Solar panel to recharge battery from fridge drain?

[gary in ohio]

As with any solar project, Power in vs power out. How much power do you need, How much power is used when setting idle? Your vehicle is going to be drawing power 24x7 but your only going to have good sun for 3 or 4 hour. So if your 18watts is only used for 3hrs you can only have a 4-5watt load. If thats not enough then up the panel wattage.

 

[Corey]

Glad this popped up again, as I am getting interested in the unit in this post in this thread.
http://expeditionportal.com/forum/showpost.php?p=282694&postcount=11

I do not need to power my fridge solely from it, I just want to hook up the panel to my main battery to keep it topped off while camping and using the ARB fridge in fridge mode.

I have ran the fridge up to five days at a time without starting my rig, and it started right up no problem, but I would rather be able to use one of these to keep the battery topped off while parked for awhile when camping.

 

[teotwaki]

I'd also wonder about the need for a charge controller with such low wattage panels. With a maximum of 18 to 26 watts from a small panel and the draw from the fridge I can't see that the battery will ever be in danger of overcharging, especially because the panel is never tracking the sun.

 

[ThomD]

I'd also wonder about the need for a charge controller with such low wattage panels. With a maximum of 18 to 26 watts from a small panel and the draw from the fridge I can't see that the battery will ever be in danger of overcharging, especially because the panel is never tracking the sun.

I figure that the controller is cheap insurance, so I don't think I would use a panel (other than those tiny trickle ones) without it. Why risk it?

 

[Superu]

I figure that the controller is cheap insurance

My thinking exactly. Plus, the panel I use can be easily interconnected with additional panels, at which point the controller would probably be a necessity anyway.

 

[teotwaki]

I figure that the controller is cheap insurance, so I don't think I would use a panel (other than those tiny trickle ones) without it. Why risk it?

Easy to understand the lack of risk as it is all laid out in Post #7. The Engel fridge is drawing more out of the battery than low wattage non-tracking panels can supply. You'll never overcharge the battery until you have a much larger set of panels.