Well that was embarrassing ... (1 Viewer)

Bart

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So after 2 weeks away in our 1st trip out in our new Motorhome "Wendy" it all went great ...yes Untill it came to getting of the ferry at home in Ireland.
Went to start the Mh after the 2 hrs crossing and ... .......
...........
.........
Yip cab battery flat as a pancake...so they had to get their jump start chargers out to get us going ..
Through out our 15000 mile journey we hardly would of used the cab battery much . And before the ferry we had driven 2 hrs to get to cairnryan.
OK so I left the side lights on on the Mh for the 2 hrs crossing . Along with the radio on mute . And the fridge on battery ( but doesn't the latter use the hab batteries ) ?
The hab batteries are fine they are 3 x new 130 ah batteries charged by a sterling b2b charger .. 120 ah and that worked great for us ..2 weeks and not hooked up once .. atm I have far to much hab battery power as they hardly dropped at all in voltage.. but I need that xtra for when I install an inverter.
ANYWAY back to the dead cab battery .. at home now once I stopped the Mh and went to the hab control panel ..after a few mins it said 9.9v
Could the side lights being on for 2 hrs along with the radio muted and fridge if applicable drain my cab battery to that level ?
Now I'm home and it's on the ehu using the mh charger to charge the battery
PS not once during our holiday did I switch the charger at the control panel so that it charged cab battery .. as tbh I never thought about it once.
 
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And the fridge on battery ( but doesn't the latter use the hab batteries ) ?

No, not if it's a conventional setup. It will be connected to the vehicle battery and is only supposed to be used on 12v when the engine is running i.e. when you're travelling.

If it's a manual one you need to remember to switch it away from 12v when you aren't moving and if it's an automatic one it won't choose that setting unless the engine is running anyway.

It would have been fine on the ferry with no power, just like any other fridge as long as you don't open the door it should be good for 24 hours.

ANYWAY back to the dead cab battery .. at home now once I stopped the Mh and went to the hab control panel ..after a few mins it said 9.9v

You might get it back but don't be too surprised if that is permanently banjaxed.
 

funflair

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Our fridge is fed from the habitation batteries but not all are like this, yours being a British van may well use the cab battery.

If it's an AES fridge but you switched it to 12 volts operation it would most likely ignore the fact that the engine is not running and then flatten the cab battery.

Martin

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pappajohn

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Nowt to do with your fridge or sidelights.....you have a faulty alternator which is staying active with the engine off.
Sidelights should draw less than 2amps/hour and at most the fridge will draw 10amps/hour but only if the relay has stuck closed drawing power from the cab battery.
20a from the battery is not enough to stop it cranking the engine.

If the alternator is remaining active it, in effect, becomes a motor....trying to turn the engine which it cant possibly do.. ..and will rapidly drain the battery.
 
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Bart

Bart

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Nowt to do with your fridge or sidelights.....you have a faulty alternator which is staying active with the engine off.
Sidelights should draw less than 2amps/hour and at most the fridge will draw 10amps/hour but only if the relay has stuck closed drawing power from the cab battery.
20a from the battery is not enough to stop it cranking the engine.

If the alternator is remaining active it, in effect, becomes a motor....trying to turn the engine which it cant possibly do.. ..and will rapidly drain the battery.
How could I test this , and what's the chances it's anything to do with installing a sterling b2b charger
 
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Bart

Bart

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We update . Last night I left the cab battery on to charge . Got in this morning and ..meh ... i just heard a few relay type clicks. So I went to take the cab battery out . And try the old leisure battery that came with the mh in the cab.
It was then when I took of the earth lead that I seen it all corroded inside , so I got the good old Dremil out and cleaned off all the corrosion and reconnected it back up.
Tried to start the Mh and worked fine . Stopped it turned on everything lights ,wipers , blower etc , left it for a few mins then went to start it.. and away it went fine.
So I have continued to charge it today for about 6 hrs .. will let it settle down tonight . Then tomorrow will try the same again. Except this time I'll take multimeter readings while under load and off load..
What voltage should I be getting after it sitting all night then putting it under load.

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DBK

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What voltage should I be getting after it sitting all night then putting it under load.
Something like 12.6 or 12.7 volts for a fully charged healthy battery after resting.

I wouldn't worry about the voltage while cranking, too many variables I think - if it's turning the engine it is probably fine. If it can hold its charge of course.
 
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Bart

Bart

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I also think I'll make sure i have a set of jump leads that reach from my hab batteries to my cab battery so if something similar ever happens again at least I'll be able to jump myself from my had batteries ( 3 × 130 ah batteries )
 
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Bart

Bart

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Something like 12.6 or 12.7 volts for a fully charged healthy battery after resting.

