General And my troubles are about to start

[Sonar]

As the title says I am about to get very confused.

I have a Fiat Ducato 15 JTD MWB 2003 with a 2286Cc diesal engine.

In fact it is known as a fiat ducato Sundance 600B motorhome.
However the motorhome part is a totally separate part it’s the fact that the Fiat part drags the motorhome part

Anyway after a very very long list of repairs ect to both parts I have now decided to change the motorhome part to lithium batteries ..

Anyway I am having a drawing made up of whet goes where and what parts are needed .
Now the problem. I was asked. Where the split charge relay was.
Me I have no idea .

So pushed along to a local garage he asked why si I made a mistake in telling him what I was about to do .
Now he won’t tell me where the split charge relay is as he said he will deal with it when he gets the work of the lithium system.

Not going to happen as I have always done as much as I can.

So I was told it was under the bonnet next to the starter batter but as there is only one there it’s not there .
Where should I be looking now.

The below image is the starter battery

 

[HughJampton]

Swift (who built the Sundance) were in the habit of putting the relays and fuses under the large black plastic cover centre rear of the engine compartment. Two bolts/screws and it lifts off.

I've only had experience of the 2.5/2.8, but I think the same cover is there on the 2.3 for that year. It's certainly where I'd first look.

 

[Sonar]

Many thanks it’s in storage at the moment I will get some photos on Tuesday
Hopefully it’s in the same place

 

[Sonar]

Swift (who built the Sundance) were in the habit of putting the relays and fuses under the large black plastic cover centre rear of the engine compartment. Two bolts/screws and it lifts off.

I've only had experience of the 2.5/2.8, but I think the same cover is there on the 2.3 for that year. It's certainly where I'd first look.

We’ll member HughJampton. Your right
Found the box you mentioned .

Attached are i
The images I was hoping for some reason one of the relays would say split charge relay .

My guess is one of the relays in the last image is the one I am looking for ..

 

[HughJampton]

This (which purports to be 2002 wiring, but is unlikely to have changed) might help. (Click to enlarge)



The two relays are fridge/step and split charge. The fuses should be obvious by reference to the above.

 

[Sonar]

It’s the same wiring diagram that. Have it was more a case of finding them to start with as there is another relay just above the fridge .
I thought that one was either step or fridge , no I have. no idea what it is. Yet

 

[HughJampton]

The only other (Swift-installed) relay I can think of is the "EMC" one, that switches most of the 12V habitation electrics off when the engine is running. It might well be mounted there (I don't think they were fitted in the engine compartment).

 

[Sonar]

The only other (Swift-installed) relay I can think of is the "EMC" one, that switches most of the 12V habitation electrics off when the engine is running. It might well be mounted there (I don't think they were fitted in the engine compartment).

Yes Thankyou that makes a lot of sense

 

[Communicator]

The relay unit in IMG 2773 is the glow plug controller. In IMG 2774, the fridge relay is the one on the left with the red/yellow wire attached. This makes the adjacent relay the split sharge relay, which will have brown/green, and brown/blue wires.attached. The blue wire is the D+ connection for operating both relays. The diagram shows the step relay coil being operated from the red/yellow fridge supply wire.

Please take care. The existing battery cables are only fused at 20A, and may not be adequate to connect to lithium batteries via a higher rated B2B. If for example a 50A B2B is used, then rewiring may be needed. Also what is the alternator rating, which is probably maximum rather than continuous value. Lithium battery charging currents do not quickly reduce, as is the case with lead acid batteries.

 

[Sonar]

The relay unit in IMG 2773 is the glow plug controller. In IMG 2774, the fridge relay is the one on the left with the red/yellow wire attached. This makes the adjacent relay the split sharge relay, which will have brown/green, and brown/blue wires.attached. The blue wire is the D+ connection for operating both relays. The diagram shows the step relay coil being operated from the red/yellow fridge supply wire.

Please take care. The existing battery cables are only fused at 20A, and may not be adequate to connect to lithium batteries via a higher rated B2B. If for example a 50A B2B is used, then rewiring may be needed. Also what is the alternator rating, which is probably maximum rather than continuous value. Lithium battery charging currents do not quickly reduce, as is the case with lead acid batteries.

Thankyou for a great explanation Now I know what there for . Many many thanks ..

Does that mean to avoid a lot of rewiring its best to get a 20 or 30 amp B2B instead of the. 50 amp

 

[Communicator]

Thankyou for a great explanation Now I know what there for . Many many thanks ..

Does that mean to avoid a lot of rewiring its best to get a 20 or 30 amp B2B instead of the. 50 amp

A lot depends upon what you want from a lithium battery installation, possibly reduced weight, higher useable capacity, or quicker recharging time. If the latter then thicker cables, and perhaps a larger alternator would be necessary, for best performance. The deciding factor for cable size in a 12V system is frequently voltage drop, rather than maximum current carrying capacity.
My x244 2.8jtd has a 90A alternator, and I am using a 20A B2B with lead acid batteries without problems, but I had already increased relevant cable sizes before fitting the B2B. Your alternator will probably have a similar rating to mine, and I would not be happy fitting a 50A B2B charging lithium batteries without an upgrade. Others may have different opinions. If the alternator fails, you could be stuck, unless you could run on solar power. (I have read of this being done recently, as a get home exercise.)

 

[Sonar]

Thankyou again for your valuable advice and it’s noted. Thanks again