Fridge not working from engine

[Fisherman]

Probably the fuse not seated totally and a touch loose. Those ATO fuses are not great for continuous current and get very hot. Little surprising for a circuit with limited use (only active when driving) but I had a similar issue with a fuse on the B2B circuit in my van with the fuse still ok, but the plastic melting and pushing the connector away. Chances are with a new fuse and refreshed solder, never have a problem again. ( I replaced my fuse and never had a problem since with it).

I have ordered a gas soldering iron and solder will do the repair when they arrive.
Would simply applying fresh solder suffice, or should I remove old solder first.
The fuse seemed tight, and the replacement had to be pushed in, it seemed like a good fit, avoiding arking.

 

[Jack vdl]

I don't want to worry you but fuses don't blow by themselves. By the looks of it there has definitely been a short and if the cause of this hasn't been found and fixed, then it will more than likely happen again.

 

[wildebus]

I have ordered a gas soldering iron and solder will do the repair when they arrive.
Would simply applying fresh solder suffice, or should I remove old solder first.

I would just heat joint enough to go molten and flow some new on top.
Gas iron is very handy to keep in the van for mobile repairs I've used an IRODA one for years and it is great.

 

[STEALTH]

Definately happy I took out the 3-way and fitted a 240V Compressor Fridge
tweaked the setup a few days ago and it works very consistantly and draws (including inverter overhead) no more than 1Ah/Hour. In the summertime would easy make up much more than that with a decent solar setup.
View attachment 105425

yes same here i take my large cool box 12v cost at the time £230.99 out camper had 7yrs in the end when it was hot summer day food was going off
i fitted 240v russell hobbs compressor fridge new ebay £95.99 2yrs ago works very well in hot summer day all day i fitted inverter small one 150 watts 2yrs ago for £25.99 inverter charge laptop as well but not at same time and all works fine carry on camping
have solar panels new 2 van batterys varta 200ah with 5yrs guarantee

 

[STEALTH]

Well good news on the fridge.
I first checked the continuity on the 12v element and it was reading fine at 0.8amps.
I then managed to get to two screw bolts at the back with a 1/4 Alan key with the appropriate socket fitted on the end and undo the pcb. I immediately noticed discolouration on the pcb, and right away suspected the onboard 20 amp fuse.
And as you can see from photos it was the culprit. Put it all back together and the fridge is working on all fuels now.
My only concern is what caused such catastrophic fuse failure.
It looks like a short between the 12v and ground.
Hopefully it won't happen again.
View attachment 105513View attachment 105514View attachment 105515

5 stars for finding the fuse and pcb board theres 2 black solder bits on pcb as well drowing to much power
as you say what caused fuse to melt and burn fuse very bad drowing to much power
the fridge at times is drowing to much power you need to keep an eye on the fuse 1 or 2 times a week just for now and then monthly
ill tell you short story was self employed 18 years bit taxi work and delvery of same day parcels the point am getting to is working driveing 10 hours a day driveing for 6 days a week most on nights the fuse box and the fuse for the taxi head lights was melting and burning out fuse board its dad for a working taxi and same day parcel deliverys the taxi was in the auto electrician 7 days beening chq out
the out come was head lights was drowing to much power auto electrician could not find any faults just chq fuse, fuse box every week i never got to the bottom of it only auto electrician saying head lights drowing to much power and all other fuse all was ok this was around 40 years a go so the out come is not no why but its not safe with that damage this is what i said to the auto electrician at the time you realy need this chq out its not safe and fire risk hope this story is of help to you

 

[barge1914]

How many batteries have you got Bill? And have you the basic install of an NE325 25A dc-dc power converter sitting on top of a NE287 battery charger under the drivers seat.

My fridge defrosts intermittently when travelling. Ruminating on this brings me to the following…

So. One 95AH battery charged at 10% bulk charge takes 9.5A, 205W DC fridge at 12 to 13.6V takes 13 to 15A.
15+9.5=24.5A. So 25A dc-dc NE325 is barely ok for one battery and fridge assuming no circuit losses and nothing else turned on.

Two batteries and fridge
19+15=34A, so must need 40A NE325. Hence the problem.

I had to make some assumptions since I don't have specific manufacturers data 10% of battery capacity is the normal max safe charge for AGM. 205W is off the fridge data plate.

