CBE PC100

[mikefitz]

Re the 23 volts reading.

Due to the very high Input resistance of the meter, connecting to a terminal with no circuit connected to it will give an unreliable reading. There will be stray coupling from adjacent circuits to give a false reading. On mains hookup or with the engine running the DS unit makes internal connection to this point thus providing a correct reading.

All this indicates to a open circuit between the engine battery and the DS, this could be along the cable run, at the battery terminal or the inline fuse.

I am surprised to see no RCD in the mains protection unit. All CBE systems sold in the UK have a RCD fitted as required by the regulations.

 

Mike

[Alanb]

Derek Uzzell - 2021-04-25 8:58 AM

 

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(Regarding there being no RCD, evidently this ‘omission’ is (or was) commonplace with German-built motorhomes. It was highlighted in this 2009 forum discussion.)

 

https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/arto-rcd-device/17911/

 

When some 30 years ago, I arranged the purchase of my first MH, a French built Pilote, it was described as having an RCD fitted. When I took delivery it was obviously not so equipped, and the 2 pole MCB was replaced with an RCBO.

 

Alan

[Alanb]

Brian Kirby - 2021-04-25 9:12 AM

 

I'd never understood the bridge functionality for AES fridges, but just assumed that if Knaus supplied the van with the bridge present, it would be for good reason. Can't rely on anything, can you? 8-)

 

The bridge for AES fridges connected via a CBE DSxxx unit, is a shorting link which removes the CBE internal fridge relay contacts from the fridge current circuit. This should marginally improve fridge performance on 12V.

 

An AES fridge has its own D+ / simulated D+ connection, and independently switches to 12V operation when appropriate. A 3 way fridge may be manually selected to use the 12V input only, but the supply is only made available with the bridge removed, via the CBE fridge relay, when the engine is running.

 

Alan

[Brian Kirby]

Alanb - 2021-04-25 12:44 PM

Brian Kirby - 2021-04-25 9:12 AM

I'd never understood the bridge functionality for AES fridges, but just assumed that if Knaus supplied the van with the bridge present, it would be for good reason. Can't rely on anything, can you? 8-)

The bridge for AES fridges connected via a CBE DSxxx unit, is a shorting link which removes the CBE internal fridge relay contacts from the fridge current circuit. This should marginally improve fridge performance on 12V.

An AES fridge has its own D+ / simulated D+ connection, and independently switches to 12V operation when appropriate. A 3 way fridge may be manually selected to use the 12V input only, but the supply is only made available with the bridge removed, via the CBE fridge relay, when the engine is running. Alan

Thank you Alan. I'm intrigued by Keith's idea as well, especially as the voltage variation is at B2. I don't think the OP has ever said whether he is using a chassis earth or the B2- post when testing. Just wondering. :-)

[jimbo07g41]

Hi thank you for the reply. Once the engine is running or the van s on hook up the high 23/24v reading disappears. 14v at the starter battery with the engine running and yes this is under the drivers seat (see pic). There is trips but no rcd. The Frost button is described as a fridge isolation button in the La Strada manual and is only used to switch on the ignition when using fridge on gas.

[jimbo07g41]

Interesting reading the replies about the possible ground issues with control panel and distribution unit. I have no idea where that grounds to? somewhere on the bodywork?

 

I also had an issue with a car where the diodes where knackered on the alternator and it would flatten the battery when not running.

[Alanb]

As I stated in a previous post, the earth / chassis / ground connection for the hab electrics completes the charging circuit for the hab battery from the alternator, plus fridge 12V power, and D+ / simulated D+.

 

I would start by looking for a cable running from your CBE B2 -ve terminal to the starter battery negative. As you do not have a solar panel installed, there may only be three cables at this terminal, the others being the connections to the charger -ve, and the hab battery -ve.

 

Alan

 

 

[Derek Uzzell]

jimbo07g41 - 2021-04-25 4:48 PM

 

..The Frost button is described as a fridge isolation button in the La Strada manual and is only used to switch on the ignition when using fridge on gas.

That’s interesting and quite possibly unique to La Strada.

 

Hopefully whatever is causing the faults you’ve enquired about does not involve the PC-100/DS-300 units, as (to the best of my knowledge) no commercial repair services for these equipments are available and obtaining exact like-for-like replacements from La Strada or CBE may problematical given the age of your Trento.

[jimbo07g41]

So I have put everything back and it all appears to be working.

