Leisure battery discharging whilst driving!

[robdav]

Hi

 

We've been up in Scotland, currently on Skye and our leisure batteries are currently discharging whilst driving.:-S As soon as I turn the engine off the battery starts getting charge from the solar panel.

 

I have a Nasa Marine battery monitor so I know pretty much exactly what's going in and out.

 

Has anyone any ideas why there would be more power draw on the battery with the engine running than not? I suspect a cable must have come lose (nothing easily visible) because some of the pot holes we've been over have been vicious.

 

Thanks

 

Rob

[Keithl]

Rob,

 

It will most likely be down to how the fridge is wired, assuming of course you are running the fridge on 12 V whilst driving.

 

A good installation will have the leisure battery wired directly from the starter battery with a 'Split charge relay'. and the fridge also wired directly from the starter battery with its own separate relay (and fuses obviously).

 

A 'bad' installation will have the leisure battery wired from the starter battery as above BUT then the fridge will be wired from the LEISURE battery through a separate relay. So if you starter to leisure battery link fails, when your engine is running the fridge will be running solely off the leisure battery with no charge going back into it.

 

Result, a flat leisure battery.

 

Start troubleshooting by checking the split charge relay and fuse which will likely be near the starter battery. If you have a Fiat Ducato the relay/fuse is likely to be under a plastic cover centrally below the windscreen when you open the bonnet.

 

Keith.

[robdav]

Thanks Keith

 

I should've mentioned, we always run the fridge on gas when on the move (except at the petrol station) to maximise battery charge.

 

They were charging fine until halfway through this trip.

[Keithl]

Rob,

 

Do you have a multimeter or test light? If not you really need one! (Even a cheap job for less than a tenner will do).

 

Have you located the split charge relay and fuse near the starter battery?

 

Lets start from there.

 

Keith.

[bounty hunter]

Symptons on my Carthago were 12.7v when engine running and 13.1v when engine switched off.

Culprit was relay at rear of fridge. Hope this helps.

 

John

[robdav]

Keithl - 2019-03-29 3:39 PM

 

Rob,

 

Do you have a multimeter or test light? If not you really need one! (Even a cheap job for less than a tenner will do).

 

Have you located the split charge relay and fuse near the starter battery?

 

Lets start from there.

 

Keith.

 

Hi Keith

 

Been driving all morning, now on a site but it's pouring!

 

I do have a clamp style voltmeter which can also measure DC current.

 

I know where the leisure battery is because I replaced the factory one with two new ones. The starter battery, I was told by the dealer was under the passenger seat but It isn't, according to the manual it is in front of the pedals but because it's a 2018 Fiat Ducato right hand drive I'm guessing that might mean it's on the passenger side. Certainly no easy way to see it or see the split charge relay.

 

My first question is why should the battery be discharging when driving? When stopped it shows as charging because of the solar panel. If I remove the solar charge controller fuse there is zero in, zero out, as expected.

 

Second question is if I can find the split charge relay when it's stopped raining and assuming it's still light, what do I need to test.

 

Don't really expect this for a van less than 12 months old.

 

Many thanks

 

Rob

 

 

 

 

[pottypam]

What type of fridge do you have? Is it an AES?

 

We had a similar problem a few years ago. Not sure if it was happening whilst actually driving as the battery monitor wasn’t visible from the front seats but on a couple of occasions when we had stopped but the engine was still running, I noticed a large draw on the leisure battery. It was so large that we thought it could only be the fridge.

 

Our dealer had no idea what could be causing it neither could a fridge engineer who happened to be at the dealers at the time. After asking lots of experts (including on here), we were eventually put in contact with a director of Adria in Slovenia, who told us to check the fuse box and if there was a fuse in the place marked ‘fridge’, to remove it. Removed the fuse and problem solved.

 

We had had the van for some time before this happened with no problem. The van had been serviced shortly before. Pretty sure somebody saw there was no fuse and put one in!

[spirou]

The question here is what turns on when the engine is running that consumes more than the panel produces? Any idea how much current is going out? Since you're running the fridge on gas it must be something else.

[robdav]

The fridge is a Dometic three way fridge with no AES but always runs on gas unless on EHU.

 

Everything else is switched off when driving so nothing could be charging from USB or 12v sockets.

 

I may have never actually checked the battery monitor whilst driving until today (when my wife was driving) as I'd noticed the batteries were way down after 3 days off EHU and with v little sun for the solar but at least 5 hours of driving in the 3 days.

