Carthago vehicle battery charging issue

[eddie]

OK, So before you do anything else, get the battery tested

 

[Pausim]

The CBE unit used in the Carthagos provides a maximum of 2A to the engine battery and gives priority to the leisure battery. My engine battery always sits at a much lower voltage than the leisure battery, one or two green blobs compared to the leisure with all the green blobs lit. However it never seems to drop out of the green altogether.

Another factor may be the smart alternator system which I think you will have on a brand new motorhome. I read on another Fun thread that in some systems the engine battery voltage is allowed to drop so that energy recovery can be used when engine braking is occurring. May well be worth asking the Fiat Professional about this.

 

[andy63]

It does look likely that the problem may be the charger.

I'm not sure that's so..your hab batteries are been charged when on hook up and charger is on.. that been so then if the engine battery if not been charged the fault could lie in the electronic circuit that sees to the engine battery receiving its maintenance charge.. that is part of the ds300 type cbe unit..the part with the 12v distribution fuses..
I would want to establish if the charging voltage is been delivered by using a meter to check the voltages.. the hab battery will have to be well charged before it happens so give it time
I have a similar cbe system but mine uses two relays which which contain the main 50 amp fuses for the hab and start battery..they also have a smaller 5a fuse in the relay housing box and the one in the start battery housing is the one that I thought might have gone..I believe it is on the circuit that the start batter receives the charge on from the cbe board..
Ill post a photo in a min or two of my relay housings..on mine they sit just behind the drivers seat but I have seen them located by the cbe board..
Andy

 

[andy63]

The picture of my relay housings..the two grey boxes..one is connected to start battery the other the hab batteries
Your cbe system may not use them.. if it doesn't then I'm not sure if there is a fuse on the start battery charging circuit..

 

[Minxy]

The CBE unit used in the Carthagos provides a maximum of 2A to the engine battery and gives priority to the leisure battery. My engine battery always sits at a much lower voltage than the leisure battery, one or two green blobs compared to the leisure with all the green blobs lit. However it never seems to drop out of the green altogether.

Another factor may be the smart alternator system which I think you will have on a brand new motorhome. I read on another Fun thread that in some systems the engine battery voltage is allowed to drop so that energy recovery can be used when engine braking is occurring. May well be worth asking the Fiat Professional about this.

That's interesting, our cab battery is often one blob down compared the hab ones which are usually 100% and we have 2 x 100w solar panels, hubby mentions it occasionally but so far it's never lost more than one blob, however as we have EHU at home we can just plug it in as/when necessary. Our batteries never ever get as low as the OPs though so once the battery is swapped out it will be interesting to hear what the difference is.

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[Paul Frost]

I've now tested all the fuses in the attached photo and all are OK.
Going for a drive this afternoon to see if the alternator gets the vehicle battery voltage up.

 

[Wagoneer]

Another factor may be the smart alternator system which I think you will have on a brand new motorhome. I read on another Fun thread that in some systems the engine battery voltage is allowed to drop so that energy recovery can be used when engine braking is occurring. May well be worth asking the Fiat Professional about this.

The Schault Booster WA121525 shown in post #29 obviously acts as a DC-DC (Battery to Battery charger) to overcome the limitations of the Euro 6 smart alternator. This should keep the hab batteries nicely topped-up whilst driving. However, the in/out cabling to the 25 amp Booster do not appear particular thick, possibly 10mm sq, but probably adequate.

It's debatable whether this Booster also helps the starter battery to receive a supplementary charge. I guess it depends on how the Booster is wired into the system.

 

[Pausim]

Paul Frost I think your dealer may be right and the system is ok. My 2019 Carthago does not have the Schaudt WA121525 Booster and this has probably been added because the vehicle has a smart alternator. The Booster looks after the leisure battery and the Fiat ECU looks after the engine battery, at different voltages. It keeps the 2 systems separate. On the control panel you should expect the engine battery to have fewer green blobs than the leisure battery. I would only start to worry if the engine battery falls to no green blobs.

autorouter put me right about smart alternators and battery voltages on this thread. https://www.motorhomefun.co.uk/forum/threads/b2b-preference.212700/page-2#post-3702056
at #59. I was wrongly thinking the engine battery should be charged to a higher voltage. I suggest caution before you change anything.

