Battery + Charger - chicken or egg?

[audiorob]

Just sorting out the caravan and have a problem with the battery or charger.
The van is a 2011 Elddis Breeze (Xplore special edition) that I have owned since its first birthday - and this the distribution panel:


Went out to the the van on my driveway the other evening, switched on one 12v ceiling light which was totally dull. The MCBs were both in the off position - RCD in the up/on position. Generally the battery which is 110Ah is left on charge plugged in within my garage- its now nearly 6 years old. In the position in the photo I have mains power to the sockets. However when I switch on the left mcb (fridge, lights, charger) it clicks out immediately and triggers the garage mcb too. Having removed the fuses for the lights and fridge the same occurs so I conclude the charger is causing the trip. I have taken the battery off the van and using an external smart charger the battery is clearly defunct - after a day on charge it reached 11.6v before stating 'Error'. This morning with no load overnight it was at 6.6. Although I don't think relevant the panel by the door Mains/lights/awning light/pump is all switched off.
So... Chicken vs egg!
Can you offer any advice as to whether the charger has a problem which has allowed the battery to discharge and therefore die
or...
has the battery died in which circumstance the charger will be expected to trip when the battery cannot accept a charge.

Please bear with me as I am a long time caravan enthusiast but by no means an electrician!
Thanks in advance!

 

[toad a caravan]

Is the any chance you could substitute your battery for a known good one to narrow down the problem?

 

[birdman101]

As said try a good battery and if it still trips suspect the charger faulty or wires from charger to battery shorting out somewhere.

 

[JTQ]

I concur the battery is US.
Have you a mains supply fuse to the charger, or know how to unplug it if it has a plugged in feed?
Doing either and then seeing if the MCB or RCD still trips or not ought to give a strong indication. If either still trip then there is an issue elsewhere even if there is a charger fault or not. If there is no trip then the charger would be confirmed the issue.

Certainly battery failures can lead to the charger consequently failing, note "can", not necessarily will.

 

[ProfJohnL]

Just sorting out the caravan and have a problem with the battery or charger.
The van is a 2011 Elddis Breeze (Xplore special edition) that I have owned since its first birthday - and this the distribution panel:
View attachment 8735

Went out to the the van on my driveway the other evening, switched on one 12v ceiling light which was totally dull.

This indicates the 12V circuit has low voltage.

The MCBs were both in the off position - RCD in the up/on position. Generally the battery which is 110Ah is left on charge plugged in within my garage- its now nearly 6 years old. In the position in the photo I have mains power to the sockets.

That concurs with switch settings

However when I switch on the left mcb (fridge, lights, charger) it clicks out immediately and triggers the garage mcb too.

This indicates you have a significant current overload, especially if it is tripping the MCB in your garage. The concern is we don't know if its the Charger, fridge or lights. or the 230Vac wiring in the caravan.

Having removed the fuses for the lights and fridge the same occurs so I conclude the charger is causing the trip.

Your assumption is incorrect. The fuses you have on the left hand side are only for 12V circuits not the the mains 230V circuits, so the removal of any of the fuses should not affect the 230V systems.

I have taken the battery off the van and using an external smart charger the battery is clearly defunct - after a day on charge it reached 11.6v before stating 'Error'. This morning with no load overnight it was at 6.6.

This confirms the Battery is is totally failed.

Although I don't think relevant the panel by the door Mains/lights/awning light/pump is all switched off.

I'm not familiar with the exact panel you have nor how it is wired up, so I can't confirm your conclusion.

So... Chicken vs egg!
Can you offer any advice as to whether the charger has a problem which has allowed the battery to discharge and therefore die
or...
has the battery died in which circumstance the charger will be expected to trip when the battery cannot accept a charge.

My suspicion is the charger has failed hence the MCB's tripping. But we have insufficient evidence to clearly determine the sequence of events, but I think that both the caravan charger and battery have seen better days.

I could make an argument for both the battery or the charger failing first, however either scenario could be wrong. But I am pretty sure both need to be replaced.

Please bear with me as I am a long time caravan enthusiast but by no means an electrician!
Thanks in advance!

 

[IanB1485]

Based on years of experience with caravan battery chargers/PSUs and other similar power supplies the charger has had it. Even charging a dead battery wouldn't cause the charger to trip the MCB. The internal circuitry circuitry has current and voltage monitors and these feed back to the primary switch mode control IC , which even if the output was dragged down and the output current was at maximum this wouldn't draw anywhere near the 40A which would cause a 10A type B MCB to trip in less than 5 seconds . The main cause would be the switch transistor has failed short circuit in the attached photo this is marked as Tr7. In the attached schematic there is a 5A A/S glass fuse which would have popped , but some PSUs dont have an input fuse as the MCBs in caravan are double poled a neutral to earth short may still trip it. Short answer - change the charger module , Sargent do a 20A one:- PX300 or you could get one of the Victron blue smart types.

 

[audiorob]

Thanks for all your prompt replies.
My way forward would seem to be replace the battery as we have established that is essentially dead.
Then if I am exceedingly lucky installing the new battery might just charge normally.
However if not can I remove the distribution unit and get it reconditioned or rebuilt for me?
Does that make sense in light of your replies?

 

[Martin_E]

Disconnect the battery, if it still trips then it’s the charger