hot under there.

Dunno why we don't see more passive HWS heating coils making use of all that waste heat.

Interesting point. You almost want some sure space in there then, simply to give proper ventilation. Do panels claim any specific specs for clearance?

[john61ct]

Nope. The wind resistance from going too high is an issue too.

Best solution is a rack that's low when flat but allows tilting to point at the sun.

Can double total Ah output per day too.

[Ronnie]

Mine are 2" to the top of the panels from the roof, with some air gap.

[Ghaniba]

Originally Posted by Ronnie

Mine are 2" to the top of the panels from the roof, with some air gap.

Got any pics of the install? Have you experienced any heat issues being so close?

[Ronnie]

No pictures but could take some. I used 1.5" aluminum angle to make the frame. I have not had any trouble with heat.

[Ronnie]

Here are a few pictures.

[Ghaniba]

Originally Posted by Ronnie

Here are a few pictures.

Awesome! Thanks so much!

[Iceni John]

I made a walkway between my two roof hatches that is about 5" above the roof. To this walkway are hinged my eight panels; when down against the roof for travel the panels' support frames extend about an inch or two higher than the walkway, meaning that my bus's overall height is now about 7" higher than stock. At the closest point to the curved roof they are about an inch above it, enough to allow plenty of air to circulate under them even when parked. Down against the roof they're at 21 degrees below horizontal, but they can be easily raised to 21, 33 or 45 degrees up for ideal year-round insolation. 21 degrees just happens to be the ideal fixed angle for SoCal, but being able to raise half the panels to 45 degrees in the winter will greatly improve solar harvest.

John

[bus-bro]

Hi John. How do raise and lower the panels?

[Iceni John]

Originally Posted by bus-bro

Hi John. How do raise and lower the panels?

By hand, on a step ladder! I thought about making some power-operated system, but that's an awful lot of complexity for very little benefit. The panels are supported by stainless-steel struts that can be extended by hand, no tools needed, so it's actually a very easy exercise - it only takes two minutes tops, including getting the ladder out and back inside.

John

[john61ct]

There are all kinds of rack designs, from DIY to OTS.

Most are manual and require getting up there, but raising with a pole should be do-able.

If you go DIY ensure high lifting forces at highway speeds are taken into account as much as weight

[pengyou]

Originally Posted by john61ct

Be aware if gets **very** hot under there.

Dunno why we don't see more passive HWS heating coils making use of all that waste heat.

Maybe part of the answer to this...a lot of diy or ots hot water systems suffered from leaking...at least in the first generation. The newer systems have that problem mostly fixed. Hot water solar systems are heavy - that would increase the center of gravity of the bus a bit. They also use glass (fragile) tubes. Also..I have not seen the backs of solar panels - is there some kind of metal that coils could be soldered to? Maybe the best answer is to build a lightweight set of air coils and attach them directly under the panels with a fan blowing through the coils. This hot air could be useful for something - it also would reduce the temperature of the panels and would make the panels more efficient - panels are more efficient when they run cooler, and produce more electricity.

[Sleddgracer]

Originally Posted by john61ct

To maximize square footage for panels, some people raise them high enough to put the opening vent cover for the fan underneath.

Be aware if gets **very** hot under there.

Dunno why we don't see more passive HWS heating coils making use of all that waste heat.

https://www.youtube.com/watch?v=btQtPQpUf90

[john61ct]

Yes, and commercial versions have been launched a few times, remember seeing one at a conference in Australia in the 80's.

On a big house roof there's room for a unit dedicated to that function, just surprised nothing's succeeded in the camper / boating markets.

[dredman]

I love my folding panels, and I reused some other panels for portable, shade-parking solar

https://www.youtube.com/watch?v=N2WDsZdh9Sw

[Ronnie]

Originally Posted by john61ct

Yes, and commercial versions have been launched a few times, remember seeing one at a conference in Australia in the 80's.

On a big house roof there's room for a unit dedicated to that function, just surprised nothing's succeeded in the camper / boating markets.

For a skoolie that is used as a home this would be great, and I am all for it.

However for those of us that use it as a motorhome, the added complexity of the coils, circulating pump, water tank to store the heated water all add up to making winterization quite a bit more of a task.

I have mine set up to open two valves and pull a plug on the water heater (instant on type) and I am winterized. Makes it easy to refill anytime and go, and drain when I get back.