Thread: Solar Inverter Sun Screen

Hi BT,

Nice job. I like the SMA inverters, good German quality design and well made, probably the pick of the inverters out there. You could probably get replacement lexan front panels as a spare part if you wanted.

One of our big selling designs is (was) a solar powered irrigation flow meter, these days it is made in Sydney, we made the first 3000. last I heard they had sold 40 million $ worth, ( wish I could get royalties on that. ) Anyway our solution to the UV degrading the lexan panel was to put a stainless steel hinged flap over the panel. Without that cover the lexan would start to deteriorate with a few short years.

If you are worried about heating, just get out the IR thermometer and measure the enclosure temperature with, and without the shield, I think you will find the shield will shade the inverter from direct sunlight and keep the enclosure much cooler. You have enough of a gap that the heating of the shield will create some convective air flow past the inverter that will help keep it cooler than shading alone would. ( very clever design ).

Ray

Bob,
I think you have done an excellent job on providing a thermal barrier and there's plenty of airflow space around the unit and heat rising would tend to create thermal flow anyway and also the Freo doctor would provide some afternoon cooling breeze. If you wanted to really go first class stick some sheep wool (insulation) on face of the plate, they don't overheat
Alan

Why did the inverter have to go up near the ceiling? My brother had this problem with his installment. He was told that was how they did it from memory. He suggested that if they wanted to be paid for their work then they would put it where he wanted it, as the customer, and where it had been planned to be placed. They agreed to put it where he wanted.

We have a couple of PLC's at work with your problem. A stainless cover just bigger than the screen was made and hinged in position. It had the sides folded in to hold the face of the cover about 10mm away from the screen.

Dean

Mirror finish the Aluminum (at least on the "inside")
But as others have said I doubt you've made things worse.

Stuart

Originally Posted by Oldneweng

Why did the inverter have to go up near the ceiling? My brother had this problem with his installment. He was told that was how they did it from memory. He suggested that if they wanted to be paid for their work then they would put it where he wanted it, as the customer, and where it had been planned to be placed. They agreed to put it where he wanted.

We have a couple of PLC's at work with your problem. A stainless cover just bigger than the screen was made and hinged in position. It had the sides folded in to hold the face of the cover about 10mm away from the screen.

Dean

Dean,

There is a window at the end of the laundry, on one side there are 2400 high cupboards, and on the other side, where the inverter could have gone, there is a clothes dryer mounted above the washing machine. The dryer which is used maybe twice annually, would have needed to be externally ducted. Big deal.

Where it is mounted on the wall, I still have to stand on a milk crate to view the screen.

All in all it doesn't sound like I'm going the bake the inverter. Thankfully.

And thank you Ray and Alan for your comments and approval.

Bob

Originally Posted by Stustoys

Mirror finish the Aluminum (at least on the "inside")
But as others have said I doubt you've made things worse.

Stuart

Stu,

You replied while I was typing with one finger.

The aluminium is shiny on the inside. It wore a protective plastic sheet.

And you are right about parallax with our scopes. It was awkward positioning my eyeball yesterday while peering through the Isoma. The image would shift slightly while I struggled to get into a comfortable position. I couldn't.

BT

Originally Posted by Anorak Bob

You replied while I was typing with one finger.

I'm back to six finger typing no more thumb typing for awhile.

Originally Posted by Anorak Bob

The aluminium is shiny on the inside. It wore a protective plastic sheet.

Well the only way heat can get from the sun to the inverter from the Aluminium plate is Radiation right?(no conduction, no convection). Polished Aluminium radiates 2/10ths of stuff all... right?
Only problem I could see is if the inverter shed heat by radiation... you're now reflecting it. but I doubt it does??

Originally Posted by Anorak Bob

And you are right about parallax with our scopes. It was awkward positioning my eyeball yesterday while peering through the Isoma. The image would shift slightly while I struggled to get into a comfortable position. I couldn't.

So the Isoma does it as well? thats a little sad. I should get a chance to play over the next couple of days. As I said, might be an easy fix, might not.

Stuart

Hi Bob.
Be glad your inverter is outside. They make a very intolerable sound which changes with the brightness of the sun as clouds go past. I wanted mine (also SMA) installed inside and was strongly advised against it on the day. I'm glad I followed the advice!

Very neat job Bob.

Two other ways to drill neat holes in thin ally sheet are a Forstner bit or one of those sheet metal stepped drills.

The thing doing the damage to the plastic is almost certainly the UV so a sheet of just about anything transparent over the top would work and not need to be removable.
Something like a piece of polycabonate would do, It would yellow over time but it would remain transparent.

That aside LCDs can be affected by heat so the Ally is probably a better direct sun shield although I'd bet the heat from the unit itself is not inconsiderable, and the radiation off those bricks prolongs the heat exposure after the sun goes down.

