Quick update from the OP. 2022 Fiat Ducato. Had a Lithium battery plus Victron B to B fitted a few months back and have never had a problem with the stop start working, before or since Lithium/B to B fitting. The strange reading I get is that on a long drive the battery voltage (cab) can drop to as low as 12.1v according to the Phantom alarm which monitors and logs battery condition over a running 30 day period. It then recovers up to normal levels and the Victron battery master maintains it at 12.9v in storage. Even with fluctuating voltage reading the stop start has always worked and the van has never even felt like it will not start so not really sure what the voltage read out is telling me other than maybe the alternator cuts out for long periods whilst driving and clicks back in at quite low voltage.
Smart alternator, 3 way fridge and 8 hour drive
- Thread starter Dolmen
- Start date
You need to re code the battery management module, known as shunt, some pl, will unplug that (on some cars works), to make the alternator run all the time. Trouble is ecu will see that’s not feeding data and throws a fault code.
I'm sorry I do not know I had it fitted, however, I was told that an isolation relay had to be fitted to prevent the stop start over riding the b to b, believe the installation was along these lines, cannot say exactly, however, I can say is I have been around Aberdeenshire and Brittany and it all works well in practice.
The smart alternator doesn't actually cut out. If the alternator voltage is 14.4V and the battery would be say 12.5V at resting voltage, then the alternator will push charge into the starter battery. It will also power any other devices at 14.4V. Just like a standard alternator does.
When the electronics works out the the starter battery has had enough charge, it drops the voltage to about 12.5V. That voltage is not enough to push charge into a battery with a resting voltage of 12.5V, so the battery charging stops.
However it is still generating power at 12.5V, so any other device will work normally, at 12.5V. The vehicle lights, fan, wipers etc will all work fine at 12.5V. So will the fridge 12V heater element. And if you connect a B2B, it will take that 12.5V power and boost it up to 14.5V or whatever the leisure battery needs to fully charge it.
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Last edited:
- Aug 9, 2020
- 564
- 968
- Funster No
- 74,151
- MH
- Wildax
- Exp
- ~20 years
I get the same. The first time I saw the cab battery has dropped to 12.1v I was quite concerned, but it seems to be normal.
My best guess is that the 12.1v is the battery under load (B2B drawing power for leisure battery and fridge), and that when the load stops the battery voltage will recover to 12.5-ish, which is where the van likes to keep it.
That describes exactly what is happening to my vehicle, and like yours, it just works. Thanks for the reply always good to know your not alone.
People say the fridge runs from the alternator when the engine is running but I'm pretty sure on mine it runs from the leisure battery which is being charged from the alternator. The D+ signal wire at the fridge pcb just tells it to run on the high current 12v supply which comes from the 20 amp supply from the Nordelectrica charging unit.
I don't have a smart alternator but I assume if you do you will have a b2b charger so if the leisure battery drops the alternator will kick in to keep it charged. Is my thinking correct?
I don't have a smart alternator but I assume if you do you will have a b2b charger so if the leisure battery drops the alternator will kick in to keep it charged. Is my thinking correct?
- Aug 9, 2020
- 564
- 968
- Funster No
- 74,151
- MH
- Wildax
- Exp
- ~20 years
Mine definitely works that way. I have a 30Amp B2B. The fridge and Leisure battery are both connected to the output from the B2B.
The fridge draws about 17 Amps, and the remainder is available for the leisure battery.
We had this problem on a long drive through France in a fairly new Iveco based MH. Stopped for fuel after a long stretch on the motorway using the cruise control a lot and the engine would not start as the starter battery was flat. Luckily we had a generator with us so we were able to charge the battery. The problem persisted for the rest of our journey. When we got I home I did some research on smart alternators and found out that the dealer can override the software using a laptop and configure it to operate without the smart function. A visit to our local Iveco dealer, who was aware of the problem, and a few minutes later the problem was solved. That was three years ago and it has never reoccurred. Apparently long periods of constant revs, such as the conditions we were using and the alternator is designed to come off load to aid fuel consumption, which is great in a car but in a MH with so much power usage in the background it gradually drains the battery.
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Hi, would it be possible to change the smart alternator for a "normal" one?
