Several JOF members are using Renogy panels, including me.
The size of the solar panel and the number of batteries are related to one another.
If you have 1 12 volt battery, let's say an 80 amp hour battery, you should generally only be draining that by 50% ( to prevent damage to the cells )
So if you use 40 amps overnight, then you need to be able to put 40 amps back in the next day
The renogy panel produces 100 watts at an optimal 19 volts which is converted down by the controller to a charge voltage of approx 14.8 volts
100 watts / 14.8 volts = 6.75 amps per hour.
On a average day, you should expect about 6 solid hours of optimum sun and charging , or about 40 amps of charge capacity
There you go..... 100 watts can manage a single 80 amp hour battery based on proper use.
Two batteries would allow you to have 80 amps of power over night, but you wont have the ability to recharge them unless to expand the wattage of the solar panels
Having more batteries is OK also, in case you have a rainy day for example, but your ability to fully recharge is limited to the wattage of the solar panel
I would really try to get the controller as close to battery as possible.
Voltage is lost over wire lenght.... this is one reason why the solar panels start at 19 volts, to allow for the voltage loss of the cable run from the roof down to the power room.
The charge voltage from the controller is already reduce to 14.8volts. You don't have much room for loss in this critical voltage total to the battery.
Jim & Kim from Colorado
2014 Eagle 30.5 RLS
2015 Dodge 3500HD SRW 6.7L
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