I wouldn't worry about the voltage while cranking, too many variables I think - if it's turning the engine it is probably fine. If it can hold its charge of course.


Thanks :)

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Bart

Bart

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Well i went out this morning and before i did anything i checked the cab battery with the voltmeter , it said it was 12.4 v , i then turned on all the lights , fan on full , wipers , etc and 30 secs later checked the battery and it read 11.6 v while everything was running , i then started the MH and it turned over fast with no signs of struggle.
So all looks ok , i'll re check the cab voltage in a few days / weeks and make sure its holding the charge ok.
I now also have a set of jump leads in the MH that reach from my Habitation Battery bank to my Cab Battery, i take it this is perfectly ok to jump start the MH this way should i ever need to ?
 

TerryL

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You should only "jump" the cab battery through the under bonnet terminals provided by the manufacturer. Connecting directly to the cab battery is frowned upon as it has a danger of upsetting, or even seriously damaging, the engine electronics. I presume that is what they did on the ferry?

Hope your "jump" leads are long enough......
 
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Bart

Bart

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You should only "jump" the cab battery through the under bonnet terminals provided by the manufacturer. Connecting directly to the cab battery is frowned upon as it has a danger of upsetting, or even seriously damaging, the engine electronics. I presume that is what they did on the ferry?

Hope your "jump" leads are long enough......
Yip ,, i never knew suck a jumping point existed , mine is a 2007 fiat ducatto chassis , does it have them ?

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Yip ,, i never knew suck a jumping point existed , mine is a 2007 fiat ducatto chassis , does it have them ?

Yes, under the bonnet. Check your manual

Pete

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Bart

Bart

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Yes, under the bonnet. Check your manual

Pete

Thanks after much much searching of the Manual i finally found the section.
However i have only found the Positive connection at the fuse box and am unsure where they mean for the negative to go ,, do they just mean on a bolt in that area so it connects to the Chassis > ??
see the images here :
http://www.manualslib.com/manual/803246/Fiat-Ducato.html?term=jump&page=141#manual

With mine being jump started at the battery , what damage should i be looking for to see if i anything got damaged , the motor home has hardly done any miles since jump starting.
 
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A note for consideration having been where you were

We bought a long set of leads that would definitely reach from hab to cab, covered the where to connect under the bonnet bit, then had a flat cab batt (third inside a year o_O) got leads out, there is no way I can connect to the top of the leisure batteries without removing it (not easy in my case)

so still had to call out a breakdown service, then when home changed cab batt, not had an issue since

good luck with your problem
 
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Bart

Bart

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i'm still wondering where they mean to connect the negative jump lead to . as that are just has a bolt same as the other side.

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Apr 27, 2016
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How could I test this

If you're just doing voltage measurements, you're trying to guess the current drain by taking voltages at different times, and guessing what's caused the change.

You need to measure the current (amps) to/from the battery.

People don't suggest this because with a standard multimeter it is difficult. You have to disconnect the battery terminal and connect the meter between the terminal and the cable. Oops, you've just lost all your radio settings, now what was that code again... And why has the alarm gone off... It can cause more problems than it solves.

However with a clamp meter, measuring current is easy. Just clip the clamp around the cable you want to measure. When everything is off, the current (amps) should be zero. If the alternator is leaking enough to discharge the battery in a few hours, it will show up as a non-zero reading. OK, I know the radio permanently takes a tiny current, and so does the alarm, but it's so small it won't register on a clamp meter.

You can clip the clamp over the positive or negative wire, it doesn't matter. Sometimes the positive battery terminal takes several wires, some even have a fuse box mounted directly on the terminal. In that case measure on the negative wire to get the total battery current.

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Bart

Bart

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@autorouter Luckily the multi meter i bought for the MH is also a clamp meter so ill try and measure it that way also.
yes my positive on my batter has like 5 leads , so ill have to measure it at the negative lead ( which i never knew you could , thanks )
So i take it the engine/alternator remains OFF for the whole test ?
Then i Set it to DC & the lowest amp setting on the meter , then put it around the negative lead , but i must leave it like that for a few hrs , checking the reading every so often
Is that correct ?
 

TerryL

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Thanks after much much searching of the Manual i finally found the section.
However i have only found the Positive connection at the fuse box and am unsure where they mean for the negative to go ,, do they just mean on a bolt in that area so it connects to the Chassis > ??
see the images here :
http://www.manualslib.com/manual/803246/Fiat-Ducato.html?term=jump&page=141#manual

With mine being jump started at the battery , what damage should i be looking for to see if i anything got damaged , the motor home has hardly done any miles since jump starting.

