Club 80-90 Forums

I've recently become the owner of a Autohomes Kamper MkII fitted with a Zig CF 8 unit. One of the previous owners had removed the mains hook-up socket and leads, but the 12v circuit seems to work as it should. I've got a couple of questions about the electrical system though.

In the cupboard under the gas rings are a pair of 4.5mm cables (one red & one black) fitted with ring terminations but not connected to anything? They seem to come from the leisure battery judging by the voltage across them. Does anyone know what they would have originally connected to?

The other question is about the voltage of the leisure battery. At the weekend I drove for about an hour and when I stopped I checked the voltages of both batteries. The main battery was reading 12.6v but the leisure battery was down around 9v? I left the camper parked for a couple of hours, and when I checked the batteries again both were reading around 12v. Should the batteries equalise like this or should the leisure battery charge up when the camper is running?

I think a zig is essentially a couple of diodes, coming from the alternator, so the two batteries can both charge from it, but not charge from one to the other.

The other way, ie. with a split charge relay, is when the 2 batteries are connected together when the engine is running, and isolated when its not.

In any case, 9v sounds really low, you might have a dodgy cell in that battery.

BOXY wrote: In the cupboard under the gas rings are a pair of 4.5mm cables (one red & one black) fitted with ring terminations but not connected to anything? They seem to come from the leisure battery judging by the voltage across them. Does anyone know what they would have originally connected to?

These could be the cables from the old mains hook up charging system which the previous owners removed.

Dunno what the wires are (a picture might help.......). The split charge system should enable both batteries to charge off the alternator when you're driving. When you've stopped and turned the ignition off the relay should drop out severing any connection between the leisure battery and the van electrics. Provided you had a decent drive, both batteries should be pretty much the same unless the leisure one is knachered OR the split charge isn't working. As there shouldn't be any connection between them when your stopped, no 'equalisation' should take place at all.

Thanks for the answers. I've got the van parked inside at work this week so I'm going to leave the Zig unit switched to "mains" and 12v-on which should only draw power for the leisure battery, shouldn't it? I'll leave the interior lights on and flatten the leisure battery. If the starter battery goes flat as well I'll know I've got a link between the two I shouldn't have.

One other thought occured to me that might explain the low voltage and the strange recovery? When the van is running the fridge is powered by the 12v supply. If the leisure battery is a bit "iffy" could the 9 volt reading be a result of it being just underload powering the fridge for a few seconds with the engine off before the relay isolated it? Once the load has gone could a battery recover its charge?

I think the two "mystery" wires could be for charging the leisure battery from the "missing" mains hook-up. Does anyone have a circuit diagram showing how the original mains circuit would have been wired. The one I've got just shows an input socket connected to a juction block and then connected to the control unit, but no real detail and nothing showing a pair of cables going back to the leisure battery?

what's the point of switching the Zig to 'Mains' if the mains has been removed? Disconnect the leisure battery and try the camper lights - if there is still a connection to the van battery they won't go out; leave the Zig 12v switch 'on' though. The fridge will be powered by the alterator and the instant you stop the engine the relay will drop out so the fridge would not be connected to the leisure battery even for a second. This is assuming it's wired up properly.....

Think Leasure batteries take a lot longer to charge than starter batteries as they can only take about 30A at once, surply or charge, unlike the starter batt that can use full altinator output, plus alot. If its a big depleated leasure batt it'll take hours of driving to reach full, so a mains charger is a good idea if the van gets plugged in.

At 9v a lead acid is at [or even below] rock bottem so yes a fridge running could make the voltage drop right down and not recover, it shouldn't be this dramatic when the batt is working though. Its possable the battery is damaged if its been that low more than breafly - really deep discharge isn't good for any battery, and lead acids aren't too keen on it.

Give it a really good charge on a mains charger and see where you are afterwards.

I left the leisure battery powering the two tube lights, spot light,and a TV & freeview box this afternoon and after less than two hours there was only enough power to dimly light the spot light. The voltmeter was only reading 3-4 volts after two hours under load so I guess the battery is shot.

I did try the 12v circuit with the leisure battery out and with just the 12v switch selected. Everything worked and and the green status light was on. When I switched to "mains" everything went off so I think the ZIg unit needs to be switched to mains & 12v to run off just the leisure battery, if "mains" isn't selected the starter battery will power the 12v circuit as well.

How long should a 55 amp hours battery run the lights & a 7" LCD for? Shouldn't it be 20 hours plus?

BOXY wrote:I left the leisure battery powering the two tube lights, spot light,and a TV & freeview box this afternoon and after less than two hours there was only enough power to dimly light the spot light. The voltmeter was only reading 3-4 volts after two hours under load so I guess the battery is shot.

I did try the 12v circuit with the leisure battery out and with just the 12v switch selected. Everything worked and and the green status light was on. When I switched to "mains" everything went off so I think the ZIg unit needs to be switched to mains & 12v to run off just the leisure battery, if "mains" isn't selected the starter battery will power the 12v circuit as well.

How long should a 55 amp hours battery run the lights & a 7" LCD for? Shouldn't it be 20 hours plus?

There's your culprit - filament lamps drink electricity...........

The 'Mains' switch shouldn't make any difference whatsoever unless mains are connected. It's the 12v switch that matters. When you say the leisure battery was "out", do you mean it was disconnected? There should be no way that your camper electrics can connect to your van electrics unless the engine is running and they connect upstream via the leisure battery & the split charge.

