Anyone with good cleaning tips?

[bando]

The high here tomorrow says 63 btw

[bando]

Bando:

I'm not sure I'd hang my hat on being able to see the effect of rain on production. 1 - assuming 01/29 and 02/01 are identically clear , the arrays will see more sun because of the changing solar geometry I just mentioned. 2 - every degree of temp. diff. will change the arrays' output probably by something like .3 to .5% per degree F. Around here 01/29 ave. temp. was 64 F. Tomorrow's predicted high is 59. We're close geographically. I'd expect similar but not identical conditions.That ambient, BTW, is only part of what determines panel temp. The wind has a lot to do with it as well. 1 and 2 will likely give uncertainty of maybe 2-4 %, maybe more, maybe a lot more, probably on the plus side. If the rain washes off the dirt and that results in a further increase, how will you separate that increase from the effects mentioned ? I'd suggest you have too many unmeasured variables with too much inherent uncertainty of the same approximate magnitude as what you are trying to measure. I think it's a lot of fun, but I'd not assign a lot of confidence to it. I cleaned my array on the 14th and with a lot of data from the 3th and 14th still got little better than what I'd describe in the end as an educated dart throw. See prior post w/results in this thread.

FWIW

yes I won't know for sure however if it's sig higher than 53 I will suspect the rain had something to do with it. That's assuming tomorrow is as sunny as it was on Wednesday . I don't recall the exact temp on Wednesday (2 days ago) however I know I've been sending my boys to preschool in long sleeves all week so it wasn't warm.

I don't know how dirty your panels get but mine were really filthy prior to last night.

[J.P.M.]

some updated pics post rain. much cleaner. tomorrow is supposed to be pretty sunny so we'll see if there's any real difference in production from the rain alone. just 2 days ago (Weds, 1/29) we had production of 53.2kwh.

[ATTACH=CONFIG]3683[/ATTACH][ATTACH=CONFIG]3682[/ATTACH][ATTACH=CONFIG]3681[/ATTACH][ATTACH=CONFIG]3680[/ATTACH]

Bando:

I'm not sure I'd hang my hat on being able to see the effect of rain on production. 1 - assuming 01/29 and 02/01 are identically clear , the arrays will see more sun because of the changing solar geometry I just mentioned. 2 - every degree of temp. diff. will change the arrays' output probably by something like .3 to .5% per degree F. Around here 01/29 ave. temp. was 64 F. Tomorrow's predicted high is 59. We're close geographically. I'd expect similar but not identical conditions.That ambient, BTW, is only part of what determines panel temp. The wind has a lot to do with it as well. 1 and 2 will likely give uncertainty of maybe 2-4 %, maybe more, maybe a lot more, probably on the plus side. If the rain washes off the dirt and that results in a further increase, how will you separate that increase from the effects mentioned ? I'd suggest you have too many unmeasured variables with too much inherent uncertainty of the same approximate magnitude as what you are trying to measure. I think it's a lot of fun, but I'd not assign a lot of confidence to it. I cleaned my array on the 14th and with a lot of data from the 3th and 14th still got little better than what I'd describe in the end as an educated dart throw. See prior post w/results in this thread.

FWIW

[silversaver]

i haven't looked at mine today but wonder if i got the same spikes. when they were brand new i got up in the 10's on a 11.76 system. but i really don't see anything past the high 8's anymore.

did you get rain last night? our panels are looking much better after the first rainfall in weeks, maybe almost 2 months. maybe that might have a little bit to do with it. we've had mostly clouds today with patches of full sun. yesterday was dreadful though - only produced about 16.xx kwh.

yes, but very little. My panels were pretty clean since I wash them last week

This is my last 5 day ouputs:

1/26 13.88
1/27 23.73
1/28 22.65
1/29 24.33
1/30 7.8
1/31 14.74

[bando]

some updated pics post rain. much cleaner. tomorrow is supposed to be pretty sunny so we'll see if there's any real difference in production from the rain alone. just 2 days ago (Weds, 1/29) we had production of 53.2kwh.

rain4.jpgrain3.jpgrain2.jpgrain1.jpg

[J.P.M.]

i hope so, but it only took about 3 days after turning on to get from the 10's to the 8's.

Sometimes stuff happens quickly that time of the year.