 

[Paul Frost]

Paul Frost I think your dealer may be right and the system is ok. My 2019 Carthago does not have the Schaudt WA121525 Booster and this has probably been added because the vehicle has a smart alternator. The Booster looks after the leisure battery and the Fiat ECU looks after the engine battery, at different voltages. It keeps the 2 systems separate. On the control panel you should expect the engine battery to have fewer green blobs than the leisure battery. I would only start to worry if the engine battery falls to no green blobs.

autorouter put me right about smart alternators and battery voltages on this thread. https://www.motorhomefun.co.uk/forum/threads/b2b-preference.212700/page-2#post-3702056
at #59. I was wrongly thinking the engine battery should be charged to a higher voltage. I suggest caution before you change anything.

The link about the battery only being charged to about 80% is interesting. It sort of explains why it has stayed at 12.2v. It also explains why the battery might show 12.6 - 12.8v after being driven for a while and then drops to 12.2 within a few hours. But I have had a few occasions where it has gone down to 12.0v whilst it was plugged into electric.

I'm also puzzled by this stuff about "regenerative braking" and the need for the battery to be kept low so there is room for this excess charging. Before smart alternators, what happened when the battery was fully charged whilst driving along but you kept driving past that point, the battery didn't get cooked, so I'm guessing there was some sort of regulator that interrupted the flow of power once it was fully charged.
I can understand where regenerative braking is useful in electric cars, where the battery drain might be more than the alternator can keep up with. But in non-electric vehicles why would you need or want it? The risk of battery damage due to low voltage would seem to make it crazy to deliberatly keep it only just above the danger level. Park your car up for a few weeks whilst on holiday (with the alarm/tracker on) and come home to a dead battery.

 

[Pausim]

I'm also puzzled by this stuff about "regenerative braking" and the need for the battery to be kept low so there is room for this excess charging.

There is a lot of new stuff to understand and I am no expert. The vehicle manufacturers seem to have got away with creative interpretation of the emission rules until now but the new tests are forcing them to use AdBlue and smart alternators. I think the regenerative bit is to do with how much power is wasted by an alternator, so they leave it idle adding very little load when the engine is working hard. However as soon as the ECU senses braking the alternator is worked hard, which adds to the engine braking and uses some of the energy that would otherwise be wasted in the brakes to charge the battery.

As for your mains charging I would unplug the mains and remove the lid from the DS300. This should expose 3 large terminals B1(engine battery) B2 (leisure battery) and negative. Take the B1 to negative voltage reading and then the B2 to negative. Plug the mains back in and take the B1 and B2 voltages again. If they have both gone up I would say your system is working but don’t expect a big voltage increase at B1.

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[Paul Frost]

I went for a drive and the vehicle battery is now at 12.75v.

I've checked the voltage at the DS300 unit and B2 went up from 13.46v to 14.37v. B1 was 12.75 for both. I'm guessing that as B1 was already way above the 12.2v it's not getting any charge at the moment. I'll check them again tomorrow.

This thread has been really useful in understanding what's going on and why.

 

[cmcardle75]

I went for a drive and the vehicle battery is now at 12.75v.

I've checked the voltage at the DS300 unit and B2 went up from 13.46v to 14.37v. B1 was 12.75 for both. I'm guessing that as B1 was already way above the 12.2v it's not getting any charge at the moment. I'll check them again tomorrow.

This thread has been really useful in understanding what's going on and why.

Yes, your smart alternator seems to be charging the engine battery. But no evidence at all that mains charges it. Your hab battery charging seems OK.

 

[Paul Frost]

Apologies for going dark on this, but have been doing more tests.
The Fiat dealer tested the vehicle battery and says it is good. They say that whilst it may have a smart alternator it doesn't use regenerative braking. They are not aware of anything about the battery only being charged up to 12.2v as referenced in the linked thread.

Since then I have been monitoring the battery more closely.
I recently left the vehicle for 12 days without being plugged in, and the voltage gradually dropped from 12.9 to 12.2v.

