Dometic Fridges

[stratford]

Hello all, seems ages since I was on here. Hope somone can shed some light on this. We have an electric only (12 and 230volt) fridge which has not worked at all well during our last trip where we were off grid.. It flattened the batteries (two 110amp AGM) inside two days and flashed constantly that there was not enough 12v power. Running the engine for 2 hours was the only way to keep it working but it was very poor. We have a 85watt solar panel and the weather was glorious. The batteries were well charged after a 7 hour drive to Cornwall. We also have a battery to battery charger fitted which has been allowing overcharging when hooked up to the mains by not switching off the input from the solar panel. I am at a loss to work out if the charger, the batteries or the fridge (or any combination) are at fault. Anyone had a similar problem that has been sorted?? :-S

[auntyjanet1]

We have an Autocruise Rythym Sport which is fitted with a Waeco CR-80 fridge, and we have the same problem on 12 volt .On our recent trip to Scotland we were on hook up for 3 weeks and travelled 1400 miles our last port of call was off grid at the Bristol Ballon Fiesta .the fridge lasted approx 10/12 hours before the red light came on and all the food we had in the freezer compartment started to defrost.I contacted our nearest Swift agent ,who stated that in his experience the fridge was working ok as with one 100 amp hour battery fitted as standard by Swift this was the expected duration before the battery would drain to the cut off point.

I have contacted Swift customer service dept, and expressed my concerns that if I had been advised before purchasing the van as new 18 months ago that a 240/12 volt fridge would last only 10/12 hours off hook up I would have purchased a different van with a 3 way fridge ,their reply was that I should contact Dometic, which I now have , and. Still waiting for a reply from them.

And will I buy Swift again NO I will not.

[Guest Peter James]

auntyjanet1 - 2014-08-15 11:42 PM

I have contacted Swift customer service dept, and expressed my concerns that if I had been advised before purchasing the van as new 18 months ago that a 240/12 volt fridge would last only 10/12 hours off hook up I would have purchased a different van with a 3 way fridge ,their reply was that I should contact Dometic, which I now have , and. Still waiting for a reply from them.

And will I buy Swift again NO I will not.

Sadly fridges don't run for long on batteries.

Have you inquired how long the fridge will last on the battery on other makes of van *-)

[Derek Uzzell]

3-way absorption fridges are certainly heavy on 12V usage, but this can (obviously) be sidestepped by operating the appliance on LPG.

 

If 230V mains power is unavailable, a 12V/230V compression fridge will (again obviously) be unable to take the LPG route and will have to rely on the leisure-vehicle’s 12V system to operate.

 

Stratford does not specify what model of Dometic Waeco fridge he has (nor the make/model /age of his motorhome), but details of auntyjanet1’s CR-80 fridge are here

 

http://www.waecofridges.co.uk/cr80.htm

 

If one works on the basis that leisure batteries are rarely charged to their full theoretical capacity and that the electrical wiring used in motorhomes can result in a significant drop in voltage by the time power reaches an appliance, a 10-12 hour ‘usage duration’ for a 100Ah battery or under 2 days for 2 x 110Ah batteries may seem to be on the low side but (as the Swift agent advised) may well be what might be expected in practice.

 

Factoring in solar panels and B2B chargers complicates matters, but this type of fridge does eat 12V power and (in my view) isn’t suitable for longer ‘off grid’ stays. I suspect that there’s nothing really at fault in Stratford’s case, it’s a combination of what the fridge demands 12V-wise and what the motorhome’s electrical system can provide.

 

It would be worth checking what the supply-voltage is at the fridge to confirm whether or not there’s a big voltage drop and, if there were, rewiring would address this. Other than that, I doubt there’s much that can be done unless additional leisure batteries are installed.

[Robinhood]

Derek Uzzell - 2014-08-16 8:01 AM

 

It would be worth checking what the supply-voltage is at the fridge to confirm whether or not there’s a big voltage drop and, if there were, rewiring would address this. Other than that, I doubt there’s much that can be done unless additional leisure batteries are installed.

 

....or, if it's easier, measure the voltage at the leisure battery as the unit cuts-off, to see if it is still higher there than the fridge "cut-out" voltage.

 

I must say that, unless I'm missing something (brain not yet up to speed this morning), the figures quoted by Waeco look pretty odd.

 

I'm not sure how an "average" power consumption of 48 watts can translate to a "current consumption" of (say) 2.1 Ah/h at 12V. (and I'll ignore the obvious misuse of SI units here - a most odd way of specifying such an item).

 

Average power consumption of 40W to me would imply an average current drain of almost 4 amps, rather than 2.1. At this level, 10-12 hours would discharge even a fully-charged 100Ah leisure battery close to 50% (even without the use of other items) and then a small amount of voltage drop in the supply to the fridge could cause problems.

 

:-S