Batteries discharging

Kemerton 2011 plugged into mains on the drive to charge, within 24 hours both batteries were flat. Nothing we know of is switched on, charger light is on. We had to cancel weekend trip. Any ideas what’s at fault.

Morning Deb, one of our battery techie guys should be on soon, oh welcome to the forum.
Boaby

Not a battery tech but have you checked the fluid level of the battery often missed and my guess if discharged that quickly battery is past its sell by date

The leisure battery is about 3 years old and had been working fine even 2 weeks ago on a trip and wasn’t draining. I don’t think the integral charger is working maybe, the light is on though. I can’t find the source of what is using power, I’ve checked everything. The vehicle battery also got drained when power unit was on.  

The issue were also having is getting an appointment for an engineer quoted 6 weeks wait. (North Surrey!!)

hi Deb, how long were the batteries off charge before this 24 hr stint? ie, were they already very flat?
if the charger didnt seem to charge them, you need to veryify this by putting the charger on and checking the voltage at both the cab and leisure batteries...this can be done with a volt meter and the voltage should be over 14v with the charger on.
if the voltage is low, 12v or under, then the batteries havent been charging.
does your charging system charge both batteries, some models dont. an AS owner will verify what your 2011 Kemerton should be doing.
my checks are just basic generic ones and not specific to your van.

I keep the EHU attached, and alternate between leisure and Vehicle to charge, I am sure it charges both. I keep them charged up so they have not been sitting flat.

Perhaps EHU all the time with charger on is not good !

We don't have a meter to check, I've looked up on screwfix do we need a multimeter I can pick one of these up?

yes, a multimeter would do the job and is useful.
others will know how 'intelligent' your charger is and if long term EHU connectivity is OK.
If both batteries are flat then either you have a discharge on both that is greater than the incoming charge....
OR...you have a small discharge (over time) but there is no incoming charge (despite the charger giving that impression).
charge not getting to the batteries might be a fuse issue or a charger issue.
how did you check that both batteries are flat....van wont start?, no hab systems? control panel reading?
id want to know what the current batter levels are (multimeter) and then, with charger on, what charge voltage is being applied to each battery when that battery is selected on the control panel.
does that make sense?

The vehicle battery was flat not able to start it. The control panel readings were on red for both and low voltage indicators lights were on the heater and water heater controls. 

Would a multimeter help identify if it’s a fuse?

as i said, my checks are basic.....how flat is flat?....is the charger doing what you think it is?...
obviously, the charger could be working but charge not reaching the batteries for some reason...this would need someone who is familiar with the Kemerton..
however, any diagnosis will need to start with the preliminaries to try  and locate the fault area.

Only had a quick look at the comments before, but one thing did jump to mind ,how is your alternator? ,Often the diodes go short circuit and drag any battery connected down as quick as they charge them

try disconnecting batteries for a time and see if they go done if so its the battery if not its your charging circuits and this includes the alternator

Only had a quick look at the comments before, but one thing did jump to mind ,how is your alternator? ,Often the diodes go short circuit and drag any battery connected down as quick as they charge them

try disconnecting batteries for a time and see if they go down if so its the battery if not its your charging circuits and this includes the alternator

“Would a multimeter help identify if it’s a fuse?”

I’m not questioning your abilities camperdeb but does the use of a multimeter to diagnose your problem make sense? 
Just a cheap one from Screwfix will do the job and many of us will tell you where to stick the probes 

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I am the proud owner of a multimeter, spare blade fuses too. I’ve tested fuses and can’t find any issues. 

I’d charged vehicle battery overnight, took it for a run. It looks like both vehicle and leisure batteries are charging, does that rule out an alternator issue?

Starting to think Peter Brown might be right with split charge/fridge relay fault. 

Hoping to have it looked at in 10 days time now 

Planning a trip now using a torch and gas only as we can’t risk turning control panel on.

Peter Brown wrote:The only scenario that I can think of to fit the symptoms you report is that the split charge/fridge relays have faulted to a state where they think the engine is on, disconnecting mains charge, connecting vehicle and leisure batteries together and powering the fridge on 12v.

Some one will need 'hand on' to fault properly.

he could remove the fridge 12 volt fuse this well show if the relay is the fault
or remove fridge grill and test if the 12v feed has power with out the engine running

I took the fridge fuse out, the fridge display still works, it won’t let it be powered by the battery. When I put the fuse back in same it won’t connect to leisure battery. 

Does this indicate a relay issue?

Is there anything else I can do to diagnose that the split charge relay is the issue?

It  sounds likely as that would explain why both batteries are releasing charge when plugged into EHU charger (discharging to each other) 

Is there any action I could take (novice here) to mend the split charge relay?

Sorry, but it's very unlikely to be the split charge relay alone.

There are really only two possible results from a faulty split charge relay:

Either it is inoperative (stuck open) and the leisure battery is never charged when the engine is running
Or it is stuck closed and the two batteries are connected together all the time.

In the second instance, the two battery voltages will equalise - they cannot discharge into each other.

The only obvious exception to that is if one of the batteries is faulty. In that case, the good battery will discharge itself trying (and failing) to raise the state of charge of the faulty battery.

Thanks Robert, I think I’ll leave it for a man who can now, but it was fun trying to investigate.

Thanks for all the support everyone

Engineer has been, new Sargent charger unit needed. Costly but at least solution identified.