991.1 Battery Replacement DIY
#406
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I had mine done at advanced auto. Was $210 after they refunded me $25 to recycle the battery that was already in it.
AGM and the largest size H8.
Free install
AGM and the largest size H8.
Free install
#407
Rennlist Member
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Hard at work! They were eager to do it since it was their first time working on a 911.
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BGLeduc (05-11-2021)
#408
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were his shoes clean??
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scr1244 (05-23-2021)
#409
Rennlist Member
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haha
#411
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I ordered online a battery at Battery+Bulb, they gave me a call yesterday to let me know the battery is ready for pick-up and it's about 7 months old. Told them I want a new one so they said it'll get there next week.
They also install the batteries so I think I'll let them just put it in.
They also install the batteries so I think I'll let them just put it in.
#412
Instructor
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Does anyone here have experience with an old oem battery smelling?
ive been getting a horrible intermittent smell in the cabin when coming to a stop. It’s definitely coming in through the fresh air hvac intake right next to the battery. I thought it was gear oil, but I’ve checked everything with no results. Now I’m thinking I may be confusing the sulfur smell of gear oil with sulfur from a bad battery. The smell occurring at stops would be in-line with the alternator kicking in on braking/engine braking and causing some charge related smell. Anyone else have this?
My battery is still original (late 2013) and the stickers on top are bulged a bit. (Edit: bulged is the wrong word to use with a battery. I’m assuming the stickers on top are covering something up and have gas trapped under them. Battery case isn’t bulged)
Regardless, I’m going to replace the original battery with the Duracell as a trouble shooting step. Should I have the dealer check out the charging system as well? Any chance it’s over-charging the battery?
ive been getting a horrible intermittent smell in the cabin when coming to a stop. It’s definitely coming in through the fresh air hvac intake right next to the battery. I thought it was gear oil, but I’ve checked everything with no results. Now I’m thinking I may be confusing the sulfur smell of gear oil with sulfur from a bad battery. The smell occurring at stops would be in-line with the alternator kicking in on braking/engine braking and causing some charge related smell. Anyone else have this?
My battery is still original (late 2013) and the stickers on top are bulged a bit. (Edit: bulged is the wrong word to use with a battery. I’m assuming the stickers on top are covering something up and have gas trapped under them. Battery case isn’t bulged)
Regardless, I’m going to replace the original battery with the Duracell as a trouble shooting step. Should I have the dealer check out the charging system as well? Any chance it’s over-charging the battery?
Last edited by Fr3nch; 05-23-2021 at 01:10 PM.
#413
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Does anyone here have experience with an old oem battery smelling?
ive been getting a horrible intermittent smell in the cabin when coming to a stop. It’s definitely coming in through the fresh air hvac intake right next to the battery. I thought it was gear oil, but I’ve checked everything with no results. Now I’m thinking I may be confusing the sulfur smell of gear oil with sulfur from a bad battery. The smell occurring at stops would be in-line with the alternator kicking in on braking/engine braking and causing some charge related smell. Anyone else have this?
My battery is still original (late 2013) and the stickers on top are bulged a bit.
Regardless, I’m going to replace the original battery with the Duracell as a trouble shooting step. Should I have the dealer check out the charging system as well? Any chance it’s over-charging the battery?
ive been getting a horrible intermittent smell in the cabin when coming to a stop. It’s definitely coming in through the fresh air hvac intake right next to the battery. I thought it was gear oil, but I’ve checked everything with no results. Now I’m thinking I may be confusing the sulfur smell of gear oil with sulfur from a bad battery. The smell occurring at stops would be in-line with the alternator kicking in on braking/engine braking and causing some charge related smell. Anyone else have this?
My battery is still original (late 2013) and the stickers on top are bulged a bit.
Regardless, I’m going to replace the original battery with the Duracell as a trouble shooting step. Should I have the dealer check out the charging system as well? Any chance it’s over-charging the battery?
#414
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What he said. A bulging battery could explode on you. Be very careful! The battery is long past the time it should’ve been replaced, so it doesn’t owe you anything.