I've just read through the "manual" from Autohomes that originally came with the camper:-
4:3:2 When Static
When "on site" the control unit charging switch should be switched to "MAINS". This will ensure that any 12 volt current will only be drawn from the secondary battery. If for any reason the secondary battery will not operate the 12 volt equipment then it is possible to run the equipment for the vehicle battery by switching the charging switch to "CAR". Use of the vehicle battery in this condition should be restricted to avoid flattening the battery below the level for starting the engine.

The manual says the spot light is a 12v 10 watt lamp. This wouldn't draw more than 1 amp would it?

Yes a 10W lamp will draw about 0.85 amps, but then a Propex draws 1.2 amps (according to the wiki) and I know that will drag a battery right down after a few hours if running continuously. When I used mine for a while I had barely enough to power the water pump. I was just highlighting the fact that a filament lamp will draw a lot compared to your fluorescents.
Having said that ,I've just checked the power consumption of my camper TV and it's....4.5 amps so on reflection maybe the spotlight isn't the culprit .
I know batteries sound like they'll power stuff for ages but they're build for a short sharp burst. If I don't use my van for a fortnight, it won't have enough 'uumph' to start the van. The reason? The memory on the radio and the clock. Pathetic isn't it? I know someone who removed their radio for exactly this reason. I have to remove the fuse if I'm not going to use it regularly and my van battery is only a couple of years old.

I've had a gander in my Autohomes manual and although it's not quite the same as yours it does basically say the same thing about the option to use both batteries but I know for a fact that there is no connection from my Zig to my van battery as the cabling is not there. My Zig was retro fitted however so perhaps thay just never bothered fitting that cable originally as there was no point?

The two wires in the cupboard. If these are original fitment wires then they may have been for one of the following appliances that were fitted as optional extras on Autohomes models that may have been removed. Hot Water Heater/ Gas Heater. Check to see if you have an additional Flue/vent similar to the one fitted for a fridge.

Autohomes had a peculiar method of wiring the ZIG CF8 that took a feed from the main battery and made it available as an alternative feed for the leisure electrics via the CF8 switch panel in case the leisure battery became exhausted. The ZIG CF8 includes a mains operated battery charger for the Leisure battery and a switch labelled 'on-site - touring'. When 'touring' is selected the starter battery is linked via the switch to the leisure battery and the engine alternator charges both. Unfortunatley, in the event that the leisure battery becomes discharged then the main battery will dump charge into the leisure battery and the voltages will equalise until the engine is running and charging of both commences. They modified this set -up by adding an additional relay that does exactly the same as the switch but links the two batteries with a heavier guage cable when the engine is switched on. If you are still having problems I will post a diagram of the CF8 wiring but it seems as though your set up may have been modified/changed and you need to be aware of that.

If you look in the cupboard you may see an aluminiun plate stapled to the left panel. All the wiring feeds are behind thid and enter the starter battery compartment. Worth checking to see if it has been removed. Mine has been modified with a leisure battery in that cupboard and I suspect that others may have been modified similarly as it is an obvious location to fit a proper leisure battery.

AngeloEvs wrote:The two wires in the cupboard. If these are original fitment wires then they may have been for one of the following appliances that were fitted as optional extras on Autohomes models that may have been removed. Hot Water Heater/ Gas Heater. Check to see if you have an additional Flue/vent similar to the one fitted for a fridge.

If you look in the cupboard you may see an aluminiun plate stapled to the left panel. All the wiring feeds are behind thid and enter the starter battery compartment. Worth checking to see if it has been removed. Mine has been modified with a leisure battery in that cupboard and I suspect that others may have been modified similarly as it is an obvious location to fit a proper leisure battery.

The camper has a Propex heater fitted and that works fine. I think the idea of the wires being hooked up to a leisure battery makes sense. The cables are the size I'd expect to see attached to a battery, and the ring terminals would fit the bolts of a standard battery clamp bolt. Could I hook up a third battery to these wires and get some extra capacity that way?
I haven't got an aluminium plate in the cupboard and the wiring in there is just held in place with a collection of stuck on plastic clips. It all looks a bit DIY.

I fitted a four year old 45 amp/hr battery in place of the leisure battery this morning and I've had all the lights etc switched on as before, and at the time of writing the battery is still showing 11+ volts under load and everything is still running. If it keeps running everything for the rest of the day I'll leave it fitted and scrap the original leisure battery.

What year is the van? This how the circa late 80's ZigCF8 were wired by Autohomes without a split charge relay.

There are two large rocker switches on the CF8, the illuminated one connects the CF8's in built charger to the 240v supply and has no effect on the 12V leisure electrical operation other than 'charging'. The second one labelled 'On-site - Touring' (or similar) does the following depending on which way it is set:-

On-site: Links the leisure battery to the Zig Charger. In this position the habitation electrical system will only operate if a leisure battery is installed. The ZIG will not affect this one bit unless someone has altered it!

Touring: Disconnects the in built charger from the leisure battery and instead links the leisure battery to the starter battery so that it can receive a charge from the alternator. In this position the habition electrical system will operate from the starter battery and any other battery that may be installed and connected.

The 12V switch (smaller rocker switch) has to be 'On' for the leisure electrical system to function in both the above positions.

As for two leisure batteries, I wouldn't bother unless you just want a spare to drop in place if needs arise. Two flat leisure batteries connected together are not exactly kind to your poor old alternator.........up to you though (unless you intend fitting a 'smart' charging system for multiple batteries which charges them one at a time).

Could the wires be someone's connection for an inverter as they appear to be substantial and ended with ring terminals?