Our solar production

[lonndoggie]

Slightly OT: What do you guys use to clean your PV panels?

Second that. We have a two story house and no easy (or likely--it's scary high) way to get up to the tile roof (not keen on trying to wander about on a tile roof, either).

We're on a peninsula of land surrounded by canyons, so I can't even back up far enough to *see* the panels, such that I could shoot an arc of water up at 'em.

Basically, I pray for rain.

 

[LEAFfan]

Slightly OT: What do you guys use to clean your PV panels? I just got off of the roof with a rag and a bucket of water. It worked well, but I can't get to some parts of the panels without some kind of pole. I've seen some shots of Bill Nye cleaning his panels with a long extension pole with some type of duster on it (from the ground).
Anybody have any tips 'n' tricks they'd like to share?

The first time I went up on the tiled roof (very hard to keep from slipping) and used a long-handled micro-fiber mop. I used a little mister to moisten the mop and it worked great. However, it took me over and hour and a half to do it. It increased my output by a KW every other day. I called the manufacturer, and the guy said on his panels, he just uses a garden hose with a jet/power setting to hose them off. So I bought an 8' ladder, and in a day or so will hose them off. Here in AZ, they get dirty/dusty about every two weeks.

 

[Boomer23]

The first time I went up on the tiled roof (very hard to keep from slipping) and used a long-handled micro-fiber mop.

My panels are atop my second story tile roof. No way I'm going up there. But I'm lucky to have a sturdy patio cover that I can climb onto. Some plywood to make a stable platform, a six foot step ladder, a soft brush on a long extension pole and a hose and I'm golden! I can reach all of my panels with that setup, and my shoulders never rise above my eave line.

Just like washing a car, I find that actually touching the panels to loosen the dirt works much better than spraying them, even spraying them with detergent.

 

[Desertstraw]

Date total energy produced(kWh)
2/1/2011 58.42
2/2/2011 64.42
2/3/2011 63.01
2/4/2011 60.86
2/5/2011 51.22
2/6/2011 53.5
2/7/2011 57.61
2/8/2011 56.84
2/9/2011 63.96

This is from 11.5kw system in Scottsdale, installed last April, and never been washed.

 

[hill]

Date total energy produced(kWh)
2/1/2011 58.42
2/2/2011 64.42
2/3/2011 63.01
2/4/2011 60.86
2/5/2011 51.22
2/6/2011 53.5
2/7/2011 57.61
2/8/2011 56.84
2/9/2011 63.96

This is from 11.5kw system in Scottsdale, installed last April, and never been washed.

Wohahaa ! !
That must be SOME meth lab!
:lol:
. . . . . . and here I thought we did good yesterday (wednesday) doing 27.5kWh

 

[DaveEV]

I've been cleaning my panels a few times/year.

No water needed - I've been using one of those "California" car dusters and a towel. Takes me 15 min. A bit of spit here and there gets any persistent dirt off.

If my roof was more slanted I probably wouldn't bother. But since it's not (less than 5* slope) the panels tend to accumulate a pretty heavy layer of dirt on the bottom row of cells. Surprisingly, it takes a VERY heavy layer of dirt to make a significant difference in output.

Next time I go up there I'm going to try cleaning off only some of the panels. My microinverters will make it easy to tell how much cleaning is making a difference.

Perhaps I could go up there every other week and clean the array. But when doing so clean off 2 fewer panels to see the effects of dirt buildup. Would be an interesting experiment...

 

[Carlos]

Slightly OT: What do you guys use to clean your PV panels?
Anybody have any tips 'n' tricks they'd like to share?

I'm just north of downtown Phoenix and dust buildup happens quickly. I clean and physically inspect the panels every quarter. Not that I would even know what a bad panel looks like I do keep an eye out for damage from storms, hail, and errant birds. I haven't really seen any dramatic increase in kwh but I'm sure they operate better after a good cleaning.

Since my 24 panels are mounted half on my flat roof and half on a vaulted ceiling tile roof, cleaning is very easy.
I typically clean in the early morning when the panels are cool by rinsing the panels with a garden hose. Then use an expandable pole with a window mop and weak vinegar solution in my water bucket. After that I rinse again and squeegee the remaining water from the panel .

Cleaning is almost as fun as browsing the output data from the system.

Cheers

 

[hill]

The first time I went up on the tiled roof (very hard to keep from slipping) and used a long-handled micro-fiber mop. I used a little mister to moisten the mop and it worked great. However, it took me over and hour and a half to do it. It increased my output by a KW every other day. I called the manufacturer, and the guy said on his panels, he just uses a garden hose with a jet/power setting to hose them off. So I bought an 8' ladder, and in a day or so will hose them off. Here in AZ, they get dirty/dusty about every two weeks.

