How much Charge do you get from your solar panel

[C7KEN]

Solar panel output

Near Guardamar Spain
Midday 18/04/2009
75 watt poly
3.8 amps
6pm same day
1.8 amps
Panel laid flat charging 220amps capacity leisure batteries which were showing 13.2 volts

 

[olley]

18/04/09 Ipswich
12.30pm Clear sky
2x130watt poly
6.5 amps

 

[C7KEN]

Solar Panel Output

Today in Spain its raining 19/04/2009
My 75watt panel is producuing 0.12 amps at 1pm.
I am not sure thar Solar Panels are a cost effective buy for those who never leave the UK. However I do know that tilting my panel towards the sun in winter makes a big difference. Today is overcast so no sun showing but hey this is Spain so the sun will likely return tomorrow and we will be back up to 3-4 amps

 

[olley]

21/04/09 Ipswich
12.30pm Clear sky
2x130watt poly
10.5 amps

 

[olley]

29/05/09 Ipswich
12.30pm Clear sky
2x130watt poly
11.9 amps

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[ruffingitsmoothly]

Hi only just seen this thread and I know it's not midday but was in the RV today at 3pm this was the reading:

29/05/09 Southampton
3.00pm bright hot sun
2 X 85 watt
8.8amps

Regards Pat

 

[gazznsam]

29/05/09 nottingham,
13:00, cloudless sky,
3 x 123 watt,
24.6 amps,

Panels are mucky, havent been cleaned for a month, so could get maybe another 2 amps if i went on roof and washed em down, but the batteries are full... 1.4 amps going into them, the rest is getting wasted bloomin controller has just done an equalising charge the other week, so wont do another for a month, but dont think i can trigger one manualy (steca pr 30-30)

 

[olley]

Hi gazz your reading seems very high, where are you taking it from? and how. Just to explain, 123wx3=369w/17v=21.7amp. This is the theoretical maximum, which panels never achieve. You say your batteries are full so I presume you are reading the output before the controller.

Olley

 

[Pronto]

29 - 05 - 09

Preston

12:30

Cloudless

60 Watt amorphous panel, angled to sun

4 amps

 

[Wildman]

29/05/09 nottingham,
13:00, cloudless sky,
3 x 123 watt,
24.6 amps,

Panels are mucky, havent been cleaned for a month, so could get maybe another 2 amps if i went on roof and washed em down, but the batteries are full... 1.4 amps going into them, the rest is getting wasted bloomin controller has just done an equalising charge the other week, so wont do another for a month, but dont think i can trigger one manualy (steca pr 30-30)

The charge going into a battery (in this case 1.4amp) is restricted by the controller due to the fact that the battery was nearly fully charged. If a load is placed on the battery whilst the reading is being taken you will get a better idea of what the panels are producing. The other option is to take the reading before charge reaches the controller, however if you do that then any losses caused by the controller are not taken into consideration.

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[pappajohn]

30/5/09 scarborough

12.00 bright sun

1 X 120w panel

4.1 amps at the panel

1 amp at batteries...batteries 99% full

 

[gazznsam]

Hi gazz your reading seems very high, where are you taking it from? and how. Just to explain, 123wx3=369w/17v=21.7amp. This is the theoretical maximum, which panels never achieve. You say your batteries are full so I presume you are reading the output before the controller.

Olley

reading are taken directly from the controller, so could well be the short circuit current(which is 24.3 amps) afaik my controller is just a PWM one, and dosent do any MPPT stuff,

i've seen the controller displaying 26 amps before, and it claimed 25 of that was going into the batteries,
but heck, as long as i get sunshine, it keeps the battery bank charged (460AH) my batteries are badly sulphated up after over 500 cycles, so it's only my solar panels that allows me to keep going.... couldy days and the batteries hardly last 24 hours.. and that's with conserving energy to the max.

 

[gazznsam]

30/05/09, Nottingham
14:06, full sun but not directly overhead.
19.8 amps from panels... 0.3 amps to batteries,
turned on inverter and microwave (100 amp load): 19.7 amps into batteries.

the van is 31 degrees inside, so the panels will be red hot too, and as we all know, solar panel efficiancy decreases as they get hotter, hence you can see more power produced on a freezing cold day that a hot one for the same sun elevation,

And also if you take a reading when the sun comes out from behind cloud, you should get a higher reading untill the panels heat up.

 

[olley]

Hi guzznsam, never knew that about hot panels, any idea how much less?

Olley

 

[gazznsam]

For calling me Guzz i'm half minded not to answer that

panels are usually rated for a 'warm' temp, every make will be slightly different, i believe it's about 40 degrees most panels are measured at for getting their specs, but they can get a fair bit hotter than that even in england,

When the panels are cold they can actually produce more than their rated current, so if you go camping in the artic and point the panels at the sun you should see at least another amp, if not more.

someone i used to talk to in america experimented with the panels on his garage roof, by running cold water from the hosepipe over them he could get almost 1/4 of his total output more out of them.
but one day he did the hosepipe thing, and they must have been hotter than usual and he cracked a couple of them from the thermal shock, still worked for while, but eventually water got in and corroded the junctions between the wafers and output dropped dramaticaly.


i keep thinking of putting some form of solar water heating on my van, i had mooted fixing a run of pipe on the back of one of the solar PV panels, but the possibility of thermal shock has put me off doing that, and i'd imagine people would be selling solar heating and PV panels combined if it was a good idea.

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[hilldweller]

i'd imagine people would be selling solar heating and PV panels combined if it was a good idea.

Why ?

Someone has to be first on any idea. That sounds very good to me though with certain logistical difficulties. It combines two trades, plumbing and sparks so not as straightforward to sell and install.

Then there is a compromise, you want HOT water, the panels want COLD water. Maybe there is a suitable temperature.

Loads of weight where you don't want it.

Easy enough to overcome thermal shock with a bit of electronics.

 

[bushman51]

A report from Basel/Switzerland:

31st May 2009, around noon, three different panels (all together approx. 250 W, permanently bent about 5 degrees) with plenty of sunshine: 13.5 A output! 2 (two) 100 Ah leisure batteries full to their top, I could have been dealing with electricity ;-)