Alternator Problem???

[mmi]

What about hooking a battery charger and push voltage up to see if that also triggers the fault. If that happens then I’m not sure if a DC-DC charger would help.

Just have difficulties believe that alternator charging would be the culprit. More thinking that the fault is because of undervoltage – poor connection+vibration? As your heater is powered from aux battery, even the starting the engine dropping the voltage shouldn’t be the issue.

 

[Lee Steadman]

Just to let everyone know, the conversion company changed the leisure battery, VSR, Propex Heater and control panel.
Fault has now gone away but no further forward as to what the actual cause was.

 

[Brom]

Our van is a T6 Euro 6 with smart alternator. It has aPropex HS2000 heater, powered by a Varta open lead-acid leisure battery, which is connected to the main vehicle battery via a Sterling Battery-to-Battery Charger, which should regulate the output to 14.8v, and cut out the huge power spikes you get from the alternator when regenerative-braking.

We had the problem, which from browsing the Forum seems to be common, that whenever we drove the van, the Propex heater would go into fault mode (3 red flashes), which meant we had to clear the lockout every time, before starting the heater.

We kept the voltmeter running, and found that, in town, the charge was up to 15.3v, so naturally, was triggering the Propex when it went over its design limit of 15v. On the motorway, the charge going through was much lower, at around 14.4v.

Our converter thought it might be worth switching the Charger to sealed lead-acid battery status, which regulates it to 14.4v, rather than 14.8v for the open battery - and we will still do this, to be on the safe side.

However, I rang Sterling (British company, for once!), and their technical boffin asked me whether the Temperature Sensor had been fitted? (Our converter confirmed it had been). This is supplied as part of the Charger kit, and is fitted to the Leisure Battery; it helps speed the charging of the leisure battery, especially in winter, when temperatures are low. However, what they DON'T explain is that this also boosts the power output, and can easily shove it above 14.8v, up to well over 15v. I don't think it had occurred to him that this might not be good for equipment such as the Propex, or a fridge, or a GEL battery (if fitted). He was sure that if our converter removed the Temperature Sensor, the problem would not arise, and agreed that lowering the setting to 14.4v max would make doubly sure.

So, hopefully, once this has been done, we shouldn't need an isolation switch for the Propex - and then, if the fault does arise again, the Propex going into default mode will act as an Early Warning System.

I will confirm in a couple of weeks time whether this solves the problem.

 

[Dellmassive]

If that doesn't work you could try swapping the sterling out for a Redarc BCDC dc-dc charger, our readings show it doesn't pass the 15v to the leisure battery .

 

[Brom]

Update.

Our converter (Nu-Venture), removed the temperature sensor from the leisure battery, as suggested by Sterling, but we soon realised the B2B was still overcharging the leisure battery (more than the Propex heater could cope with (15v), anyway). Therefore the Propex went into fault mode, with flashing warning light.

So, back on to Sterling. They asked whether the sensor had also been removed from the B2B itself? No, it hadn't. Following instructions, I then disconnected the two sensor wires within the B2B, and rechecked the input and output voltages, which seemed OK, when the van was on tickover.

The important test, of course, is how it worked out on the road. Today we drove the van for 30 miles - on our return, there was no fault light on the Propex control, and the leisure battery was showing a charge of 14.8v - within bounds for the Propex.

So, fingers crossed, it seems the problem is solved.