theoldwizard1 wrote:
Those devices are convenient, but significantly over priced !
Definitely!
Your RV already has the battery. All you need is a solar panel and charge controller - both of which are dirt-cheap nowadays.
Here's a handy, inexpensive way of hooking solar panels up to just about any trailer - without making any modifications to the trailer whatsoever:


You simply plug your trailer's hitch connector into it. Power from the charge controller (
Renogy's $20 Wanderer 10A PWM model) is supplied to your RV's house batteries through the Charging wire in the hitch connector.
The $13
Harbor Freight Apache 1800 protective case case is waterproof (when the lid is closed), so this rig can be left outdoors indefinitely.
I use it with a
100 watt solar panel (around $85) connected by 50 feet of wire. This portable arrangement allows the panel to be moved around to whatever part of the campsite has strong sunlight, and allows the panel to be quickly removed and stowed.