I can hear the relay clicking every few seconds once the engine is warm. The vehicle is 12 years old and I have had it since new. It only started doing it this year. I have put a new relay in recently but it is still doing it. Your thoughts on why please? I suppose I need to monitor the alternator voltage and check for a bad earth but other than that I'll see what you people suggest.
Split charge relay - odd behaviour
- Thread starter pmb
- Start date
If it's a Mondeo or Focus, it's probably always done it - they were fitted with smart alternators from the late '90s onwards and the voltage varies according to battery state - and number of other brands have followed suit in the intervening years.
Simply towing relays, specifically the Smartcom, aren't suitable for use with smart alternators.
Simply towing relays, specifically the Smartcom, aren't suitable for use with smart alternators.
It could also depend on what other pieces of equipment are working, for example if the cooling fans cut in they can take quite a current which might drop the alternators output voltage enough for the smart relay to break the feed to the caravan.
Some split charge relays are adjustable for voltage trip , I'm almost sure the smartcom is . If you visually inspect the relay you may find a recess with a flat screwdriver adjuster within , turn this adjuster slightly ( maybe 10 degrees ) and monitor the relay change , this may well stop the relay chattering . Off hand I think the relay should cut in around 13.4 v and cut out around 12.8 v .
The Smartcom can't be adjusted enough to cope with smart alternators - and if it could it wouldn't stay energised with engine off.rosies said:
My Hyundai has a smart alternator and the system voltage varies between 14.1v and 12.5v, even with the caravan fridge drawing about 10A - the easiest way to wire modern cars like this is to throw away the Smartcom and use a simple ignition-driven relay - it runs the risk of flattening the battery if you sit parked with ignition on but engine not running but who does that for any length of time.
I remember my Kia ( Hyundai group ) having a smart alternator and I fitted a smartcom relay and it worked perfectly once it had been adjusted .
Surely that is the object of a smartcom relay to trip the through power to caravan fridge etc if the car engine is stopped , thereby not draining power from the car battery . Prior to smart relays we used such as Hella relay with the switching power coming directly from the alternator which vehicle manufactures did not like .
Surely that is the object of a smartcom relay to trip the through power to caravan fridge etc if the car engine is stopped , thereby not draining power from the car battery . Prior to smart relays we used such as Hella relay with the switching power coming directly from the alternator which vehicle manufactures did not like .
I'm not sure what make my VSR is apart from it being rated at 30 amp, but it charges my caravan battery and cools the fridge.
Edit even with a smart alternator system.
Edit even with a smart alternator system.
RogerL wrote ;- The Smartcom can't be adjusted enough to cope with smart alternators - and if it could it wouldn't stay energised with engine off.
It should not stay energised with the engine off !
I also had a Ford Focus with smart alternator AND smartcom fitted and worked as it should . I even fitted a small shiny piece of tin plate on the caravan fridge at 90 degrees to the fridge on/off light ,so I could see this light through the caravan front window whilst I was driving in the focus . This to ensure that the fridge worked constantly while on the move due to my thoughts that the 12v operation of the fridge element is poor , as we all know now .
It should not stay energised with the engine off !
I also had a Ford Focus with smart alternator AND smartcom fitted and worked as it should . I even fitted a small shiny piece of tin plate on the caravan fridge at 90 degrees to the fridge on/off light ,so I could see this light through the caravan front window whilst I was driving in the focus . This to ensure that the fridge worked constantly while on the move due to my thoughts that the 12v operation of the fridge element is poor , as we all know now .
rosies said:
The 12 volt operation of the fridge depends on what model is fitted.
My fridge has a 130 watt element which is controlled by the thermostat and has sufficient power to cool it. The mains element is 135 watt.
The dealer initially fitted a Smartcom to my Hyundai - it chattered and cut-out so much the fridge ran warm - this was adjusted to minimum cut-in voltage - it eventually burnt out because of all the chattering.
Co-incidentally, I had fitted a Scangauge II and had one of the X-gauges set to monitor system voltage - which is from 12.5 to 14.1v. The Smartcom cut-in is only adjustable between 13.2 and 13.5v so simply unsuitable for such a smart alternator, as Ring themselves advided when I contacted them
An auto-electrician resolved the problem by fitting a Durite 140A VSR which stays latched on even on long daytime journeys when the system voltage was at 12.5v most of the way from the Channel up to the Midlands today.
I always over-specify the car cabling, by a long way, to minimise voltage drop and never, normally, get any problems with fridge cooling - after all, the fridge 12v heating element is rated at the same power as the 230V and gas elements!
Co-incidentally, I had fitted a Scangauge II and had one of the X-gauges set to monitor system voltage - which is from 12.5 to 14.1v. The Smartcom cut-in is only adjustable between 13.2 and 13.5v so simply unsuitable for such a smart alternator, as Ring themselves advided when I contacted them
An auto-electrician resolved the problem by fitting a Durite 140A VSR which stays latched on even on long daytime journeys when the system voltage was at 12.5v most of the way from the Channel up to the Midlands today.
I always over-specify the car cabling, by a long way, to minimise voltage drop and never, normally, get any problems with fridge cooling - after all, the fridge 12v heating element is rated at the same power as the 230V and gas elements!
The idea of something like a Smartcom is that it is fitted at the back of the vehicle making installation quicker and easier.
For an older car or in any situation like this the best solution is to do it the old fashioned way. Run a decent sized cable from the back to the front of the car and power it through a relay which is switched by the warning light output of the alternator. Once the alternator is charging at no matter what voltage and the alternator warning light has gone out the relay will be switched on.
For an older car or in any situation like this the best solution is to do it the old fashioned way. Run a decent sized cable from the back to the front of the car and power it through a relay which is switched by the warning light output of the alternator. Once the alternator is charging at no matter what voltage and the alternator warning light has gone out the relay will be switched on.
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