911sanantone

I own 4 Battery Tenders. The oldest is 14 years and still going strong.
I have never had a single issue !
The Battery Tender Plus has all the technology you will need at less than half the price of CTEK.

BradB

I have both but prefer the CTEK connector design and plug/connection accessories.

SDaddy

The 991 GTS has an AGM battery and the CTEK model that Porsche brands includes a setting for AGM batteries. If you go with a Battery Tender Plus, I suggest making sure it is designed to work with AGM batteries.

jennifer911

The “plus” in the Deltran battery tender plus, means it automatically does both regular and AGM batteries.

TorqueChap

Thanks SDaddy and jennifer911.

Per Battery Tender's website:

RECHARGING AGM BATTERIES: The Battery Tender® has an absorption charge mode, but the the Battery Tender® Plus has a different absorption mode maximum charge voltage and a timer to hold the absorption voltage longer. These specific changes were made to accommodate the charging requirements of Absorbed Glass Mat (AGM) style lead acid batteries.

SDaddy

dloines

i have both battery tender and CTEK, they are about the same as far keeping the battery charged, i have been using battery tenders on my motorcycles since the late 80s, they usually last 10-15 years. I purchased the CTEK for my cayman s in 2008 and now use it on the 991, i do like the connections better on the CTEK and although i use it in the garage they are suppose to be weather proof....

Roosell

Get the Porsche version. It's faster.

TK11069

I have the 3300. It didn't seem to be charging at all after 20 hours until I realized it had to be on the 'snowflake/AGM' setting. Then it charged right up in a few hours while plugged into the foot well outlet. I bought the charger, extension and cig lighter adapter all for less than the Porsche branded Ctek.

I like that the 3300 has different connection options especially the extension between the lighter and charger which lets me have the charger on the garage wall (easily visible) rather than on the floor or in the car.

I don't know if the Porsche version allows disconnection of the cable or how long it is. Also, since the 3300 has a specific setting for AGM batteries, I assume this is the only setting on the Porsche version.

kayjh

Does anyone have the dealer installed version? Do they install it with a detachable pug near the front like BMW and then wire it into the car so all you have to do is plug it in? Personally, I'd be happy just to have the portable version and plug it into the lighter over the winter and then just store it on a shelf in my garage over the summer.

I have a 2 car garage, so my car will go into heated storage somewhere over the winter months. Don't know if I'll have electricity in the storage location, so the battery might be coming out each winter.

Is there anything required in the spring, other than putting the battery in and resetting clock, favourites etc.?

mad_max

I have the CTEK 3300 with lighter adapter. Best bang for buck

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1