Starter battery voltage.

[Andy-B]

Hi all,
I have had the dreaded airbag ECU failure. Had it reset by Crashdata but it faulted again. I have a new unit to fit but I am now concerned that when fitted the voltage showing Vue Multiecuscan is 14.4 volts. I have looked everywhere and can't find a definitive answer to what voltage the alternator should be putting out. The main ECU reads 13.9volts.
It's a 2013 Fiat Ducati 130.
Can anyone tell me if the voltage is fine?
I emailed Jean at Crash data but she has not replied.

Regards
Andy

 

[Martin How]

A quick google says 13.8 to 14.8 is the expected output range. My car a Vauxhall runs at 13.9. My motor cycle (Honda vfr) 14.4 and my Ducati based Homer 14.2.

My Oxford bike battery maintainer cuts in below 13.8 and fold back charges (decreasing the charge current) and cut out at 14.4.

It sounds like you are in range but not sure why your Vue ecu monitor differs. Maybe the ecu has an internal voltage stabiliser.

 

[Sandancers]

When running the alternator on our Mk7 transit delivers 14.4 volts to the cab battery.

 

[Phill D]

as I understand it you dont need constant low voltage to create a problem, a brief low trough appears to be enough .

interestingly i was able to reset my airbag ecu recently and the 2 faults were; earth fault which was a physical issue with the ecu which was rectified and low voltage.
i was gobsmaked by the low voltage as i have a good quality battery about a year old and a monitor on my battery when it failed never went below 12.7v.

HOWEVER; i ran a simple test :-
ensured battery was charged then rested it was showing 12.8v.
attached a meter to the battery, same 12.8v.
I then switched on the ignition and immediately it showed a drop to 12v it recovered within a second on so to 12.7v.

then i cranked the engine and started and the voltage dipped again this time to 11.9v.

so i just wonder if this is when the low voltage damage is being done.

i have subsequently done a simple load test on the battery and all appears fine.

 

[Andy-B]

Thanks for the replies.
I am almost confidant now that it will be ok.

Andy

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[Andy-B]

My problem has not been a low voltage, more what should be normal being reported as a high....


Andy