Where does you 3 way fridge take it's power from on 12V when driving?

[VXman]

So after a lot of discussion re my melting fuse problem here - https://www.motorhomefun.co.uk/foru...engine-not-charging-leisure-batteries.290430/ I have fitted a new fuse and fuse holder (Seems to be behaving but a longer trip will be needed to check)

I did a little testing this morning and I am convinced that the fridge takes it's 12V power from the the leisure battery when the engine is running.

I am confused as I was led to believe that all motorhomes took the 12v from the starter battery/Alternator when the engine was running. My manual states there is a 20amp fridge fuse on the starter battery - which there is - but it doesn't seem to do anything. There is another 20 amps fuse (the one that melted) by the leisure and this seems to be doing the work. This fuse is not mentioned in the Burstner manual for my model.

I can see that when I turn the fridge on while the engine is running that the leisure voltage drops form 14.8 (charging voltage) to 14.3 so it clearly is drawing power from the leisure. Of course, the leisure is in turn being charged from the alternator (is that correct? or is it charged from the electroblock?) so I assume it's not a problem but it's not the way I understood it is generally done.

I have asked Burstner about this fuse but they are not willing (able?) to tell me.

BTW - it was like this from brand new - no modifications.

So, anyone know that this is the set up on theirs?

 

[Jev88]

Has anyone tinkered before just to confuse you?

Some choose to wire items like fridge and radio via leisure

 

[Lenny HB]

The normal arrangement when an Elektroblock is fitted:-

The 12v supply to the fridge is connected to a relay in the EBL which switches the supply between the Leisure battery when the engine is not running and to the Starter battery when the engine is running, relay is switched by the D + signal from the alternator.

This is from my van.

 

[Bramidan]

I thought that if your fridge is set on Auto it takes power in set steps.
EHU it takes electric. If not on EHU,thus no electric, it goes to gas.
When you start the engine ( as long as you have not set the fridge to gas manually) it takes power on the D+ feed ( I might have mis described that ) This feed is only “ maintain” and only keeps the fridge “on” it does not cool.
On that basis I thought it must be from the engine (alternator)
This is what I understood from my system (Adria) because I had a problem with fuse blowing on the 12v “maintain” circuit when I first got the motorhome.
I must point out I know very little about the actual wiring system other than what I gathered from speaking to the dealer when discussing the problem.
It might have been convincing rubbish to naive new owner!

 

[Bramidan]

Bloody hell, I just read Lenny HB’s post.
There is hope for me yet.

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[VXman]

Has anyone tinkered before just to confuse you?

Some choose to wire items like fridge and radio via leisure

No - this is how it was at new from the factory. The radio is also wired to the leisure.

 

[VXman]

The normal arrangement when an Elektroblock is fitted:-

The 12v supply to the fridge is connected to a relay in the EBL which switches the supply between the Leisure battery when the engine is not running and to the Starter battery when the engine is running, relay is switched by the D + signal from the alternator.

This is from my van.
View attachment 837591

Well, as said before mine certainly doesn't use the leisure battery when engine not running - never has. Will will auto select gas in that situation. If you try to manually select 12v it will just flash an error.

Is it possible something is not functioning properly that means it is not selecting the starter battery?? What could that be? The relay you mention?

 

[VXman]

I thought that if your fridge is set on Auto it takes power in set steps.
EHU it takes electric. If not on EHU,thus no electric, it goes to gas.
When you start the engine ( as long as you have not set the fridge to gas manually) it takes power on the D+ feed ( I might have mis described that ) This feed is only “ maintain” and only keeps the fridge “on” it does not cool.
On that basis I thought it must be from the engine (alternator)
This is what I understood from my system (Adria) because I had a problem with fuse blowing on the 12v “maintain” circuit when I first got the motorhome.
I must point out I know very little abouto the actual wiring system other than what I gathered from speaking to the dealer when discussing the problem.
It might have been convincing rubbish to naive new owner!

This is the way I thought it should work and does - except it used the leisure not the starter.

Actually our 12v is very good. It's a 205watt. Element - not much less power than the 240v which is 240watts so pretty much keeps it as cold as the other sources.

 

[Bramidan]

They actually replaced my EBL, although the dealer said it was the solar, which they had fitted!
In a previous visit they had wired the solar independently to both batteries effectively bypassing the EBL.
Anyway Solar controller replaced and the technician said they replaced the EBL simply because Adria had sent them one and Adria was convinced it was the EBL. He reckoned it was the relay “chattering”
I was also told it was much better to have the solar wired independent of the EBL because there had been ”reports of problems” plugging the solar into the EBL. I managed to keep my mouth shut because my immediate thought was “ if you knew that why did you wire it in that way?”
I’m just trying to say, in a round about fashion, that the EBL is not infallible and neither is the original wiring.

