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battery problems

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    battery problems

    Hello Ant

    Hope you can help with battery problems.
    We have 1.6 diesel T25 camper. When we bought it we were not sure if the leisure battery was working properly and when having the van serviced they looked at it and said that the fuse box in the engine bay was corroded so they put in another one, so now the engine battery charges the leisure battery when we are driving and it will not take power from the van battery unless the engine is running. So far so good.

    Now we went away a couple of days ago and drove for about an hour and a half. It was a ‘no hook up’ site and we stayed there for approx 36 hours. During a lot of this time the 12v was switched on and the fridge was switched to ‘battery’. The fridge did not work. When we came to leave the engine started no problem and we drove for an hour and a half to get home. During this time we put on the 12v switch and on the fridge we put on both switches – the one with picture of a battery and the one with the picture of the hook up on them. With this, the fridge worked.

    The next day – ie after driving home for 1.5 hours and just parking up and leaving the van – I tried to start the engine and the battery was flat. Does this mean that operating the fridge and putting back charge into the leisure battery drains the van engine so much that even after 1.5 hours driving, the van battery will be flattened? Any thoughts would be gratefully received.

    The fridge is wired so that it will only run from 12v when you are travelling. It is wired using a "split charge relay" the same as charges your leisure battery when travelling. Fridges don not work from either battery on their own because they would flatten them very quickly.


      Hi Kiwitax.
      Peter is right that the fridge shouldn'twork without the engine running, some earlier conversions had not mastered that. it sounds like yours is not incorrectly wired if you sat on a site with it turned on for 36hrs and still managed to start the van. Was the leisure battery also flat ? or did it keep its charge when the starter battery died? If they both died there must be a link somewhere. I'm not sure how old your van is but the early T25 used to eat Alternator regulator diodes which meant the battery tried to power the alternator when the engine was stopped. A couple of hours would kill off any battery if that was the case. Or you're simply unlucky and your starter battery just decided it had had enough!
      I would charge the battery up and have it load tested, if its ok fit it and have the alternator regulator diode tested. If its ok you have a camper wiring problem to the fridge, check the work done on the new fuse box, it seems to have been ok before that.


        The fridge can only be used on 12v to keep it cool while the engine is running and you are en-route. When you get to camp, it should be switched over to EHU or gas, or your leisure battery would go flat in a few hours or less. I found mine pretty ineffective on 12v so I never bothered with it, just put in a few ice blocks from the freezer along with the food (some frozen as well if it was for another day) and that kept the whole thing cool until I got to where I was going, then I just turned on the gas as I only had a two way.

        I now do the same with my caravan fridge - that's a three way, but I dont bother with the 12v bit as I only have single electrics on the car.



          Cheers for those answers folks. I borrowed a neighbers 'charger' a couple of days ago and the engine battery is on full charge - just put it back and van started fine.

          We are off to Skye tomorrow so don't have time to get it load tested or have the alternator regulator diode tested. But if we have any more probs I will get that done. We are staying on 'official' sites as we go up there so a jump start should be available and if everything stays well and we don't need jump starts then we will free camp on the way back and keep our fingers crossed!



            Have you charged your leisure battery up as well? I think I would just in case.

            If your leisure battery is flat, then your 12v lights (and maybe a water tap pump if you have one) won't work. so take a torch/battery operated light and a small water carrier.

            when I wild camped, I found the 12v water pump drained the battery quite quickly (nearly flat after four days) so I would use the pump to fill the kettle and also a water carrier at the same time (I used a 4ltr spring water container, 99p from Morrisons) to save on battery power.

            With the caravan I have now, there is no charge up of the leisure battery whilst travelling as I don't have twin electrics. But I find that charging before I go makes sure that i have battery power for the 12v lights. I don't have a 12v pump but a hand operated gravity lever pump so there is no drain there. When on EHU I have a small 'smart' charger which keeps the leisure battery charged if required. Without EHU, I use the battery until the lights start to dim, then switch to my camping lights.