If your hose is spraying hard water, the panels will build up huge amounts of mineral deposits in quick order. Thus, you need to dry 'em off to prevent the build up . . . . or alternatively, get a soft water attachment for your hose. They're not too expensive, and the replacement cartridges aren't too expensive either.

 

[Azrich]

Our solar panel installers recently added our system to their display of "Case Studies" on their website. We filled out their template of information and sent some photos to them.

Take a look at: http://tfssolar.com/solar-residential/

Go to the Clingaman/Embry Residence case study. There are four photos and a link to a daily production graph. We're very glad we were able to have this system installed.

 

[LEAFfan]

The first time I went up on the tiled roof (very hard to keep from slipping) and used a long-handled micro-fiber mop. I used a little mister to moisten the mop and it worked great. However, it took me over and hour and a half to do it. It increased my output by a KW every other day. I called the manufacturer, and the guy said on his panels, he just uses a garden hose with a jet/power setting to hose them off. So I bought an 8' ladder, and in a day or so will hose them off. Here in AZ, they get dirty/dusty about every two weeks.

If your hose is spraying hard water, the panels will build up huge amounts of mineral deposits in quick order. Thus, you need to dry 'em off to prevent the build up . . . . or alternatively, get a soft water attachment for your hose. They're not too expensive, and the replacement cartridges aren't too expensive either.

Yeah, I thought about that too, but the manufacturer told me that he has the same panels and he just uses a hose (jet position) with tap water. He said those few spots don't hurt. I didn't ask him, but what do YOU think about using the outdoor faucet that has the water softener water? What about the salt in it?

 

[mwalsh]

32.89kWh today. Best day so far since the system went live.

 

[hill]

which is just enough power to rebuild our $450 surplus money (was over $500) that SCE is going to have to pay us for our growing surpluss.

hill, how do you figure that SCE will pay you at that rate? I have a $230 surplus going into month 12 of my net metering calendar, with about 1700 kWh surplus, but from what I've been reading, SCE may pay at some wholesale rate like 5 cents per kWh. . . . . . . . . . . . . . . snip

I called SCE to ask them if the dollar amount on the bill is based on the rate that SCE expects to pay us. As you know . . . the monthly bill (or running tabulated surplus) shows a bar graph, with differing months as usage or surplus - see a piece of an old bill that I scanned :

The way SCE explained their plan to me - SCE computes each month's kWh surplus based on the tiered amount it'd fall in. Thus, if you're pumping a TON back onto the grid, you'll build a credit amount based on that higher tier. Conversely, if you only push a teeny bit back for 11 months, then eat up TONS of power in month 12, you'd wipe out your surplus ... and end up owing hundreds. The snippet of our SCE bill above represents a typical computation, on your basic grid tied "tiered" computations. HOWEVER, we just switched over to TOU last month . . . so now we'll have a basis of comparison to see if our surplus grows slower - faster - or the same on TOU, versus the regular tiered system.

Yeah, I thought about that too, but the manufacturer told me that he has the same panels and he just uses a hose (jet position) with tap water. He said those few spots don't hurt. I didn't ask him, but what do YOU think about using the outdoor faucet that has the water softener water? What about the salt in it?

A water softener's discharge has salt in it ... but only the teeniest bit is actually entering through to your source water. That's how are Montana water softener guy explained it to me. That's why softened water (via salt) doesn't taste salty. It acts like a kind of membrane in order to trap water's existing minerals. Our CA home doesn't have a water softener. I don't feel good about it in CA . . . but our MT home has it (goes into the septic tank). The discharge is so polluting to water treatment plants, that some communities ban or restrict its use:
http://articles.latimes.com/2009/jun/26/business/fi-culligan26
So I towel dry our panels. Have you ever seen a shower door that never gets squeegee'd ? ... or towel dried? How do YOU spell:
L i m e - a w a y ... or C L R ?

No thanks . . . I'm all for 'an ounce of prevention' when it comes to keeping deposits at bay.

 

[hill]

32.89kWh today. Best day so far since the system went live.

mwalsh, I note your signature states your PV is 6.2 DC. Does that mean the 32kWh day's output is DC? or do you read one, one-way, and one the other. The reason I ask is because our 7.2kWh AC rated PV just hit 30kWh yesterday & today for the 1st time this year . . . and so I'm trying to reconcile the #'s.

 

[LEAFfan]

Yeah, I thought about that too, but the manufacturer told me that he has the same panels and he just uses a hose (jet position) with tap water. He said those few spots don't hurt. I didn't ask him, but what do YOU think about using the outdoor faucet that has the water softener water? What about the salt in it?

So I towel dry our panels. Have you ever seen a shower door that never gets squeegee'd ? ... or towel dried? How do YOU spell:
L i m e - a w a y ... or C L R ?

