Renault Trafic 3, fridge unit voltage drop in the van

[PuG]

Afternoon. I have posted this question on the Renault forums but im a new member and awaiting to be approved.

We sell beef direct to customers andhave a box fridge unit that slides into the back of the van which runs of the mains (when plugged in) and then via an inbuilt inverter direct from the van battery. We've just replaced our old van (Ford Courier) with a 2019 Traffic 3. Fridge pulls about 235 watts when running, and 40 idle.

I've run some 50mm2 (I worked out a voltage drop of 0.45 over 8 meters) cables directly from the battery to the rear bay to run the fridge unit to discover we have a problem (typically on the morning off to the butcher, having tested fine before). When the van is turned off then it runs from the battery with no interruption - however after starting the engine, the fridge inverter then suffers from low voltage and shuts down, presumably from voltage fluctuation's coming from the battery (I need to double check with a meter if I can crawl in beside the fridge unit). Yesterday we solved the problem temporarily by running the van with main beam lights switched on (I presume given the alternator steadily output power to charge the battery/run electrics), however today not even that has helped.

I never really knew about smart alternators and guess its fitted for the emissions. The cables are attached directly to the battery terminals (not via the relay on the ground side/negative which the rest of the van is connected).

What I don't understand is why does it run fine when the engine is off, but as soon as shes started we then get the low dc voltage issues even though surly the alternator must be outputting to top up the batter.

Any ideas?!

Cheers, James

 

[PSQ]

Renault

There’s the problem: French volts.
Volts = potential difference.
French volts = potential indifference.

 

[ACEngineering]

Afternoon. I have posted this question on the Renault forums but im a new member and awaiting to be approved.

We sell beef direct to customers andhave a box fridge unit that slides into the back of the van which runs of the mains (when plugged in) and then via an inbuilt inverter direct from the van battery. We've just replaced our old van (Ford Courier) with a 2019 Traffic 3. Fridge pulls about 235 watts when running, and 40 idle.

I've run some 50mm2 (I worked out a voltage drop of 0.45 over 8 meters) cables directly from the battery to the rear bay to run the fridge unit to discover we have a problem (typically on the morning off to the butcher, having tested fine before). When the van is turned off then it runs from the battery with no interruption - however after starting the engine, the fridge inverter then suffers from low voltage and shuts down, presumably from voltage fluctuation's coming from the battery (I need to double check with a meter if I can crawl in beside the fridge unit). Yesterday we solved the problem temporarily by running the van with main beam lights switched on (I presume given the alternator steadily output power to charge the battery/run electrics), however today not even that has helped.

I never really knew about smart alternators and guess its fitted for the emissions. The cables are attached directly to the battery terminals (not via the relay on the ground side/negative which the rest of the van is connected).

What I don't understand is why does it run fine when the engine is off, but as soon as shes started we then get the low dc voltage issues even though surly the alternator must be outputting to top up the batter.

Any ideas?!

Cheers, James

Your problem is almost certainly the new euro 6 emissions crap!

Euro6 cars and Van's have smart alternators with stop start tech.

Alternator only charges battery to about 80% then switches off hense the drop in volts.

The remaining 20% is only charged during braking when you brake the alternator kicks back in and fires a massive high amp burst and up to 17 or 18volts back in the battery!

This plays havoc with voltage sensing relays and aux battery systems on camper Van's etc.

I have a 12volt heated sink with voltage sensing relay and half the time it does not kick in as voltage too low, I have got to run a switch feed from fuse box to the relay so it knows ignition is on.

 

[ACEngineering]

What you probably going to have to do is use an aux battery charged via a suitable battery to battery charger set up specifically for the smart alternator.

Or if your inverter has it run a switch ignition feed to it to tell it engine is running rather than it use voltage sensing to turn on.

With smart alternator you cant just hook a aux battery up and a voltage sensing relay cause the van system will never know the state of charge of the aux battery so could end up overcharging it!

Theres tons of info in you tube and if you google camper van converters.

 

[Nearly]

Time for a brick on the brake pedal? @ACEngineering ?

 

[Netherfield]

Obviously there's a way around it, or all the butchers and supermarket vans would be in the same boat.

 

[ACEngineering]

Obviously there's a way around it, or all the butchers and supermarket vans would be in the same boat.

Cause there is, but you cant just bypass the smart alternator system as it wouldnt meet the emissions. Look at what happened to the likes of VW when they messed about with emission figures and got caught!

 

[PuG]

Thank you for the reply, unbelievable! I did a quick search on the auxiliary battery setup, lots of systems to choose from but getting one that supports smart alternators seems to be pricey but I'll have to get it sorted out this month. What a palava.

