Three Batteries have Died in 11 Months Alternator Appears OK.

[pjbailey]

Vhicle: Fiat Grande Punto 1.2 Petrol.
24/9/2021 The original battery died and was replaced: I'll put that down to old age.
It was replaced with a Lion brand 40 AH that I was later told was not the recommeded battery for the vehicle.
A month later the Alternator Sized Up and was replaced.
12/3/2022: The Lion Battery Died and was replaced I paid extra and took and Exide 44AH that was recommended as the correct battery by Fiat.
All Seamed Fine untill Friday evening 5/8/2022 Battery died and would bearly turn the engine over. Instead of going out I too the battery off and put it on an overnight (15Hr) Trickle Charge. @ 9AM on Sat 6/8/2022 it was showing a fully charged and I refitted the battery.
Two 15 Mile Journeys 3 Hours Appart (Out and Return) no problems.
Sunday 7/8/2022 @ 1PM went to the care and Battery totally dead not even enough power for a click of the solenoid. I called the RAC Home Start who came and did a full diagnostic test on the battery and starting and charging circuits.
Results:
Rating of Battery Tested 400EN
Battery Test Rating 12EN
Amp Hour 44
Initial Bat Voltage Befor Test 10.79 V
Battery Test Result: Replace Battery
Reserve Capacity Poor Reserve..

Charging Test
Starter Motor Current 201.8 Amps
Alternator Voltage (loaded) 14.32 V
Alternator Currant (loaded) 39.6 A

I specifically asked about the alternator output and wheather it was over charging the battery. He Answered that the alternator was perfect and behaving correctly.

Today 8/8/2022 Replaced battery Like for Like under warenty. If it fails again they wont change it / Refund it untill its been sent away for testing which sounds fare under the circumstances.

The Make of the prvious is Exide so a good make.
New Battery Exide 44AH (202)

Further Testing:
After putting the new battery on and starting the car at tick over Measured 14.23 V accross Battery Terminals.
After 5 Minutes Tick Over Measured 14.16 V Accross Battery Terminals.
After 15 Minutes Tick Over INC 3 Mins at 3,000 Rpm Measured 13.79 V Accross Battery Terminals.

This test was in line with what I expected as the new battery was taking further charge. And to my Non Expert Mind indicates that the charging Regulator is reducing the charge as required and confirms the RAC Mans statement that the alternator is OK.

OK Here is my Question

What can be killing the batteries other than the alternaor. OR have i just been unlucky with two duff batteries and all should be ok in futher????

Further Info: I'm retured and my annual milage is only 3,000 Miles. ( No Commuting )

Thank you in anticipation of your advice

Yours
Philip

 

[newfutile]

Have you checked for parasitic draw ? Something may not be going to sleep and drawing excess current or keeping can bus alive when it’s supposed to sleep

 

[pjbailey]

Have you checked for parasitic draw ? Something may not be going to sleep and drawing excess current or keeping can bus alive when it’s supposed to sleep

I pulled the fuse to the non standard radio but that should even a full power would not kill the battery. It did test as faulty not jus flat. Everything else is standard Fiat Kit.

 

[pjbailey]

Have you checked for parasitic draw ? Something may not be going to sleep and drawing excess current or keeping can bus alive when it’s supposed to sleep

Further the test showed whil on test the battery had only 0.1 A of draw and that was the test load. So No does not look like a Parcite.

 

[newfutile]

I would put an oscilloscope on the battery when engine is running to check for AC being supplied to the battery , 100 ma seems quite high ,not sure what you mean by test load,it could be something waking up and drawing current, a good way is to charge battery with an external charger ,after an hour on the vehicle measure and note the voltage, do the same many hours later and compare the amounts measured

 

[pjbailey]

I would put an oscilloscope on the battery when engine is running to check for AC being supplied to the battery , 100 ma seems quite high ,not sure what you mean by test load,it could be something waking up and drawing current, a good way is to charge battery with an external charger ,after an hour on the vehicle measure and note the voltage, do the same many hours later and compare the amounts measured

A Job for a well equiped vehical electrician.

 

[James]

3000 miles per year is so low, it may be that the battery gets less charge put into it than it used for alarm, starting lights etc.
start batteries do not last long if they are regularly left below fully charged.

 

[DPG]

At such a low amount of usage it may be worth leaving it connected to an optimiser.

 

[Jim_e_Jib]

If the voltage on a lead acid battery drops below a certain value, damage can occur that shortens the life of the battery. If you rarely drive the car, it may well be, as James says, that your battery is never being properly charged and is sitting at too low a voltage.

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