Yesterday afternoon (Mon 2nd) I tested both batteries before going for a 50 minute drive. The leisure battery was 12.17v and the vehicle 12.27v. Afterwards the leisure was still 12.17v and the vehicle up to 12.70v.
Which confirms my thought that the leisure battery isn't being charged whilst driving. I also found that the fridge was not working on battery whilst driving, I get a warning light/noise. This has been a problem before.

At 8pm I plugged in the electric so I could run the heater overnight. At 8:17pm the vehicle was down to 11.61v and the leisure up to 13.57v. At 10:32 the vehicle was at 11:28v and leisure at 14.28v. So I unplugged from electric.

At 9:40 this morning (Tue 3rd) the vehicle was 11.02v and the leisure 13.46v. The vehicle will not now turn over the starter motor.
All these voltage readings are using a multimeter on the terminals of the DS300 as advised in a previous post.

Early in the ongoing electrical problems was that the fridge didn't work on battery when driving and the electric step warning sound didn't work if left out. The motorhome dealer traced it to a 3am fuse that had blown and was part of the circuit to to detect if the ignition was on. With the fuse replaced it worked fine for our drive home from the dealer. But when home and plugged in to electric the warning buzzer sounded when the step was out. I replaced the fuse 3 times and it keeps blowing. So we can't use the step when plugged in.

On our last trip away the toilet flush pump just started working whilst we were watching TV. The only way to stop it was to turn off the water pump power switch. That is still happening.

The vehicle is booked into the dealer for 10th November but I'm not sure if that will happen due to the latest Covid lockdowns.

After all my troubleshooting I think that the problem may be connected with the Schaudt WA121525 booster. As I understand, this should improve the charging of the vehicle battery whilst driving and is fitted to compensate for the use of smart alternators. But it looks to me like it is not charging the leisure battery whist driving and then when plugged into electric it drains the vehicle battery.
In the short term I wonder if I can/should just disconnect the booster (but not sure how)?

 

[eddie]

Have you had a proper test carried out on the engine battery? IE removed, fully charged, left overnight and then tested?

Irrespective of the charging regime which sounds all wrong anyway, 12.2 down to 11.0 Volts overnight suggests a problem

 

[andy63]

Your start battery is charging when driving g but your leisure isn't.. do you know if your
WA121525 requires an engine run signal to activate it..
I suspect it does..your problems def seem to stem from a issue with that simulated engine e run signal..the fuse you say keeps blowing..
There may well be a problem on the distribution board causing that to happen..you say the pump started running for no apparent reason.. the relay fir the pump is part of the cbe board..
To me it seems to be pointing to an issue there..
On hook up again you are not getting a maintenance charge to the start battery..that is another function of the electronics on the cbe board that don't appear to be working..
Andy..

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[Pausim]

Unfortunately I can not suggest anything useful, my Carthago does not have the new smart alternator and WA121525 arrangement. I hope you get the problem sorted quickly.

I think the term regenerative braking is sometimes used to mean different things. A smart alternator should work harder when slowing down than when the engine is under load. I guess it makes sense to keep some battery capacity so that the otherwise wasted energy can be used. I found this explanation helpful https://www.redarc.com.au/alternator-vs-fixed-alternator

 

[Paul Frost]

Irrespective of the charging regime which sounds all wrong anyway, 12.2 down to 11.0 Volts overnight suggests a problem

It went from 12.7 to 11.6v within 18 mins of being plugged in, then down to 11.28v 2 hours later.
They didn't remove the battery to test it but attached a diagnostic device, which he said tested more than just the voltage. But the major problem seems to be related to when it's plugged in.

I suspect it does..your problems def seem to stem from a issue with that simulated engine e run signal..the fuse you say keeps blowing..
There may well be a problem on the distribution board causing that to happen..you say the pump started running for no apparent reason.. the relay fir the pump is part of the cbe board..
To me it seems to be pointing to an issue there..
Andy..

When you say the distribution board I assume you mean this, the DS300?

I did look at this for a fuse that I could pull to isolate the toilet flush pump, so that we could still have running water. But couldn't find anything.
But do you think a fault with the DS300 also drain the vehicle battery when plugged in?

 

[Lenny HB]

It went from 12.7 to 11.6v within 18 mins of being plugged in, then down to 11.28v 2 hours later.

