GrantG

Not sure if relevant, but my GT4 shows voltage (when dash menu so configured) of 14.7V. I wonder if this is higher than what I'm used to due to AGM technology? I seem to remember typical voltage of around 13.8V with more common batteries.

jfr0317

Would you please take a look at and then post which battery you have? Just looking for another GT4 data point. Thanks.

Kelsey

I too have seen my voltage up to 14.7 V on the GT4. Also, please note that I took a careful look at my battery and saw that it has VRLA battery stamped on it. This stands for valve-regulated lead-acid battery (a type of AGM battery). Upon further investigation this is why it has a vent tube. From online searches (not sure how accurate this is) VRLA has a absorptive range of 14.2 to 14.5 volts and the typical float is 13.2 to 13.5. AGM has an absorptive range from 14.4 to 15 Volts and a typical float of 13.2 to 13.8 Volts. I am still looking into these values to see how accurate they are. Some literature suggests that a battery maintainer for an Odyssey AGM battery provides a constant voltage of 14.7 V and a voltage during the float stage of 13.6 Volts. A typical lead acid battery maintainer has a constant voltage of 14.4 V and a voltage during the float stage of 13.4 volts. So now I am checking to find out what Porsche suggests for a battery maintainer. If the above values are correct, I would assume you would want to keep the voltage at 14.4 V and a voltage during the float stage of 13.4 volts. Should have more information soon.

Mike in CA

Kelsey, the correct battery maintainer voltage for AGM batteries has been discussed at some length. In general, they benefit from a slightly higher charging voltage as indicated by your info on the Odyssey battery. Banner also recommends a higher voltage for their AGM battery which, in the case of the CTEK chargers, means using the cold weather "snowflake" mode or the setting with the "*". The older Porsche chargers (made by CTEK) don't have this mode. I don't know about the newest ones.

Kelsey

Hi Mike, I am right with you. Thanks. I have 3. A CTEK with the snowflake and two BatteryMinders 2012 and 2012 AGM; one for regular lead acid battery and one for a AGM Odyssey battery. The Battery Minders have a temperature compensation probe which is nice as the temperature outside the garage can get very HOT in the summer. That way if I leave one car outside with the maintainer it should adjust for the outside temperature. Talk soon.

Kelsey

Hi Mike,

Here is some interesting information I found (see attachment). Interesting as I and others have observed voltage up to 14.7 volts on the vehicles dash gauge while the car is warming up. I'm not worried about it. Just thought it was interesting. I'll need to get a copy of the entire document.

MACH 86

More battery confusion: The recent Porsche charger has only two positions Motorcycle and Auto positions
and the CTEK 3300 has three positions Motorcycle, Automobile, and * AMG battery positions. This would lead one to believe that the porsche has a lower voltage charging rate than the CTEK does when the CTEK it is in the * AMG battery position. Looks like I should charge the car with the Porsche charger only or the CTEK in the automobile position. Another point of confusion is what type battery do I have. Car is a 2015 GT3.

Kelsey

Based on the document that I saw all 2009 and up (2014 notice) 9X1 vehicles have an AGM battery. I think that has been confirmed. But based on this excerpt and based on that my battery states ...VRLA battery ...right on the battery (also means its a AGM battery) and the fact that a typical VRLA Absorptive range (Constant Voltage stage (CV)) should be between 14.2 and 14.5 volts I am thinking that I should use a battery maintainer with the specifications of 14.4 Volts for CV and 13.4 Volts for Float stage. The AGM charger for my Oddessy battery has a CV of 14.7 and a float of 13.6 Volts. Probably wouldn't hurt anything but I have no clue. I am still waiting to hear back from a Porsche as to what voltage to use to maintain for a battery maintainer before I try.

Mike in CA

Confusing for sure. Kelsey, mcsmcs1 and I had this conversation via PM messages last November. He contacted Banner directly and they told him to use the 14.7 volt snowflake mode on the Ctek 3300 for their AGM battery. (see post 6 in this thread). However, this conflicts with the information provided in the PDF you've posted. I don't know what to think.

MACH 86

I have 3 battery chargers. One Porsche that I bought 17 years ago, One CETK 3200 that I purchased in 2014 and A Porsche charger that the dealer gave me when I took delivery of my 2015 Porsche. What to use? The Porsche charger that I used on the 993 for 16 years was perfect. I replaced the original battery only once in 16 years.AMG not used at that time. Bought the CETK 3200 for a new 2014 Cayman S. CETK because it was half the price of the Porsche charger. The Porsche charger is made my CETK. Using the CETK on the 2015 Porsche and will use the Porsche charger on a CC. Seems that charging a battery should be easier that this. What to use? Lets not talk about oil.

Kelsey

I have a call into Porsche so perhaps we can get some additional information. I too am confused. You would think this would be easy. I'll let you know what I find out. Thanks

mcsmcs1

I wrote Banner last year and asked the following:

"I own a 2014 Porsche 911 GT3 (USA Model) which has Banner battery
999-611-070-10 as original equipment. The battery is 12V 70Ah 760A. Is this
an AGM battery? If yes, do I need to use the snowflake/AGM setting
(14.7V/3.3A) on my CTEK 3300 maintainer? The other choice is normal mode of
14.4V/3.3A. Thank you!"

They replied as follows:

Dear customer, thank you for your query.

Yes, your battery is an AGM technology.

Please use the setting with the snowflake (14,7V) for recharging.

Greetings from Austria!

mit freundlichen Grüßen
Banner GmbH
Banner Straße 1
4021 Linz
AUSTRIA
Tel.: +43/(0)732/3888-0
Fax.: +43/(0)732/3888-0
www.bannerbatterien.com

Maybe someone would like to write/call them again and confirm?

Mike in CA

Thanks for repeating that info, Matthew. You'd think that the manufacturer of the battery would know how best to charge it......

Kelsey

Thanks for the follow up. I too emailed Banner and they told me my battery was also an AGM battery. I spoke to my buddy at Porsche and he is checking into this. will follow-up soon. Thanks for the great communication.

Kelsey

Hi Guys. I asked the PCNA this question via the PCA site: I have been in touch with Porsche NA and many dealerships and cannot get a straight answer. The question is: What type battery maintatiner should be used on a Banner battery part # 99961107012 which is used in a 2016 GT4? This battery is a VRLA battery (listed right on the battery). Online information indicates VRLA batteries (Type of AGM battery) has a typical absorptive range from 14.2 to 14.5 volts.

Contacted Banner in Austria (also others with GT3's have contacted Banner). Banner suggested using a CTEK Maintainer on the snowflake mode (14.7 Volts).

I received a Porsche Bulletin No 1401 that stated " All 9x1 vehicles use AGM batteries. Any battery changer/power supply used must be set to this type battery. It is critical for AGM batteries that charging voltage not exceed 14.5 volts for more than very brief periods. I would interpret this as one should use a typical Lead Acid battery maintainer as it's absorptive phase is 14.5 volts. However, in most Porsche vehicles with AGM batteries, the voltage displayed on the dash shows 14.7 volts somtimes. So this becomes confusing as the bulletin states not to exceed 14.5 volts for more than very brief periods. Any help would be appreciated? Porsche NA is still looking into this. Also, Porsche parts department told me that they are no longer going to sell the Porsche maintainer as the batteries being used have changed. Thanks

The response was "I checked with both my local dealer parts department and PCNA and got the same answer, Porsche part 95504490054. It is a CTEK maintainer and is supposed to work in this application"

So this is the typical battery maintainer (Lead Acid) not for AGM batteries. Voltage is 14.5 volts if I recall correctly. Thought I would share.