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How old is my Bosch battery?


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I recently purchased my first motorhome so I am going through something of a learning curve. The motorhome is a 2007 Fleurette Migrateur with a Fiat Ducato 3.0L engine.


On my first overnight stop in France without EHU I managed to drain both the leisure battery and the starter battery so the engine would not start in the morning. I later realised that I had left the fridge on the wrong setting - running off the battery rather than gas!


I can understand why the leisure battery was flat but can anyone explain why the starter battery was also flat?


When on EHU both batteries get charged up at the same time so I appear to have a some kind of a "split charge relay" already installed. Does this have anything to do with it?


The starter battery is a Bosch S5 and I am trying to find out how old it is. On the top of the battery there are two code numbers: H3C006283 01 and below that 53603. I understand that "H3" might indicate the eighth month of 2013 - i.e. August 2013.


Can anybody tell me if this is correct or not?

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Can't help you with the battery's date code but if you ring up a specialist battery suppler (or better still go and see them if they are local) they should be able to help. The Bosch S5 is a fairly modern battery technology so it might well be as recent as 2013 but ask them. A 2007 motorhome might just still have its original starter battery but probably not.


As to discharging both batteries that is a puzzle too. Motorhomes vary in the type of 12 v controller and battery charger they use and whether they allow a 12v supply to the fidge when th engine is off (most don't but my Hymer does) but I've never heard fo a motorhome allowing a drain on both batteries together in the way you describe so that suggests a fault and the need for investigation. Some MHs don't charge the starter battery when on an EHU, others do. Some use a diode (called a split charging diode) to protect the starter battery from discharge while allowing the engine alternator to charge the leisure battery while driving. You could have suffered a failure of this diode I suppose, if you've got one.


is there a manual with your MH which tells you what you've got? Can you find out from the MH manaufacturer what you MH has? If you can provide specific information about this it will b more likely that someone will be able to help you.

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Casimir, what you describe should not have happened and, as Stuart says, indicates that a fault may exist. Most motorhome electrics are designed to ensure it cannot happen insofar as running the starter battery flat is concerned. Many also incorporate a cut-off to protect the leisure battery when the voltage falls to a pre-set level. Fleurette are regarded in France as a better quality van, and the company is now owned by Rapido who have maintained its independent appeal.


I don't know how separation of the starter battery from the fridge on 12V power is arranged by Fleurette, but there will be an alternator actuated relay, or similar, somewhere. When the alternator is producing power the relay closes to connect the fridge 12V power circuit to the starter battery, which is then being charged by the alternator. When the engine stops, the alternator stops generating, and the relay opens to isolate the fridge from the starter battery. This ensures that the fridge demand cannot drain the starter battery.


Similarly, another relay (sometimes combined with the former) also actuated by the alternator, connects the alternator output to the leisure battery. So, when the alternator is generating it is charging both batteries plus running the fridge. This relay is also designed so that the bridging of the leisure battery and the starter battery is cut when the engine is stopped, to prevent the leisure battery dragging the starter battery capacity down as you draw energy from the leisure battery.


That you flattened both by leaving the fridge on 12V suggests to me that a) the relay feeding the fridge did not isolate it when you stopped the engine and b) that the relay feeding the leisure battery also failed to isolate this, leaving the leisure battery connected to the starter battery, and c) since the simultaneous failure of two indepent relays is too great a coincidence, it is a combined relay.


It is fairly normal to feed the fridge controls, and its interior light, from the leisure battery, as these must function whether the energy source is gas, 240V, or 12V.


However, there are devices (called battery to battery chargers, or B to B chargers, or similar terms) that delibarately link both batteries to give extended capacity when parked. These should prevent the starter battery being discharged below a set level so that there is always sufficient power for starting the engine. I suppose it is possible one such may have been fitted to your van and has failed, leaving the two batteries connected. However, this would be unusual, both in the fitting of a B to B, and in its failing in that way. So, back to the top, I suspect it is just that relay that has failed.


But, as said above, not all vans are wired the same.


