Battery Replacement - GranTurismo

Masser50

Member
Messages
235
To extent it helps others I had to replace my OEM FIAMM battery (per 4 photos). Manged to get 4.5 yrs out of it, although that’s with CTEK support.

Getting a proper Battery sizing between European and Australian conventions is a real PITA. At any rate I worked out that the FIAMM L5 shape battery is the same as most local batteries the DIN85 or DIN88 designation.

I decide to go to AGM (yeh I know it’s not a requirement). Having hunted around the major brands Supercharge, Century, AC Delco etc I went for Century DIN85LH AGM with 850cca and 36mths warranty (single photo) as it has exactly the same dimensions of the old one and I was happy with the price after haggling down Battery World.

Maserati Sydney switch them to SuperCharge non-AGM and AGM’s with 24mth warranty when the OEM dies.
 

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Gazcw

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7,700
I know others have used agm before without issue, but I read somewhere (toilet cubicle maybe) that they require a larger alternator for charging properly. No idea if that is bs or due to battery or alternator issues after.
 

Zep

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9,110
I know others have used agm before without issue, but I read somewhere (toilet cubicle maybe) that they require a larger alternator for charging properly. No idea if that is bs or due to battery or alternator issues after.

Yes, my view on this is that the AGM applications with stop / start needed bigger alternators because the charging period is shorter and the potential is for deep cycling in traffic is higher.

With stop / start cars with larger alternators they also add a charge controller to reduce voltage when the battery is fully charged to the float voltage, this is, in essence like having a c-tech charger built into the car.

In theory, fitting and AGM battery to a car without these things is not ideal as it may overcharge an AGM battery and cause it to vent and reduce its life. In reality, it should last at least as long as a standard VRLA type battery.
 

Vince2

Member
Messages
192
Went to change my BMW battery recently and was made aware the vehicle has to be programmed to accept the new battery. Via the programming port, it needs to be told the exact Amphour, cold crank etc and that it is a new battery because the car's brain takes account of the age of the existing battery in how it charges. If I put in a new battery without having this done, it wouldn't last as the 'brain' would treat the new battery as the old one with totally different methods and hence much reduce it's life. First time I've ever heard this but a bit of research shows a few cars now do this. Particularly start/stop. Don't know if Maserati do a similar thing?
 
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Masser50

Member
Messages
235
Yes, my view on this is that the AGM applications with stop / start needed bigger alternators because the charging period is shorter and the potential is for deep cycling in traffic is higher.

With stop / start cars with larger alternators they also add a charge controller to reduce voltage when the battery is fully charged to the float voltage, this is, in essence like having a c-tech charger built into the car.

In theory, fitting and AGM battery to a car without these things is not ideal as it may overcharge an AGM battery and cause it to vent and reduce its life. In reality, it should last at least as long as a standard VRLA type battery.
All I can say is the main (here it’s the only) Dealers for Maserati are happy to fit AGM and this is me talking to the senior mechanics and nothing about alternator issues.
 
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Masser50

Member
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235
One topic that hasn’t been discussed about re AGM in our GT’s is the question of whether the venting tube should some how be attached to the AGM. See venting tube at top of photo. It won’t fit if you, well that is what I found but there’s not a lot said about the following. Per a Porsche site:


“In normal operation an AGM battery does not vent. They are VRLA. The H2 and O2 that are produced will recombine inside the battery and no gases escape or are "vented". The benefit is that no water addition is needed during the normal life of the battery. Hence it is maintenance free. However, AGM batteries will vent during an overcharge condition. This might occur in the other 5 cells if one of the cells shorts. Or it might occur if the voltage regulation goes high for some reason. This possibility overcharging condition is what requires "venting". The battery cannot be installed in a sealed space or indoors without venting. This could result in an explosion in the event of H2 and O2 released into a sealed space”
 

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Zep

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It has never been in question. All valve regulated lead acid batteries, including AGM, must be vented to prevent the buildup of flammable gases. Anyone, including main dealers, that fits these and doesn’t reconnect the vent pipe is taking a risk.
 

conaero

Forum Owner
Messages
34,594
We refit so many that have fallen off or the elbow has snapped but you do want to follow the vent pipe all the way along to exit to make sure it’s not crushed, we see this time and time again.
 

Davanger

Junior Member
Messages
34
Yes, my view on this is that the AGM applications with stop / start needed bigger alternators because the charging period is shorter and the potential is for deep cycling in traffic is higher.

With stop / start cars with larger alternators they also add a charge controller to reduce voltage when the battery is fully charged to the float voltage, this is, in essence like having a c-tech charger built into the car.

In theory, fitting and AGM battery to a car without these things is not ideal as it may overcharge an AGM battery and cause it to vent and reduce its life. In reality, it should last at least as long as a standard VRLA type battery.
Hi @Zep - I read your note and wanted to seek clarification. I have an AGM battery on my GT and was planning on putting it on CTEK MXS 5.0 as I will not be driving it for a week or so. Is that not advised?
 

Zep

Moderator
Messages
9,110
Hi @Zep - I read your note and wanted to seek clarification. I have an AGM battery on my GT and was planning on putting it on CTEK MXS 5.0 as I will not be driving it for a week or so. Is that not advised?

I imagine there is an AGM option on the CTEK, that will be the one to go for.
 

Davanger

Junior Member
Messages
34
Ok great....yes, there is indeed an AGM mode on the CTEK. Thought I'd check in with you before I plugged it in.

Sent from my SM-G991B using Tapatalk
 

Tallman

Member
Messages
1,833
I have been using a CTEK MXS 5.0 on my QPV and 650i which both have AGM batteries without any issues for a couple of years now. I alternate between the cars when I don’t use them and don’t leave it on for more than a few weeks on end.
 

Davanger

Junior Member
Messages
34
Ok cool. Is there any ideal time period beyond which you wouldnt leave the CTEK plugged in for? The CTEK manual implies that you can plug & forget...
I am thinking of 'hanging up' the GT later this year if the winter gets harsh.....
 

SE_123

Member
Messages
415
Ok cool. Is there any ideal time period beyond which you wouldnt leave the CTEK plugged in for? The CTEK manual implies that you can plug & forget...
I am thinking of 'hanging up' the GT later this year if the winter gets harsh.....

Most leave it on all the time.

There was some chat on here about how you should leave it off for 3 days, put it on for 1 then off, then on, then off, then on ....

I'd just leave it on as a new battery is only 130.

My CTEK sometimes gets an error, maybe that was due to my old battery dying, but worth checking the charger occasionally to check it is still working properly.