EBL 119 not charging from alternator

[autorouter]

It sounds like you have a Smart Alternator but do not have a B2B.

He's getting 14.4V to the EBL, but it's not getting to the leisure battery. The D+ seems to be always zero, so the split charge relay is not switching on.

 

[Lenny HB]

He's getting 14.4V to the EBL, but it's not getting to the leisure battery. The D+ seems to be always zero, so the split charge relay is not switching on.

Read it too quick.

 

[pastrana]

It sounds like you have a Smart Alternator but do not have a B2B.

What means that? Reading the EBL 119 you can find many references about charging leisure batery:

Even if it is not possible. Should I have always 14V on D+ signal when the engine is on, no?

 

[pastrana]

Block 2 is the inputs to the EBL, from the D+, starter battery pos and neg, and leisure battery sensor wires. Getting 14.4V there doesn't mean that the fridge is working.

The output of the EBL to the fridge is on Block1. The D+ is Pin2, and the 12V output power to the fridge is either Pin 1 or Pin4, depending on which of the two fridge relays the installer decided to use.

Of course if the D+ coming in on Block2 is zero, the output on Block1 will be zero too. There should be a set of three fuses near the starter battery, with a big 50A fuse for the split charge relay, a 20A fuse for the 12V fridge element power supply, and a 2A fuse for the D+ signal. Have you found the 50A and 20A fuses?

You mean the fuses which are close to the primary battery?

There are three fuses there, 50A, 20A and 15A. All of them looks fine.

 

[pastrana]

He's getting 14.4V to the EBL, but it's not getting to the leisure battery. The D+ seems to be always zero, so the split charge relay is not switching on.

Right

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[autorouter]

There are three fuses there, 50A, 20A and 15A. All of them looks fine.

Yes, usually there is a 2A or 5A fuse in that set of fuses, for the D+. I don't know where it is if it's not there. Maybe you could trace the wire from Block 2 of the EBL. With any luck it will be a distinctive colour - often it's yellow.

To check that's the problem, you could try to power Block2 pin 3 (the D+ input) with a short link wire from Pin1 (the starter battery feed). If the leisure battery gets 14V or more with that link in place, that shows it is definitely the D+ that is the problem. Also the fridge should work too, but it may be hard to tell if it's working if it doesn't have a light showing it's on 12V power. Maybe you can hear the relays clicking when you touch the link onto the pin.

Obviously just use the link only for a few seconds, just to try it, and see if the leisure battery connects to the alternator/starter battery OK if the D+ is substituted by another 12V signal. Don't leave it in place along time, it will flatten your starter battery over a few hours if the engine isn't running so that the alternator produces charge.

 

[pastrana]

Yes, usually there is a 2A or 5A fuse in that set of fuses, for the D+. I don't know where it is if it's not there. Maybe you could trace the wire from Block 2 of the EBL. With any luck it will be a distinctive colour - often it's yellow.

To check that's the problem, you could try to power Block2 pin 3 (the D+ input) with a short link wire from Pin1 (the starter battery feed). If the leisure battery gets 14V or more with that link in place, that shows it is definitely the D+ that is the problem. Also the fridge should work too, but it may be hard to tell if it's working if it doesn't have a light showing it's on 12V power. Maybe you can hear the relays clicking when you touch the link onto the pin.

Obviously just use the link only for a few seconds, just to try it, and see if the leisure battery connects to the alternator/starter battery OK if the D+ is substituted by another 12V signal. Don't leave it in place along time, it will flatten your starter battery over a few hours if the engine isn't running so that the alternator produces charge.

Hi,

I was tracing the two D+ cables, I want to understand what is happening before linking some signal.
Block 2 Pin 3 D+ signal (purple wire), goes to a relay which is under the pilot seat, just behind the EBL.

On the other side, Block 1 Pin 2 D+ signal (purple wire) goes to a power strip.

I do not understand why there is not other cable connect it.

It could be possible that relay is the source of the problem? I do not understand which is its function.

 

[autorouter]

If you look at the relay, is there another wire connected to the same relay pin as the purple D+ wire? or is it the only wire to that relay pin? It's hard to see from that picture.

A relay is often used on the D+ wire. The D+ is a 'signal', and is quite a weak supply. If you load it too much, and try to take too much current out of it, it will have problems. But all it is is a signal that is about +12V when the engine is running, and 0V when the engine is stopped. So what is often done is to connect it to the coil of a relay, so that it can switch a relay on and off. Then you can wire some beefy wires to the power contacts of the relay, and supply it straight from a battery (through a fuse of course). Then you have a good solid signal that goes on and of when the D+ goes on and off, and you don't have to worry about loading too much.

It's quite common in motorhomes, that use the D+ to switch a lot of different devices: fridge, split charge relay, B2B, awning light, step alarm/retraction etc.

 

[pastrana_]

If you look at the relay, is there another wire connected to the same relay pin as the purple D+ wire? or is it the only wire to that relay pin? It's hard to see from that picture.

