Solar panels

[jx2mad]

Who cleans their solar panels? Mine have been up for two years now and I decided to clean them. Boy, were they dirty even though we have just had 50mm rain on them. I bet the output jumped.

[JDNSW]

I cleaned mine a couple of times - made no measurable difference to output, and were not actually all that dirty. I think how dirty they get will depend on where you are and the angle of the panels - if nearly flat, rain will not wash them as well as if they are at a steeper angle.

John

[Lotz-A-Landies]

I would think a dull panel, rather than a dirty one would actually absorb more light so work more efficiently than one with a shiny/reflective outer surface.

[1950landy]

Our power bill used to be around $1200 a 1/4 in summer & before we fitted solar panels & droped to $600 & our last account was $150 & that was using the ducted air for heating over winter . I'am in Brisbane & we have 8 the panels face north & 8 faceing West. I also keep my 80" which only gets used once every pancake Sundayis on a solar charger & the last battery lasted 12 years .
I have also bought a solar charger for my MG because the batteries solsated at around 1 year & had to be replaced.

[JDNSW]

I would think a dull panel, rather than a dirty one would actually absorb more light so work more efficiently than one with a shiny/reflective outer surface.

Depends on the dirt - if the dirt is translucent it may help by scattering light so that more light reaches the cells than would otherwise do so, particularly where the sunlight is not close to normal to the surface. (Although if it is scattering light then some is proably scattered back to the sky!) But most dirt is probably opaque (dust, soot etc) so each particle is simply a small shadow.

Absorbing light at the surface of the glass to be turned into heat is not what is needed. The ideal would be a protective coating on the cells that has the same refractive index as air, but protection is more important, particularly since there is no such material. Providing the sunlight falls close to normally on the surface, the amount reflected is fairly small, and any treatment of the surface to reduce reflections, such as is sometimes used for eyeglasses, is almost certainly expensive compared to simply increasing the panel size, and nowhere near as durable as glass, which is what is usually used.

John

[Lotz-A-Landies]

Our power bill used to be around $1200 a 1/4 in summer & before we fitted solar panels & droped to $600 & our last account was $150 & that was using the ducted air for heating over winter . I'am in Brisbane & we have 8 the panels face north & 8 faceing West. I also keep my 80" which only gets used once every pancake Sundayis on a solar charger & the last battery lasted 12 years .
I have also bought a solar charger for my MG because the batteries solsated at around 1 year & had to be replaced.

Out of interest, what sort of solar chargers did you purchase/use for the pancake day car?

I bought some from SuperC... but not sure how effective they are, they have no regulator.

[1950landy]

Out of interest, what sort of solar chargers did you purchase/use for the pancake day car?

I bought some from SuperC... but not sure how effective they are, they have no regulator.

I bought them off the Ebay, I think they are Projecta 100 12V 1.5w trickle chargers . Payed around $35 with free delivery at the time. Last January I had one damaged by hail , had a deny in glass about 12mm deep & cricket ball size in dia. The panels just lay on the roof of the garage.

[RANDLOVER]

I also cleaned my panels recently and noticed no change in output. I couldn't even tell how dirty they were being black, but after cleaning I could see a film on some of the panels that I didn't do properly. The solar hot water panel was more noticeably dirty as the glass is a white/grey colour.