 

Will check the fridge fuse suggestion.

 

Any more ideas please?

[pottypam]

robdav - 2019-03-29 10:46 PM

 

The fridge is a Dometic three way fridge with no AES but always runs on gas unless on EHU.

 

Everything else is switched off when driving so nothing could be charging from USB or 12v sockets.

 

I may have never actually checked the battery monitor whilst driving until today (when my wife was driving) as I'd noticed the batteries were way down after 3 days off EHU and with v little sun for the solar but at least 5 hours of driving in the 3 days.

 

Will check the fridge fuse suggestion.

 

Any more ideas please?

 

I wouldn’t remove the fuse (if there is one) as the solution we were given was specifically for an AES fridge/freezer

[Keithl]

robdav - 2019-03-29 5:08 PM

 

Second question is if I can find the split charge relay when it's stopped raining and assuming it's still light, what do I need to test.

 

Don't really expect this for a van less than 12 months old.

 

Many thanks

 

Rob

 

Rob,

 

It sounds as though you may be at the end of 'simple' testing as you don't even know where the split charge relay, etc. are located so seen as your MH is under 12 months old may I suggest you return to your dealer, or another dealer for your make, and ask them to investigate.

 

Keith.

[robdav]

Hi Keith

 

I will go into the dealer when we return from Scotland but in the mean time it's going to make life difficult to keep the batteries toped up unless the sun continues to shine! I would also like to learn and understand this tuff.

 

I have found the D+ Relay, is that what I'm looking for?

 

Thanks again

 

Rob

[Derek Uzzell]

Evidently Rob’s motorhome is a 2018 Fiat Ducato-based Pilote “Van” (I don’t think he has ever identified the exact ”Van” model) and, as it (apparently) has a CBE CB510 battery-charger (I’m surprised it’s not a CB516) then it’s reasonable to assume that the functionality of a ’split-charge relay’ will be provided by a coupler/separator on the PCB of a CBE “DS” distribution board. Where the DS ‘box’ might be will depend on Pilote’s whim (under a cab seat?) but it won’t be where the starter-battery is housed (in a lidded compartment in the left footwell of the cab) as there won’t be room for it there.

 

Rob has altered his motorhome’s original specification

 

https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Leisure-battery-charging-simultaneous-solar-and-EHU-damage-/51180/

 

but whether this is relevant to the problem mentioned here is anybody’s guess...

 

Obviously the Pilote’s leisure batteries should not be discharging when the vehicle is being driven, and the vehicle’s alternator ought to be able to cope with the demand of an AES fridge operating on 12V.

 

When a leisure-vehicle is being driven a 3-way fridge is designed to operate from a 12V supply not from gas. I can appreciate that running a 3-way fridge from gas while en route might maximise the charge produced by the motorhome’s alternator and, although I think the practice may not be illegal in the UK, it’s definitely forbidden in France as the safety-related implications are so obvious. If a motorhome’s electrical system is unable to cope with the 12V demand of a 3-way fridge while the vehicle is travelling, it’s the system’s inability to do this that should be addressed, not choosing to run the fridge on gas.

[Keithl]

robdav - 2019-03-30 9:04 AM

 

Hi Keith

 

I will go into the dealer when we return from Scotland but in the mean time it's going to make life difficult to keep the batteries toped up unless the sun continues to shine! I would also like to learn and understand this tuff.

 

I have found the D+ Relay, is that what I'm looking for?

 

Thanks again

 

Rob

 

Does the relay 'click' when the engine is started?

 

And if not can you measure voltages on the terminals.

 

PS A photo would help confirm you have the right part.

 

PPS And Rob's fridge is NOT AES.

 

Keith.

[robdav]

Hi Derek

 

It's a Pilote panel van conversion V600G from last year but there is very little about them on the Internet.

 

It does have a CB-516 battery charger (not CB-510) located next to the DS-300 distribution box located under the rear fixed transverse bed. There are also some other fuses and relays as per the attached photo (with English translations).

 

Thanks

 

Rob

 

[robdav]

Keithl - 2019-03-30 9:20 AM

 

robdav - 2019-03-30 9:04 AM

 

Hi Keith

 

I will go into the dealer when we return from Scotland but in the mean time it's going to make life difficult to keep the batteries toped up unless the sun continues to shine! I would also like to learn and understand this tuff.

 

I have found the D+ Relay, is that what I'm looking for?

