Leisure battery charging

We have a 1995 Symphony and today found that nothing worked that runs off the 12v leisure battery. Presuming it had gone flat, we had a long run out in it (engine battery was fine) expecting this to charge the leisure battery. But on returning home, found it was still flat? I was under the impression that running the engine would automatically recharge the leisure battery. Are we mistaken on this, or correct? We put it on EHU at home and this appears to have charged it up. Can anyone clear up our confusion on this. Derek & Ann.

....I'm sure somebody will come along with a technical explanation of what's involved with batteries...as far as I understand it in general, both batteries can't be directly connected - one reason is that it shouldn't be possible for either of them to drain the other one completely, resulting in the possibility of the engine not starting - another reason is that vehicle and leisure batteries are constructed in different ways, because they are made for two different uses, one is for a lot of power for a short time, the other is for a smaller amount of power over a longer period.

Thanks for responding report, hopefully we will receive a clear explanation for this but what you say makes sence.

there will be a blown fuse in the system for charging from the engine.we have a rambler gl so i can't say where your fuse box is.good luck g.

hi the fuse could be close to the leisure battery in the input wire,in a connector ours is.g.

Thanks fisherman3, it seems by your reply (& report) that it should charge up when the engine is running as I thought it should. I will have a go at finding the relevant fuse, but if not I will get it checked by an auto electrician. Derek.

Yes, both batteries should charge when the engine is running.
The problem will probably be the 'split charge' relay, or the fuse that protects it.
You need to look for a cluster of 3 relays (and a similar number of fuses) that were obviously added by AutoSleeper, and were not part of the original base vehicle. I'm not sure where these are located on your Symphony, but they may be near the leisure battery.
Likely causes are: fuse blown, relay stuck, or any of the contacts that the relays or fuses plug into making a bad connection. If the fuses are intact, it might be work simply unplugging each of the relays, and plugging it back in to clean up the contacts.
Do you have a voltmeter (~ £10) with which you can check whether the battery is charging ?

On a Symphony you find two fuses hanging above the engine battery. One is for the 12v circuit for the fridge the other is for the split charge system which is the one to check. Both these fuses and their holders suffer from corrosion due to water entering the engine bay from the windscreen scuttle . Check/replace these first before looking for relays.

Thanks to everyone who replied to my problem. I loaned a multimeter and got a bit of basic instruction on how to use it. The result was that the fuse had indeed blown, but holder not corroded. Fitted a new fuse and now the leisure battery charges as it should do when the engine is running. Thanks again. Derek.