12v/24v only Dometic fridge error that is causing me to tear out my remaining hair

[Robmac]

Could be the case - in WHICH case my suggestion of "start the engine" is simply changed to "plug in the mains charger" in order to boost the hab battery to perform the same test


Sounds like you want a tent with wheels
I could not go down that route for a second. I like to be able to plug something in and have it work. individual batteries for individual devices would be a blooming nightmare!
Bad enough when you have to juggle batteries in remote controllers because you forgot to bring a spare set. Extend that to EVERYTHING and it would be hell! what names will you be called when the rechargable battery for the shower goes flat while in the middle of shampooing hair?

I love tent camping and have recently taken it up again in the last couple of years having had several successful trips out on the bike.

It's not that difficult in a van considering we only ever go away for a maximum of a week and usually only 3 or 4 days and then we are often on camp sites these days so showers are available as is EHU. (I would carry a non built in EHU lead as supplied by Go Outdoors etc). But a decent rechargeable shower will last for 5 or 6 showers and if that's not enough you can recharge whilst driving.

Our portable rechargeable LED light will last up to a week and we often use it in the van now to save the leisure batteries. I have a small woodgas stove which I can use to heat up my 7.5 litre campfire kettle for showers or smaller kettle for washing up. I have a COBB BBQ for main meals which will cook a full roast dinner on 6 briquettes so the camping stove would only be needed for breakfasts and coffee etc.

As said, I would also carry an Eco Flow or similar for emergencies.

The more I think about it the more it appeals to me.

 

[wildebus]

This video (no commentary) shows the surge on the fridge. The noise when the compressor kicks in is the 400W Inverter going into overload starting the "50W" Fridge and drawing over 50A while doing so.

 

[Robmac]

It's a cable issue almost certainly

The first test I would do is the one I said... Boost the Hab Battery voltage by whatever means available ... Engine Starting; Mains Charger, even jump leads from Starter Battery if need be, and see if the fridge kicks in then.
The typical symptoms for this situation goes along the lines of "The fridge always works when I am plugged in or driving and the first night, but it won't go on even though the battery is good and at 12.5V". Followed by "the installer checked the manual and says it draws 3A when running, and that 1mm cable is rated at 11A so plenty big enough".

If the cable is not a minimum of 4mm2 then there will be an excessive drop. and the longer the cable run, the thicker the cable needs to be. The 'Small Dometic Compressor Fridge' is probably a Waeco Fridge. Nice Fridges, but low-voltage intolerant and not adjustable as far as I am aware (certainly not in the past).
You get additional drops for every connection made, so a fuse is a voltage drop (but it is needed, of course); an additional handy switch to turn the fridge on and off is a voltage drop (NOT needed - the fridge has that already)

It would be good to know what cable has been used. When I fitted my van out everywhere I read it was drummed into me to use at least 4mm cable for the fridge (and by my mate Jim who helped me with the electrics) to avoid a voltage drop.

 

[Robmac]

Bad enough when you have to juggle batteries in remote controllers because you forgot to bring a spare set. Extend that to EVERYTHING and it would be hell! what names will you be called when the rechargable battery for the shower goes flat while in the middle of shampooing hair?

Incidentally David, I wouldn't have to carry spare batteries - I'd just have to remember to take the charge cables, they are all built in.

 

[merl]

It's a cable issue almost certainly

The first test I would do is the one I said... Boost the Hab Battery voltage by whatever means available ... Engine Starting; Mains Charger, even jump leads from Starter Battery if need be, and see if the fridge kicks in then.
The typical symptoms for this situation goes along the lines of "The fridge always works when I am plugged in or driving and the first night, but it won't go on even though the battery is good and at 12.5V". Followed by "the installer checked the manual and says it draws 3A when running, and that 1mm cable is rated at 11A so plenty big enough".

If the cable is not a minimum of 4mm2 then there will be an excessive drop. and the longer the cable run, the thicker the cable needs to be. The 'Small Dometic Compressor Fridge' is probably a Waeco Fridge. Nice Fridges, but low-voltage intolerant and not adjustable as far as I am aware (certainly not in the past).
You get additional drops for every connection made, so a fuse is a voltage drop (but it is needed, of course); an additional handy switch to turn the fridge on and off is a voltage drop (NOT needed - the fridge has that already)

Sure, completely get all of that and voltage drop would have been top of my list of possible causes for sure, after all the fault code says "low voltage issue".
I'm just wondering exactly how fast the non start/ cut out/ reset happens. The OP said he'd measured the voltage AT THE FRIDGE and hadn't detected the drop in voltage, I'm pretty certain all of my DVMs would pick the issue up so I was trying to understand why the OPs meter didn't that's all. I was wondering if you'd ever measured at the the fridge your self and if so did your DVM capture the volts drop?

