240V / 12V system

[jamieww]

Ok, am gonna try explain this as best as I can..

My Romahome has a std 240v fuseboard for hookup to run sockets. All the lights and fridge (along with gas of course) run off 12v (this being the main van battery).

What is my best option to be able to hook up some sort of charger for a second battery to run the 12V system as I don't fancy running down the main battery if I am on a site that doesn't have 240v hookup available.
Is there a way of connecting a second battery to the alternator to run the 12v system and disconnect the current 12v feed from the main battery?

Is there also a way of converting the 240V from the hookup to run the 12v system when hooked up?

I hope the above makes sense, it sort of does to me but thats not saying a lot

Thanks

[peterholden]

Our C15 was fitted with a charger for the leisure battery and an electrical control unit to run all the 12v units. Is this not standard on all? Otherwise why have a 240v input?

[jamieww]

As far as I can see, the 240v only connects to the sockets - there is no leisure battery and I don't think it runs the lights.... though I haven't tried connecting up with the battery disconnected.
In my opinion the fuse board for the 240v supply is very basic and only has a single input connected to the external coupling and a single output connecting to the sockets... There are no other components or cables coming from the fuse board, although there are two rcd's and I haven't taken it apart to look inside to see whats connected.

It does seem pretty pointless only to have the sockets wired up, that's the main reason for my question - I want to be able to run the full 12v circuit off the 240v input is possible.

[Derek]

jamieww said:

Is there a way of connecting a second battery to the alternator to run the 12v system and disconnect the current 12v feed from the main battery?

Yes, cut the feed from the vehicle batt and fit a split charge relay. The leisure batt is wired onto the caravan side of the electrics.

I think the normal size of leisure batt is 85 AH, if fitted inside the van a sealed box vented to the outside must be used.

jamieww said:

Is there also a way of converting the 240V from the hookup to run the 12v system when hooked up?

Yes, a Zig unit is normally used which is connected across the leisure batt and wired into the mains system. It is a 13.8V, constant voltage power unit, that floats the leisure batt when on mains.

Lots of info in the Haynes "Build your own Motorcaravan" manual.

If you only want to run the 12V kit from mains I would fit a 12V mains power unit and switch between that and the vehicle batt.

Hope this helps

Derek

[jackie]

Hi Jamie, Thanks for your welcome, it would be nice if we did see each other around, I am dying to meet another Romahomer.

Anyway, I don't know if this info will help you at all......taken from the original owner's handbook & guide (mine is an N reg, without 2nd battery (at present))......

'Mains electric power is taken from the10 AMP MCB to the 13 amp switched socket on the nearside bunk. A further supply is taken from the 5 AMP MCB to the CD51P logic charging and distribution unit. This dual purpose equipment acts as a BATTERY CHARGER for both the VEHICLE BATTERY and secondary one (if fitted)'

I appear to have all the original handbooks, including the Zig X-7, mains unit and wiring diagrams. You are very welcome to look at them all. I don't know how far you are from Brecon, (I am 15 mins w of Brecon).

Am busy trying to sus out how everything works, and getting it loaded up ready for use. Invited my neighbour into it for a cuppa this morning, hehe.

Best wishes,
Jackie