Solar panel isolator

[AllanandJackie]

The 2008 Heritages were the first caravan that Fleetwood fitted a small 5 watt PV solar panel to as standard. Its purpose was to overcome the constant discharge of running the alarm system while the caravan was in storage without the facility of a mains supply.

The problem being with it is that the electronics are not protected from voltage spikes that can occur when disconnecting the battery and can cause serious damage to the 12 volt controller when it sees 22volts, which is the open circuit voltage of the PV cell, when the battery is not in circuit. So the PV cell needs to be either covered over or isolated from the caravan 12 volt system before the battery is disconnected.

You need a step ladder to cover the cell if you're a short guy like me so that option when on a site is out for me. So isolation is my only option.

This can be done in a number of ways, namely, remove the three connectors from the rear of the 12 volt controller, disconnect the multi connector that's installed between the PDU3 unit and the controller located under the front seat, or install an isolator switch in the wardrobe at high level.

The latter being the permanent fix and will only take you around 20 mins to complete. I used a 240 volt double pole switch and surface mount patress. If you remove the wood screen next to the radio in the top section of wardrobe you'll see the wire come through the roof from the PV cell, its the small two core lead, the other end is connected through a connector to the radio. Disconnect at the connector, if you've got a tester it's worth checking the PV cells open circuit voltage which should be around 21.5 volts. Cover over the PV cell so no or very little direct light can get to it's surface, check the voltage again and this time it should be down to around 0.5 volts. Make the connections to the switch ensuring that brown in/out through the switch is on the same pole and the same for the white/red wire. Hey Presto all done, remove the cover from the PV cell and check the voltage at the switch in both the off and on positions, when done reconnect the connector to the radio.