That sounds like a fault on the CBE charger and it is putting a load on the battery.

 

[andy63]

When you say the distribution board I assume you mean this, the DS300?

Yes..

But do you think a fault with the DS300 also drain the vehicle battery when plugged in?

Its possible..but I couldn't explain how im afraid.. stuck relays etc..
You have a 3 amp fuse that keeps blowing..that fuse is responsible for the simulated engine run signal ..
If thats not present the leisure battery won't charge..thats why I asked you if the battery to battery charger you have fitted requires an engine run signal to work..I think that will be the case..
When on hook up your vehicle battery won't charge..it should..your mains charger has a sense wire that activates relays on the cbe board to achieve that..its not happening..again I think a problem with the board..


When you say toilet flush pump..
On mine there is only one pump..thats the fresh water pump.. there is a solenoid operated valve on the toilet..when that opens the pump will run just like opening a tap.. so it could be its the toilet solenoid that is getting a feed and operating..the pump doing exactly what it should

Andy

 

[Robert Clark]

It went from 12.7 to 11.6v within 18 mins of being plugged in, then down to 11.28v 2 hours later.
They didn't remove the battery to test it but attached a diagnostic device, which he said tested more than just the voltage. But the major problem seems to be related to when it's plugged in.


When you say the distribution board I assume you mean this, the DS300?
View attachment 438130
I did look at this for a fuse that I could pull to isolate the toilet flush pump, so that we could still have running water. But couldn't find anything.
But do you think a fault with the DS300 also drain the vehicle battery when plugged in?

I reckon you have the same fault that we had on our Carthago
Fridge not working on 12v and leisure battery not charging whilst driving

It was the 50a fuse on the engine battery which feeds to the split charge relay.
Looked ok at first glances, but when removed and replaced was found to be faulty

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[eddie]

It went from 12.7 to 11.6v within 18 mins of being plugged in, then down to 11.28v 2 hours later.
They didn't remove the battery to test it but attached a diagnostic device, which he said tested more than just the voltage. But the major problem seems to be related to when it's plugged in.

So what was his diagnosis?

You can only test a charged battery

My £800 Battery Test Computer to me that! ;-)

Did I ever mention that 44 years ago my first job was actually making batteries and filling them with acid in the Newton Abbot branch of The Longlife Tyre and Battery Company.

You can only test a charged battery

My £800 Battery Test Computer to me that! but I knew that as my manager Peter Arscott told me 44 years ago!

 

[andy63]

I reckon you have the same fault that we had on our Carthago
Fridge not working on 12v and leisure battery not charging whilst driving

It was the 50a fuse on the engine battery which feeds to the split charge relay.
Looked ok at first glances, but when removed and replaced was found to be faulty

It could be ..but if he can read both battery voltages at the cbe board that would indicate that the start battery is still connected to the board..if the main fuse was gone surley that wouldn't be possible..
He also has a battery to battery installed that should be charging the leisure battery regardless ..well certainly if its connected directly to the batteries like the Stirling one..
And then there is still the issue of no charge to the start battery when on mains..
And to my mind the one I keep coming back to...that 3amp fuse on the simulated run signal that keeps blowing..
Andy

 

[Pausim]

Just a thought but from the pictures I notice there is no negative connection to the WA121525 on the leisure battery side. You might think that the negative connection on the engine battery side would serve both but that is not always the case, there could be separation within the unit. The Schaudt instruction manual for the booster shows both negatives connected.

https://www.ampanet.com/$WS/sta1/websale8_shop-sta1/benutzer/navigation/grafiken/Download/900001_Instruction_manual_Booster_WA_121525_EN.pdf

I have a Victron Orion unit which I use for occasional engine battery charging from the leisure battery, when using my Efoy. Although it is a different unit there are similarities. When I first installed it I made the mistake of thinking that connecting only one negative would be sufficient, after all they have a common grounding to the chassis. Wrong it did not work with only one side connected. Eventually I deduced that there must be some internal separation of circuits that meant they both needed connections. I connected the second negative to the same negative grounding as the first and immediately everything worked properly.

I think it would be well worth trying an extra negative connection.

