My sola panel

[laurieash]

How do I know what wattage my solar panel is.
Without getting on the roof to investigate.
Full sun in the afternoon the most it reads on the over door meter 3.4

 

[Guigsy]

How do I know what wattage my solar panel is.
Without getting on the roof to investigate.
Full sun in the afternoon the most it reads on the over door meter 3.4

I assume that's 3.4 amps? Multiply by 12 volts and you're getting about 40 watts. But at this time of year in the UK, that's probably half what the panel is capable of.

Also, when the battery is approaching full charge, the charger will go into absorption mode where it pushes much less in. So it might be that the charge rate would have been higher if the battery was flatter or there were additional loads on the system.

Basically, it's at least 40 watts. It's probably 80-100 watts. But it could be a 200 watt panel...

 

[laurieash]

Sorry I should have said I am in Portugal with full sun over the panel in the afternoon.

 

[meanders]

Roughly what dimensions is it. That will give more of a clue.

 

[funflair]

Roughly what dimensions is it. That will give more of a clue.

That's cheating Robin the OP doid say without going on the roof to check
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But I agree it would get the guesswork a bit/lot closer.

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[laurieash]

40cms by 80cms of top of my head cannot check without getting on roof and i don't have a ladder with me.
Thinking of putting another panel up there when I get back as it's trying to charge two 100ah leisure batts plus engine battery.

 

[meanders]

That's cheating Robin the OP doid say without going on the roof to check
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But I agree it would get the guesswork a bit/lot closer.

I did say 'roughly' Martin. If you can see the panel from a higher spot, it's easy to estimate it's size without climbing up the van.

Or perhaps send up a drone and get a photo!

 

[Bolti]

40 x 80 will be about 60w

 

[Lenny HB]

Take a photo of the roof from an upstairs window and scale using other items of a known size.
Anyone you know near you with a van with a known amount of solar you could park next to, both run your batteries down to about 80% then measure the solar output, it needs to be done at the same time.

 

[meanders]

40cms by 80cms of top of my head cannot check without getting on roof and i don't have a ladder with me.
Thinking of putting another panel up there when I get back as it's trying to charge two 100ah leisure batts plus engine battery.

Well ours is only about 50 x 50 80W because there are so many rooflights, I have 2x 130Ah batteries and it copes admirably. Mind you, to be fair we rarely stay more than 5 nights in one place, and that's at the show rallies with no hookup, but have never run out of power although we are careful, rarely use an inverter, don't carry a hair dryer, or a TV.

I would suggest yours will be 100 to 130W.

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[laurieash]

Right boys sticking my head out of a roof light and a piece of wood we have a measure of 120x 60 CMS.

 

[Manic]

Inundated you can’t go my panel size, I changed the ones on my 2001 Hymer and the original one was 65watts and the new ones are 100watts and they are the same dimensions.

 

[Lenny HB]

Inundated you can’t go my panel size, I changed the ones on my 2001 Hymer and the original one was 65watts and the new ones are 100watts and they are the same dimensions.

The originals would have been Polycristaline the new ones Monocrystalline, you can see the difference in the cell structure.

 

[Lenny HB]

Right boys sticking my head out of a roof light and a piece of wood we have a measure of 120x 60 CMS.

Probably 120 watts if they are Monocrystalline or 100 watts if Polycrystalline.

 

[laurieash]

Panel is about 10 years old

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[laurieash]

The originals would have been Polycristaline the new ones Monocrystalline, you can see the difference in the cell structure.

What is the difference looking at them?

 

[Lenny HB]

What is the difference looking at them?

This is fairly typical of a Mono but they are not all like it.