Technical battery light

[confuszd]

Hi you fellow fiat fanatics. Many thanks in advance to anyone who can offer any advice. Along with my Fiat 500, which be my fun work runaround, last year, I treated myself to a 2007 fiat ducato Adria mobil, which was also lots of fun until it wasn't. First there was the windscreen wiper motor and the bottle wash motor, but hey they were easyish to get to and replace. Not to much brain damage.
On our next trip away, we broke down (twice)owing to what now seems to have been an alternator issue - replacing it was a horrid job, but the battery be once again charging, which be a huge relief, however that pesky red battery might be still there taunting me on the dashboard as it has been for months (kind of ignored it until the alternator died), but am bit concerned if I continue to ignore it, it might cause more problems.
So any ideas???
I have checked all those earths and fuses, all seems fine. Think there also an issue with that split charging relay as mains fridge doesn't work and leisure battery only charges from solar panal. Could this be causing my battery light issues and if so where is it hidden

 

[confuszd]

you get a bit of warning first, engine starts behaving weirdly and strange engine warning lights come on. From now on I will always carry a spare battery, although the last trip made it back with jump leads attached to the leisure battery

 

[koalar]

We can't try a different BSI easily as it's also coded to the keys and ECU

Running out of options

Voltage drop test is the last I can think of

Top of the negative battery post to a clean part of the alternator case should be less than 200 mV while cranking

 

[confuszd]

We can't try a different BSI easily as it's also coded to the keys and ECU

Running out of options

Voltage drop test is the last I can think of

Top of the negative battery post to a clean part of the alternator case should be less than 200 mV while cranking

sort of difficult to say at moment of cranking, as its flickering through to peaking at just less than 400mV once cranked

 

[koalar]

Is the 300+ mV with the engine started ?

 

[confuszd]

Is the 300+ mV with the engine started ?

yes, but only initially, then it went right back down again

 

[koalar]

Mmm should never reach 300+ mV with the engine started

Should be 0mV or very close

The highest value should be the second you turn the key and the starter isn't turning, Should stay under 200 mV but I would be alarmed at twice this, as the starter starts to turn it should be falling then instantly it catches it should be zero or very close


Is you meter very slow, if you measure the battery voltage and then touch the probes together does it read zero or takes a few seconds to wind down

 

[confuszd]

Mmm should never reach 300+ mV with the engine started

Should be 0mV or very close

The highest value should be the second you turn the key and the starter isn't turning, Should stay under 200 mV but I would be alarmed at twice this, as the starter starts to turn it should be falling then instantly it catches it should be zero or very close


Is you meter very slow, if you measure the battery voltage and then touch the probes together does it read zero or takes a few seconds to wind down

will have another go tomorrow during my lunch break and let you know, many thanks

 

[Communicator]

@koalar . May I interject with some Ducato specific information, of which you not be aware. From the introduction of the x250 model in 2006, the starter battery is under the LHS cab floor. Local braided earth is designated C003 A on diagrams. There is a second earth strap between gearbox/engine assembly and chassis, designated C002 - C003 B. This second earth strap is a known source of problems, as it suffers from internal corrosion. It is of course in the starting and battery charging circuits.

@confuszd I find that I admire your tenacity in this investigation.

 

[confuszd]

will have another go tomorrow during my lunch break and let you know, many thanks

lunch break investigation; several attempts, the results are at start of crank voltage goes up to 400mV, then rapidly starts to drop. It is less than 200mV by the time the engine starts to turn, dropping then almost instantly to 0V. many thanks janet

 

[confuszd]

@koalar . May I interject with some Ducato specific information, of which you not be aware. From the introduction of the x250 model in 2006, the starter battery is under the LHS cab floor. Local braided earth is designated C003 A on diagrams. There is a second earth strap between gearbox/engine assembly and chassis, designated C002 - C003 B. This second earth strap is a known source of problems, as it suffers from internal corrosion. It is of course in the starting and battery charging circuits.

