12v Charging Check

[john_5042169]

Can anyone please advise how I can check the output voltage to the caravan battery from the car via the grey socket?

Can it be done without the car be done without the car being connected to the caravan?

Thanks, John D

 

[rayc]

John, yes you can do it without the van connected to the car. If the van is pre 98 convention remove the caravan battery and connect a meter or 12v bulb across the battery terminal leads. Connect the battery, using suitable adaptors to 12S pin 2 (+) and pin 3 (-). The meter should read the battery voltage or thec bulb will light.

If it is post 98 then connect the battery across pin 4 (+) and 3 (-). The battery will then be acting as the car 'permanent feed' and the van 12v lights will work if switched on. With the battery still connected as above connect (+) to pin 6 and (-) to pin 7. This is the fridge supply, which also operates a 'habitation' relay in the van. This relay will switch the 12v on pins 4 & 3 from operating the 12v equipment to charging the battery. The van internal lights will go out and the battey voltage can be read across the meter or the bulb will light.

 

[Bri2]

John, you can do a preliminary check with a multimeter, a cheap one will suffice, analog best, can also be used to check for Indicator 12v feed, the needle will bounce from 0 - 12 volts. Back to the 12S, pins 4 and 3 are used for the operation mention on post 1999 European standard wired towbar electrics. Pin 3 is the return, common, and pin 4 the power feed for charging the battery via a relay in the caravan. Check for 13.8 V at pin 4 with the cars engine running, this is a common voltage for charging 12v from an alternator. Try this link for further info, www.caranninglinks.co.uk/electrics_wiring_code.htm

Brian

 

[MikeP]

I occasionally check mine, but with the car connected - the best way to make sure that everything is OK. Check the battery voltage unconnected - usually around 11.6 to 11.9v. Then connect the car, run the engine at about 2500rpm and the reading on the caravan battery should be around 13.4 to 13.8v.