# Flat Battery



## Caldyman (Jan 11, 2009)

Hi
I have a Fiat Ducatto 2001 2.8 JTD(Hobby 750 FMSE Motorhome).
Sinc the first cold spell some weeks ago , the Cab Battery was flat ,and i called out the AA , they got the van started and secured a loose Earth connection in the engine compartment. 
The Cab Battery then went flat again , called the AA out again , they jump started me again , they recommended that i replace the battery.
Since then i have replaced the battery with a New one , this keeps going flat after about a week of none use.
I have had an auto electrician fit a switch next to the battery so its cuts off any connection to the internal Leisure batteries , as he said that they were draining the Cab Battery.
Went to the Van this morning after a week of none use , and the Battery is flat as a pancake , down to 9.50 Volts.
Sometimes when starting the van , it blows a 30 amp fuse which is located under the drivers seat and connected to the Leisure battery , when this blows ,  the electrics to the inside of the motorhome go off.
Has anybody out there got any ideas what the problem could be , or who i could go to to get this problem sorted , as i dont seem to be getting anywhere , as i am back to squre one after paying out for a new battery and an auto Electrician.
Any help would be most appreciated.

Thanks

John


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## lenny (Jan 11, 2009)

Hiya Candyman, I would first of all suspect a faulty split charger, maybe you could disconnect this for a while to see if it makes any difference.


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## Tony Lee (Jan 11, 2009)

You haven't said whether the leisure battery was also flat when the engine battery was flat. The fact that it used to (presume it doesn't now that the extra isolating switch has been added) blow the leisure battery fuse indicates that the relay controlling the auto chharge from the alternator is closed all the time, so that much of the starting current was coming from the leisure battery. If the auto electrician has fitted the isolator in the correct place - and it is a full current isolator, then that shouldn't be happening now either.

You need to find out what sort of phantom/parasitic loads there are and where they are. If there are no undue loads, thedn having the leisure and engine batteries hooked together by a fault still shouldn't result in flat batteries - otherwise you would always have one or the other go flat whenever the rig sat for a week.

You can only find out what is causing the flat batteries by installing a ammeter in series with the battery - 10 amp should be enough - and then pulling fuses until the current drops to zero. A simple job for anyone with a little knowledge, but potentially dangerous (to equipment rather than life or limb) if you haven't a clue.

You probably have two faults - a faulty connection relay, and some sort of excessive load on either the leisure or engine battery. Don't forget that it needn't be a big current. 1 amp will kill a  fully-charged 100Ah battery in 4 days. Far less if you have been relying on the alternator to charge the batteries because you will be lucky to get 80% charge let alone 100%.

[If it is any consolation, I have a Hobby 650 and the auto connect and antenna retract are not working because the signal from the ignition switch is not getting to the electrical management system. Middle of Morocco is not the place to pull everything apart but one day I will check out where the open circuit is. In the meantime, my inverter isolator has been pressed into service as a manual battery interconnect. Will do for now as long as I don't forget to isolate if we are camping without hookup for several days.


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## Caldyman (Jan 11, 2009)

Hi Tony / Lenny
Thanks for the Advice ,i will pass this on to the Auto electrician , as he should know what to do , as i would't have a clue.

Tony
Only the Cab Battery was Flat , when i renewed the fuse on the Leisure battery the internal electrics came into life.

Lenny
Any idea where the split charger would be located , and how could this be isolated.

Thanks again

John


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## Geoff.W (Jan 11, 2009)

From the information given I think it would be a base vehicle problem not a habitation one. 

A quite regular problem that only shows on vehicles that are stood, is a faulty diode in the alternator letting a small back current flow (discharge). The alternator can work fine when charging, and if the vehicle is used daily the problem is never noticed.


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## lenny (Jan 11, 2009)

Lenny
Any idea where the split charger would be located , and how could this be isolated.

Thanks again

John[/QUOTE]

Hi John, I dont know much about modern vans but I will assume your split charging relay is under the same seat,close to the suspect fuse. In my older vans it is easily recognisable cos of the fact It,s red in colour.

