Good morning all....does anyone use a solar panel to charge a car battery ? I have a 20w panel with a cmp decoder (regulator) wiring up is easy but there are 2 connections for a load (picture shows a bulb) I would guess 12v but what wattage, anote with the controller says make sure the rated voltage of the panel battery and load are the same......thanks

I use a small solar panel to trickle charge my 7, the panel is on the garage roof, and the cable runs down into the garage
My reasoning is that's its convenient, and can be left on without any risk of fire, and its free

I also use one in our caravan, same deal

steve

A old style 12v lead-acid battery when fully charge has a no-load voltage accross the terminnals of 12.6-12.7 volts this voltage varies a bit with temperature (low temperature gives lower voltage) and battery chemistry.
To actually float charge a battery the charger needs to output about 0.7 volts above the battery voltage.


https://en.wikipedia.org/wiki/Float_voltage






[Edited on 20/11/16 by britishtrident]

I use the a car battery to power the door opener on my chicken coup.

The solar panel is wired to the charge regulator, the regulator to the battery then the door controller to the load terminals on the regulator.

If you are just trickle charging a car battery over the winter you don't need anything on the load terminals.

I have 2 on my motor home, one that keeps the leisure battery going and a small one for the engine start battery. Touching wood, they have been trouble free for the past several years. I'm about to undertake a winter trip and will be interested to see the charge rate in winter sun.

Thanks all for your help.......