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I see that the wires coming from my 230 watt panel seem pretty big. So I wonder what size wire I should use. It is low voltage but fairly high amperage. Is there a need to really use heavy duty wire.
By the way I found a liquid plastic paint that I decided to use instead of covering the cracked glass with a plastic panel. So far it seems a good solution. All the little tempered glass pieces are sort of glued together and there is a thin layer of plastic over everything.
______________________________________________________________ Fallow our Camper and other adventures here:
www.johnandluisa.blogspot.com
It's all to do with voltage drop between the panel and the controller/battery.
Your panels should push out around 15 amps (assuming they are 12 volt), and at that current a 2.5mm cable will drop approx 0.1 volt per meter. If you only have 1m of cable run, that would probably be ok. If you have a 10m run of cable, the resulting 1.0 volt drop would be a bit of a waste.
Voltage drop will be inversely proportional to the cable size (cross sectional area in sq mm).
With 230 watts of panel and assuming you will need a cable run of perhaps 4 metres to reach the regulator / batteries, I have looked at a few online cable calculators and they suggest you will need cables with cross section of at least 4mm sq. and possible 6 mm sq. in order to keep losses in the range 2-3%. 3% is typically considered the maximum acceptable for practical use.
panel is 29 v 7 amp so you can use a much thinner cable than for a 12v panel ......
That is about right, so where do I end up with cable size. It's 30.2 and 7.62.
Next problem is the regulator is only good up to 25 volts, but I already have it so I wonder if it might have a bit of safety factor and also what happens if I go over the rated voltage. I already had the regulator and the panel was kind of a gift, that is it's glass got shattered and I was able to grab it. Right now I have run a temporary cable to the regulator just to see if things are working. This cable is only 1mm. My volt meter said it was putting out 21 volts today at about 3:30
I just searched one of those size calculators and at 3m it comes up with 4mm. Guess I will have to look at an auto electric place. I can't find that at the hardware store.
______________________________________________________________ Fallow our Camper and other adventures here:
www.johnandluisa.blogspot.com
While I have your attention, this panel is big about 1m x 1.6m, I had to put it on the over cab section. It seems to look fine there. I attached a 1m alu. angle to the two short ends which sits on the roof, raised up about a cm. I still need to secure it. So I am trying to decide between screws and glue or both. Any recommendations?
______________________________________________________________ Fallow our Camper and other adventures here:
www.johnandluisa.blogspot.com
i put 6 brackets, 3 on each of the long sides of the panel and screwed and glued because having gone to court after a lazy lorry driver shed a 4 ft square piece of aluminium that wrapped around the nose of my car ....
I d never ever want anyone to experience similar ...
if you ve just fixed the short sides i d worry the air at 70mph on a 1.6 meter panel could have quite an effect on it ....
i put 6 brackets, 3 on each of the long sides of the panel and screwed and glued because having gone to court after a lazy lorry driver shed a 4 ft square piece of aluminium that wrapped around the nose of my car ....
I d never ever want anyone to experience similar ...
if you ve just fixed the short sides i d worry the air at 70mph on a 1.6 meter panel could have quite an effect on it ....
The brackets on the short sides are continuous the whole width of the panel. But I will give some thought to putting a couple on the front long side. Another thought might be a continuous piece of plastic angle to act as a wind break. I don't to put more holes in the roof than I have to.
What size wires did you use, and what regulator? Oh and one more thing, where is it.
______________________________________________________________ Fallow our Camper and other adventures here:
www.johnandluisa.blogspot.com
i used 4mm and thats excessive as i planned to fit a second panel that folded out from the first when parked up.... the regulator is an ivt but 30a but a 20a would have done and i would have opted for a different one on ebay with the new "super capacitor" technology if i was starting again (and its cheaper). The regulator is outside in the electrical locker half a meter from the battery with 65a cable on the output to prevent voltage drop as it can deliver up to 15a in that section of the circuit.. It has a temperature sensor on the battery from the regulator as this becomes more important when charging at higher amps ...
why not sycaflex the plastic angle to the panel and roof and avoid screws on that section but gain the stability....
Since the solar panel only puts out 7 amps I wonder why even a 20 amp regulator would be necessary. I think I will use the plastic piece on the front glued instead of screwed. But I and not sure if the panel needs to have ventilation under it.
The problem for gluing right now is the cold, there is ice on the roof and I have no indoor option.
______________________________________________________________ Fallow our Camper and other adventures here:
www.johnandluisa.blogspot.com
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