 

[Paul Frost]

I reckon you have the same fault that we had on our Carthago
Fridge not working on 12v and leisure battery not charging whilst driving

It was the 50a fuse on the engine battery which feeds to the split charge relay.
Looked ok at first glances, but when removed and replaced was found to be faulty

I checked the fuse with a multimeter and it's OK.

So what was his diagnosis?

You can only test a charged battery

My £800 Battery Test Computer to me that! ;-)

Did I ever mention that 44 years ago my first job was actually making batteries and filling them with acid in the Newton Abbot branch of The Longlife Tyre and Battery Company.

You can only test a charged battery

My £800 Battery Test Computer to me that! but I knew that as my manager Peter Arscott told me 44 years ago!

When the Fiat dealer tested the battery it was probably fully charged as it was after a 50 min drive to the garage.

My local garage has lent me a <Broken link removed>. Looking at the instructions I need to set what type of battery, I'm guessing it will be Absorbed Glass Mat/Gel and not Calcium (it's a 2020 model and should have stop/start)?

 

[Paul Frost]

Thinking back to my tests I forgot to mention that I had run the leisure battery down a bit prior to going for the drive, it was only 12.17v. I'm now wondering if that's why the vehicle battery went down so quick when I connected to electric. Did it draw power from the vehicle battery to get the leisure one up quicker? In the past, the drop in vehicle battery voltage has been less severe when connected, it's taken hours rather than minutes. But normally the leisure battery wouldn't have been so low when I connected to electric.

Given that there is definitely some sort of problem with the charging of both batteries and causing the 3amp simulated run signal fuse blowing, is the fault more likely to be in the:
a) PC180 control panel
b) CB516 Switching battery charger
c) DS300 distribution box
d) Schaudt WA121525 booster
e) somewhere in the wiring
I'm wondering if swapping out one of the above may be a quick fix and if so where to start?

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[Pausim]

I continue to think the missing second negative connection to the WA121525 may be the problem, see #53 above. As I found out when wiring a similar device it can be a mistake to assume that the two negative connections are common within the device. I can even see that failure to ground the second circuit might cause problems with the D+.

 

[Lenny HB]

I continue to think the missing second negative connection to the WA121525 may be the problem, see #53 above. As I found out when wiring a similar device it can be a mistake to assume that the two negative connections are common within the device. I can even see that failure to ground the second circuit might cause problems with the D+.

But that is only for charging the hab batteries from the alternator and that's working.
The fault is when on EHU, hab batteries charge but starter battery discharges.

 

[Paul Frost]

I continue to think the missing second negative connection to the WA121525 may be the problem, see #53 above. As I found out when wiring a similar device it can be a mistake to assume that the two negative connections are common within the device. I can even see that failure to ground the second circuit might cause problems with the D+.

It seems hard to believe that a company the size of Carthago would have got this wrong, and wouldn't it mean that all owners would be having the same problem?

 

[eddie]

Isn't Hymer doing a recall to sort out regen charging issues?

 

[Pausim]

But that is only for charging the hab batteries from the alternator and that's working.
The fault is when on EHU, hab batteries charge but starter battery discharges.

I was thinking that with one of the circuits being incomplete perhaps one of the internal relays was not opening or shutting as it should which was compromising the engine battery circuit and possibly the D+ too. If the D+ was turning live when it should not it might also account for the fuse blowing. The unit has 3 negative connections, 2 on the Ausgang side and 1 on the Eingang side. This suggests to me that it allows for 1 negative grounding on the paired 2 on the Ausgang side, with a short loop across the divide to the single one on the Eingang side.

I am no electronics expert but why provide 3 negative connections instead of 1 if the second circuit didn’t need one. At present neither of the right hand pair appears to be in use.

It seems hard to believe that a company the size of Carthago would have got this wrong, and wouldn't it mean that all owners would be having the same problem?

I agree but mistakes can happen. This could have been an isolated mistake by someone who was new to the device. Carthago are new to the complications of smart alternators because until recently Fiat turned the smart alternators off at the request of constructors. It made charging leisure batteries more complicated.

I am not saying this is necessarily the cause of your problems but as it is not wired to the Schaudt manual it seems worth checking it out before you start swapping out expensive items. My apologies if I am wrong and leading you on a wild goose chase.

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