 

Thanks again

 

Rob

 

Does the relay 'click' when the engine is started?

 

And if not can you measure voltages on the terminals.

 

PS A photo would help confirm you have the right part.

 

PPS And Rob's fridge is NOT AES.

 

Keith.

 

Hi Keith

 

I will have to move some stuff about to get into the cupboard and will check the click on start and try and take a photo later.

 

As you say fridge is definitely not AES.

 

Thanks

 

Rob

[Alanb]

I do not wish to distract or detract from the course of investigation suggested by Keith, and I endorse Derek's remarks about operating the fridge on gas, while travelling.

 

That being said may I make some observations based on the information supplied, and that publically available regarding the CBE DS300 unit.

 

1.There are photos on the internet showing DS300 boards with and without integral split charge relays. (The split charge relay can be identified as a black coloured 25mm cube.)

 

2. As a separate D+ relay is mentioned, it may be that in this Pilote installation this external relay is the split charge relay.

 

3. If it were not for the fact that Robdav states that he does not operate the fridge on 12V, I would have suggested that a faulty D+ fuse/connection or starter battery (B1) connection, would cause the fridge to drain the habitation battery (B2), as is happening. (In CBE installations the fridge relay is integral with the DS300, and is connected on the B2 side of the split charge relay.)

 

4. Spirou posed the question as to what is taking current while driving, as it does not seem to be the fridge. Given that F5, in Robdav's photo is labelled "Cab radio", is the radio a possible culprit? (The presence of the fuse suggests that the radio supply is taken from the habitation battery.) Is the radio used while driving? I do not expect the radio to draw anything like the current taken by the 12V element of the fridge, but what else is there?

 

5. Following from the above, may I suggest a failure somewhere in the split charge connections. This includes the connection to B1 +ve, the 50A fuse F2, the connections to, and the split charge relay. The negative connection between B1 -ve and B2 -ve, is also an essential part of the charging circuit for B2.

 

6. If the DS300 board lacks the integral, black 25mm cube shaped split charge relay tne it is possible

that the D+ relay is the split charge relay, but if it looks like the drawing shown in the picture, it seems to have too many connectors. It may be difficult to hear the relay "click" when the engine is started. An alternative check for operation may be to hold a finger on the relay case while the engine is started by partner.

 

7. The standard CBE system does not use a normal D+ signal from the alternator, instead an ignition switched supply is monitored internally, and operates the split charge relay when the voltage reaches charging level. This simulated D+ is made available to operate other relays external to the DS300. In contrast, I understand that on modern vehicles, a special ecu derived D+ signal may be made available for convertors use.

 

Finally I find myself bemused by the term "foot walk relay" shown in Robdav's photograph. I can only assume that it means electric step relay. Any other translations?

 

Alan

 

 

 

[weldted]

Just a thought? Why not if you can pull the fuse for the fridge, just in case there is a short as the discharge only happens when driving. Possibly check what happens if the ign is on without the engine running so there is no output from the D+ terminal. Although the I have a different van when my fridge is on 12 volt when driving it really effects the charging to the leisure batteries hence why I run mine from an inverter that is connected to the engine battery. I have a 150 amp alternator and the Thetford fridge requires around 17 amps at 12 volt well within the alternators capacity plus 300 watts of solar but even in bright sunlight it still knocks the charge to the leisure batteries down. Has done from new.

[BruceM]

Alanb - 2019-03-31 2:21 PM

 

 

Finally I find myself bemused by the term "foot walk relay" shown in Robdav's photograph. I can only assume that it means electric step relay. Any other translations?

 

 

Yes, a 'marche' is a step and in context (but not this one) may also be translated as 'walk', so it relates to the (electric) foot step relay.

[Derek Uzzell]

The photo Rob provided carries the description “RL = Relais Marche Pied” - hence the “foot walk relay” translation. As you rightly say, the reference is to a relay for an electric entrance-step.

 

(Years ago I contacted Pilote for some technical advice and they sent me a hardcopy of their English-language motorhome owner handbook. I emailed back thanking them, unwisely adding that, although the manual was a creditable effort for a French person with an English dictionary, it could be much improved and I’d be happy to proof-read the next version to remove the linquistic oddities. What a mistake, as a year later they posted another hardcopy manual to me (quite unlike the earlier one and in French not English) and asked if I would translate it. This was not at all what I had anticipated doing as I was unfamiliar with Pilote motorhomes generally and with much of the equipment they used. And, of course, the damn thing was in paper not softcopy. I think it took me a fortnight of concentrated effort to transform the French manual into an English equivalent that could be emailed back to Pilote. Taught me a valuable lesson about volunteering...)