 

[upnortheast]

Obviously there's a way around it, or all the butchers and supermarket vans would be in the same boat.

The op has a seperate 240v fridge he plugs into the van via an alternator

Fridge & freezer vans have built in 12v units with the compressor belt driven off the engine.
So totally different setup

 

[Mur Huwcun]

It could be worse and could be a VW/Audi that needs a new battery coded to the car for it to work and be charged!!

Has the van got a towbar? If it had a towbar and 13 pin it would have a pin for a caravan fridge which would be wired through the vehicle electrics setup etc and would work with the smart charging. This could be used to charge the auxiliary battery I shoukd think. Not ideal though but a possibility

 

[ACEngineering]

It could be worse and could be a VW/Audi that needs a new battery coded to the car for it to work and be charged!!

Has the van got a towbar? If it had a towbar and 13 pin it would have a pin for a caravan fridge which would be wired through the vehicle electrics setup etc and would work with the smart charging. This could be used to charge the auxiliary battery I shoukd think. Not ideal though but a possibility

No i don't think its as simple as that, the Vehicle ECU will not know when to stop charging the aux battery as it wont be monitored to 80% like the vehicle one, so when you hit the brakes and the smart alternator fires in 18volts and 150 plus amps or what ever amps the alternator is rated at the aux could already be 100% charged and cant take any more.

Its a total load of crap IMO and a waste of time, for a hybrid car or van then it would make more sense to use brakes to help restore lost charge on drive batteries but for a starter battery its completely pointless and not achieving anything over what a normal alternator would.

 

[Exfarmer]

Your problem is almost certainly the new euro 6 emissions crap!

Euro6 cars and Van's have smart alternators with stop start tech.

Alternator only charges battery to about 80% then switches off hense the drop in volts.

The remaining 20% is only charged during braking when you brake the alternator kicks back in and fires a massive high amp burst and up to 17 or 18volts back in the battery!

This plays havoc with voltage sensing relays and aux battery systems on camper Van's etc.

I have a 12volt heated sink with voltage sensing relay and half the time it does not kick in as voltage too low, I have got to run a switch feed from fuse box to the relay so it knows ignition is on.

Ace, always respected your advice, but is this serious?
I am old school, trained that braking is a no go unless in emergency, drive to the conditions , blah blah blah.
I have very rarely needed to need new brake shoes thanks to this.
However our Mini continually needs topping up with a charger as the low battery light always seem to come on.
I have already changed one battery and it has only done 12,000 miles.
Is this really because it is not charging properly?

 

[Mur Huwcun]

No i don't think its as simple as that, the Vehicle ECU will not know when to stop charging the aux battery as it wont be monitored to 80% like the vehicle one, so when you hit the brakes and the smart alternator fires in 18volts and 150 plus amps or what ever amps the alternator is rated at the aux could already be 100% charged and cant take any more.

Its a total load of crap IMO and a waste of time, for a hybrid car or van then it would make more sense to use brakes to help restore lost charge on drive batteries but for a starter battery its completely pointless and not achieving anything over what a normal alternator would.

Quite possible but somehow my car (which I had to get coded for the towbar to work!!!) can now run fridge and top up the caravan battery with the gadgety gizzmo box that’s in the caravan.

It does though have a few charging identity crisis and had a meltdown when I disconnected the battery when I fitted the towbar and informed me I had to drive for 30 minutes then another day it had a handbrake malfunction because I jumped in, started it up, handbrake off and moved it out of the way. Apparently that was a voltage issue aswell as I moved off too quick after starting it! Oh, and I had an ESP fault one day that again could be related to battery voltage!!! Oh, and to top it off the garage doing the MOT had to change the brake pads for me as it’s got the electric handbrake and needs the VCDS to wind the calioers back and calibrate them!!

 

[ACEngineering]

Ace, always respected your advice, but is this serious?
I am old school, trained that braking is a no go unless in emergency, drive to the conditions , blah blah blah.
I have very rarely needed to need new brake shoes thanks to this.
However our Mini continually needs topping up with a charger as the low battery light always seem to come on.
I have already changed one battery and it has only done 12,000 miles.
Is this really because it is not charging properly?

Yes serious google it, every system is slightly different but the basics are the same, that's why a lot of stuff now has AGM batteries etc
I cant see how never having the battery fully charged and often forcing way more than the normal 14.4volts in for short bursts with silly high amps for a 12volt battery can be good for long term battery life IMO

I speced the optional higher capacity battery with my new van, but there was also 3 optional extra higher output alternators, think the highest was 220amps!?? at the time i thought nah i only need it to charge the battery not weld with 4mm rods