BruceM Posted July 25, 2019 Share Posted July 25, 2019 As part of our check list when striking camp and driving off we always turn off the habitation 12v supply. Just recently thinking about it though I’m beginning to question whether it’s necessary. Wracking my brains I haven’t been able to come up with a rationale in favour. Am I protecting anything by turning the supply off? The Elektroblock remains powered up after all. Any reasoned thoughts would be welcome. Link to comment Share on other sites More sharing options...
StuartO Posted July 25, 2019 Share Posted July 25, 2019 I don't bother to switch off the 12v on our Hymer and we've had no problems in 13 years. Our Truma Heating is rated for use while driving, although we've never found it necessary to use it. As I recall there are some British made MHs which recommend switching off but I don't know why. Link to comment Share on other sites More sharing options...
Keithl Posted July 25, 2019 Share Posted July 25, 2019 StuartO - 2019-07-25 2:50 PM I don't bother to switch off the 12v on our Hymer and we've had no problems in 13 years. Our Truma Heating is rated for use while driving, although we've never found it necessary to use it. As I recall there are some British made MHs which recommend switching off but I don't know why. ElectroMagnetic Compatibility !!! There is a UK Vehicle regulation which states that no electrical system on a vehicle shall cause or be affected by any electrical interference or EMC. The quick way round this regulation for Motorhome builders is to disable the habitation electrics whenever the engine is running, typically by the use of a relay. This relay is then called an 'EMC Relay' Foreign (ie non UK) manufacturers either test for interference and compliance or more likely ignore the regulation. Keith. Link to comment Share on other sites More sharing options...
aandncaravan Posted July 25, 2019 Share Posted July 25, 2019 Some units are designed to be left on, like the Reich e-Box range which give out warnings as you drive. There is no really an advantage or disadvantage either way on the Schaudt kit, but older units we take in for repair tend to have worn out control panel switches. One owner had a failed switch after only 4 years he said he turned it off every time they left the vehicle, even for the day when on holiday and back on when they returned. We always suggest leaving it on, except in storage. Link to comment Share on other sites More sharing options...
colin Posted July 25, 2019 Share Posted July 25, 2019 aandncaravan - 2019-07-25 3:36 PM We always suggest leaving it on, except in storage. That's what we have been doing for the last 8 years. Link to comment Share on other sites More sharing options...
BruceM Posted July 25, 2019 Author Share Posted July 25, 2019 aandncaravan - 2019-07-25 3:36 PM . . . One owner had a failed switch after only 4 years he said he turned it off every time they left the vehicle, even for the day when on holiday and back on when they returned. We always suggest leaving it on, except in storage. . . . Excellent and many thanks all – it stays on then. Interestingly, last year my rocker panel switch failed resulting in me being unable to switch the 12v off. On investigation I discovered that one pin of the switch had been soldered with the smallest shred of solder imaginable. The on/off switching motion had eventually (after 15 years) caused the solder to crack and lose connection. Just took a fresh blob of solder to sort it out permanently. Link to comment Share on other sites More sharing options...
spospe Posted July 25, 2019 Share Posted July 25, 2019 The system fitted to our Autosleeper Warwick Duo turns the 12 volt off when the engine starts and we regard it as a good thing. For our use, I cannot think of any reason why the 12 volt supply should be left on whilst driving. The fridge stays on if required, but why would I need the lights, or the water pump, or the TV on? There is a risk of leaving the 12 volt on when exiting the 'van and thus potentially flattening the battery (say at the end of a trip when parking the van for a week or so). Perhaps you have an installation which needs 12 volt power in the habitation part of the vehicle, in which case having the 12 volt on is understandable, but for our use over the last 19 years it has not proven to be a needed feature. Link to comment Share on other sites More sharing options...
spirou Posted July 25, 2019 Share Posted July 25, 2019 The only switch we touch on demand is the water pump as we've melted one while driving and couldn't hear it was on. There was no water coming out of the tap but the microswitch was somehow on, running the pump until it melted, taking the fuse with it. We leave the electroblock and everything else constantly on, even while parked at home. Link to comment Share on other sites More sharing options...
stevec176 Posted July 25, 2019 Share Posted July 25, 2019 I leave my 12volt on and then charge the phones and tablets while on the move. Link to comment Share on other sites More sharing options...
