Models: K, Years: ALL

My first attempt at installing a 12 volt supply for my AM/FM Radio/CD Player didn't work out too well. I used a Solar Converters EQ 12/24-20 Battery Equalizer and a set of relays to create the 12 volt supply. The battery equalizer worked well enough, but I had a lot of problems with phantom ground loops and I was a little apprehensive that I might let the smoke genie out of some expensive components. Then there was also the inconvenience of losing the radio's memory when I turned off the battery disconnect switch.

I removed the battery equalizer and returned the battery wiring to the stock configuration, but that left me still searching for a 12 volt supply. I had an 18 watt solar panel left over from my 1993 expedition to Iceland and this is how I used it to create a totally independent 12 volt supply for my Pinz.

First, I installed the solar array on the roof of my 710K (this might be a little problematic on an 'M).

The next step was to install a Optima Yellow Top (deep cycle) battery in a marine battery box mounted on the right rear wheel well. Then I installed a Morningstar SS-20L Solar Charge Controller. Why a charge controller? The charge controller provides PWM regulation to prevent cooking the battery, temperature compensation, low voltage load disconnect to prevent draining the battery, PV disconnect after dark, etc.

Here's a close up of the charge controller.

Here's a photo of the wiring junction box behind the passenger seat. There is a relay to control the radio (energized by the ignition circuit). The switch by-passes the relay so that I can play the radio when the truck in not running. There is some other wiring in here as well. The important thing to remember is that the 12 volt system is totally independent of the truck 24 volt system.

My solar panel, although only 18 watts, will charge the battery even during the dim winter days (when I don't drive the truck to much). In summer, the PV array is more than adequate for the radio and most other 12 volt accessories that I may care to use while traveling and camping.

Contributed by Jay Reich