• Whilst on with pondering my original electrical installation and doing the below manual-relay-override conversion, I measured the consumption of a few other bits of hardware when in standby state.

    NB, all @24V:

    40A relay = 85mA

    60A relay = 165mA

    18A DC-DC Converter = 280mA

    1800W Inverter = 330mA.

    Leaving this combination of items on standby was something that we sometimes did when out and about and it came as something of a surprise to realise that to do so was 'costing' us 860mA an hour.

    We're normally parked up for about 17hrs per overnighting spot so were effectively giving away 14.62A. One 24hr period would equate to the consumption of 20.64A - and all this without actually using any domestic equipment.

    Put another way, these losses might otherwise run the compressor fridge on a low setting and in moderate ambient temperature. Proper shocker.

    I'm glad I did the measurements. Manufacturers tend to underplay standby / quiescent loads and I confess I had - until recently - pretty much just shrugged the issue off. I'd urge everyone - who hasn't already - to reduce / eradicate these pointless losses - battery performance / longevity can only be improved.

    Incidentally, using extrapolated figures from real-world solar panel use, it would have taken an 80W solar panel from dawn till dusk on a sunny summer day just to offset the 20A loss that my 40A relay / 60A relay / DC-DC / converter / inverter combination would 'steal'. On a sunny winter's day, you'd be looking at 600W of solar array to offset the loss.

    Read more...
  • These two relays are master switches for my 24 and 12V systems and when we are travelling are - through necessity - permanently on. I did some testing and found they draw approx 165mA each when in use. This might seem inconsequential but when extrapolated can be an eye-opener - it was for me, anyway.

    We normally travel each day when out and about but usually 'camp' from somewhere late afternoon to mid morning the following day, usually a period of around 17hrs. In that time it's costing us almost 6A just to hold the relays in. Now, because we travel each day we've never really succumbed to huge battery capacity or auxiliary charging solutions so our 24V battery capacity is comparatively small. As such, 6A is just about 6A more than I'd like to be losing for no good reason. I'd much rather that 6A be available for the compressor fridge.

    Even worse, though I never intended our truck to be used for shows, I have been to a few and parking up late Thursday to Sunday afternoon would see the relays suck 24A. Ouch.

    And so, I've tweaked them to enable manual override. With the knurled screws 'out' the relays still operate just as Durite intended. Once the relays are switched on though, I can now tighten the knurled screws in and lock the contacts closed. When that's done, turning the relays off saves all the power previously required just to activate the coils. From now on I'll 'lock' them when setting off on a break and 'unlock' them on our return.

    It seems like a decent work-around and though it's a bit of a bodge it's saved me from having to disturb my original wiring looms. Lesson learned: if I built again, I'd utilise purely manual switches instead…

    Read more...
  • The Fridge, the fridge…

    I sent the below email to Dometic Customer services in early January 2017: it outlines our recurring fridge problem:

    “I purchased a Waeco CR110E CoolMatic on 22/03/2012 from an authorised dealer: Jacksons Leisure Supplies.

    The fridge was installed in our camper van in accordance with manufacturer's instructions with particular attention being paid to adequate gauge wiring, a short wiring run, and proper ventilation.

    The fridge was commissioned in August 2012 and worked well (on the occasions we were travelling) for about two years. It then developed a fault. It would not turn off properly after it had been through a cooling cycle. The compressor would start properly and would run for what would seem like a full cooling cycle, but would then stop running: only to immediately start up again, run for a few seconds, then stop, then start again, run for a few more seconds, then stop - and do this over and over and over again until eventually the internal thermostatic switch could be heard to 'click'. Only at this distinctly audible click would the compressor then finally stop running.

    I checked the voltage at the fridge terminals and also to make sure that there was no issue with dust / fluff build up around the compressor / fan but all was in order. Voltage was in accordance with tolerance and the compressor / fan were as clean as when new.

    I complained about what appeared to be a fault with the thermostat 'pod' failing to properly finish the cooling cycle to the original retailer who was, essentially, of no help. I then complained to yourselves and, around December 2014, you were kind enough to supply a new thermostat pod.