 

[Duetto 1999]

It's a cable issue almost certainly

The first test I would do is the one I said... Boost the Hab Battery voltage by whatever means available ... Engine Starting; Mains Charger, even jump leads from Starter Battery if need be, and see if the fridge kicks in then.
The typical symptoms for this situation goes along the lines of "The fridge always works when I am plugged in or driving and the first night, but it won't go on even though the battery is good and at 12.5V". Followed by "the installer checked the manual and says it draws 3A when running, and that 1mm cable is rated at 11A so plenty big enough".

If the cable is not a minimum of 4mm2 then there will be an excessive drop. and the longer the cable run, the thicker the cable needs to be. The 'Small Dometic Compressor Fridge' is probably a Waeco Fridge. Nice Fridges, but low-voltage intolerant and not adjustable as far as I am aware (certainly not in the past).
You get additional drops for every connection made, so a fuse is a voltage drop (but it is needed, of course); an additional handy switch to turn the fridge on and off is a voltage drop (NOT needed - the fridge has that already)

Albeit that my wife was expecting me to help with packing up the house (we have sold it and it is completing next week), I spent the morning on the drive seeing if I could cobble up some sort of test of the supply cable (given that I have almost nothing of use here in our holiday home). Some hours later, I can report:
1. The electrics in this van do need a complete overhaul - cheap installation with simply day use in mind.
2. The problem with the fridge was indeed a matter of an incorrectly sized supply cable/earth cable - I can't imagine that it ever worked but, what do I know... ?
3. You lot are absolutely amazing - THANK YOU
4. My wife is a bit miffed (she cleaned the oven - a job she hates) so I need to go eat humble pie - now!!!!
5. I still have a tiny bit of hair on my head although I can already feel this van beginning to drain my wallet - a sensation I do not like.

 

[Robmac]

Albeit that my wife was expecting me to help with packing up the house (we have sold it and it is completing next week), I spent the morning on the drive seeing if I could cobble up some sort of test of the supply cable (given that I have almost nothing of use here in our holiday home). Some hours later, I can report:
1. The electrics in this van do need a complete overhaul - cheap installation with simply day use in mind.
2. The problem with the fridge was indeed a matter of an incorrectly sized supply cable/earth cable - I can't imagine that it ever worked but, what do I know... ?
3. You lot are absolutely amazing - THANK YOU
4. My wife is a bit miffed (she cleaned the oven - a job she hates) so I need to go eat humble pie - now!!!!
5. I still have a tiny bit of hair on my head although I can already feel this van beginning to drain my wallet - a sensation I do not like.

Good to see you have it sussed.

I would at least now install a split charge relay. There are many quite sophisticated systems on the market but if you want something simple for nothing I THINK I have one of these lying around somewhere;

https://www.amazon.co.uk/0-727-33-sensitive-intelligent-Split-Charge/dp/B00N8P975S/ref=asc_df_B00N8P975S/?tag=googshopuk-21&linkCode=df0&hvadid=696452099252&hvpos=&hvnetw=g&hvrand=3677133935214810621&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9050359&hvtargid=pla-697686749251&psc=1&mcid=d2af5528a486334182f1a7e42b4cd945&gad_source=1

If you want it I will try and dig it out and send it to you.

 

[Nabsim]

I would either go to Simply Split Charge or get David (Wildebus) to make me up the cables for either a split charge relay or a B2B whichever was to be used. That way I only need to measure how long the run is and say what I am running and I know the cables, fuses, crimp ends etc will be correct Like I said earlier though I aren't a sparky lol

 

[Duetto 1999]

If you want it I will try and dig it out and send it to you.

Thanks @Robmac but I think I should hang fire for the moment until I decide exactly what I want to achieve with the rewire and which, if any, existing components I shall keep. If I am going to have to do this, I want to do it once and for all!