- May 19, 2023
- 103
- 94
- Funster No
- 96,073
- MH
- Adria V65SL Abarth
I do think these companies who build these vans must not use them and stay in hotels as we need to be able to replenish the battery when it’s been used dc-dc and decent solar and in the modern World please start fitting an eco flow or similar so we can have electric for a small kettle or hob
Just leave it on gas, like many do. It uses hardly any. You can stop anywhere for a cuppa or lunch etc and use the cooker/hob etc. It does not switch to 12v automatically when you start, unless you switch it to 12v. Mine is a brand new fridge/freezer. You do need to switch off gas, if on the train or ferry. My Gaslow system has automatic shut-off in case of a collision.
I agree. After our problems (listed above #40) we always travel with the gas on.
If you stop for fuel you need to switch off the fridge of it's set to gas manually. Preferably before you get to near the pumps. If set to 'auto' this happens automatically.
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I've just done a 1000 km in a few days with the fridge manually set to 12v, I presumed that would keep the leisure battery charged. The van alarm suddenly set itself off apparently because the lb was flat, on the final days travel. It's a 2020 Elddis, so am assuming it has a smart alternator. I don't like the idea of running the fridge on gas while driving. I will be returning to the UK in a day or two, and will not have time to change the set up. I am amazed that that even happened but reading this thread has worried me about the return journey as all campsites are closed now, I'll be on Aires with n po leccy. Is there anything I can do to stop it happening again other than running the fridge on gas?
- Aug 9, 2020
- 564
- 968
- Funster No
- 74,151
- MH
- Wildax
- Exp
- ~20 years
You could freeze some ice blocks when you have the fridge on, then transfer them to the fridge [turning the fridge off] to keep it cool when driving?
Ps the solar panel is working ok and it's very sunny.
Thanks for that suggestion, I was thinking more of a possible change to the alternator setting. Also I have a gel lb which I gather needs a higher charge rate.
The Coops
LIFE MEMBER
When we had a Hobby van we had a problem with the fridge whilst touring Germany, It necessitated a trip to a German Hobby dealership to try and fix the problem, his answer was * Why do you not run the fridge on gas all the time? Only the English switch it off! It has a cut off valve fitted if there is a crash* ( It was a 12v/240v electrical problem) Seems its the norm in Germany.
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Yes I do intend to do that, in spite of my qualms.
All sounds fascinating to me but fortunately I don't have a smart alternator, or lithium or B2B (as far as I know for the latter). Still, you never know so maybe this article is helpful for those of you that are concerned about such things - https://www.12voltplanet.co.uk/auxiliary-battery-charging-in-vehicles-with-smart-alternators.html
Not a solution to your problem, but lots of aires have electricity points. Camping Car Parks aires for example, there are hundreds in France. It's only 6A, but that will run the fridge and top up your battery overnight. And on the app you can see if there is space available.
PeterCarole29
LIFE MEMBER
Hi Raul can you say which is the correct negative connection and why just like to confirm if I have done mine correctly
Trouble is I can't find any on my route. I've been looking at them already on the app. I've been on a couple, but most others I've driven past. Especially when they're new they look more like prison encampments!
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Hi Peter, negative should be connected of the chassis, not battery post. If you take it of the battery post you bypass the shunt. All systems with smart alternator, the battery negative has a shunt, and from there to the chassis.
So any connection of the chassis, the shunt will see a draw and tell the alternator to charge. If it’s of battery post, it’s before the shunt, and it won’t see a draw.
Hope this explains.
PeterCarole29
LIFE MEMBER
Much to my disappointment we pulled into a site as my wife wanted to swim we’re eating to much and no excercise
6amps is the electric supply so I have tested in practice what will work on ehu
Tower air fryer
Kettle
Inverter charger at 50amps I think
All only one at a time
I was pleased knowing what worked in practice
thanks mine is working so I suspect it’s correct but will check cheers
Is it a Victron Multiplus inverter/charger? If so what model is it? You can do much better with a 6A hookup if you have one of those.
PeterCarole29
LIFE MEMBER
It’s a sterling power inverter charger did think about the victron but at the time had been spending a lot on the build and the sterling was on offer
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