# of watts solar system needed to MAINTAIN coach batteries?
Class A with 2 12 volt coach batteries. Want to maintain while not in use.
Forum Discussion
2 watt is more than enough if batteries are disconnected.
My 5 batteries (2 coach, 1 chassis, 1 SUV and 1 motorcycle) were fully charged (12.7v) after almost 5 months in low-light Boise.
Nature Power Solar Battery Maintainers and Trickle Chargers- 2-watt Catalog Item # 56004 $28
model is weather-resistant for indoor or outdoor use
Dimensions: 16" x 5" x 1 1/2"
Manufacturer: Rdk Products
Mfg Part #: 40019
CW low-cost Solar Battery Charger worked over winter
In Nov, I removed the batteries, connected them in parallel, and used an externally mounted CW solar charger (I believe it was a Nature Power Solar Battery Maintainers and Trickle Chargers- 2-watt Catalog Item # 56004 $28) to keep them topped off. I mounted the panel pointing to the south and at an angle I guessed would be perpendicular to the sun's rays during winter there.
This solar charger has no regulator, so I feared its reverse current draw (during night and low light) might do more harm than good by draining the batteries and ruining them.
However, it worked well. Newer models say they have a built-in blocking diode to prevent reverse flow of electricity
I would LIKE to think manufacturers would state the reverse draw of their products but such is often not the case. The year before the solar battery maintainer I purchased from CW, Sun Force 1.8W, User's Manual says nothing about reverse draw. When I got to my RV storage location and measured it, the draw was of an amount that I guessed it would ruined the batteries. So I had to leave them without charging over the winter. Next year I had to replace both the coach batteries.
Sunforce 50012 is $17 from Home Depot
My 5 batteries (2 coach, 1 chassis, 1 SUV and 1 motorcycle) were fully charged (12.7v) after almost 5 months in low-light Boise.
Nature Power Solar Battery Maintainers and Trickle Chargers- 2-watt Catalog Item # 56004 $28
model is weather-resistant for indoor or outdoor use
Dimensions: 16" x 5" x 1 1/2"
Manufacturer: Rdk Products
Mfg Part #: 40019
CW low-cost Solar Battery Charger worked over winter
In Nov, I removed the batteries, connected them in parallel, and used an externally mounted CW solar charger (I believe it was a Nature Power Solar Battery Maintainers and Trickle Chargers- 2-watt Catalog Item # 56004 $28) to keep them topped off. I mounted the panel pointing to the south and at an angle I guessed would be perpendicular to the sun's rays during winter there.
This solar charger has no regulator, so I feared its reverse current draw (during night and low light) might do more harm than good by draining the batteries and ruining them.
However, it worked well. Newer models say they have a built-in blocking diode to prevent reverse flow of electricity
I would LIKE to think manufacturers would state the reverse draw of their products but such is often not the case. The year before the solar battery maintainer I purchased from CW, Sun Force 1.8W, User's Manual says nothing about reverse draw. When I got to my RV storage location and measured it, the draw was of an amount that I guessed it would ruined the batteries. So I had to leave them without charging over the winter. Next year I had to replace both the coach batteries.
Sunforce 50012 is $17 from Home Depot
