General RV Solar Questions?
I'm planning to add a couple of new high end Kyocera 140 panels and build up a new system out of them. Currenly I have what my old 95' Squire 400 came with which is a substandard and smaller panel wi...
Forum Discussion
Someone thinking of solar should first do two things, install a Trimetric so they can measure their average demand and know how much of a battery bank they need and how much solar output to restore the bank back to 100% during the day. Second is to read the excellent books by Bill Mohler
The Complete Book of Boondock RVing: Camping Off the Beaten Path
and if you need more information:
RV Electrical Systems: A Basic Guide to Troubleshooting, Repairing and Improvement
Most folks, including myself overkill it. Many go for 97-99 percent efficiency which only means a difference of 10-20 minutes in charging time. After installing my setup I found that it was double what we actually need.
I now recommend starting with a digital charge monitoring device and spending the $200 to know what your actual usage is at any given time. The most I was ever able to draw down my 220 AH battery bank was 22%. That took the two 6 amp output solar panels all of about 4 hours to bring the bank back to 100%. On an average trip, winter of summer our demand is less than half that amount and within 3 hours the batteries are fully charged.
The 1 Watt per AH of battery is a rough guide that works. A 100 AH battery provides 50 AH of usable current as you do not want to regularly draw it down past 50% DOD. A 100 Watt panel should provide 5-6 amps output and be able to restore the 50 AH used in 8 hours with a good charge controller and that is plenty good enough.
A good source for information and kits is Amsolar.com in Oregon. Their kits seem expensive except many of the part for which you may need only the two can be purchased elsewhere only in larger quantities so you do not save money and spend more time trying to find alternatives. They can also modify a kit so if you need a longer panel to C-box cable they can simply cut it however much longer you want it to be.
Controllers are not made for the RV industry but for house and commercial uses and so they usually have bus connections for small 12ga wiring as that is all that is needed for a normal installation with 10-20 panels wired in series. For an RV with much lower voltages larger gauge wiring is advantageous but if you need to downsize it with jumpers to get it attached to the controller this will double the space needed - fine if you have it and a royal pain if you do not.
The Complete Book of Boondock RVing: Camping Off the Beaten Path
and if you need more information:
RV Electrical Systems: A Basic Guide to Troubleshooting, Repairing and Improvement
Most folks, including myself overkill it. Many go for 97-99 percent efficiency which only means a difference of 10-20 minutes in charging time. After installing my setup I found that it was double what we actually need.
I now recommend starting with a digital charge monitoring device and spending the $200 to know what your actual usage is at any given time. The most I was ever able to draw down my 220 AH battery bank was 22%. That took the two 6 amp output solar panels all of about 4 hours to bring the bank back to 100%. On an average trip, winter of summer our demand is less than half that amount and within 3 hours the batteries are fully charged.
The 1 Watt per AH of battery is a rough guide that works. A 100 AH battery provides 50 AH of usable current as you do not want to regularly draw it down past 50% DOD. A 100 Watt panel should provide 5-6 amps output and be able to restore the 50 AH used in 8 hours with a good charge controller and that is plenty good enough.
A good source for information and kits is Amsolar.com in Oregon. Their kits seem expensive except many of the part for which you may need only the two can be purchased elsewhere only in larger quantities so you do not save money and spend more time trying to find alternatives. They can also modify a kit so if you need a longer panel to C-box cable they can simply cut it however much longer you want it to be.
Controllers are not made for the RV industry but for house and commercial uses and so they usually have bus connections for small 12ga wiring as that is all that is needed for a normal installation with 10-20 panels wired in series. For an RV with much lower voltages larger gauge wiring is advantageous but if you need to downsize it with jumpers to get it attached to the controller this will double the space needed - fine if you have it and a royal pain if you do not.