    I did not fit this 'pod' immediately as our camper was not being used at that time. In March / April 2015 we went on a trip with the old (original) thermostat pod still in place and during this trip the fridge failed completely. At this point, I fitted the new thermostat pod that you had supplied and this completely solved all issues. The fridge worked perfectly..

    We have used the camper on numerous trips since (in both warm and cool climates) and the fridge has, for the duration of the trips, worked perfectly.

    However, we have just returned from a week-long trip over Christmas and exactly the same fault as I originally reported has returned: ie at the start of a cooling cycle, the compressor starts properly and runs normally until the internal temperature is reduced to the point where we would expect to hear an internal 'click' - and for the compressor to stop running. This is not what happens, though. Instead, even though there is no tell-tale 'click', the compressor stops running anyway: only to immediately start up again, run for a few seconds, then stop, then start again, run for a few more seconds, then stop - and do this over and over again until eventually the thermostatic switch is heard to 'click'. Only at this point, after numerous 'false' re-starts, does the compressor then finally stop running.

    This is incredibly irritating and it would seem the current thermostat pod has developed exactly the same fault as the original one did. I expect, as with the original, it is only a matter of time before this one fails completely too.

    I would suggest that we have either been incredibly unfortunate or this is a known design fault.

    To confirm, I have again checked the cleanliness of the area around the compressor / fan and all is spotless. I have experimented by running the fridge whilst the batteries that power it are themselves receiving a charge from our camper's alternator and the higher voltage at the fridge terminals at this point makes no difference. The fault remains exactly the same. I also confirm that after trips, the fridge is immediately wiped out to remove all internal moisture and is stored with the door in the 'vent' position.

    Please advise. I am most reluctant to purchase yet another (third) thermostat pod if it is only going to last, at best, two years. Indeed, the lifespan is not even this good. In reality, because the fridge is only used when we are actually travelling, each thermostat pod has only survived perhaps 12-15 weeks of use.

    This product seems wholly unfit for purpose. I suggest that a fridge costing £600 should reasonably be expected to provide reliable service for far more than 12-15 weeks.

    I look forward to your early assistance with a remedy that will afford good service for a time commensurate with the expected lifespan of a purportedly high-quality compressor fridge.”

    Dometic UK technical and customer ‘services’ both ignored me. This has happened many times before. About two weeks after the original email, I sent another one and this time copied in Dometic’s Head of Group Business Control and Investor Relations in Sweden. Hey Presto, the same day Dometic UK responded thus:

    “Dear Sir,

    Were sorry to read of the on going problems. After read your email we have a few questions as it might not be the thermostat thats at fault. Can you confirm the distance from battery to fridge? Does it go via fuse block or control panel? What cable size is the run? Have you checked the voltage when the fridge is off load and on load? To do this the fridge has to be pulled forward and the voltage checked at the input terminals.

    Personally I think you fault might be two things on is ambient temp and the other is resistance.”

    My immediate thoughts were - I confess - FFS. Incensed with fridge-rage, but with an eye on the long game, I responded in the politest terms I could muster. Dometic UK responded and eventually (there were more tooings-and-froings) agreed to have an engineer come out to me to investigate. About two weeks later an engineer duly arrived. He spent about two minutes in the truck and said:

    “The thermostat’s faulty.”

    My response:

    “No shit.”

    He then spent another two hours at the truck and on the phone to Dometic. He was utterly perplexed by the fact that the compressor would cut out before the electro-mechanical switch had audibly ‘clicked’. It was obvious that neither he, nor anyone at Dometic technical, had - up to this point - believed my repeated description of the fault. He fitted a new thermostat pod with the promise that he’d disassemble the faulty one at his workshop and get back to me to let me know what had gone wrong. That was about six weeks ago.

    I have a feeling this one isn’t over just yet…

    Read more...

Tweaks and fixes are an ongoing part of the project. This series of pages form a blog - of sorts - and is intended to give a flavour of the day-to-day realities of living with the truck as issues crop up and tweaks and fixes progress. Many of the posts eventually end up getting written up properly and included in the main body of the Trip Truck site; so if you think you have read any of the older posts somewhere else, you almost certainly have.

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