author=Itsu link=topic=3985.msg85527#msg85527 date=1606209965]
no i never did anything with my panels, they were installed on the roof to which i have no easy access and are always connected.
It is really quite simple.
Heat energy is converted into electrical energy when the circuit is complete.
If the circuit is open,then no electrical energy is being converted from the heat energy impacting the solar panel in the form of light. As they say,energy can only be transformed,and so when the circuit is complete,then some of the heat energy is converted into electrical energy,and so the panel cools when there is electrical energy being delivered to a load from the panel.
Thanks, good advice, i knew already about these "own micro inverter or optimiser" for not to shut down a complete stream of panels when one gets shadowed.
That is mostly incorrect.
First watch this video,as it is another clasic example of so called !!ex-spurts!! getting it wrong.
In this case,it was the guys from enerdrive Australia giving the wrong information.
I will explain after the video-series or parallel
https://www.youtube.com/watch?v=-36nUpjBcVMI will say first up that the guys from Trip in a Van are an awesome couple,and have many great video's of our wonderful country. You could spend days watching there video's,and never get board
Enerdrive has just given them the bum steer ,and he is just saying what Enerdrive tells him to say.
There are no if,buts,or why's when it comes to hooking up multiple solar panels in an array-->it should always be in series. Now,this requires you to use the correct solar panel's,which Enerdrive obviously do not. You would think that these !so called! solar experts (Enerdrive) would know better,but as we clearly see,they seem not to.
Problem is,everyone that now watches that video will be thinking that they are getting the best possible information,when in fact,they are getting information on how to put together the most inefficient solar system you can get.
It is clear from that video that you should steer clear of Enerdrive's solar panels,as they are clearly cheap nasty china panels. So here is why the whole array will drop out if you place a hat over just on cell of the panel-->it is a cheap solar panel that has no bypass diode's. This is the only reason you will loose the whole array by covering just one cell when the panels are hooked in series-->no built in bypass diode's. All decent panels have built in bypass diodes,and when one panel is completely covered the rest will continue to keep the current flowing.
The best and most efficient system you can have is panels hooked in series-good quality panels with built in bypass diode's,and an MPPT charge controller--there is no question about it.
By hooking in series,you cut your ohmic losses right down,and also your cable size,resulting in lower cost's.
BTW,i use the EPever Tracer series of MPPT charge controller's on most of my install's,as i have found them to be the best bang for buck $
So let's look at a 400 watt-12 volt system.
Here we use 4x 100 watt 12 volt panels.
Each panel can deliver a maximum current of 5.5 amp's
Now,i know you are going to say that that cant be right,as 5.5 x 12.5v(the voltage we use to calculate for a 12 volt system) is only 68.75 watt's. Well that is because a 100 watt 12 volt panels maximum power is calculated using 18-18.5 volt's,not 12 volts-->and that is the very reason we use an MPPT charge controller,so as we get the full 100 watts from the solar panel,and not the 69 watts we would get when using a PWM charge controller.
Anyway,we hook all these panels in parallel,and we have a total max of 22 amp's flowing through the cabling to the charge controller. In most cases,from the solar array to the charge controller on caravans(depending on size of van) ,we use an average of 5 meters of cable. Let's say that this cable has a resistance of 1 ohm over that 5 meter's,and we are pushing 22 amps through it. This means we are burning off(loosing) 22 watts of power as heat via the cable.
Now we hook the panels up in series.
We now have a maximum current of just 5.5 amp's through 1 ohm of cable resistance.
So now we are loosing just 5.5 watts as waste heat,instead of the 22 watts in the parallel configuration.
The second reason we hook up in series is to get the voltage up high,which the MPPT then converts to a lower voltage(battery voltage),but a higher current. With a higher system voltage,your array will produce more power earlier in the morning,later in the evening,and in heavy overcast/shading situations.
So when some one tells you not to hook up in series ,as you will loose the whole array if one part of one panels is shaded,you now know that is only the case with cheap ass panels that have no built in bypass diode's.
Now you sound like another Aussie who always tells me he (they) are lightyears ahead of the rest of the experts. 
Lol.im nothing like Chris
I just had one of them dumb thoughts one day,and posted it here.
It's more just by chance that some one actually is making it work,rather than my expertise in particle physics lol.
yes, would be good to know if there is a workable solution to that heating up problem which still exsists then.
As i stated,make a panel that reflects the infrared spectrum(heating part of all light),and works just from the remaining light. It's much like the difference between the light from an incandescent bulb and an LED--one produces lot's of heat with low light per watt,and the other produces lot's of light and low heat per watt.
In fact,there is a great little test i could carry out. Using a set amount of power,can we get more power from a solar panel using LED's or incandescent bulb's as a light source for that given amount of input power
And which light source would cause the panel to heat up more?.
Maybe a big bunch of cooling fin's on the back of the panel?
Brad
Never let your schooling get in the way of your education.
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