Does replacing stock battery with AGM battery require calibration afterwards?

[250gtswb]

I am considering replacing my Si's battery with a high-quality AGM battery, and am wondering whether I will need to have the car recalibrated for the different style of battery. I have read that if the car's system is not recalibrated, the alternator might overcharge the new battery and cause the battery to fail soon after replacement.

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[REBELXSi]

Got a source?

 

[CameraGuy]

I think AGM still functions the same, it’s just more stable. I haven’t heard of any sort of thing but who knows, people still think you can’t set a battery on the ground without placing it on a piece of wood.

 

[fenix-silver]

Alternators just apply 13.8 volts all the time to the battery. There is no intelligence (at least in normal cars) built in as far as charging goes.

 

[Justinus]

Alternators just apply 13.8 volts all the time to the battery. There is no intelligence (at least in normal cars) built in as far as charging goes.

Not true. In the quest for better fuel efficiency, clutched, variable voltage alternators are becoming more common. Both my 2014 Malibu and my 2012 Cruze would charge at a variable rate up to 15.9 volts, then if the battery was charged sufficiently the clutch would release and disable the alternator.

With charging voltages that high it seemed like the system was designed for an AGM battery, as 15.9 volts could ruin a normal lead acid battery. Regardless, the cars both came with lead acid. I replaced them both as they died with AGM and they work excellently.

I haven't watched the voltage on my Si to see if it's either clutched or variable voltage, nor have I seen any factory documentation that describes the alternator's function (I had seen the Cruze's function described in the service manual, and watched it behave as described.)

Would be interesting to know the function parameters for the civic.


Edit:

It looks like, at the very least, it's a dual mode alternator. This paper is 11 years old, and its possible the latest platforms have an even smarter system like the Chevys. Can't find any details about them to confirm or deny.

 

[250gtswb]

Got a source?

From http://www.thelongestlecture.com/charge-agm-battery-with-normal-charger/:

...in some vehicles, there is an extra step required to consider that the battery has already been replaced.

These vehicles are equipped with a sensor module or a system that requires recalibration or a scan tool to tell that the battery is already replaced.

If the system is not calibrated, it will risk the alternator to overcharge the battery that will lead to battery failures.

 

[Justinus]

From http://www.thelongestlecture.com/charge-agm-battery-with-normal-charger/:

...in some vehicles, there is an extra step required to consider that the battery has already been replaced.

These vehicles are equipped with a sensor module or a system that requires recalibration or a scan tool to tell that the battery is already replaced.

If the system is not calibrated, it will risk the alternator to overcharge the battery that will lead to battery failures.

I'm sure if we could get ahold of the service manual battery replacement procedure, it would outline everything we would need to know.

 

[fenix-silver]

TIL, thanks. Makes sense that they'd have smarter alternators by this point to lower the engine load. A quick search makes it sound like regular flooded lead-acid batteries are fine w/ a 15.9 v charging voltage.

 

[250gtswb]

I'm sure if we could get ahold of the service manual battery replacement procedure, it would outline everything we would need to know.

Does anyone have access to the service manual for the Si? I would love to know what it says before I replace my battery myself.

I have been reading (on various websites, including those catering to other makes) that many modern cars require that new batteries be "registered" (the electrical system recalibrated) in order for the new battery to be charged properly (not over- or under-charged), especially if changing from a conventional battery to an AGM type. I also wonder if I did the swap myself and then soon afterwards took my car to a battery place (or Honda dealership) for recalibration if that would prevent damage being done either to the new battery or some other component in my Si's electrical system.

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