Knaus electrics

creekseacaravaner
creekseacaravaner Forum Participant Posts: 9
edited June 2021 in Caravans #1

I have a starclass 695 and have been told that Knaus do not wire up the fridge on 12v as the current pull is too high for the car to cope with so fridge warms up on a journey. Has anyone else come across this cheers

Comments

  • Vulcan
    Vulcan Forum Participant Posts: 670
    edited June 2021 #2

    Isn't there a wiring diagram in your manual, the majority of other vans do not have a problem but then again German car manufacturers are well known for exporting vehicles not wired correctly to international standards.

  • Lutz
    Lutz Forum Participant Posts: 1,564 ✭✭✭✭
    edited June 2021 #3

    I don't know what you mean by not wired correctly to international standards. The standards only state which applications are assigned to which pin, but they don't require all pins to actually be connected.

  • JVB66
    JVB66 Forum Participant Posts: 22,892
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    edited June 2021 #4

    Thats a new onesurprised

    The problem is /was that most modern cars fitted with "smart?" Alternators need to be kept under load to supply power for any thing other than what is fitted to the car

    ie the fridge on caravans, 

    I would do as suggested and check your c/van wiring diagramme to check that 

    A decent tow bar fitting company can sort itwink

     

  • LLM
    LLM Forum Participant Posts: 1,555 ✭✭
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    edited June 2021 #5

    Have you connected the car and checked to see if the fridge operates on 12v?  

  • Unknown
    Unknown Forum Participant
    edited June 2021 #6
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  • dave the rave
    dave the rave Forum Participant Posts: 806
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    edited June 2021 #7

    One can only assume that they dont wire their motorcaravans to run on 12 volt whilst on the road!!!!The electrical connections would be through a relay and thereby not be a huge load!!!wink

  • JVB66
    JVB66 Forum Participant Posts: 22,892
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    edited June 2021 #8

    Commercial vehicles alternators are normally capable of much higher output than a car, as they are very often asked to do a lot more than a car, and the length. of cable would be much shorter than to a caravan combination surprised

  • Vulcan
    Vulcan Forum Participant Posts: 670
    edited June 2021 #9

    You are of course correct, I was generalising and should have said "some German car manufacturers".

  • LLM
    LLM Forum Participant Posts: 1,555 ✭✭
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    edited June 2021 #10

    The vast majority of car alternators will easily cope with the relatively low power demand of an LV absorption fridge running on 12v therefore the cabling does not need to be extra large.  Of course it would help if the OP was to give the fridge model number and car details.  

  • Vulcan
    Vulcan Forum Participant Posts: 670
    edited June 2021 #11

    ISO standards exist to ensure quote "products, processes and services are suitable for their purpose". how can it be suitable for purpose if it is not connected.

  • Lutz
    Lutz Forum Participant Posts: 1,564 ✭✭✭✭
    edited June 2021 #12

    The purpose referred to is towability and compliance with road vehicle construction and use regulations, and that doesn't include use of a refrigerator while on the move.

  • richardandros
    richardandros Club Member Posts: 2,681 ✭✭✭
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    edited June 2021 #13

    As another Starclass 695 owner, I can confirm that Knaus do not connect the fridge for 12v supply whilst towing.

    It seems the 12v fridge supply on the Schaudt control unit is not rated high enough to adequately supply the 170w Dometic fridge. That is obviously why Knaus don’t connect it though it begs the question why Knaus build and supply a van with incompatible components! 

    I am sure KnausCol (another Starclass 695 owner) will be along before long to explain the lengthy investigations he has had done by his dealer, including bringing in a '12v electrical expert' to investigate the problem he had with his.  It has been resolved by by-passing the Schaudt unit and wiring the fridge directly to the car supply. So it's nothing to do with smart alternators or the like.

    I'm leaving ours as it is for the moment because, even after towing on a hot day for 3 or 4 hours, we haven't had a problem with the freezer defrosting - it just acts like a big cool box and is fine for that sort of period - but it may be an issue if you are contemplating lengthy trips in Europe in the summer.

     

  • richardandros
    richardandros Club Member Posts: 2,681 ✭✭✭
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    edited June 2021 #14

    Just as an aside, creekseacaravaner - if you are not aware, there is a Knaus Caravans Group on Facebook on which this topic has been discussed at length - and many others - and is a useful source of information for us Knaus owners. Well worth joiningsmile

  • Unknown
    Unknown Forum Participant
    edited June 2021 #15
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  • JVB66
    JVB66 Forum Participant Posts: 22,892
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    edited June 2021 #16

    They will if the wiring has been modified  to the caravan to fool the "smart ?"alternator that the fridge needs power as well as the tow vehicle cool

  • Unknown
    Unknown Forum Participant
    edited June 2021 #17
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  • creekseacaravaner
    creekseacaravaner Forum Participant Posts: 9
    edited June 2021 #18

    Checked circuit diagrams no sign of 12v supply to fridge I wished I had known this before I bought the van just assumed as it was built for UK market it would have a 12v supply whist towing. Have checked cars socket with meter and is okay and the car is registered as a commercial vehicle so should be man enough

  • creekseacaravaner
    creekseacaravaner Forum Participant Posts: 9
    edited June 2021 #19

    Thanks for all the info

  • richardandros
    richardandros Club Member Posts: 2,681 ✭✭✭
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    edited June 2021 #20

    CSC - I was of the same opinion - but as I have said - in practice, it hasn't presented us with a problem which is why I've not bothered to do anything about it.  We always have the fridge/freezer on for two or three days before we go away, so it's well down to temperature before we set off and three or four hours without any power to it hasn't had any discernable effect.

  • EmilysDad
    EmilysDad Forum Participant Posts: 8,973
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    edited June 2021 #21

    I assume the Knaus caravan is fitted with a standard caravan 3 way fridge despite no wiring for the 12v heater, if so, it should just be a case of adding a few feet of cable to the back of the fridge from where the cable enters the front of the caravan (& maybe adding the 12v heater)

  • NicoT
    NicoT Forum Participant Posts: 1
    edited August 2021 #22

    Starclass 695 owner here, with the same issue, which I thought I had cleverly resolved.

    I convinced my dealership to fit a 12V line to the fridge, but the problem I have now encountered is that the Schaudt unit turns itself off every time the ignition is switched on, thus turning off the fridge (there is 12V feed, but no 12V control signal).

    No biggie, you may think, but pair the van to a car with a smart alternator (and not many without one under 10 years old) and the result is that 10 minutes into your drive, the alternator stops supplying the battery, and when it starts resupplying, you guessed it, the bloody control unit turns itself off, and the fridge stops working.

    Apparently, the unit is designed to do exactly that, go figure.

    Hyundai are so far as useful as a room heater in the Sahara, and I am starting to think that it might indeed become an intractable problem. If anybody knows of a reliable tech wizard that might be able to reprogram the car to change it's behaviour while towing, please let me know.

    Admitedly, on the shortish journeys we have undertaken in the UK (6 hours the longest so far), the freezer seems to have coped with the adventure untouched, but I a, reluctant to travel longer distances with stuff in the fridge.

  • cyberyacht
    cyberyacht Forum Participant Posts: 10,218
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    edited August 2021 #23

    I always managed overnight ferry journeys, about 8/9 hours allowing for loading/unloading,  without stuff thawing out. When you stop for lunch, turn your gas on and give the fridge a boost.

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