 

I have attached a picture of the control panel to help any La Starda owners that come this way.

[Robinhood]

Derek Uzzell - 2021-04-26 9:54 AM

 

Hopefully whatever is causing the faults you’ve enquired about does not involve the PC-100/DS-300 units, as (to the best of my knowledge) no commercial repair services for these equipments are available .........

I think Apuljack Engineering would have a go....

[Derek Uzzell]

Thanks for that suggestion.

 

I see that the Apuljack Engineering website’s Product and Repair List includes CBE equipment.

 

http://www.apuljackengineering.co.uk/product_repair.html

 

A generic UK-specification DS-300 Distribution Box currently costs under £90, but that would probably be unsuitable if the original DS-300 is bespoke as I assume the La Strada Trento's is - and similarly for the PC-100 contol panel. That’s when repair may prove the better option.

 

 

[jimbo07g41]

So quick update.

 

All the CBE equipment was tested by the earlier mentioned electrical engineers and found to be working correctly. So the issue is in the wires!

 

There was a remote relay in place behind the stereo that controlled the connection to the leisure battery and starter battery. This was so you could use the stereo on site and not flatten the starter battery if not on hook up. The numpty who refitted my stereo just wired direct to the leisure battery and removed the relay. So I believe the starter battery was disconnected from the CBE circuit.

 

I believe the relay interlocked the starter battery and leisure battery once the engine was running or on hook up.

 

I just need to come up with a solution to put this all back in place.

[Alanb]

Hi Jimbo,

 

I am unable to understand the exact function of the relay from your description.

 

With the same aim of not draining the starter battery, I transferred both radio supplies to the habitation battery, but added a relay close to the radio to maintain ignition control of the radio. The relay that I used was a changeover micro relay, and with the ignition off, the radio can be switched from a separate switch in the habitation area.

 

For habitation battery charging you previously posted photos of you CBE DS300 show that it has an integral split charge relay. (Approx 1" black cube with a green dot.)

 

In the CBE system the split charge relay is operated via a simulated D+ signal. This signal is derived in the DS300 by monitoring an IGN + input. The split charge and fridge relays are operated when IGN + input exceeds approximately 13.2V (alternator charging). Provided that you have the appropriate connections to the DS300, B1, B2, and IGN +, and there is a connection between both battery -ves, perhaps via chassis, then all should function.

 

To improve charging rates you could use an external split charge relay, operated from the simulated D+ output of the DS300, which can be taken from a 0.25" blade connector at the RHS of the DS300 pcb. I do not think that behind the radio would be a sensible location for such a relay.

 

Alan

 

In view of the currents involved, I would recommend a minimum cable csa of 10 sq mm.

 

Alan

[jimbo07g41]

Alanb - 2022-01-19 9:41 PM

 

Hi Jimbo,

 

I am unable to understand the exact function of the relay from your description.

 

With the same aim of not draining the starter battery, I transferred both radio supplies to the habitation battery, but added a relay close to the radio to maintain ignition control of the radio. The relay that I used was a changeover micro relay, and with the ignition off, the radio can be switched from a separate switch in the habitation area.

 

For habitation battery charging you previously posted photos of you CBE DS300 show that it has an integral split charge relay. (Approx 1" black cube with a green dot.)

 

In the CBE system the split charge relay is operated via a simulated D+ signal. This signal is derived in the DS300 by monitoring an IGN + input. The split charge and fridge relays are operated when IGN + input exceeds approximately 13.2V (alternator charging). Provided that you have the appropriate connections to the DS300, B1, B2, and IGN +, and there is a connection between both battery -ves, perhaps via chassis, then all should function.

 

To improve charging rates you could use an external split charge relay, operated from the simulated D+ output of the DS300, which can be taken from a 0.25" blade connector at the RHS of the DS300 pcb. I do not think that behind the radio would be a sensible location for such a relay.

 

Alan

 

In view of the currents involved, I would recommend a minimum cable csa of 10 sq mm.

 

Alan

 

Thank you for the reply Alan, This is spot on and there was also a manual switch in the glovebox. There was a small remote that also operated the relay. I think all this did was select whether the stereo was running off the starter or leisure. I think the wiring from the starter to the CBE distribution unit was also disturbed. It might be easier and safer to come up with another solution.

 

 

There is a fused thick red cable that comes from an engine fuse box. I think I need to start dismantling and following some of the wires.