If the batteries actually receive a higher charge rate than I've assumed at the maximum output from NE325 of 13.8/14.4V then combined with the fridge the figure would likely exceed the capacity of the 25A unit, or maybe the unit would be restricting the output meaning fridge and/or batteries would receive a reduced charge. Not knowing exactly how the unit controls voltage and current I can't get any further along these lines.

Anything particular you think dodgy about the maths please let me know, I'd rather be warned before I tackle the dealer...who (as an NCC Workshop)should have been capable of working this out for himself.

Incidentally the attached file recommends the 40A version of NE325 for powering a fridge.

https://www.aboutcampbtob.eu/wp-content/uploads/2018/04/N24_Nordelettronica.pdf

Happy to have comments from anyone with better technical know how than me.

 

[wildebus]

How many batteries have you got Bill? And have you the basic install of an NE325 25A dc-dc power converter sitting on top of a NA287 battery charger under the drivers seat.

My fridge defrosts intermittently when travelling. Ruminating on this brings me to the following…

So. One 95AH battery charged at 10% bulk charge takes 9.5A, 205W DC fridge at 12 to 13.6V takes 13 to 15A.
15+9.5=24.5A. So 25A dc-dc NE325 is barely ok for one battery and fridge assuming no circuit losses and nothing else turned on.

Two batteries and fridge
19+15=34A, so must need 40A NE325. Hence the problem.

I had to make some assumptions since I don't have specific manufacturers data 10% of battery capacity is the normal max safe charge for AGM. 205W is off the fridge data plate.

If the batteries actually receive a higher charge rate than I've assumed at the maximum output from NE325 of 13.8/14.4V then combined with the fridge the figure would likely exceed the capacity of the 25A unit, or maybe the unit would be restricting the output meaning fridge and/or batteries would receive a reduced charge. Not knowing exactly how the unit controls voltage and current I can't get any further along these lines.

Anything particular you think dodgy about the maths please let me know, I'd rather be warned before I tackle the dealer...who (as an NCC Workshop)should have been capable of working this out for himself.

Incidentally the attached file recommends the 40A version of NE325 for powering a fridge.

https://www.aboutcampbtob.eu/wp-content/uploads/2018/04/N24_Nordelettronica.pdf

Happy to have comments from anyone with better technical know how than me.

I don't know about your specific van, but I think your logic is slightly off.
The 12V DC Supply to the fridge should not go through the same relay/DC-DC converter as the Leisure Battery charge will. It should be via a direct relay, so the ~20A the fridge will pull is off the alternator and not the split-charge system.

 

[barge1914]

How many batteries have you got Bill? And have you the basic install of an NE325 25A dc-dc power converter sitting on top of a NA287 battery charger under the drivers seat.

My fridge defrosts intermittently when travelling. Ruminating on this brings me to the following…

So. One 95AH battery charged at 10% bulk charge takes 9.5A, 205W DC fridge at 12 to 13.6V takes 13 to 15A.
15+9.5=24.5A. So 25A dc-dc NE325 is barely ok for one battery and fridge assuming no circuit losses and nothing else turned on.

Two batteries and fridge
19+15=34A, so must need 40A NE325. Hence the problem.

I had to make some assumptions since I don't have specific manufacturers data 10% of battery capacity is the normal max safe charge for AGM. 205W is off the fridge data plate.

If the batteries actually receive a higher charge rate than I've assumed at the maximum output from NE325 of 13.8/14.4V then combined with the fridge the figure would likely exceed the capacity of the 25A unit, or maybe the unit would be restricting the output meaning fridge and/or batteries would receive a reduced charge. Not knowing exactly how the unit controls voltage and current I can't get any further along these lines.

If I took account of a reduced duty cycle on the fridge, and batteries partially charged at set off, then the figures may not be as bad, but when wild camping in winter batteries could be fairly low leaving less juice for the fridge, still leaving it struggling with the 25A unit, especially if the max continuous current for the NE325 is 20A.

Anything particular you think dodgy about the maths please let me know, I'd rather be warned before I tackle the dealer...who (as an NCC Workshop)should have been capable of working this out for himself.

Incidentally the attached file recommends the 40A version of NE325 for powering a fridge.

Happy to have comments from anyone with better technical know how than me.

 

[Fisherman]

How many batteries have you got Bill? And have you the basic install of an NE325 25A dc-dc power converter sitting on top of a NA287 battery charger under the drivers seat.

My fridge defrosts intermittently when travelling. Ruminating on this brings me to the following…

So. One 95AH battery charged at 10% bulk charge takes 9.5A, 205W DC fridge at 12 to 13.6V takes 13 to 15A.
15+9.5=24.5A. So 25A dc-dc NE325 is barely ok for one battery and fridge assuming no circuit losses and nothing else turned on.