The illustration seems to show them using a bolt for the negative terminal, but mine has a plate fixed just under the top bonnet lip a bit left of centre looking at the engine bay. Have used it in the past with no problem. Sorry, the motor is in storage otherwise I'd do a photo.

If everything is working okay, you've probably got away without damage to the electrics - but would advise you don't do it again.
 
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Bart

Bart

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NP Terry , hopefully someone else here with a Fiat Ducatto based MH aprox 2007 will be able to provide a picture or something , but at end of the day suppose its not overly important where the Neutral is connected as long as its on a good earth point, inst that right ?

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Apr 27, 2016
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So i take it the engine/alternator remains OFF for the whole test ?
Yes
leave it like that for a few hrs , checking the reading every so often
It's easier than that. When the engine is off, and it's parked up doing nothing, with everything off, doors closed so no interior lights on etc, there should be no current from the cab battery. So simply clip around the negative wire, and see if it's zero. If not, you could then clip around each of the five positive wires in turn to see which one is carrying the current.

You will then have a clue as to which part is leaking current. You can clip round any wire to test for current, so you could try the alternator, alarm, etc.

Modern electronic gizmos can have complex faults. For example, engine control units are supposed to go into 'sleep mode' when the ignition is off. It's possible that it will fail to do that if it's faulty, so will be drawing current when the engine is off, draining the battery over a few hours or days. Any other electronic unit on the vehicle can develop similar faults. So tracking down where the current is actually going using a clamp meter is a great help.

The 'checking every so often' thing is what you have to do when you can only measure voltage. A small current takes several minutes or hours to pull down the battery voltage by a measurable amount. By measuring current you can get the picture immediately.
 
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Bart

Bart

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@autorouter My multimeter goes to sleep after a few mins to save the batteries , so ill just have to check it every 30 mins and see if i get any reading . earlier i have it on DC at 2 amps , and think it showed something like 0.076 , ill look more at it tomorrow
 
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Bart

Bart

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ok checked the neutral lead on the Cab battery with the clamp on the multimeter and set it to DC 2Amps
i got a reading of between 0.19 & 0.24 amps , this is on a cheap meter so not sure how accurate it is ,, as once reset it was reading about 0.600 on the meter gauge untill i recalibrated it
when i set the clamp meter to 20amps , it read 0.000 as it never went over 1amp

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TerryL

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I wouldn't have thought that was too bad actually. There is always a tiny amount being used by the electronics, more if you've an alarm or the radio is connected to the cab battery (it requires a small supply to maintain the settings). I see more than that on the control panel, which is one of the reasons I've now got a solar panel to keep the hab batteries charged and a Battery Mate to top up the hab battery when they're fully charged.
 

Bobby22

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NP Terry , hopefully someone else here with a Fiat Ducatto based MH aprox 2007 will be able to provide a picture or something , but at end of the day suppose its not overly important where the Neutral is connected as long as its on a good earth point, inst that right ?

Clearly marked on my fiat.....the bolt just below the bonnet latch - and the the silver mid right for + .........hope this helps

Ps the sticker under the bolt reads ....for jump start only....
 
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If the clamp meter is not clipped round a wire, the current should read zero. If not, press the ZERO button, which should zero it. Maybe after a few minutes it will drift from zero, so you'll have to repeat, especially on the most sensitive range.

Anyway, 0.190 to 0.240, call it 0.200 amps, is going to take at least 100/0.2 = 500 hours to discharge your cab battery, assuming it's about 100 Amp-hours. So that is not the cause of your ferry starting problem.

As I see it, either the battery wasn't charged as much as you expected, or there's something draining current faster then you expected. Or the battery is defective and not holding charge.

Of course you might already have sorted the problem, because the bad earth connection you found probably caused charging problems. Quite likely the battery wasn't fully charged as you expected.

If you're not convinced, the next step is, try to reproduce the fault. Set it up like it was on the ferry - fridge on, sidelights on etc. Then measure the current from the both the cab and leisure batteries. The fridge has a thermostat so it's not drawing power all the time. It will draw about 10 to 15 amps when it's cooling. It would be useful to know which of the batteries the fridge draws its current from. Sidelights are about half an amp each if they're filament bulbs, much less if they're LEDs. Keep an eye on the voltage too, over the 2 hours, and stop the test if it drops below about 11.5 when drawing current.

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