No thanks . . . I'm all for 'an ounce of prevention' when it comes to keeping deposits at bay.

You wouldn't be towel drying OUR panels unless you want to climb on a 22 degree steep tiled roof and break your legs and arms when you slip and fall. So which do you think would be better (least spotting) to use for me, regular tap water or the water softened water?

 

[LEAFfan]

32.89kWh today. Best day so far since the system went live.

mwalsh, I note your signature states your PV is 6.2 DC. Does that mean the 32kWh day's output is DC? or do you read one, one-way, and one the other. The reason I ask is because our 7.2kWh AC rated PV just hit 30kWh yesterday & today for the 1st time this year . . . and so I'm trying to reconcile the #'s.

I'm willing to be that's DC, because we had the best output today too. According to the pre-production monitor, each panel put out over 1.2KWh DC for a total of 24Kwh, but our actual output EU meter read 18Kwh. However, I was told by the manufacturer that the AC output would be about 80% of the DC output. It has been online since Jan. 5th, and before that rain and colder weather, we were only +11Kwh. Soon, it will be in the minus sector. :mrgreen:

 

[mwalsh]

I'm willing to be that's DC, because we had the best output today too. According to the pre-production monitor, each panel put out over 1.2KWh DC for a total of 24Kwh, but our actual output EU meter read 18Kwh. However, I was told by the manufacturer that the AC output would be about 80% of the DC output.

It is DC. But I'm pretty sure my inverter efficiency is closer to 95%. At least that's what the State says in their ratings (95.5%), even if you take SMA's claims of the efficiency of my Sunny Boy with a grain of salt.

Plus my panels are the 4th most efficient of all those currently available.

 

[wsbca]

I'm willing to be that's DC, because we had the best output today too. According to the pre-production monitor, each panel put out over 1.2KWh DC for a total of 24Kwh, but our actual output EU meter read 18Kwh. However, I was told by the manufacturer that the AC output would be about 80% of the DC output.

It is DC. But I'm pretty sure my inverter efficiency is closer to 95%. At least that's what the State says in their ratings (95.5%), even if you take SMA's claims of the efficiency of my Sunny Boy with a grain of salt.

What device do you have that's showing you DC output? The monitor on the SMA inverter itself reports AC, as does the Sunpower web site and the remote monitor. Assuming a modestly good panel orientation, a Sunpower system in SoCal de-rates to about 87% from DC to AC - you have to account for the efficiency of the inverter, and of the panels themselves, and the wiring etc. (eg. we have a CEC-AC rating of 2.987 from a DC spec of 3.44 on our Sunpower/SMA system). 32.89 sounds about right (great) for AC production for a clear cool day yesterday, that's 6 "solar hours" (32.89 divided by your ballpark CEC-AC rating of 5.4kW - ie .87 * 6.2).

Yesterday we got 5.72 solar hours (production of 17.08 divided by CEC-AC rating of 2.987) - we had a few clouds. JimmyDreams had 6.04 solar hours (35.81 kWh / CEC-AC rating of 5.93kW).

 

[Boomer23]

I'm willing to be that's DC, because we had the best output today too. According to the pre-production monitor, each panel put out over 1.2KWh DC for a total of 24Kwh, but our actual output EU meter read 18Kwh. However, I was told by the manufacturer that the AC output would be about 80% of the DC output.

It is DC. But I'm pretty sure my inverter efficiency is closer to 95%. At least that's what the State says in their ratings (95.5%), even if you take SMA's claims of the efficiency of my Sunny Boy with a grain of salt.

What device do you have that's showing you DC output? The monitor on the SMA inverter itself reports AC, as does the Sunpower web site and the remote monitor.

I agree. Mike, I think you're reporting AC kWh from your inverter output, right?

 

[Boomer23]

32.89kWh today. Best day so far since the system went live.

mwalsh, I note your signature states your PV is 6.2 DC. Does that mean the 32kWh day's output is DC? or do you read one, one-way, and one the other. The reason I ask is because our 7.2kWh AC rated PV just hit 30kWh yesterday & today for the 1st time this year . . . and so I'm trying to reconcile the #'s.

hill, if it helps, our 5.16 DC system logged 27 kWh yesterday here in Irvine. That's 27 kWh AC.

 

[mwalsh]

What device do you have that's showing you DC output? The monitor on the SMA inverter itself reports AC, as does the Sunpower web site and the remote monitor.

I agree. Mike, I think you're reporting AC kWh from your inverter output, right?[/quote]

Umm....no idea now. I thought it was DC right up to the output side of the inverter and that the monitoring happened before that. But without breaking out the user manual, I'll take yous guys word for it.