I think this is a good idea for winter de-icing, and would seriously consider one for the car and my van.
As far as keeping a pump running, well we did have a need once when the previous leisure battery started to fail. Good thing the wife was around to sit in the van with the engine running so the 2 of us could finish the job we were doing.
When I put son's van together, I included a changeover switch that he could choose between the leisure battery or van battery to run his pump. In those days I felt this was another feature that could be used if necessary.
He has never used it and I haven't bothered on my van or my son in law's van.
I'm surprised that the Zafira only uses 0.2litre of diesel with the engine idling. The little Wabesto water diesel heater I have uses 0.3 of a litre per hour and that's tiny.
Hi mate can you please tell me how you wired up your change over switch
james
Hi James
We bought a 10 amp change over toggle switch from Maplins but this is similar on ebay.
http://www.ebay.co.uk/itm/Electric-Toggle-Switch-SPDT-Changeover-15amp-/150575649421?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item230f02128dWe have one 15amp cable coming from the main van battery into the cabin where his leisure battery is fitted under the front passenger seat. (He has an 800LX Peugeot Partner). This cable terminates at his intelligent split charge relay which is next to his leisure battery. On the SCR output, 1 terminal goes to the leisure battery's positive terminal which charges the leisure battery when the engine is running. The other output is a direct connection from the input and is live all the time. The 3rd terminal is connected to earth.
The idea is to run a wire from the live terminal on the SCR to the changeover switch. Then run another wire from the leisure battery to the changeover switch. The third terminal on the changeover switch will be live and will go to the pump or flow contoller.
Each switch will have a wiring diagram but can easily be worked out with a voltmeter.
The switch can be mounted anywhere but mustn't be shorted out. We have mounted it sideways on the seat frame I can't remember which terminals were which but it could be that the center terminal was the feed to the controller and the other terminals were the input from either the leisure battery or van battery.
Depending on which throw of the switch is selected, it will either switch the supply current from the leisure battery to the contoller, or if operated the other way, will disconnect the leisure battery and activate the van battery supply.
I hope you can understand that.
Spruce