Sargent EC328s on Nuevo 2015

As above I am having problems with leisure battery , I have had the van 3 months and use it regularly, park on drive at home. Leisure battery runs out in about 1 hr down to 6 or 8 volts.

Had a new battery fitted, same issue.

If I plug in mains supply and charge battery, the CO2 alarm goes off and inside smells of battery gas.
If I leave parked with no 230v supply, leisure battery soon drops to 8 volts, switch on charger shows 14 volts immediately.

Last weekend set off with fully charged battery, 3 hrs drive, leisure battery 8 volts, Switch on to combine with engine battery and all good, used all faciklities and next morning engine battery still good.

Any ideas?

I am going to phone Sargent in the next day or so. Van has solar panels , 2 separate sets not sure wattage.

I think van should be capable of keeping topped up with the setup, even given short days. I am away again this weekend would like to fix it!

RG

Richard G wrote:If I plug in mains supply and charge battery, the CO2 alarm goes off and inside smells of battery gas.

Some CO alarms can be set off by hydrogen.  Hydrogen gas can be given off by lead acid batteries.  This is why lead acid batteries must either be fitted into a battery compartment that drains outside and is completely separate from the habitation space, or, have a vent tube fitted to them that passes outside of the habitation space usually through a dedicated hole in the floor.  It sounds as though your vent tube has become detached or is missing altogether.  This is very easy to check and put right.  Although this will not help with the underlying problem, it will improve safety.

Richard G wrote:Leisure battery runs out in about 1 hr down to 6 or 8 volts.

It's always difficult to diagnose electrical faults at a distance, but this suggests that the leisure battery probably isn't being properly charged to start with. The reason I say that is that a typical leisure battery is generally rated at 100Ah. If it were fully charged to start with and had dropped to 6-8V (i.e. effectively completely flat) in an hour then something must have been taking many tens of Amps for the whole of that hour - in fact in theory you would need to dissipate 100A's worth of energy for the whole of that time. There aren't many things in a camper van that can do that without catching fire!

There are a few things such as tank heaters which can take a lot of power (does your van have tank heaters?) but even those don't come close to consuming 100A.

So that suggests that in the example you give, the battery was probably only partially charged. You say that the charger immediately shows 14V. That is low, but it would be of no concern if it fairly quickly increases to around 14.4V.

One thing you should not do is rule out the possibility that the new battery is faulty. It may seem unlikely, but it does happen if, for example, the battery has been dropped heavily while in transit.

Another thing that you should be sure of: Does the voltage on the panel actually reflect the voltage at the leisure battery terminals? It's important that you check this, because the presence of a solar panel can really confuse matters here.

You say that you've had the van for only 3 months - did you buy it from a dealer? If so, can you ask them to investigate?

It won't harm to phone Sargent to see if they have any ideas, but they will be in the same position as everyone else here - trying to make sense of an electrical system problem without actually being able to put any test equipment on it. That is not easy!

Cymro wrote:I think it's called "sulphating"

Sorry, but "sulphating" is a completely different effect, and one you can't smell! That is where lead sulphate forms on the plates due to the battery being left in a state of partial or full discharge. It insulates the plates from the electrolyte and prevents it from operating properly.

The reason for the smell is typically when a battery is being overcharged and, alongside hydrogen and oxygen, it gives off small amounts of (I believe) Hydrogen Sulphide gas, which smells bad. The cause can either be a fault in the battery, or a fault in the charger.

in short, it needs checking by someone who knows what they are doing, the dealer as its a new van......
is the charger working correctly, can the battery hold that charge, is the battery faulty, is there an unusually large draw from the battery by the van's electrical systems.

good luck

Thanks for all the helpful replies so far. 
As suggested the battery is overcharging , so I am pursuing this line of enquiry hopefully tomorrow.
I don't have much faith in selling dealers warranty (one vague page) as they would not replace battery , had one fitted at a local Approved workshop which probably also confuses any warranty claim. 
Van has only one leisure battery. Handbook says battery in in an unvented box, which it is.

I note that there is a relay taken off battery (fused) lying loose next to battery so will investigate what it does, Van has 2 separate different size solar panels so maybe one is an add on. Will report back!

Have you checked the voltage at battery terminals with EC328 connected to mains. It should be around 14.4V initially and then, after an hour or two fall to around 13.2 to 13.5. You can also see those voltages on the control panel as a first indication. The panel will also tell you the current that is going to or from (minus values) the battery.

as Ron suggests, check voltage at leisure battery with hook up connected, and also with the engine running as your OP suggests its nit getting charged properly (or its seriously knackered), but i would use a voltmeter to check readings...

One all that on advice from Sargent, but now they are closed for Xmas so will seek further advice in new year, meanwhile away in van for weekend!