[bando]

Bando: You don't usually see past the 8 kW power right now mostly because the sun's zenith angle (complement of elevation angle) is greater than when you had the system installed. Dirt may have a BIT to do w/it also. Zenith angle is also a big part of the reason why you'll likely see larger power readings in May for non May-gray days. and through most of the summer.

i hope so, but it only took about 3 days after turning on to get from the 10's to the 8's.

[J.P.M.]

i haven't looked at mine today but wonder if i got the same spikes. when they were brand new i got up in the 10's on a 11.76 system. but i really don't see anything past the high 8's anymore.

did you get rain last night? our panels are looking much better after the first rainfall in weeks, maybe almost 2 months. maybe that might have a little bit to do with it. we've had mostly clouds today with patches of full sun. yesterday was dreadful though - only produced about 16.xx kwh.

Bando: You don't usually see past the 8 kW power right now mostly because the sun's zenith angle (complement of elevation angle) is greater than when you had the system installed. Dirt may have a BIT to do w/it also. Zenith angle is also a big part of the reason why you'll likely see larger power readings in May for non May-gray days. and through most of the summer.

[bando]

i haven't looked at mine today but wonder if i got the same spikes. when they were brand new i got up in the 10's on a 11.76 system. but i really don't see anything past the high 8's anymore.

did you get rain last night? our panels are looking much better after the first rainfall in weeks, maybe almost 2 months. maybe that might have a little bit to do with it. we've had mostly clouds today with patches of full sun. yesterday was dreadful though - only produced about 16.xx kwh.

[J.P.M.]

I got this today with Locus monitoring and comfirm the same result with SMA inverter. It is now Jan 2014 and it is no way to get that kind of output, it must be the light reflection from clouds. Now I know if under good sun light my 6.63kW DC can generates the output of 5.97kWh instantaneous power.

I agree with your conclusion about cloud reflections. The solar irradiance monitor located about 3' north of my array records @ 1 min. intervals. Today it has regularly recorded readings in excess of 800 Watts/m^2 horizontal irradiance. Peak was 852. Under cloudless conditions that reading could be expected to be no more than about 650 W/m^2 Max. @ solar noon ( ~~ 12:01:53 P.S.T), this day at this location in zip 92026. Before noon mostly cloudy. Things cleared some after noon probably ~~ 60-70% cloud cover in the P.M. My system output was also quite a bit higher than expected for intermittent 5 min. periods.

[silversaver]

I got this today with Locus monitoring and comfirm the same result with SMA inverter. It is now Jan 2014 and it is no way to get that kind of output, it must be the light reflection from clouds. Now I know if under good sun light my 6.63kW DC can generates the output of 5.97kWh instantaneous power.

[silversaver]

That is pretty normal in this season. You should be glad your panels are much easier to clean from ground level unlike mine.... try not to look at them haha. As you see, the panels are spread out in 4 rolls (can't see the 4th roll, at bottom). It makes them harder to clean from ground. It required a tall ladder to do the cleaning job..

[bando]

thought you all might like to see actual pics of the dirty panels ...

i hosed off the panels two weeks ago (Jan 11) in the afternoon. not one drop of rain in that time period , and no rain in the immediate forecast. i can't really comment on output loss since this past week has been partially cloudy, and yesterday was very cloudy from morning til evening and only produced 19.61.

here is what it looked like this morning you can see from the far away photo that there is just this brown haze on the bottom of each panel . and of course on the close up photos you can see how dirty/dusty each panel really is. might have to hose it off again this evening.

dusty1.jpgdusty2.jpgdusty3.jpg

[bando]

The gaskets on the PV panels are NOT rated for the force of a pressure washer, and you ARE likely to screw them up. I'd try a carwash kit with the soft brushes and lots of water flowing to prevent the grit from scratching.

whoops, sorry for the confusion - i meant we are pressure washing the house, not the panels. we usually have some areas of the roof done (east and north facing sections) where green algae has built up from prolonged time in the shade as well as pressure wash the white stucco walls around the house and landscaping. then we follow up with window cleaning, and we will ask them to wash and squeegee the panels...

[Mike90250]

...... we are planning some spring cleaning ourselves with some pressure washing and window cleaning and will probably have them do the panels just for our own research's sake this time.

The gaskets on the PV panels are NOT rated for the force of a pressure washer, and you ARE likely to screw them up. I'd try a carwash kit with the soft brushes and lots of water flowing to prevent the grit from scratching.