Hi there,

I have a 2009 Jaguar XF 2.7 Diesel with a 100 AH calcium battery in the boot. When towing our small caravan I would like to charge a small 40 AH calium / lead 'house battery' mounted in the caravan from the car. We only tow our caravan a few times a year for a few days at a time. I want to set up the connection between the two batteries in the most cost effective way and safe way possible. I do not want to run the risk of damaging any sensitive electronic equipment in the Jag.

Does anyone have experience of making these types of connections? If so how was it done and was it successful?

Does anyone know if my car alternator is variable voltage and ECU controlled? I understand if it is I will not be able to use a VSR (Voltage Sensitive Relay) to make the connection (which would be quite cheap and easy to do), but will need to use a DC to DC charger unit which is much more expensive.

Thank you,

Philip