Help locating split charge relay on a 99 Rimor Superbrig 728 on sprinter chassis

rustynutz

I recently noticed that the alternator in my camper isn't charging the leisure battery at all. Likewise when I choose the option to "parallel charge" the vehicle and leisure batteries on the habitation control panel, the vehicle battery isn't charging from the onboard charger. The fridge isn't working when the vehicle is running either.

I have done a bit of research and my understanding of how a typical motorhome charging system works is as follows:
The alternator should charge both the vehicle and leisure battery once the engine is running, the split charge relay controls this, and when the engine isn't running and the vehicle battery drops below a certain voltage the split charge relay separates the battery's to avoid flattening the vehicle battery. Is my understanding correct, is there another really to control the fridge?

I have checked all the fuses I can find with a multimeter so I am hoping it is just the relay stuck or faulty, problem is I can't locate it, and don't really know what it looks like if I did, can anyone shed some light on it please?

How old is the service battery?
Make model electroblok-thing?

rustynutz

The leisure battery is only a couple of months old, the control panel is Arcilicii and the charger seems to be a SME Components unit, although I cant find any information on that brand online.

Service battery holding voltage? Did you find what was draining the old one?

rustynutz

Yes, the service battery is holding voltage, it did run flat lad week, even though it was plugged into EHU but I have that traced to a poor connection which is now fixed. I'm 99% sure the previous issue I had with the leisure battery running flat was due to the fan for the heating system left on, having did that, I noticed last night that something was pulling 0.19 amps even though everything in the habitation area was turned off.

crabbypaddy

rustynutz wrote: »

The leisure battery is only a couple of months old, the control panel is Arcilicii and the charger seems to be a SME Components unit, although I cant find any information on that brand online.

What model is the arsilicii? It probably has the relay integrated.

rustynutz

Its this model http://www.arsilicii.com/public/Documents/AS00006_GB.pdf

Yurp my betting it's in the blok.

2.5w parasitic load is acceptable, could be lots of things combined.
I'd be more inclined to wire a new system than fix the old.
Bigger, better, more faster.

rustynutz

Sir Liamalot wrote: »

Yurp my betting it's in the blok.

2.5w parasitic load is acceptable, could be lots of things combined.
I'd be more inclined to wire a new system than fix the old.
Bigger, better, more faster.

Thanks for that, lots of info there, I think my system is slightly older the one in the manual you linked, while the control panel is similar (minus the 4 buttons under the screen) my charger/ecu is completely different. Mine doesn't have any Arsilicii branding on it at all, it's SME components. Plus it has only 2 plugs, total of 6 cables, plugged into it, and the 220v supply, it also has 2 fuses built in. I don't see any reference in that manual to the control unit having the split charge relay built into it, that's not to say its not there.

What is my quickest and cheapest way to get the alternator to charge the leisure battery and fridge in your opinion?

The relay is between the B1 and B2 terminals.

Quickest & Cheapest? Fix what you have.

Best: Disconnect the Engine Battery from the blok. Take a feed from the D+ line to trigger a new contactor switching a fused welding cable between the alternator & Service Battery.

I reckon its the D+ not the relay. It's common to both circuits.

rustynutz

Sir Liamalot wrote: »

I reckon its the D+ not the relay. It's common to both circuits.

What is D+ ? Sorry if the answer should be obvious, electrics wouldn't be my strong point!

crabbypaddy

rustynutz wrote: »

What is D+ ? Sorry if the answer should be obvious, electrics wouldn't be my strong point!

D+ is the bottom connection in RED you see its marked Motor D+ it should be earth with engine off and 12v-15v with engine running.

It's the feed activated by the alternator when it's generating.

It turns the battery light in the dash off. I think the D is for diode.

rustynutz

Thank you both for all the info, so as I don't see a fuse on that feed (at least not on the diagram) would I be looking for a loose or corroded connection?

rustynutz

By the way the alternator light goes out on the dash when the engine starts if that's relevant

crabbypaddy

rustynutz wrote: »

By the way the alternator light goes out on the dash when the engine starts if that's relevant

Just check the voltage on the bottom terminal as described then you'll be further along.

rustynutz

rustynutz wrote: »

By the way the alternator light goes out on the dash when the engine starts if that's relevant

Problem is downstream.

rustynutz

crabbypaddy wrote: »

Just check the voltage on the bottom terminal as described then you'll be further along.

