Rennman

Is it alright to use a trickle battery tender brand on my 17 991.2?

shammerman

Yes it is.

Kitc2246

Looks like an older maintainer on a lead acid battery. Should be fine. If you ever upgrade to an AGM you should buy a newer maintainer that support flooded lead-acid, AGM and perhaps lithium.

Rennman

thanks so much for your quick responses
Rennman
Bill NJ

asellus

aren't the OEM batteries for the .2 AGM?

z168

Yes

PorscheC2S

I would suggest buying a AGM trickle charger. You can find them on Amazon for like $90. Plus use the pigtails supplied and just attach to the battery and rout the pigtail to the side of the hood by the windshield this way you wont have to open the hood each time. That's what I've done.

Dans911C

I use the ctek battery maintainer that plugs into the 12V sockets inside the car. Same as the Porsche chargers but half the price.

Kitc2246

I Googled the part number. It showed a lead acid, not AGM. If you switch to AGM you have to code the new battery as AGM. Many threads on coding. The one that makes the most sense to me is if the start-stop doesn't work and you have error codes you need to code the new battery. Otherwise the BMS will treat the new battery like the old failing one and overcharge. A preemptive change based on age only should not need coding.

asellus

What exactly did you google? I show AGM when I google 999.611.080.12, which makes sense as the OEM Banner batteries are AGM.

There's even verbiage around "this is a start/stop vehicle, so AGM is used" on a few sites that come up.

RennListUser01

If it doesn't say AGM somewhere on the battery, you should be able to check the Banner website with the product codes.

CSK 911 C4S

I use a 4 bank of the same charger and it does very well with AGM and Flooded batteries.

Keeps everything topped off and ready to start.

IXLR8

The battery shown is the same exact battery in my 991.1 GTS. It is an AGM battery and they all fall under a "lead acid" battery. That is why they are called VRLA (Valve Regulated Lead Acid) batteries which include AGM and GEL. And yes, they can leak acid if overcharged and no, they are not "sealed" as so many think they are...for safety reasons.

They take a slightly higher charge voltage compared to a standard flooded lead acid battery. In fact when I got my GTS and thinking it had a standard flooded lead acid (FLA) battery, I was seeing 14.9-15.0V on the MID at 6°C. Wow, way too high I thought. In fact, perfectly normal when looking at the chart below from East Penn batteries.

RennListUser01

The fellow is fast and somewhat irritating, but seems to be thoughtful about his testing ... and, he tests a LOT of stuff!

My takeaway from this test - which included AGM batteries is ... no need to buy AGM batteries, unless you have a spill issue?

IXLR8

I've seen some of his tests. I worked in a lab a good portion of my life. Sorry to say but that guy in my books is not very analytical. Now I can tell you about some great YouTube diagnostic videos like DiagnoseDan and some others.