Final thought. If your van is a 2007, it is now about 7 years old. Motorhomes tend to stand around for long periods, and may not be kept connected to mains. On-board systems, and some additions such as alarms, place a continuous demand on the starter battery. So, over a period of weeks the starter battery can become depleted. Repeatedly allowing this to happen will shorten its life. OTOH, it is not uncommon for leisure batteries to be heavily discharged while the van is in use and, depending on the size and type of battery fitted, this can also shorten its life. The starter battery should still be good at 7 years, but will be nearing the end of its life, so any abuse will have taken its toll. Ditto the leisure battery. It is possible that your batteries died not because the fridge continued drawing 12V, but because they had remained connected when they should have separated with the engine stopped, but both together had insufficient power for your overnight stop due to their age.


It just needs testing with the engine stopped and 12V selected for the fridge (with no mains connected), whether the fridge is actually getting power, and also whether the starter battery remains connected to the leisure battery at the same time. This should be fairly straight forward to check, and any motorhome workshop should be able to do so. If you are not familiar with the electrics yourself it would be wise to leave this to the professionals. Similarly, once the relay is located, and assuming it is defective, it is a relatively cheap item and quite simple to swap. The time will go in trying to locate that relay, so some delving into the manuals for the electrical system, where it's location should be clarified, could save you some labour costs.

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Regarding the starter-battery’s age, the following advice tallies with your August 2013 assumption




However, if you want to be sure, I suggest you contact Bosch themselves




(I assume there is no date-code stamped into the top of one of the battery’s terminals?)


As has already been advised, even if a motorhome’s electrical system allows a 3-way fridge to be powered from the leisure-battery (a dangerous strategy), the vehicle’s starter-battery should not be affected.


I don’t know what electrical equipment Fleurette would have fitted in 2007, though I suspect it might be from Nordellectronica. If you can identify the make (eg. from information shown on the motorhome’s control-panel) there may be a company specialising in that equipment that can comment.


A far as I’m aware there is currently no official UK Fleurette agent, though Southdowns Motorhome Centre at Portsmouth used to handle them for a while some years back. Certainly, within the UK, Southdowns should be your best bet for technical advice.

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Thank you very much for your interest and for the useful information and suggestions. I realised that I needed to check a few things and I thought you might be interested in my progress so far.


Yesterday I turned the fridge on without EHU (or gas). At the start of the test the Nordelettronica control panel displayed 12.7v for both the starter and leisure battery. To my surprise the fridge was drawing on the starter battery and not the leisure battery. After about two hours the starter battery was down to about 12v but the leisure battery remained at 12.7v. In fairness the Dometic instructions do state that the fridge should only be used on 12v when the engine is running. However I had assumed that the system would have protected the starter battery and that the fridge would have been fed from the leisure battery only. (Yes, I know, never ever assume anything).


The Fleurette “manual” is not a proper manual and has been of little help. It is just a few A4 sheets with some information poorly translated from French. I am going to email Fleurette in France and ask if a proper manual is available. My Fleurette Migrateur van is almost identical to a Rapido 7065+ so I have searched the web for a Rapido 7065+ user manual but so far without success. This might or might not be useful.


I have managed to establish that the leisure battery (Tayna EXV110) is less than one year old. As far as the Bosch 110AH S5 starter battery is concerned it would be good to find out how old it is and as suggested I have emailed Bosch direct to enquire if the code (H3C2006283) means anything. There is no date code stamped on either terminal. It would be unreasonable to expect a reply for at least a few days at best.


There is a sturdy cable which appears to connect the starter battery with the leisure battery. At each end is an in-line fuse holder with a 50Amp fuse. I need to check this out but, is this how both batteries get charged at the same time?


Since the original flat battery problem in France back in April I have had a number of days away at various campsites but always on EHU. If not on a campsite then I have switched the fridge to run off gas. I have had no battery related problems since April but I would be quite happy to replace the starter battery even if only as a precaution.


However based on your collective thinking it seems that the most likely root cause of the problem is a relay switch and not the starter battery.


If it is a relay switch, can anybody suggest where might it be located?


Thanks again.




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Casimir - 2014-08-03 3:29 PM.................If it is a relay switch, can anybody suggest where might it be located?............

I think the most likely places are in the engine bay, possibly somewhere under the windscreen scuttle, or adjacent to, or even incorporated into, the main 12V fuseboard and/or mains charger. Unfortunately there is no standardisation among manufacturers, and various makes of charger/fusegear are used.