BTW I would consider painting the ally sheet white to reduce reradiating to the other side.

Hi Bob,
Looking at the pictures the perspex looks to me like it has a protective plastic film on it. If so pull it off and things should be a lot clearer on the lcd. As you know I have plenty of acrylic so yell out if I can help.

My solar inverter bit the dust some time in the last two months and only discovered it on Monday. Just when our power usage is high as the air conditioner has been running quite a bit. Fortunately it is covered by warranty but it will take them 3 weeks to get here.

Originally Posted by jhovel

Hi Bob.
Be glad your inverter is outside. They make a very intolerable sound which changes with the brightness of the sun as clouds go past. I wanted mine (also SMA) installed inside and was strongly advised against it on the day. I'm glad I followed the advice!

Hello Joe,

Most people I know that have inverters have them located out of hearing range in an uninhabited space such as a carport or garage. My carport is on the other side of the house and if the laundry was inconvenient for the installers, the carport would have been more so. I didn't know about the noise, a yellowed LCD is a small price to pay for the lack of irritation some background noise would have certainly caused me. The older I get the more those noises wind me up.

Originally Posted by BobL

Very neat job Bob.

Two other ways to drill neat holes in thin ally sheet are a Forstner bit or one of those sheet metal stepped drills.

The thing doing the damage to the plastic is almost certainly the UV so a sheet of just about anything transparent over the top would work and not need to be removable.
Something like a piece of polycabonate would do, It would yellow over time but it would remain transparent.

That aside LCDs can be affected by heat so the Ally is probably a better direct sun shield although I'd bet the heat from the unit itself is not inconsiderable, and the radiation off those bricks prolongs the heat exposure after the sun goes down.

BTW I would consider painting the ally sheet white to reduce reradiating to the other side.

Thanks Bob,

Had I not looked at the display last week I would have probably left it until there was nothing visible. It is a bit of a pain in the neck to get to if a milk crate or ladder isn't handy Realising I was running out of time I had to come up with the simplest means of keeping the sun off the inverter. Initially I carved up a large Nylex crate so that it would act as a cover. I'd fashioned a covered vent in the front ( the bottom of the crate ) and it wasn't until I stood on a ladder to work out how I would fix the crate back to the wall that I discovered how much heat the inverter generated. A cover would have cooked the thing.

The sheet of aluminium had been in the shed for 21 years so I was glad to have finally found a use for it. Surprisingly the plastic protection simply pealed off. The keyhole-ish mount was used rather than hinges or screws because it was the easiest thing to produce with the gear I had. I haven't machined much aluminium before, the stuff is like butter. I might acquire a taste for it.

I have some white acrylic and the sheet's non polished face is slightly oxidised. Should be a good tooth for some paint.

Bob.

Originally Posted by rodm

Hi Bob,
Looking at the pictures the perspex looks to me like it has a protective plastic film on it. If so pull it off and things should be a lot clearer on the lcd. As you know I have plenty of acrylic so yell out if I can help.

My solar inverter bit the dust some time in the last two months and only discovered it on Monday. Just when our power usage is high as the air conditioner has been running quite a bit. Fortunately it is covered by warranty but it will take them 3 weeks to get here.

I had better have a close look in the morning young Rod.

The bloke I work for, the one who convinced me to drop the what now seems excessive amount for our installation told me a somewhat similar story the other day but his story had a happier ending. He had noticed a massive jump in his electricity account. He ventured down into his basement to find out his inverter was not working. A plumber had turned it off 3 months earlier.

Bob.

OK I checked the screen this morning. What looks like an additional layer in the photo isn't. The plastic is cracked around the edges. I sent SMA an email yesterday querying the availability of a replacement screen. No response so far.

Polish the "inside" surface? Nup. Paint it flat black, stop it radiating the heat towards the inverter. Black bodies and all that.
Mirror polish the outside, but birds might attack it.
Our Mudlarks are really agro lately
Neil

[QUOTE=Neil317;1845254]Polish the "inside" surface? Nup. Paint it flat black, stop it radiating the heat towards the inverter. Black bodies and all that.
Mirror polish the outside,[ /QUOTE]

Sorry that's incorrect on both counts.

Black absorbs and radiates the most.
When bright and shiny, metal surface are the best reflectors of heat but within weeks of exposure to the atmosphere the oxide layer on the surface (it can be so thin that it's invisible) will be a poorer reflector than a white surface. Metal oxides are also very poor emitters in the infrared so any heat that is absorbed is retained.
This is why galvanised roofs get so hot and are a poor choice for roof colour.
Zincalume is supposed to be better but I noticed no difference when we had our roof re-clad.
Aluminium is better that galv or Znalum but a white painted surface will be better still
Gold is a very good reflector because it does not oxidise anywhere near as quickly.