              Battery still a query

              As a follow up to the previous discussion. We went to Skye and stayed on hook up sites. On the way back we spent one night on a hook up site and one night free camping and the engine started fine. Drove for another 200 miles and parked up. 2 days later, tried to start van and it’s dead. So, from what I can deduce, that either means the van engine battery just can’t sustain the charge (so I will get it load tested?) or there is something bizarre going on with the leisure battery in that it is draining the engine battery when the van is stood still. The garage looked at this though and said the leisure battery would only drain off the engine battery when the van was turned on.

              Slight worry with this however is that the man we bought the van off said he never used the leisure battery (it was disconnected) and when I have disconnected the leisure battery and put the 12v switch down we still get power to the lights. So I wonder if there is some dodgy wiring somewhere. I’ll get the engine battery checked out first.

              Quick question – when you are on a hook up, does that charge your engine battery aswell as your leisure battery? Cheers


                Originally posted by kiwitax View Post

                Slight worry with this however is that the man we bought the van off said he never used the leisure battery (it was disconnected) and when I have disconnected the leisure battery and put the 12v switch down we still get power to the lights. So I wonder if there is some dodgy wiring somewhere. I’ll get the engine battery checked out first.

                Quick question – when you are on a hook up, does that charge your engine battery aswell as your leisure battery? Cheers
                Ah ha! if you're still getting power to 12v lights with a disconnected leisure battery the wiring is definately wrong somewhere *unless that 12v switch is switching to the car battery, thus draining it.. It could be that your leisure battery even when connected, is not taking over the running of 12v things, definately points to maybe it's 1. not working at all. If the previous owner never used it, it could have been flat for a long time in which case it won't be able to be charged. or 2. Not connected through the little boxlike contraption (or something) which switches over the power when the engine is off. The little box thingy also charged the leisure battery whilst on the go, and stopped when the engine was off. There was a little box thingy full of wires and fuses in my roma, can't remember what it was called (not a zig) but that did the switch over. Could be a fuse blown or a wire loose.

                When you are on hook up and you have a charger the the EHU will charge your leisure battery. This may be an inbuilt leisure battery charger, usually a zig unit. If you haven't got a charger, EHU alone won't charge anything. I got a smart charger which I plug in to a standard 3-pin socket when on EHU and it trickle charges the leisure battery.
                Last edited by jayjay; 11-05-2011, 20:27.


                  Just discovered that the little black box thingy is called a split charge relay... so that's what stops the car battery going flat.

                  Here's a good simple description of how its all supposed to work:


                    Recharging at the moment

                    Thanks Jayjay

                    I have just taken the van engine battery out to recharge it and then tried the lights which should still theoretically have run off the leisure battery – they did not work. This could mean that the leisure battery is flat but when I last charged up the 2 batteries the engine battery took about 3 days to charge and the leisure battery was fully charged. I will recheck the charge of the leisure battery before putting the engine battery back in but I have a sneaking sensation that it is a wiring problem. Before I reconnected the leisure battery we did not have theses problems and the previous owner had the leisure battery unconnected.

                    If it is a wiring issue, I think I will leave it. I spoke to a VW mechanic a while ago about stuff and I remember him saying that if it was a wiring problem he would just charge out his hourly rate (something like £35 an hour) and then keep looking. He said however, that he might look for 8 hours and still not find the problem so do I want to face that potential cost? No way! not on our finances.

                    Anyway, I will check the charge on the leisure battery and if it is still full I will disconnect it and we will go away running just on the engine battery and see what happens So if the lights dim we will turn them off. And if we can’t restart then it may be new engine battery time! Ah – the ins and outs of owning a van!


                      How about disconnecting the leisure battery and connecting a 12Vbulb between the leads? If it lights without the engine running and "ignition switch" off, then the engine battery is definitely feeding the leisure battery when it should not. Or if the engine battery is at lower voltage than the leisure battery - vise versa. Because one battery will feed the other until the voltages match.
                      A simple and less technical way round that would be to put a switch in the wire which feeds the leisure battery from the engine and REMEMBER to switch it off when on site or not in use without the engine running.
                      Keeping people waiting is stealing a part of their lives.


                        this is the site iused when doing mine



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