A relay is often used on the D+ wire. The D+ is a 'signal', and is quite a weak supply. If you load it too much, and try to take too much current out of it, it will have problems. But all it is is a signal that is about +12V when the engine is running, and 0V when the engine is stopped. So what is often done is to connect it to the coil of a relay, so that it can switch a relay on and off. Then you can wire some beefy wires to the power contacts of the relay, and supply it straight from a battery (through a fuse of course). Then you have a good solid signal that goes on and of when the D+ goes on and off, and you don't have to worry about loading too much.

It's quite common in motorhomes, that use the D+ to switch a lot of different devices: fridge, split charge relay, B2B, awning light, step alarm/retraction etc.

Thanks for the explanation. There was not more wire connected to that D+ cable on the relay side:

Then, If I understood it correctly, the D+ signal activate that relay, then the green and red line will be joined.
This is even more upsetting, If Block 2 Pin 3 D+ signal is an input which is also connected to this relay, how it is possible the 12v goes to the cable?

 

[ChrisL]

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[fred_jb]

There is usually a relay outside of the EBL which generates the D+ signal. The relay coil is powered by two connections from the vehicle, usually originating from under the panel at the bottom of the right hand B pillar cover, at least in a Fiat Ducato . On my van if I remember correctly there is a red wire which is live with ignition and a green wire which goes to 0V when the engine is running, so these activate the relay coil only when the engine is running.

The contacts of the relay close when the relay coil activates and this connects an incoming 12V to an outgoing connection which is what provides the 12V D+ signal, usually on purple wire going to a distribution block, from where it gets connected to the EBL and anything else that needs it, such as a B2B. In my van the 12V supply to the relay contact comes via a 2A fuse in a fuseholder stacked on top of the relay, so it is worth checking this fuse and relay to make sure the D+ signal is being generated correctly.

 

[autorouter]

Usually on a 40A power relay like this one, the thin wires go to the coil, and the thick wires go to the power contacts. However from what fred_jb says, the red and green wires could be going to the coil, and the purple and black wires could be going to the power contacts. Is it possible to check the terminal numbers? On the diagram it says the coil is 85 and 86, and the power contacts (COM and NO) are 30 and 87. You could unplug the relay from its socket and look at the numbers on the base, to see which wire goes to which terminal.

If that's true, then you need to look at where the black wire gets its power from. Note that in Germany-built motorhomes, the negative is usually brown, not black as in the UK. And black is often the positive.

 

[fred_jb]

Usually on a 40A power relay like this one, the thin wires go to the coil, and the thick wires go to the power contacts. However from what fred_jb says, the red and green wires could be going to the coil, and the purple and black wires could be going to the power contacts. Is it possible to check the terminal numbers? On the diagram it says the coil is 85 and 86, and the power contacts (COM and NO) are 30 and 87. You could unplug the relay from its socket and look at the numbers on the base, to see which wire goes to which terminal.

If that's true, then you need to look at where the black wire gets its power from. Note that in Germany-built motorhomes, the negative is usually brown, not black as in the UK. And black is often the positive.

I think on mine there was a red 12V supply wire going to the fuse, either directly from the EBL or maybe from a 12V supply on distribution bus thing, and a black wire coming back from the fuse to one of the relay 30/87 contacts. I will have another look at it tomorrow.

 

[fred_jb]

I have just checked this. The red and green wires which come in together from under the floor go to the relay coil via sections of the busbar. The relay contacts provide a 12V D+ signal.

When the relay coil is activated, one of the normally open contacts provides the D+ signal on the adjacent busbar via a purple wire . The other one connects to a 12V source which comes from a 1A fuse mounted on top of the relay. The 1A fuse is supplied from a section of the busbar which has an always on 12V supply via being wired to a 15A fuse in the starter battery compartment.

Hope that helps!

 

[pastrana_]

Hi,

First of all, thanks for the support. Now I understand much better how it works and I could find the problem. Thanks fred_jb to tell me how it is done the connection in your case.

The problem was a wiring connection too weak. The red wire that goes to the relay was not connected to the power strip, therefore, the relay was not switching and the D+ signal was off (I have doubts if it was connected since the beginning, the connection was a mess). This is the cable connected properly to the power strip:

And here where it goes to the relay:

Once I checked that every cable was properly connected to the power strip. I switched on the car, and I can see the 14.2V on leisure battery.

It was pretty hard to debug it, because I had to remove the pilot seat. I was also following the rest of wires that goes to the relay, just for a better understanding ant to write here.

The black wire comes from a 2A fuse, which is under the pilot seat in the front side, easy to access:

That's the famous 2A fuse which is connected to the D+ signal, once the relay is active (engine on).

The D+ Signal is 14v when the engine is on, and 0v when is off.

And the exact model of my van is a RoadCard 540 Fiat Ducato 2.0 multijet 115ps from 2017.

If anyone needs more pictures, just as, I have lot of them from pilot and copilot under seats.

Thanks again for the support!

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