Solar height? How short can it be?

[Ronnie]

For my solar panels I do not want to climb anything, ladders and me do not get along. So fixed panels do well. I put more panels then I thought I needed for just this reason. I know it is not optimal.

By the way has anyone seen a chart that gives how much a panel will give in percentage at different angles to the sun?

[john61ct]

https://www.pveducation.org/pvcdrom/...lar-insolation

[Ronnie]

Thanks. I know what I have works, but would like to do the math and have a better idea as I plan a northern trip this fall.

[Iceni John]

Originally Posted by Ronnie

By the way has anyone seen a chart that gives how much a panel will give in percentage at different angles to the sun?

Like this?
Optimum Tilt of Solar Panels
https://rredc.nrel.gov/solar/pubs/redbook/PDFs/VA.PDF
https://rredc.nrel.gov/solar/old_dat...redbook/atlas/

This is why tilting panels is a good idea, especially in more northern latitudes.

John

[Ronnie]

So it looks like about 1/3 less at my latitude for flat panels versus tilted to latitude.

[john61ct]

No, regardless of latitude can double production

adjusting for the E-W angle, 2-4 times a day

some higher efficiency from cooler substrate

[JDOnTheGo]

My 'latitude' experience is tainted because of the excess wattage I have to cover for the winter months. That said...

My flat mounted panels, during the summer months between south (Arizona/New Mexico) and north (Montana/Minnesota), produce about 80% of rated power. The days are long and power is plentiful.

The same flat mounted panels produce a maximum of about 60% of rated power during the winter months in AZ/NM. It is during this period that I occasionally think of adding a tilting mechanism. I've not been north (with the coach/solar panels) during the winter months to compare.

There is no doubt that tilting them would increase output. I decided against doing that as I have no interest in messing with them manually. A semi-automated/electric system (probably using linear actuators) would be great but I already have plenty of projects (and the complexity of that various with the coach roof, panel size, etc.).

A few more considerations...

• Panel sizes vary - some may be more 'manageable' than others. Mine are 7' x 2.5' and weight 56 lbs. each.
• Wind is a VERY powerful thing. When constructing a tilting mechanism, please consider this (from all angles).
• Ones style of use may make a difference. I typically remain stationary for 2-3 weeks at a time and that, at least in my mind, aligns fairly well with tilting the panels (once every 2-3 weeks). If I moved every day or every couple days, messing with the panels each time would VERY quickly become a serious nuisance.

[john61ct]

Yes push-button automation is IMO silly, KISS.

It's just the height makes it hard.

Something like the old shop awning winders would help.

[pengyou]

https://www.instructables.com/id/Hyb...c-and-thermal/ Photovoltaic and hot water together. How water is pretty useful in a home. Heating, cooking, washing. Plus, the more heat you can carry away from the roof, the easier it is to keep the bus under the panels cooler, even if you were to install cooling fin on the bottom of the collectors and direct air over them.

[Sharee100]

The panels I looked at (rigid panels) say at least one inch clearance for air flow.

[o1marc]

If you are getting 80% efficiency is that enough or more than enough to cover your needs? Wouldn't it be easier to add more panels and not have to adjust them?

[PNW_Steve]

Originally Posted by o1marc

If you are getting 80% efficiency is that enough or more than enough to cover your needs? Wouldn't it be easier to add more panels and not have to adjust them?

I agree.

Panels have gotten cheap enough that it was an easy decision for me to add more fixed panels versus a tilt mechanism.

Many times I don't have much control over which direction I am parked. If I am stuck pointed North, which way do I tilt the panels? East or West?

[JDOnTheGo]

Originally Posted by o1marc

If you are getting 80% efficiency is that enough or more than enough to cover your needs? Wouldn't it be easier to add more panels and not have to adjust them?

If you are asking me, the answer is yes and maybe (but it's not that simple).

Yes, 80% efficiency meets my electrical power needs. However; there are many times when you do not get 80%. The winter months, for example. Throw in a week of poor weather and suddenly you have a power deficit. During those times, it may not be possible to have enough panels to provide sufficient power (due to roof space constraints).

Adding more panels sounds easy but it isn't in all cases. Roof space is the most significant problem. Then add cabling, charge controller sizing, etc... to the mix.

I am not a fan of tilting the panels manually (height, weight, forgetting about them sticking up, weight of an adequate tilting mount system, wind, etc.) but there is no doubt that it is a good way to improve the efficiency of the panels if you are constrained and cannot simply add more.

[o1marc]

Originally Posted by JDOnTheGo

If you are asking me, the answer is yes and maybe (but it's not that simple).

Yes, 80% efficiency meets my electrical power needs. However; there are many times when you do not get 80%. The winter months, for example. Throw in a week of poor weather and suddenly you have a power deficit. During those times, it may not be possible to have enough panels to provide sufficient power (due to roof space constraints).

Adding more panels sounds easy but it isn't in all cases. Roof space is the most significant problem. Then add cabling, charge controller sizing, etc... to the mix.

I am not a fan of tilting the panels manually (height, weight, forgetting about them sticking up, weight of an adequate tilting mount system, wind, etc.) but there is no doubt that it is a good way to improve the efficiency of the panels if you are constrained and cannot simply add more.

I suppose no matter how many panels you have you may end up in a situation where it is not optimal.

[PNW_Steve]

Originally Posted by o1marc

I suppose no matter how many panels you have you may end up in a situation where it is not optimal.

Absolutely!

I am installing 1800 watts of panels initially. That, by my load calcs, should supply my needs in most conditions. Most conditions........ When I visit the family for Thanksgiving in Seattle I WILL be running the generator...

[Ronnie]

Originally Posted by o1marc

If you are getting 80% efficiency is that enough or more than enough to cover your needs? Wouldn't it be easier to add more panels and not have to adjust them?

Yes that is what my thought was. I figured 200 watts for my needs, however put 400 watts on the roof flat. That has worked out well for me. I often can not park in the best direction that a tilting panel would tilt the right way.

Every one needs to figure what their needs are, then decide how best to achieve that.