[robdav]

Alanb - 2019-03-31 2:21 PM

 

I do not wish to distract or detract from the course of investigation suggested by Keith, and I endorse Derek's remarks about operating the fridge on gas, while travelling.

 

That being said may I make some observations based on the information supplied, and that publically available regarding the CBE DS300 unit.

 

1.There are photos on the internet showing DS300 boards with and without integral split charge relays. (The split charge relay can be identified as a black coloured 25mm cube.)

 

2. As a separate D+ relay is mentioned, it may be that in this Pilote installation this external relay is the split charge relay.

 

3. If it were not for the fact that Robdav states that he does not operate the fridge on 12V, I would have suggested that a faulty D+ fuse/connection or starter battery (B1) connection, would cause the fridge to drain the habitation battery (B2), as is happening. (In CBE installations the fridge relay is integral with the DS300, and is connected on the B2 side of the split charge relay.)

 

4. Spirou posed the question as to what is taking current while driving, as it does not seem to be the fridge. Given that F5, in Robdav's photo is labelled "Cab radio", is the radio a possible culprit? (The presence of the fuse suggests that the radio supply is taken from the habitation battery.) Is the radio used while driving? I do not expect the radio to draw anything like the current taken by the 12V element of the fridge, but what else is there?

 

5. Following from the above, may I suggest a failure somewhere in the split charge connections. This includes the connection to B1 +ve, the 50A fuse F2, the connections to, and the split charge relay. The negative connection between B1 -ve and B2 -ve, is also an essential part of the charging circuit for B2.

 

6. If the DS300 board lacks the integral, black 25mm cube shaped split charge relay tne it is possible

that the D+ relay is the split charge relay, but if it looks like the drawing shown in the picture, it seems to have too many connectors. It may be difficult to hear the relay "click" when the engine is started. An alternative check for operation may be to hold a finger on the relay case while the engine is started by partner.

 

7. The standard CBE system does not use a normal D+ signal from the alternator, instead an ignition switched supply is monitored internally, and operates the split charge relay when the voltage reaches charging level. This simulated D+ is made available to operate other relays external to the DS300. In contrast, I understand that on modern vehicles, a special ecu derived D+ signal may be made available for convertors use.

 

Finally I find myself bemused by the term "foot walk relay" shown in Robdav's photograph. I can only assume that it means electric step relay. Any other translations?

 

Alan

 

 

 

Thanks for this Alan. I'm still on the move in Scotland.

 

There is an audible click if I stick my head in the cupboard and get the wife to start the engine. However, it appears there are two clicks on switching the ignition on and one when switching it off. I need to get the bed up so I can access the cupboard properly.to diagnose further.

 

With the engine on, there is a constant drain of about 0.4-0.5 Amps with the radio on this increases to 1.5 Amps. I suspect the 0.4-0.5 Amps is the radio as well because it has a reversing camera fitted on the Pioneer unit which I suspect needs power to detect when engaging reverse gear. There is literally nothing else it can be as nothing is switched on and the 12v control panel is completely off.

 

Thanks again

 

Rob

 

 

 

 

[Keithl]

Rob,

 

It is not the discharge you need to be chasing but the fact the battery is not being charged when the engine is running.

 

Suggest you start troubleshooting the split charge system starting wherever it is tapped into the Fiat electrics.

 

Keith.

[Will86]

I see the solar panel as the problem. Take a drive with it completely disconnected.

[Alanb]

Rob,

 

I fully agree with Keith, so may I suggest a simple start, which is not weather dependent.

 

A CBE DS300 is usually installed in conjunction with a control/display head PCxxx. As well as tank content display, and control switches these units can also show battery voltages. (N.B. These indicated readings can be adjusted, so may not be accurate.)

 

1. Check and note both starter and habitation battery voltages with engine stopped.

 

2. Start engine. The display should indicate that the batteries are coupled. Repeat the voltage checks. I would expect these to be close to each other. (The CBE system does not monitor the voltage at the batteries, but only at the DS300 board. You will effectively be checking either side of the split charge relay.)

 

3. If the expected result of nearly identical battery voltage readings is not achieved in 2. above, it may be because your D+ relay is a split charge relay, external to the DS300. At this stage it would be helpful to confirm if this is the case. AFTER REMOVING ANY RINGS OR METAL WRIST WATCH, carefully remove the cover from the DS300. ( 2 off Phillips? cross head screws.)