@confuszd I find that I admire your tenacity in this investigation.

hi did check all the earths at start of investigations, but will double check this one during tomorrows lunch break; many thanks janet

 

[koalar]

Right not ideal, needs looking at one day, and possibly cleaning up,

But not your problem, need to raise to around 5V to effect the dash light

Same test but to the actual chassis, somewhere not painted and not the earth strap eye, I don't think it will be you problem but we do need to put it to bed once and for all

 

[confuszd]

Right not ideal, needs looking at one day, and possibly cleaning up,

But not your problem, need to raise to around 5V to effect the dash light

Same test but to the actual chassis, somewhere not painted and not the earth strap eye, I don't think it will be you problem but we do need to put it to bed once and for all

same test to chassi s instead of alt case
gives 180mv peak dropping to more or less 0v as eng starts turning

 

[koalar]

same test to chassi s instead of alt case
gives 180mv peak dropping to more or less 0v as eng starts turning

That's a good result

We have ruled out earth as the issue you are seeing with the battery light

 

[koalar]

Running out of things to check

The voltage at the BSI from the alternator is correct ignition off, ignition on and engine started

If we unplug the connector the voltage is correct, the BSI is cable of sending the correct voltage as it also behaves correctly while charging

the integrity of D+ is correct

Reference ground at the BSI is correct

Block and chassis grounds are correct

I few things I haven't asked but I doubt it will make any difference

The light is on solid not blinking indicating it's in logistics mode

was the light on a long time before the first alternator failed, or did the light come on and then the battery went dead

 

[confuszd]

Running out of things to check

The voltage at the BSI from the alternator is correct ignition off, ignition on and engine started

If we unplug the connector the voltage is correct, the BSI is cable of sending the correct voltage as it also behaves correctly while charging

the integrity of D+ is correct

Reference ground at the BSI is correct

Block and chassis grounds are correct

I few things I haven't asked but I doubt it will make any difference

The light is on solid not blinking indicating it's in logistics mode

was the light on a long time before the first alternator failed, or did the light come on and then the battery went dead

the battery light first appeared in January, but as the battery and alternator were ok, decided to live with it. Driven about 3000km since - no problems until the alternator went on way home last trip.
A huge thank you for accompanying me through all these tests, I have learn a lot. You help and support has been amazing. If you ever find yourself in the beautiful nontron area, do get in touch.

 

[Communicator]

the battery light first appeared in January, but as the battery and alternator were ok, decided to live with it. Driven about 3000km since - no problems until the alternator went on way home last trip.
A huge thank you for accompanying me through all these tests, I have learn a lot. You help and support has been amazing. If you ever find yourself in the beautiful nontron area, do get in touch.

If deciding to live with the warning light, you could try one of these. (Link to eBay.)

 

[koalar]

the battery light first appeared in January, but as the battery and alternator were ok, decided to live with it. Driven about 3000km since - no problems until the alternator went on way home last trip.
A huge thank you for accompanying me through all these tests, I have learn a lot. You help and support has been amazing. If you ever find yourself in the beautiful nontron area, do get in touch.

Definitely running out of easy things to check

You could try restarting resetting the BSI

Just disconnect the battery/batteries for a few seconds

Also if you have some bidirectional software such as MultiECUscan you could try and toggle the light off and on, which would confirm the dash is working correctly and the BSI is talking correctly to it

I was concerned the D+ was a slightly lower voltage than the B+ but when I look at my old photos they are the same

 

[confuszd]

oh la la and all my giddy aunts, miracles do happen. Early this morning want to move the camper to nearer water pipe ready for my 3 day trip away. Started the camper and within a couple of minutes the battery light went out. No idea why suddenly today was the day, but am overjoyed and relieved. No idea if it will continue to stay off, but here be hope and optimism.
Once again, many thanks to all who responded. Your help, kindness, patience and wisdom has been fantastic. Have learnt so much about the wonderfully fiat fraternity (entraide as it's known here) and my lovely ducato (she be called Adrienne, after my amazing 93 neighbour)