biggsy216 Posted July 25, 2019 Share Posted July 25, 2019 On our Chausson Allegro, switching off the 12v electrics causes the Truma heating system to dump the water from the boiler, some 12l of water. If I turned off the electrics every time we travelled we would go through quite a bit of water refilling the boiler each time. In the six years of having the van, we have only turned the 12v off at the end of a journey when the van is being stored. This has resulted in zero problems....touch wood! Link to comment Share on other sites More sharing options...
vindiboy Posted July 25, 2019 Share Posted July 25, 2019 biggsy216 - 2019-07-25 6:48 PM On our Chausson Allegro, switching off the 12v electrics causes the Truma heating system to dump the water from the boiler, some 12l of water. If I turned off the electrics every time we travelled we would go through quite a bit of water refilling the boiler each time. In the six years of having the van, we have only turned the 12v off at the end of a journey when the van is being stored. This has resulted in zero problems....touch wood! I have a Chausson Allegro but with Diesel heating I have never turned the 12 volt off , I see no reason to do this I have had this van for 6 years and the 12 volt has never been off, I had an Hymer for 10 years before my now van,and never turned the 12 volt off on hat either ? Link to comment Share on other sites More sharing options...
Alanb Posted July 25, 2019 Share Posted July 25, 2019 I would like to relate a cautionary tale. Many years ago, in our first MH we used to travel with electrics off, particularly because we had found a minor water leak on the vehicle when new and did not want to risk pumping water through a leak while travelling, when we would not hear the pump clicking. On one trip our teenage son helped himself to a drink of water during a short halt, switching on the 12V system to energise the pump. Sometime later while driving I could smell burning. Nothing obvious under bonnet, handbrake not left partly on etc. Continued but still that burning smell at the RHS of the cab. More serious investigation required. In that vehcle (Pilote R390) we stored rolled up sleeping bags, self wedged against the RH side of the luton. In this position they covered the 10W incandescent light fitting. When we removed the sleeping bags, the cover of the light fitting had melted, and the cotton fabric of one sleeping bag was scorched to the extent that it required my wife's skills to patch it. We can only assume that the light was accidently switched on, as the sleeping bags were packed. In our current PVC we tend to travel with the 12V system live, but then we do not have a light fitting adjacent to our sleeping bag stowage. We do prefer to specifically turn the pump off when travelling and overnight. An anomally with this is that while we can use the toilet even with the 12V switched off, we have to turn the water pump on in order to wash our hands afterwards. Alan Link to comment Share on other sites More sharing options...
david lloyd Posted July 26, 2019 Share Posted July 26, 2019 Never used to turn off 12v before travelling (and still don't) but the Autosleeper Worcester (and all Autosleepers, I believe) automatically turns off when engine running. I don't mind so much just have to turn it on when we stop mid joirney for tea or to use the loo. Now the solar panel is wired direct to the batteries I can leave it off at home but as wired originally the Sarget would only send solar charge to the leisure battery. David Link to comment Share on other sites More sharing options...
StuartO Posted July 26, 2019 Share Posted July 26, 2019 Keithl - 2019-07-25 3:05 PM StuartO - 2019-07-25 2:50 PM I don't bother to switch off the 12v on our Hymer and we've had no problems in 13 years. Our Truma Heating is rated for use while driving, although we've never found it necessary to use it. As I recall there are some British made MHs which recommend switching off but I don't know why. ElectroMagnetic Compatibility !!! There is a UK Vehicle regulation which states that no electrical system on a vehicle shall cause or be affected by any electrical interference or EMC. The quick way round this regulation for Motorhome builders is to disable the habitation electrics whenever the engine is running, typically by the use of a relay. This relay is then called an 'EMC Relay' Foreign (ie non UK) manufacturers either test for interference and compliance or more likely ignore the regulation. Keith. Interesting. And simply switching off (or automatically switching off) gets around the requirement to ensure compatibility? Not much of a regulation then! Link to comment Share on other sites More sharing options...
Derek Uzzell Posted July 26, 2019 Share Posted July 26, 2019 The issue was discussed in this 2017 forum thread https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Why-disable-the-Habitation-12v-electrics-when-the-Engine-starts-/46665/ and background is provided in my posting of 25 March 2017 8:32 AM there. Link to comment Share on other sites More sharing options...
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