UKC

The leisure battery on my T4 isn't charging. I have replaced the relay but there is no change. The voltage doesnt go up on the leisure battery when enging is running but main battery charges fine so it is not the alternator. Both sides of old and new relay show 12v when engine isn't running which suggests power going through relay which should only happen when engine running.
Radio needs resetting every morning and comes on by itself. I believe it may be wired to leisure battery for watching dvds when parked. Could this be cause or effect?

Any suggestions of where to look next welcome? Is there a way of checking relay in case I have replaced with faulty one?

In reply to cas smerdon:http://www.vwt4forum.co.uk/ I cant help you with your battery problem but if you click on this link I`m sure you will find somebody to help.

In reply to cas smerdon:

is the leisure battery charging ok via the mains, off the van?

a knackered battery can still show almost 12v.

In reply to deepstar:

I have posted there as well thanks

In reply to cas smerdon:

Disconnect the leisure battery and confirm that there is 0v showing on that side of the relay. Start up and verify there is charging voltage on that side of the relay. You might here it click too. If the relay is working ok then the leisure battery must be buggered! The radio would reset if there wasn't enough voltage. Or the radio may have some odd fault that's discharging the battery. Not unknown.

In reply to winhill: Good point. Will try that today

In reply to cas smerdon: Any more advice? Does how I set switches on zig unit affect charging or just where I get power? it is a zig cf9 by the way.

In reply to cas smerdon: Can only echo what other have said. Isolate each part of the system and test for function. You know the alternator works, but the battery ? try removing it from the van and putting it on charge in the house, then put it back in, if things work, its probably further up the chain. Isolate the next thing int he change towards the alternator and test.

I think batteries can also get fickle in the cold, I assume this has just started happening ?

HTH

dave

In reply to dave frost: Has been happening since September when I had my fridge repaired. Had fridge man back out but he can't see that he has caused problem and says there are just 2 wires to fridge and they are ok.

In reply to cas smerdon: I should add that first off my main battery kept going flat. I bought a new one and that went flat overnight. Checked battery and there was a 3 amp drain so removed every fuse in turn until we isolated a thin wire going from van battery to leisure battery. This was apparently so that if leisure battery was flat it could take power from main battery. I took fuse out of this wire and main battery has been fine since but leisure battery now keeps going flat. Some days it is ok again though and not connected with whether it has been on a long journey or not.

You do know that the fridge can use the full working capacity of your standard battery in 1 day?

Explanation.

Typical bat is 100ah
Should only be used to 50% SOC or DOD
(SOC = State Of Charge. DOD = Depth Of Discharge)
12v fridges use about 50ah per day

Recharging a bat is not just about replacing X number of ah. Lead acid bats need Time as well as ah to recharge. To get back to 100% SOC takes a long time. Failing to do so allows sulphate to build up which reduces the total capacity of the battery. With each cycle the battery gets smaller & the DOD larger for the same usage.

So unless your engine is running for over 8 hours per day the fridge is on it will be getting hammered & eventually stop working.

In reply to Richard Wilson: Ok. But I only use the fridge on battery when the engine is running. Only used it once since September. When it is parked I use gas.

In reply to cas smerdon:

Ok,

Did you try Digby's suggestion of disconnecting the bat & testing the voltage at the terminals with & without the engine running?

In reply to cas smerdon:

Is the relay a volt sensitive relay? If so it may not charge the leisure battery until the starter battery is full.

If the starter battery is duff then the leisure battery won't be charging and may also be helping the starter battery in starting the engine.

That's all from rusty knowledge on how split charge systems and vsr 's work.

Do you have a circuit tester? As suggested isolate everything, give both batteries a good long trickle charge up to 12.6 v and then have a good test of the voltages in each part of the system.

Good luck! Let us know how you get on

In reply to cas smerdon:


The wire from the starter to leisure battery should have a relay interrupting the connection between the two batteries when the ignition is off,

There is no isolation built into the cf9 hence an additional relay is needed.

An average fridge draws about 4A so will flatten a leisure battery pretty quick as mentioned,

I'm very familiar with these systems and work as a car security/ audio/ motor home engineer,

Have u got access to a multimeter?

In reply to cas smerdon:

Defo missing a relay! And need to locate the drain on leisure battery side