Had an issue late September when our vans
battery was completely flat after being parked for two weeks. This is pretty normal for us and, over the three years we have had it, has never been an issue. Started it with power pack and ran fine, three hour run each way to kent, sat for another two weeks and started ok. Then Thursday ( another two week park up) it was dead again. We replaced the
battery, assuming that this was damaged beyond recall now. Garage checked no drain when fitting new
battery, but this is obviously a slow drain somewhere which we really want to identify as don't want another
battery damaged. Garage said checking all the fuses was very time consuming ( costly) and he couldn't think it was likely to identify anything. How would an issue with split relay show up and is there a way to check it. Overnight the only thing on van
battery was the light for the lock which flashes overnight ( nothing new) and the
battery on the van was 12.6 now 12.3. is that normal.?
Any ideas would be appreciated. In Kent for a few more days. Thanks
Garage is right in saying tracking down things like this can be costly due to the time spent.
How would a issue with split-charge relay show? if there is a fault, it will be a matter typically of it sticking on, or sticking off. it is pretty well that simple. checking depends on what access you have and what tools you have. If you have access and a multimeter, then you can put the meter into Ohms/Reistance, put one probe on +ve IN, one on +ve OUT. if a virtual short-circuit (no or very little resistance), than the relay is on. If open-circuit (infinate or very high resistance), then the relay is off. Relay should only be on when the engine is running typically. If it is on without the engine running, the effect is the starter and leisure batteries are connected together and you will get current flowing one way or the other as the batteries tend to equalise their voltages together.
If the two batteries are not the same voltage (give or take a slight variance for cable volt drops), then a relay will not be on. If the Starter
Battery is dropping in voltage and is also below the voltage of the Leisure
Battery, then the issue will not be with the Split-Charge relay.
The above is true for just about any van fitted with a split-charge relay, but there will always be the odd installation which is different of course.
The classic reason for a starter
battery going flat in a car used to be the boot light sticking on. Glovebox light is another culprit.
2 weeks to flatten a
battery could be an alarm - I had a car with an undersized
battery (officially the right size) and that would flatten after 2 weeks of being parked up. Toyotas response .... "normal, try not setting the alarm if leaving it parked up long term". Useful.
Another very common one is the radio. If your radio can be used without the ignition key, it means it is always connected to the
battery and using power even when "Off" (the "Off" button on modern car radios is NOT an "Off" button, it is a "Standby" button). If it works like that, you need to either rewire so the ACC +12V goes through either the ignition or to a switch you can turn off. (I have sold literally hundreds of radio wiring kits to VW Transporter owners to do this).
Have you changed the radio or changed any wiring on the radio in the last year or so?