PS My 30 amp fuse has blown 3 times over the last 12 months or so but I dont have the problem of a flat engine battery apart from the weekend when I forgot to flick the switch on the zig unit to caravan and drained the engine battery whilst camping on 12 volts.

PPS  Sorry for calling you Candyman in my previous post


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## sozucantparkere (Jan 13, 2009)

*switchovers/ relays*

we have just had a load of problems with our little box that switch;s our vehicle battery to our leisure battery. on the advice from a friend he thinks we should upgrade the amps we have been into halfords but they only stock one with the full set of leads that lead back to the rear of the van. all we need is the unit with more amps can you give us any advice where to get hold of one.


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## Deleted member 775 (Jan 13, 2009)

Geoff.W said:


> From the information given I think it would be a base vehicle problem not a habitation one.
> 
> A quite regular problem that only shows on vehicles that are stood, is a faulty diode in the alternator letting a small back current flow (discharge). The alternator can work fine when charging, and if the vehicle is used daily the problem is never noticed.


having only just gone through this set of posts i think geoff s idea is of some merrit . as the only prob you seem to be having is on the starter side or cab side. this time of year even if you use your car or van even for comuting you will flatten even a new battery as lights, heater rear screen (ok not on a m/home) are in use most of the time   but the amount a single start in the morning takes out of your battery can take more than your charging system can put back even on a 10 mile run with your heater and lights on


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## Deleted member 207 (Jan 13, 2009)

God I hate flat batteries, but you can isolate the suspect circuit and save yourself a few quid at the auto electricians if you dont have a multi meter.

Make sure the battery is charged up properly in the first place.
Disconnect all but one of the fuses and leave the vehicle overnight.
Replace the fuses and try and start it in the morning, or see what charge is in the battery.
If it does nt start/low volts then you've hit the suspect circuit 95% of the time.
If it starts/good volts, its onto the next fuse and another overnight wait I'm afraid.
BTW this check does not work if the problem is between the battery and fuse block - likely?

There are so many possible causes for a battery going flat on modern vehicles that its almost impossible to diagnose without being there and knowing which circuit is suspect. But the usual culprits are relays, connectors and switches on the "always live" circuits - lights, ignition/starter, interior light, others will be vehicle specific.  

Check for any recent water ingress or dampness as this can often be the area where an always live circuit will have just enough of a connection to earth to drain the battery but not blow a fuse.

You can buy a little electronic battery and alternator tester which just hooks onto your battery and then does a quick diagnostic of the battery and the altenator output - probably only a few pounds nowadays.


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## d20wns (Jan 13, 2010)

Hi John I also have a Hobby 750 with battery trouble
      I have just read about your problem with your battery going flat, i to have the same problem and have read through the replies that you have had and it seems clear as mud to me.
My battery goes flat within 1 to11/2 weeks so do my liesure batteries, the engine battery is about 3 months old (the second in 4 months) and the liesure batts are about 18 month 2 years old. I asked an auto electrition put put a cut off on the battery but said that he would fist check to seeif something was draining the battery, after having the van for a day he said that nothing was draining the battery and the battery was good. I have had battery problems since the early part of 2009 but when i did start the van for an outing the engine and the liesure would fully charge and would just about last me weekend after a 150-200 mile journy to site. Can you tell me have you been able to sort your problem out, or anyone reading this can you help
Cheers Rich


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## maingate (Jan 13, 2010)

If anybody thinks there is a fault in their split charging system, here are a couple of places that will be helpful. They show the circuits involved.

www.marcleleisure.co.uk/Sund001/SplitCharge01.htm

www.mottsorg/SPLIT%20CHARGING%SYSTEM.htm


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## rickboy (Jan 15, 2010)

sozucantparkere said:


> we have just had a load of problems with our little box that switch;s our vehicle battery to our leisure battery. on the advice from a friend he thinks we should upgrade the amps we have been into halfords but they only stock one with the full set of leads that lead back to the rear of the van. all we need is the unit with more amps can you give us any advice where to get hold of one.




Hi. Try eBay for a choice of split charge relays and battery isolators.

If you go for a battery isolator with a small by-pass fuse this will still drain your battery if their is a fault.Find the fault first then fit the isolator.(or leave the by pass off for now)

Put your multimeter between the battery earth(-) and the lead. This will shown any drain.   

