Solar Panel output

Have just purchased a watt meter which indicates what SP output is. All ok although the maximum wattage it is recording is around 12w from my 100w SP.
Is it the case that the higher wattage would only be seen when the battery is discharged a bit?
If not maybe a problem with SP or its installation.   If so all I can say is Oh !

Broadway, had 30w which was replaced with a 100w using existing wiring to Sergent 328.

All ok although the maximum wattage it is recording is around 12w from my 100w SP

just wondering how sunny it is today where you are?

with the best will in the world you are never going to see 100W from your 100W panel - except possibly at noon somewhere on the equator.
I am guessing that yours like everyone elses is mounted horizontally on the roof of your MH so the sun is only ever going to hit it obliquely  - even more so at this time of year when in the UK the sun never climbs very high in the sky.

Your 100W panel will only give 100W on a very sunny day when your panel is mounted at the optimal angle (which depends on the time of day and your latitude) and your MH is oriented in a way that put the panel at right angles to the sun - and to be honest it might not reach 100W even then!


For most people in the UK 100W panel should be regarded as a trickle charger although in the hieght of summer it may make reasonable amounts of juice.

On my house I have 6kW worth of panels and today the best I got was 750W

And any way if your batteries are fully charged there is no where for the panel to put the charge so they wont produce

Thanks raymondo.
Very helpful information.
Panic over!

Kind regards

raymondo wrote:For most people in the UK 100W panel should be regarded as a trickle charger although in the hieght of summer it may make reasonable amounts of juice.

Probably agree with this, I've just had my first year with the 100W panel and have been really impressed during the summer months. Being off grid is no problem at all in summer as the panel charges the battery up the following day nicely with the long days, even if overcast.

However now the nights are drawing in and there is a lot more cloud cover most days, I doubt I would be able to go off grid for long at all and would only consider it as keeping the battery topped up rather than actually charging it. Even with a roof full of panels, in winter in the UK you don't get enough quality sunlight for long enough to get a lot of charging.

Interesting - we will see how it goes through the next summer we get.

I should stress I don't see this as a negative of solar, just the realistic side of things.

I'm actually a massive convert to the benefits of solar panels. If I did more off grid camping I'd probably put a second panel up there.

Hi Noggin,

I have been looking to fit a panel for ages, can I ask you what type did you fit, ie rigid or flexable and any particular make. I do not need a controller as I have a Sargent able to go up to 120w?  Thank you

I went for a rigid Photonic Universe 100W panel with the Bosch cells - supposed to be more efficient but not really sure if that's just marketing talk.

I did a lot of reading on them before buying and although many suppliers exist, Photonic Universe got good reviews and I certainly was very happy with their service. My friend also bought through them after my purchase and also was happy with the results.

He went for a flexible panel. pro's and con's to both but generally I would say a rigid is easier for a motorhome roof (he has a T25 campervan and the flexible has a low profile so unobtrusive).

On our first m/hme which we had for nine years, we had three 75watt solar panels covering virtually the whole roof, and during that nine years found that to use the m/hme comfortably from early October through to mid March electric hook up was the only choice. No doubt panels have improved over time, but I find our present 130watt panel only good enough to keep the batteries in good health during the horrible dark winter time.
Best wishes to us all and safe travels.  Ed.

Noggin wrote:

raymondo wrote:For most people in the UK 100W panel should be regarded as a trickle charger although in the hieght of summer it may make reasonable amounts of juice.

Probably agree with this, I've just had my first year with the 100W panel and have been really impressed during the summer months.  Being off grid is no problem at all in summer as the panel charges the battery up the following day nicely with the long days, even if overcast.

However now the nights are drawing in and there is a lot more cloud cover most days, I doubt I would be able to go off grid for long at all and would only consider it as keeping the battery topped up rather than actually charging it.  Even with a roof full of panels, in winter in the UK you don't get enough quality sunlight for long enough to get a lot of charging.

I have the same with a 100w solar panel and one 110ah leisure battery.  But, I've changed all my lamps including the porch light from 10w tungstens to 1.5 & 2w LEDs.  Now the biggest load on the battery is the telly and the fan when the heating is on - no problems all year round now.
Rich..