For reference I am assuming that it is mounted traditionally, with the fuses at the top. At the bottom RHS there will be two or three M6 brass electrical terminal studs. With tthree studs I would ecpect the split charge relay (25mm cube) to be immediately above the RH two studs. It may have a green circular spot on it. With only two studs (-ve & B2+ve) I would expect the relay not to be fitted. A third possibility is for the relay to be fitted but not used. In this case I would not ecpect to see any connection to the RHS B1+ve stud.

Before carefully replacing the cover, examine the connections at the M6 studs for any signs of looseness. DO NOT USE A METAL TOOL HERE WITHOUT FIRST REMOVING 50A FUSES F1 & F2.

 

4. If the "D+" relay is the split charge relay it would be a logical progression to locate starter battery, and repeat test 2. above but measuring at both starter and habitation battery terminals using you meter.

 

5. With access to the starter battery look for any obvious added cables a nd check that any located are not loose.

 

6. If no obvious extra cables at the starter battery, I have read that Fiat may provide a converters connection facility. Memory suggests near the RHS B pillar. Check for any loose connectors in this area.

 

I do not think that I can assist further without further information. You may find it encouraging to note that one contributor with similar problems to yourself, eventually found a badly soldered CBE relay assembly in the connection to the starter battery,

 

Alan

 

 

[robdav]

Alanb - 2019-04-01 3:38 PM

 

Rob,

 

I fully agree with Keith, so may I suggest a simple start, which is not weather dependent.

 

A CBE DS300 is usually installed in conjunction with a control/display head PCxxx. As well as tank content display, and control switches these units can also show battery voltages. (N.B. These indicated readings can be adjusted, so may not be accurate.)

 

1. Check and note both starter and habitation battery voltages with engine stopped.

 

2. Start engine. The display should indicate that the batteries are coupled. Repeat the voltage checks. I would expect these to be close to each other. (The CBE system does not monitor the voltage at the batteries, but only at the DS300 board. You will effectively be checking either side of the split charge relay.)

 

3. If the expected result of nearly identical battery voltage readings is not achieved in 2. above, it may be because your D+ relay is a split charge relay, external to the DS300. At this stage it would be helpful to confirm if this is the case. AFTER REMOVING ANY RINGS OR METAL WRIST WATCH, carefully remove the cover from the DS300. ( 2 off Phillips? cross head screws.)

For reference I am assuming that it is mounted traditionally, with the fuses at the top. At the bottom RHS there will be two or three M6 brass electrical terminal studs. With tthree studs I would ecpect the split charge relay (25mm cube) to be immediately above the RH two studs. It may have a green circular spot on it. With only two studs (-ve & B2+ve) I would expect the relay not to be fitted. A third possibility is for the relay to be fitted but not used. In this case I would not ecpect to see any connection to the RHS B1+ve stud.

Before carefully replacing the cover, examine the connections at the M6 studs for any signs of looseness. DO NOT USE A METAL TOOL HERE WITHOUT FIRST REMOVING 50A FUSES F1 & F2.

 

4. If the "D+" relay is the split charge relay it would be a logical progression to locate starter battery, and repeat test 2. above but measuring at both starter and habitation battery terminals using you meter.

 

5. With access to the starter battery look for any obvious added cables a nd check that any located are not loose.

 

6. If no obvious extra cables at the starter battery, I have read that Fiat may provide a converters connection facility. Memory suggests near the RHS B pillar. Check for any loose connectors in this area.

 

I do not think that I can assist further without further information. You may find it encouraging to note that one contributor with similar problems to yourself, eventually found a badly soldered CBE relay assembly in the connection to the starter battery,

 

Alan

 

 

Hi Alan

 

I removed the cover of the DS300 somewhat awkwardly in such a tight space and the split charge relay appears to be on-board the DS300 as you expected. The RL2 doesn't appear to have substantial enough sized wires to be the split charge relay.

 

I removed fuses F1 & F2 and checked the tightness of the M6 studs and the GND was definitely lose. I tightened it as much as was sensible rather hoping that might have been the problem but upon starting the engine the battery meter was still showing discharge.

 

I have tried to attach three photos but may need a separate posts to get the three files attached. I fear maybe there is nothing more we can do on the road?

 

Thanks again

 

Rob