 

[VXman]

They actually replaced my EBL, although the dealer said it was the solar, which they had fitted!
In a previous visit they had wired the solar independently to both batteries effectively bypassing the EBL.
Anyway Solar controller replaced and the technician said they replaced the EBL simply because Adria had sent them one and Adria was convinced it was the EBL. He reckoned it was the relay “chattering”
I was also told it was much better to have the solar wired independent of the EBL because there had been ”reports of problems” plugging the solar into the EBL. I managed to keep my mouth shut because my immediate thought was “ if you knew that why did you wire it in that way?”
I’m just trying to say, in a round about fashion, that the EBL is not infallible and neither is the original wiring.

My solar is aftermarket. It is wired directly to the leisure batteries. It is simper that way. Yes it could go through the EBL but seems little point and routing the wiring was far easier going direct.

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[VXman]

I made some discoveries today. I found a picture of my fuse set up in a Burstner Manual online -

It appears that this fuse set up is only used when the Schaudt Charging Booster (WA 121545) is used. The 1 amp fuse I wondered about is the voltage sensor for this booster. Why a 20 amp fridge fuse is there I am still not sure as it is still not explained but I wonder it is significant having the booster?

 

[autorouter]

Maybe the power from this 20A fuse on the leisure battery is going to the EBL, Pin1 of the 5-way connector. Power to this pin normally comes from the starter battery via a 20A fuse near the starter battery. Maybe they modify this when fitting the Booster.

You could check this by looking at the voltage on Pin1 of the 5-way connector on the EBL. It should be about 12V. When you remove the 20A fuse by the leisure battery it should drop to zero.

If it doesn't, you could try removing the 20A fuse by the starter battery, which is the other possible alternative. It should then drop to zero. In most other EBLs (without the Booster) it's powered from that 20A fuse by the starter battery, as in Lenny HB's diagram.

 

[Lenny HB]

Well, as said before mine certainly doesn't use the leisure battery when engine not running - never has. Will will auto select gas in that situation. If you try to manually select 12v it will just flash an error.

That comes down to individual converters wiring, Hymer wire the fridge so it can run off the the leisure battery but not all converters do it that way.

 

[Lenny HB]

Maybe they modify this when fitting the Booster.

I heard recently that Carthago now wire the fridge to the B2B, not seen one like that myself.

 

[VXman]

Maybe the power from this 20A fuse on the leisure battery is going to the EBL, Pin1 of the 5-way connector. Power to this pin normally comes from the starter battery via a 20A fuse near the starter battery. Maybe they modify this when fitting the Booster.

You could check this by looking at the voltage on Pin1 of the 5-way connector on the EBL. It should be about 12V. When you remove the 20A fuse by the leisure battery it should drop to zero.

If it doesn't, you could try removing the 20A fuse by the starter battery, which is the other possible alternative. It should then drop to zero. In most other EBLs (without the Booster) it's powered from that 20A fuse by the starter battery, as in Lenny HB's diagram.

I will have a look later this week when I have time but i have noticed there is a red cable coming from the starter battery, through a 20 amp fuse towards (underneath) the EBL. You couldn't have 2 cables from different batteries going to the ebl could you?

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[VXman]

Maybe the power from this 20A fuse on the leisure battery is going to the EBL, Pin1 of the 5-way connector. Power to this pin normally comes from the starter battery via a 20A fuse near the starter battery. Maybe they modify this when fitting the Booster.

Hmm....could be something here. I connected my Van Bitz Battery master to the wire going to pin 1. (as suggested in other threads on fitting the battery master to a EBL119) If pin 1 is not the starter battery but the leisure could this cause a problem. Coincidentally, I didn't have these issues before I connected the Battery master.

The reason I'm wondering this is that another Burstner owner on the Burstner Facebook group had a similar problem with this fuse melting and he contacted me to say that he discovered it was due to the way his Battery master was connected up.

 

[Lenny HB]

I will have a look later this week when I have time but i have noticed there is a red cable coming from the starter battery, through a 20 amp fuse towards (underneath) the EBL. You couldn't have 2 cables from different batteries going to the ebl could you?

If the fridge is connected to the output of the B2B that would mean it's connect to the leisure battery. If this is the case as the fridge does not run on 12v when stationary there must be a relay switching it.

Also if its only a 25amp B2B, with the fridge running there won't be much left to charge the leisure battery.

 

[VXman]

If the fridge is connected to the output of the B2B that would mean it's connect to the leisure battery. If this is the case as the fridge does not run on 12v when stationary there must be a relay switching it.

Also if its only a 25amp B2B, with the fridge running there won't be much left to charge the leisure battery.

The technical detail from the 'Booster' (B2B) manual suggests its can deliver between 45 to 70 amps. When it was working properly it never had any problem keeping the Leisure batteries topped up.

 

[LithiumConvert]

I have come to the conclusion that some converters change from year to year on how they wire their motorhomes.

On my last Hymer, the fridge ran off the starter battery as shown in Lenny's diagram above.

However, with the new Hymer, there is no connection to block 1 on the EBL. The socket is empty, so the fridge certainly does not run that way.

