high voltage solar panels?
Has anyone experimented with high-voltage solar panels on their RV? I'm thinking along the lines of the 250-300+ watt panels that output 40-60 volts, versus the little 25-100 watt 12 volt panels typi...
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My Blue Sky MPPT controller will not work with more than 35 volts and the majority of panels that are small enough to work on an RV and sold by RV solar dealers are 34v or less. The home and commercial panels are sold by different dealers. I could not buy "commercial" panels for my house as the dealers were only allowed to sell the manufacturer's residential panels.
There is a safety issue when you have an ungrounded RV system and high voltage that makes it foolish to go this route. Even with my house the panels are ganged to keep the voltage level to a level that the string inverters can handle and the industry is moving to ones with lower voltage AC strings as they are safer for the workers and safer for firemen who may need to get on the roof.
There is a reduction in current loss with higher voltages but for the runs involved in a RV this is not a factor of any significance once you get up to 34 volts. I optimized my setup to have a total current loss of under 3% but afterwards realized how silly it was to have done so.
If the panels recharge the battery bank as they now do in under 3 hours of sunlight what did I gain by being at 97% instead of 94% efficiency? I gained absolutely nothing as once the batteries are fully charged the output from the panels accomplishes nothing. At 50% efficiency it could take 6 hours instead of 3 hours to recharge the batteries but unless I am using them in Alaska during the winter it really does not matter so long as the bank is recharged to 100% before the sun sets.
There is a safety issue when you have an ungrounded RV system and high voltage that makes it foolish to go this route. Even with my house the panels are ganged to keep the voltage level to a level that the string inverters can handle and the industry is moving to ones with lower voltage AC strings as they are safer for the workers and safer for firemen who may need to get on the roof.
There is a reduction in current loss with higher voltages but for the runs involved in a RV this is not a factor of any significance once you get up to 34 volts. I optimized my setup to have a total current loss of under 3% but afterwards realized how silly it was to have done so.
If the panels recharge the battery bank as they now do in under 3 hours of sunlight what did I gain by being at 97% instead of 94% efficiency? I gained absolutely nothing as once the batteries are fully charged the output from the panels accomplishes nothing. At 50% efficiency it could take 6 hours instead of 3 hours to recharge the batteries but unless I am using them in Alaska during the winter it really does not matter so long as the bank is recharged to 100% before the sun sets.