Two batteries and fridge
19+15=34A, so must need 40A NE325. Hence the problem.

I had to make some assumptions since I don't have specific manufacturers data 10% of battery capacity is the normal max safe charge for AGM. 205W is off the fridge data plate.

If the batteries actually receive a higher charge rate than I've assumed at the maximum output from NE325 of 13.8/14.4V then combined with the fridge the figure would likely exceed the capacity of the 25A unit, or maybe the unit would be restricting the output meaning fridge and/or batteries would receive a reduced charge. Not knowing exactly how the unit controls voltage and current I can't get any further along these lines.

Anything particular you think dodgy about the maths please let me know, I'd rather be warned before I tackle the dealer...who (as an NCC Workshop)should have been capable of working this out for himself.

Incidentally the attached file recommends the 40A version of NE325 for powering a fridge.

https://www.aboutcampbtob.eu/wp-content/uploads/2018/04/N24_Nordelettronica.pdf

Happy to have comments from anyone with better technical know how than me.

To technical for me.
I have two Varta 95AH AGM batteries. (I think same as you).
I had no problems with the fridge until the fuse blew. I suspect that this was caused by arcing which would have increased current to fridge from battery whilst driving and hence why fuse overheated And eventually blew. I suspect loose connection on PCB which I will repair.
Remember the 12v element is much less powerful than mains.
If travelling in summer for more than 2-3 hours I would consider running manually on gas. But in saying that we have travelled for five hours on battery. Also consider before setting off setting fridge to lowest temperature.

 

[barge1914]

How many batteries have you got Bill? And have you the basic install of an NE325 25A dc-dc power converter sitting on top of a NA287 battery charger under the drivers seat.

My fridge defrosts intermittently when travelling. Ruminating on this brings me to the following…

So. One 95AH battery charged at 10% bulk charge takes 9.5A, 205W DC fridge at 12 to 13.6V takes 13 to 15A.
15+9.5=24.5A. So 25A dc-dc NE325 is barely ok for one battery and fridge assuming no circuit losses and nothing else turned on.

Two batteries and fridge
19+15=34A, so must need 40A NE325. Hence the problem.

I had to make some assumptions since I don't have specific manufacturers data 10% of battery capacity is the normal max safe charge for AGM. 205W is off the fridge data plate.

If the batteries actually receive a higher charge rate than I've assumed at the maximum output from NE325 of 13.8/14.4V then combined with the fridge the figure would likely exceed the capacity of the 25A unit, or maybe the unit would be restricting the output meaning fridge and/or batteries would receive a reduced charge. Not knowing exactly how the unit controls voltage and current I can't get any further along these lines.

If I took account of a reduced duty cycle on the fridge, and batteries partially charged at set off, then the figures may not be as bad, but when wild camping in winter batteries could be fairly low leaving less juice for the fridge, still leaving it struggling with the 25A unit, especially if the max continuous current for the NE325 is 20A.

Anything particular you think dodgy about the maths please let me know, I'd rather be warned before I tackle the dealer...who (as an NCC Workshop)should have been capable of working this out for himself.

Incidentally the attached file recommends the 40A version of NE325 for powering a fridge.

Happy to have comments from anyone with better technical know how than me.

Sorry…duplicsted

 

[barge1914]

To technical for me.
I have two Varta 95AH AGM batteries. (I think same as you).
I had no problems with the fridge until the fuse blew. I suspect that this was caused by arcing which would have increased current to fridge from battery whilst driving and hence why fuse overheated And eventually blew. I suspect loose connection on PCB which I will repair.

Had my pcb replaced by dealer, but the problem persists. Trying to figure out why.

 

[Fisherman]

Had my pcb replaced by dealer, but the problem persists. Trying to figure out why.

I added to my reply.

 

[Fisherman]

Had my pcb replaced by dealer, but the problem persists. Trying to figure out why.

One other point I don’t understand.
Even if your fridge did not work on 12v, as mine didn’t.
If the fridge door is closed properly and not opened even in summer it would take hours to defrost. My advice would be set fridge to lowest temperature before leaving. Avoid opening door when leaving. Check that the fridge stops flashing when the engine is turned on. Also check that there’s sufficient refrigerant. Also we have a thermometer in our fridge, check that your fridge reaches temperature when turned on.