Your large, fused cable, if it does interconnect the habitation and starter batteries, sounds like an unwise DIY intervention, but it just might terminate onto a B2B charger unit designed to allow capacity sharing with low voltage protection for the starter battery, that you have yet to find. (I'm assuming you do not have two habitation batteries, and this cable is the link between them?)


I think the only way to be sure of the relay position will be to trace the 12V wires from the fridge back to the main fuseboard, and then see if you can work out how the feed to the appropriate fuse is controlled.


Because the usual means of switching the relay is the generator D+ terminal, which is only live when the generator is spinning, it is unlikely you can locate the relay by listening for a click when you turn on the ignition, as engine noise will probably mask the click. If the relay has failed, as seems more probable from your above description, it also seems unlikely it will generate any clicks. I think you'll just have to trace the wires. Hopefully someone will offer a better idea!

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Brian Kirby - 2014-08-03 9:18 PM


Because the usual means of switching the relay is the generator D+ terminal, which is only live when the generator is spinning, it is unlikely you can locate the relay by listening for a click when you turn on the ignition, as engine noise will probably mask the click. If the relay has failed, as seems more probable from your above description, it also seems unlikely it will generate any clicks. I think you'll just have to trace the wires. Hopefully someone will offer a better idea!



....if the control panel and electrics are provided by CBE (some Rapidos are, so it is a distinct possibility), a simulated D+ signal is often used, supplied from the distribution board, so even tracing from the alternator may not work.


The symptoms certainly could be associated with a failed fridge relay (I would be very surprised if there were no "engine running only" protection provided), so it would be sensible to eliminate this first.


The further information posted adds some additional confusion, however. if the Starter and Leisure batteries are permanently connected as described (50 amp fused connection), then surely both batteries would be depleted by the fridge, not just the vehicle battery (unless there is some other disconnection available). I'm confused by this lack of depletion, and also the overall provision of the link. (I wonder if it is a "non-blowable" variation on Clive Mott-Gotobed's bridging fuse?)


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I’m doubtful that a comparison between Rapido-branded and Fleurette-branded motorhomes will be productive in this case.


Casimir’s Fleurette has a Nordellectronica control-panel, so it’s reasonable to assume that the rest of the motorhome’s electrical equipment is also sourced from Nordellectronica. Rapido has used Schaudt and CBE ‘kit’ in their motorhomes but (I’m pretty sure) not equipment from Nordellectronica.


As Fleurette’s presence in the UK was short-lived I’m not surprised that only a minimalist English-language manual was offered. The chances are very small that there’s a better English-language manual, but the French version might be helpful.


I vaguely recall Pilote producing motorhomes that allowed the fridge to be run on 12V without the vehicle’s motor running. The consequences were predictable, with Pilote initially parrying owner’s complaints by saying that there was a warning about this in the User Manual, but later admitting that a relay had been omitted. It might be worth knowing if there’s a dedicated fridge On/Off switch on the Fleurette’s Nordellectronica control-panel.


Normal practice with Continental-built motothomes is to use a coupler/separator (a voltage-sensing relay) to parallel-connect starter and habitation batteries together when the vehicle’s alternator is charging, but there shoud be a relay somewhere to prevent either of the batteries from powering the fridge’s 12V cooling system when the vehicle’s alternator is not charging.

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My 2008 Swift has a Nordellectronica control panel. It has the option to connect the leisure and engine battery together. This setting should timeout after a period of time (can't remember how long). The time out function has never worked on my controller. I have to manually reset the controller to separate the batteries. Although it does reset to separate batteries after running the engine and then stopping the engine.

If the motorhome also has a Nordellectronica charger it is essential to make sure you have a good leisure battery.

It is a common fault for the charger to be damaged if it is trying to charge a duff battery.


These people are experts on Nordellectronic products:




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Casimir - 2014-08-03 3:29 PM


...At the start of the test the Nordelettronica control panel displayed 12.7v for both the starter and leisure battery...


Can you say, please, what (if any) identification markings there are on your Fleurette’s Nordelettronica control-panel (eg. NE 101).


This make of equipment has a reputation for being ‘cranky’, so if you can identify exactly what’s fitted to your motorhome ( a photo of the control-panel would be good) it might help.

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"Can you say, please, what (if any) identification markings there are on your Fleurette’s Nordelettronica control-panel (eg. NE 101). "



Charger NE186;

Fuses NE185-F R1

Control Panel NE144F (Pic attached)



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