The <span class="highlight">solar</span> panel tango

Flat all day compared to perfect angle pointing north all day is about 20% I understand.
Chasing the sun east to west all day as well would be some extra.
Personally, an extra panel on the roof is much better value, I reckon.

Cheers,
Peter
OKA196 Motorhome

It makes a lot of difference in the Morning till about 10:00 then from about 3:00 in Winter and 9:00 till 5:00 in Summer. About double at those times,

The morning in particular it is important to face the sun as the air is cool, and the batteries low. That is when the efficiencies kick in, especially with a MPPT controllers.

If you move the panels a few times like above then you will get pretty close to the available power.

The big issue is that most people simply buy too little solar. 160w for example is good for a fridge and some extra power IN PERFECT conditions. If you had 320W then you could move the panels less and still get power on cloudy days.

As a guide if you lay the panels flat. At about Sydney, if its winter ( worst case).
at 9AM you get about 25% of the sun's power
at 10 AM you get about 45.
at 10:30AM you get about 60%
at 11AM you get about 75%
at Midday you get about 85%

In summer it might look like
at 8AM you get about 25% of the sun's power
at 9 AM you get about 50.
at 10:30AM you get about 70%
at 11AM you get about 85%
at Midday you get about 100%

We put a monitor on a mates 160W panel one day at camp and were surprised at it's low output reading for the size of his panel compared to one of my 80W panels I have which I'd just checked minutes earlier. We then tilted his panel back a touch more as it was standing abit to straight up and down I thought ( though was angled in full sun already), and straight away it's output doubled.

The other factor other than the panel's angle to the sun is the internal heat of the panel. As it gets past a certain point the output drops off considerably.
This is particularly noticable with panels mounted against a flat surface without a clearance being made to allow air circulation to allow cooling.
Personally I move my 80 watt free standing panel a few times during the day (without getting too anal about it) and this connected with an MPPT controller mounted close to the DC battery powers my Engel 40 lt fridge and puts enough extra into the battery to last through the night. The fridge doesn't get opened after around 8 or 9 pm though.

Cheers
Pop

For the past week I have been holed up in a gravel pit between Meekatharra and Wiluna. I was parked pointing to the west. The best input I would get was 10.6 amps from my 420 watt panels mounted on the van roof.
I knew it should have been better and because for the past 1000k's have been dirt roads I thought dirty panels.
I got up and cleaned them up pretty good and the results were the same.
After the 4th day I moved the van to point to the North and the input rose from a maximum of 10.6 amps to a maximum of 17 amps.
These maximums didn't last very long during the day, probably from 11:00 to 14:00.
By 16:30 input was practically nil.
Whilst I was up on the ladder cleaning the panels I noticed that the air conditioner was shading a small portion of two panels when I parked pointing to the West.

Today I am sitting in a rest area, totally overcast day and charging at 6.5 amps at 10:30.
(Hopefully the generator haters will not park near me this afternoon as I feel I will have to give it a run later to top things up.)

Cheers

Yeah, camped in the Bungles a few weeks back in the low 30s, 150 w of free-standing panels yielded about 6.5 amps max. PWM controller. Was doing the dance. Should be getting more?

My son installs panels on houses, vans, house boats etc and when asked what panels are best he says the sun chaser variety.

Viz. Those of us that have portable solar.

I too have panels on the roof of the van but like to park where the hot afternoon sun is shaded from the van so that is when the sun chaser panels really do help.

Yep you can't have too much solar.