Engine & Leisure Batteries - Are both charged

Hi all,
I own a 2005 Nuevo ES.
It may seem a silly question to many owners, but when on mains hookup, do both the leisure battery and the engine battery get charged together.
Does the same apply to solar panel charging.
My Nuevo is parked on my drive and connected to mains hookup to power a small oil filled radiator for frost protection. I don't leave the onboard battery charger switched on all the time, just over a weekend once a month.
Last week, I wanted to move the 'van but the engine battery did not have enough charge to start the engine, even though I had switched on the onboard charger that weekend. I connected my automatic portable battery charger, left it overnight, and next day it had switched off and the battery was fully charged, and the engine fired straight away.
The habitation panel on the side of the wardrobe has a rocker switch to change from leisure to engine batteries to indicate the state of charge. Does this switch have to be moved to select which battery is being charged.
Any advice would be appreciated.
Thanks,
Justin

Yes you need to switch the rocker switch to veh to charge engine battery. As for solar, do you have a dual controller or a battery-master? Either should ensure that the engine battery gets charge, if you don't have either then it won't and you should get either fitted.

Thanks Paul,
That probably explains why my solar panel appears to keep the engine battery charged better than mains.
I just thought that the rocker switch was used to indicate the charge in each battery.
Am I right, then, in thinking that the habitation switch on the panel must also be turned on for charging.
Justin

I'd be inclined to take the easy way out Justin, and do what Paul suggested.

Get a Battery Master fitted and leave your onboard charger unit permanently switched on. Select habitation battery for charging, and whenever the vehicle battery drops more than a couple of volts below that of the hab battery, the latter will send charge across until they are equalised.

I think that's how it works but I'm not good with electronics. I can say however that we've had a Battery Master for years, and never had a single problem with either battery.

(I don't think they work so well with very recent vans, but on your 2005 model I think it might be your best option. I shall no doubt be told if I'm talking rubbish! )

Many thanks Dave.

Justin Case wrote:
Am I right, then, in thinking that the habitation switch on the panel must also be turned on for charging.

Unfortunately there are significant variations, but in my experience A/S tend to wire up the panel such that  - if you have a 3-way switch for Vehicle - Off - Leisure, the charger should remain connected to the leisure battery in the Off position. That's how it is on our 2005/6 Trooper with PSU2005.

But... others here with vans of a similar year have reported that their vans are wired differently, so probably the best thing to do is get a cheap voltage monitor off Ebay (or of course use a multimeter if you have one), connect it to the leisure battery and see what happens to the battery voltage in each switch position. You will clearly see a jump in battery voltage when the charger is connected.

Yes, you need to switch the rocker switch to VEH. to charge engine battery.
OFF. means both disconnected from the Charger which is still powered up if the hookup is live UNLESS the switch on the Charger is turned off! HAB. means the Charger is connected to the leisure battery.
Done that been there and checked it out!
frederic

Thanks Frederic. That should help a lot.

Unfortunately as Mojo says, it's very difficult even for our expert members to offer definitive advice when there are so many variations.

Many thanks to all responders. 
I now know more than before, and that's the reason for the enquiry.
Justin