 

[wildebus]

One other point I don’t understand.
Even if your fridge did not work on 12v, as mine didn’t.
If the fridge door is closed properly and not opened even in summer it would take hours to defrost. My advice would be set fridge to lowest temperature before leaving. Avoid opening door when leaving. Check that the fridge stops flashing when the engine is turned on. Also check that there’s sufficient refrigerant. Also we have a thermometer in our fridge, check that your fridge reaches temperature when turned on.

little suggestion to pick up on your points above ....
Get a Themometer like this one - https://amzn.to/347XWkf. It will record the temp constantly for upto 2 weeks for you to view on your phone. Means you can check the fridge is working properly (so prevents food not warming up and then cooling down without you realising - good food safety); Also means you can check the temp without having to open the door (helps prevent warming up when door opens - it is remarkable how much 'cool' is lost when the door is opened); You can also set an alarm if it goes above or below your target temps.
Excellent unit for little money.

 

[Fisherman]

little suggestion to pick up on your points above ....
Get a Themometer like this one - https://amzn.to/347XWkf. It will record the temp constantly for upto 2 weeks for you to view on your phone. Means you can check the fridge is working properly (so prevents food not warming up and then cooling down without you realising - good food safety); Also means you can check the temp without having to open the door (helps prevent warming up when door opens - it is remarkable how much 'cool' is lost when the door is opened); You can also set an alarm if it goes above or below your target temps.
Excellent unit for little money.

Thanks David at £10.99 great bit of kit, ordered it on prime.

 

[wildebus]

I've been tweaking my Fridge/Freezer temps to optimize it and used that Gove unit in the link to monitor the fridge - and a Victron temp sensor to monitor the Freezer. Below is a graph of a days monitoring ...
The green smooth line is the Gove unit - thermometer with storage and bluetooth connectivity. The Blue choppy line is the Victron Sensor which is over 3 times the price and is just a sensor and nothing else (so needed other stuff to record the blue line info).

 

[TJBi]

little suggestion to pick up on your points above ....
Get a Themometer like this one - https://amzn.to/347XWkf. It will record the temp constantly for upto 2 weeks for you to view on your phone. Means you can check the fridge is working properly (so prevents food not warming up and then cooling down without you realising - good food safety); Also means you can check the temp without having to open the door (helps prevent warming up when door opens - it is remarkable how much 'cool' is lost when the door is opened); You can also set an alarm if it goes above or below your target temps.
Excellent unit for little money.

Very interesting solution. Out of interest, do low (fridge) temperatures cause any issues with battery life?
I see (under "Frequently bought together") that there is another version that operates using both Bluetooth and WiFi, which could be useful for remote monitoring (in other situations), but it's not entirely clear whether alerts would work when there is only a WiFi connection. Does anyone have any experience of this?

 

[wildebus]

The battery life could be affected, but it is a good life anyway and is a simple AAA battery, so cheap and easy to swap.
Wifi would be nice, but that version is at a much higher price - I was ok with the Bluetooth version as can easily export the data. I would think that the alerts remotely would need the app running. Couple of screenshots ....

The Red line is when above the max temp set and reverts to Blue when within the parameters

And to get the data as a CSV (to view in Excel or Google Docs if you prefer), scroll down to the "Export Data" button (you need to have an account, but they are no cost and no details needed other than an email address)

Out of interest, the humidity graph is very interesting ... not to see the actual humidty but it tells you instantly when the fridge is powered or not. The Humidity shoots up (a lot faster than the temp) as soon as there is no cooling happening (be it from Gas or Electric).
I used to use a pair - one in the Fridge, one in the Freezer - but I use the Victron in the Freezer now as it does have an advantage of being just a sensor in an environment which can be very wet if left to defrost with pooling water (a Fridge is nowhere near as bad for that).

 

[barge1914]

It may be of interest…latest from dealer…

Hi

The fridge is fed from the engine because of the amperage needed. The feed from the engine goes to Fuse board pin J1 this goes through a relay and fuse and goes direct from the fuse board on plug J4 pin 1. This was all checked and found to be ok after fitting the new fridge power board. I am still waiting for the senior technician at Thetford coming back with more details. Charger outputs on both the charger and engine were checked and within parameters.

I will get back to you when I have an answer.

Kind regards

 

[barge1914]

Well apparently Thetfords solution to my problem is they are supplying a completely new fridge. Hope that solves it. The dealer has already checked all the voltage and current inputs and outputs on fridge, batteries, relays, chargers and power converter and everything I’d within specifications.