The problem I have is, although the control panel is Arsilicii, the charger/ECU is from SME Components, a different set up from the one pictured above, it also isn't clear what each cable if for that is plugged into it, although I have determined the cables that are hardwired (looks like a previous problem with the plug connection, before I owned it) into the unit are for charging the battery.

rustynutz

Another couple of pictures of the unit, including with the cover off

crabbypaddy

Docs are here: http://www.arsilicii.com/public/Documents/AS00000_GB.pdf

As before check D+

rustynutz

crabbypaddy wrote: »

Docs are here: http://www.arsilicii.com/public/Documents/AS00000_GB.pdf

As before check D+

That is brilliant, thanks. I couldn't find any info on my unit anywhere, I was starting to think it a replacement shoehorned in to my van

The D+ is probably the thin one. That bodge is a disaster any hacker worth their salt woulda come at it from behind. There's a IC top left not mated to the heat sink, needs to have its screw tightened. QC fail right there!

crabbypaddy

Sir Liamalot wrote: »

The D+ is probably the thin one. That bodge is a disaster any hacker worth their salt woulda come at it from behind. There's a IC top left not mated to the heat sink, needs to have its screw tightened. QC fail right there!

Yeah D+ is the thin one, I think in the pic the excess sil-pad is sagging giving the impression that the transistor is loose but its worth checking.

As far as I can see its a fixed voltage 13.5v 'charger' so your batteries are never going to be charged.

rustynutz

crabbypaddy wrote: »

Yeah D+ is the thin one, I think in the pic the excess sil-pad is sagging giving the impression that the transistor is loose but its worth checking.

As far as I can see its a fixed voltage 13.5v 'charger' so your batteries are never going to be charged.

Can you explain what you mean by fixed voltage charger please? Again forgive the amatuer questions, as already said electrics aren't my strong point but I like learning how it all works, heading for france for 2 weeks next week so at least if it lets me down I'll have some idea what to check.

rustynutz

crabbypaddy wrote: »

Yeah D+ is the thin one, I think in the pic the excess sil-pad is sagging giving the impression that the transistor is loose but its worth checking.

As far as I can see its a fixed voltage 13.5v 'charger' so your batteries are never going to be charged.

Can you explain what you mean by fixed voltage charger please? Again forgive the amatuer questions, as already said electrics aren't my strong point but I like learning how it all works, heading for france for 2 weeks next week so at least if it lets me down I'll have some idea what to check.

crabbypaddy

rustynutz wrote: »

Can you explain what you mean by fixed voltage charger please? Again forgive the amatuer questions, as already said electrics aren't my strong point but I like learning how it all works, heading for france for 2 weeks next week so at least if it lets me down I'll have some idea what to check.

A good charger will have at least 3 charging stages - bulk, absorption and float and will have settings for different types of batteries and adjust the charging profile accordingly.

I might be wrong but from their data it appears to be fixed at 13.5v which is a relatively safe voltage but your 10A charger will only put out a fraction of that 10A the majority of the time, charging will be glacial. But don't be disheartened 99% of motorhome chargers are rubbish.

rustynutz

OK, makes sense, I will check the D+ circuit in the morning. In the manual for the control panel I get the impression that the manufacturer almost recommends using a separate split charge relay to separate the battery's when the engine is running, or have I read that correctly?

crabbypaddy

crabbypaddy wrote: »

But don't be disheartened 99% of motorhome chargers are rubbish.

rustynutz

Well I ended up running out of time with the trip to France looming, with other jobs on the camper taking longer than expected, I was working on it right up till the evening before we left so I didn't get a chance to check the control unit.
But it seems that the fridge is actually working when the camper is driving, off the alternator presumably. Also the alternator seems to charge the leisure battery, but only sometimes, so looks like a loose connection somewhere. I will have a better look over the next few weeks now I have some time.

Thanks for all the advise on this