#415
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Does anyone here have experience with an old oem battery smelling?
ive been getting a horrible intermittent smell in the cabin when coming to a stop. It’s definitely coming in through the fresh air hvac intake right next to the battery. I thought it was gear oil, but I’ve checked everything with no results. Now I’m thinking I may be confusing the sulfur smell of gear oil with sulfur from a bad battery. The smell occurring at stops would be in-line with the alternator kicking in on braking/engine braking and causing some charge related smell. Anyone else have this?
My battery is still original (late 2013) and the stickers on top are bulged a bit.
Regardless, I’m going to replace the original battery with the Duracell as a trouble shooting step. Should I have the dealer check out the charging system as well? Any chance it’s over-charging the battery?
ive been getting a horrible intermittent smell in the cabin when coming to a stop. It’s definitely coming in through the fresh air hvac intake right next to the battery. I thought it was gear oil, but I’ve checked everything with no results. Now I’m thinking I may be confusing the sulfur smell of gear oil with sulfur from a bad battery. The smell occurring at stops would be in-line with the alternator kicking in on braking/engine braking and causing some charge related smell. Anyone else have this?
My battery is still original (late 2013) and the stickers on top are bulged a bit.
Regardless, I’m going to replace the original battery with the Duracell as a trouble shooting step. Should I have the dealer check out the charging system as well? Any chance it’s over-charging the battery?
+1 on what lex said about taking precautions...
#416
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So I went through this entire thread and there still seem to be 2 schools of thought on battery registration. Has this been settled definitively, either way?
I'm leaning towards "yes" on registration and will inquire with a local Indy, as my BMWs have a similar IBS (intelligent battery system) that requires registration for the precise reason listed in this thread (the car has to be told that the battery is new so that it doesn't overcharge it).
I'm leaning towards "yes" on registration and will inquire with a local Indy, as my BMWs have a similar IBS (intelligent battery system) that requires registration for the precise reason listed in this thread (the car has to be told that the battery is new so that it doesn't overcharge it).
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GSBruce (05-01-2022)
#417
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So I went through this entire thread and there still seem to be 2 schools of thought on battery registration. Has this been settled definitively, either way?
I'm leaning towards "yes" on registration and will inquire with a local Indy, as my BMWs have a similar IBS (intelligent battery system) that requires registration for the precise reason listed in this thread (the car has to be told that the battery is new so that it doesn't overcharge it).
I'm leaning towards "yes" on registration and will inquire with a local Indy, as my BMWs have a similar IBS (intelligent battery system) that requires registration for the precise reason listed in this thread (the car has to be told that the battery is new so that it doesn't overcharge it).
#418
Rennlist Member
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So much for all those people on forums that claim batteries are "sealed" which of course none of them are. They are either vented (in a regular battery) or a VRLA (Valve Regulated Lead Acid) battery.
Battery acid when it gases has a very distinctive smell, just like engine coolant has a very distinctive smell.
You either have an old battery that is defective or the vehicle is overcharging the battery. What does your MFD say on the dash?
Battery acid when it gases has a very distinctive smell, just like engine coolant has a very distinctive smell.
You either have an old battery that is defective or the vehicle is overcharging the battery. What does your MFD say on the dash?
Last edited by IXLR8; 05-23-2021 at 01:25 PM.
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Porsche0911 (05-23-2021)
#419
Instructor
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So much for all those people on forums that claim batteries are "sealed" which of course none of them are. They are either vented (in a regular battery) or a VRLA (Valve Regulated Lead Acid) battery.
Battery acid when it gasses has a very distinctive smell, just like engine coolant has a very distinctive smell.
You either have an old battery that is defective or the vehicle is overcharging the battery. What does your MFD say on the dash?
Battery acid when it gasses has a very distinctive smell, just like engine coolant has a very distinctive smell.
You either have an old battery that is defective or the vehicle is overcharging the battery. What does your MFD say on the dash?
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IXLR8 (05-23-2021),
Porsche0911 (05-23-2021)
#420
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I take it you have a factory AGM battery.
This is what you should be reading based on the ambient temperature. My 991 at 6C (43F) was showing 14.9V. Spot on!
![](https://cimg5.ibsrv.net/gimg/rennlist.com-vbulletin/755x510/agm_d0619d122bfc0c319474a0e3d6805bfe36541dfb.jpg)