Good luck    Rick                        ---------


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## rickboy (Jan 15, 2010)

*Amps*

May be teaching you to suck eggs but switch mulitmeter to Amps .

AS Geoff W said it could be one of the alternator diodes,these can be intermittent failures.

The diodes can be damaged by charging at too high a rate from a battery charger (up 3 or 4 amps is o.k. more than that you are taking a chance when connected to the alternator).I have charged at much higher rates and got away with it but it is not "best" practice.

The diode pack can get also get  burnt when asking too much of the alternator.Ask anyone who disagrees to pay for a new alternator when yours packs up!!

Rick


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## wintergreen (Jan 15, 2010)

*flat battery*

hi,just a thought on the battery prob,i have had  the same problem (though no leisure battery involved) on my range rover since christmas,r.a.c out auto sparks out no problem found.
 all this turned out to be down to next door fitting a remote weather station transmitting on the same...or close...R.F signal as the key fob to my car,the same prob can apparently be caused by cctv or mobile phone mast,
 i was told that every time the weather station remote transmitted it ..woke up.. the security system on my car causing a almost constant drain on the battery,nice neighbors,took transmitter down,prob solved.
  just grabbing straws but wont cost to check.
    cheers n good luck    john
p.s ...cough..flat battery gives you more space to pack things,same as driving with curtains open,makes van lighter and better to drive.


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## maingate (Jan 15, 2010)

Lidl are selling battery chargers for £12.99. They only charge at 3.8 amps max but are ideal to leave on for long periods as they automatically switch to maintenance mode when the battery is charged.

They also have a pulse charge capability which is supposed to bring dead batteries back. Dunno if that works though. It does 6v and 12v up to 120ah.


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## rickboy (Jan 15, 2010)

maingate said:


> Lidl are selling battery chargers for £12.99. They only charge at 3.8 amps max but are ideal to leave on for long periods as they automatically switch to maintenance mode when the battery is charged.
> 
> They also have a pulse charge capability which is supposed to bring dead batteries back. Dunno if that works though. It does 6v and 12v up to 120ah.



Good tip Maingate.

I have one called a Tronic t4x      mode 1 14.4 v    0.8a
                                                      2 14.4       3.6
                                                      3 14.7       3.6
Great little charger for the money.


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## grasscutter (Jan 15, 2010)

May not be related to your problem, but I had battery flattening out every week on my 2005 Ducato. Auto electricians traced the problem to two faults.

1 :- The radio was faulty and drawing more current than normal.

2 :- The panel of switches (on my model) below the radio, 4way flashers and fog lights etc were also found to be faulty and constantly drawing power.

Fortunately for me they sorted out my problem and now van starts even if stood for 5 weeks.

Hope you get it sorted.


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## PaulC (Jan 15, 2010)

I don't know if this is any help, but my Brother had a similar problem with his Renault Master panel vana few years ago. The battery went flat so many times when he rang the AA "Is that the Renault". After a carry on it was found that the relay for the glow plugs was faulty and they were in effect on all the time! Draining the battery dead after a few days! Hope this is some help! And he had auto electricians looking at it but when he took it to a particular garage they said "I know what that is!"
PS
When it was fixed and turned the ignition on, after a few seconds you could hear a very faint click, that was the relay switching off!


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## Kontiki (Jan 15, 2010)

I had my engine battery go flat while we were in Portugal, as the van was only 3 months old I took it to a Renault dealer who pronounced it dead & it was replaced under warranty.  After this I was constantly checking the new battery voltage to see if it was ok, but found this was also dropping down quite a bit overnight  I was getting a bit paranoid. I checked & found there was a current drain larger than it should be (I think it was about 1 amp). I eventually found the problem, when I wired the radio in I found that it wouldn't work unless you had the key turned to the accessory switch so I wired it to the live wire for the radio memory. This meant we could use the radio without the keys in, BUT it was feeding wire back down into the accessory circuit & from the power drain there was other stuff going on.  What I then was cut the power wire from the ignition switch & just use the live wire from the radio memory.  Battery now stays ok with very little parasitic battery drain.


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