Howver, my NDS Energy Meter shows a drain of about 15 amps on the leisure battery when the vehicle is running. I do not currently have any charging from the alternator as the B2B wiring is not yet complete and the split charge circuit (which does not go via the EBL) is disconnected.

 

[Buddy1012]

I heard recently that Carthago now wire the fridge to the B2B, not seen one like that myself.

When I swapped my Hymer over to lithium I removed the Schaudt Booster as I had replaced it with a lithium specific DC to DC and I needed the space. All this now makes sense, as on a recent trip (my fridge is manual selection as opposed to AES) I forgot to change the fridge over when I stopped driving and pulled over for the night. In the morning I noticed that the batteries were down to below 50% which surprised me as overnight use is normally negligible. I now have a bit of a dilemma, either reinstate the Schaudt Booster (Change to Lithium setting and set it on a lower charge, just to provide the fridge power ONLY when driving, or live with it as it now is and make sure I remember to take the fridge off 12v and / or take advantage of having the flexibility of using the fridge off the leisure battery on the occasions that it suits - surplus solar for example?

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[Jean-luc]

I'm over 35 years with caravans and motorhomes. The only way I've seen threeway fridges work is:
Engine running = 12v from the alternator/ engine battery
Engine not running = EHU (230v), if available or gas if 230v not available.
In pre AES times the selection is manual, with AES the priority of selection is the same.
Unless the industry has decided to change from the above convention, a different selection criteria present would seem to be down to a faulty circuit.

The exception to the above is a compressor fridge which runs off the leisure battery when the engine is not running, gas not being an option.

 

[Buddy1012]

I'm over 35 years with caravans and motorhomes. The only way I've seen threeway fridges work is:
Engine running = 12v from the alternator/ engine battery
Engine not running = EHU (230v), if available or gas if 230v not available.
In pre AES times the selection is manual, with AES the priority of selection is the same.
Unless the industry has decided to change from the above convention, a different selection criteria present would seem to be down to a faulty circuit.

The exception to the above is a compressor fridge which runs off the leisure battery when the engine is not running, gas not being an option.

Are you familiar with the Schaudt Booster and the 3 or 4 different configurations for wiring it in to an EBL system?

 

[Lenny HB]

I'm over 35 years with caravans and motorhomes. The only way I've seen threeway fridges work is:
Engine running = 12v from the alternator/ engine battery
Engine not running = EHU (230v), if available or gas if 230v not available

On our 4th van in 17 years alway been able to run the fridge from the leisure battery. Last 3 were Hymers and wired that way, current Carthago had to put a link in the distribution unit to enable it.

 

[Buddy1012]

On our 4th van in 17 years alway been able to run the fridge from the leisure battery. Last 3 were Hymers and wired that way, current Carthago had to put a link in the distribution unit to enable it.

And with a decent sized lithium battery bank along with the accurate monitoring of your consumption to keep an eye on it, it’s not really that much of an issue, just another option should you run short of LPG and no EHU available. So in my case I’m going to leave it as is and not refit the Schaudt Booster as I’m more than happy with the new set-up. Far more straightforward wiring and therefore much easier to fault find and rectify.

 

[pappajohn]

Easy, pull the fuse at the leisure battery for 24 hours.
If the fridge isnt cold it ain't powered from the leisure battery

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[AdrianChen]

On our 4th van in 17 years alway been able to run the fridge from the leisure battery. Last 3 were Hymers and wired that way, current Carthago had to put a link in the distribution unit to enable it.

Was that the FA2 FA3 spades?

I was unsure where the power for the fridge came from because the original SCR in the ds470 was closed once the engine was started and the batteries were paralleled, but presumably once the link is connected you can manually select on the fridge? So I guess the original feed is from the alternator via B1?

 

[Jean-luc]

Are you familiar with the Schaudt Booster and the 3 or 4 different configurations for wiring it in to an EBL system?

No

 

[Jean-luc]

On our 4th van in 17 years alway been able to run the fridge from the leisure battery. Last 3 were Hymers and wired that way, current Carthago had to put a link in the distribution unit to enable it.

I've that link in the distribution unit of my Rapido too. I could see myself enabling the option if I had sufficient charge from Solar to compensate for the fridge draw.
Without a compensating input the fridge would flattened the leisure battery

 

[Lenny HB]

I've that link in the distribution unit of my Rapido too. I could see myself enabling the option if I had sufficient charge from Solar to compensate for the fridge draw.
Without a compensating input the fridge would flattened the leisure battery

My plan is to switch a 12v signal via the relay in my shunt via timer to the S+ on the fridge.
By setting the shunt relay to switch on when batteries are over 90% and off at say 70%.
The timer so it only works during daylight hours with on/ff intervals of say an hour on ½ hour off, this way it shouldn't cane the batteries.

 

[LostInSpace]

The fridge in our 2022 Hymer takes its 12v power direct from the leisure battery - and is activated by the D+ signal whilst driving.

In turn, of course, the leisure battery is being charged by the Schaudt WA 121545 B2B - again D+ contolled.

Simples. That is how it came from the factory. None of the above wiring goes anywhere near the EBL.

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