bagel

Happy New Year all,

I have read a lot about which battery tender to get (CTEK). Do I even need one? Never gets below 35F here. I drive the car once every 2-3 weeks.

Thoughts?

Tupper

I got the Porsche one, which is an overpriced, rebranded CTEK. I recommend getting one if you are going to be gone for long periods of time. They are a piece of cake to use

bagel

Thanks Tupper, what would you consider long period of time? I sometimes go 3 weeks without driving.

Richard_Wallace

You do not need one. Mine (Covid) goes 3-4-5 weeks without driving. Not a problem. I have the C4S with RAS (so LiPo battery).

With that said, I have about 4 chargers in my external garage and utilize them all the time with my other cars, nice to have one if you do not use your car for a longer period 6 weeks. I actually took my 992 out the other day, after 3 weeks of not driving it, I still had good voltage but thought it needed to do a 30 minute jaunt anyway. My 992 is my DD, but just not driving much since working from home, not going out much, etc. So it stays parked, longer than I like...

The vampire drain on the 911's are not nearly as bad as the other exotics out there - so you should be good if you are driving it every 4 weeks or so.

detansinn

If you're taking it for a "real" drive every 2-3 weeks ("real" being at least an hour and not a spin around the block), you may be able to get away without one. If it's more typically 3 weeks and/or you're not taking it for a "real" drive when you do go out, get a battery tender/maintainer.

Tupper

^ Yeah, 3 weeks is probably ok.

My car is parked in a garage for a good portion of winter, so I have it plugged in.

But it might not hurt to still have a battery maintainer "just in case"

RD16RR

You can also use the one of these from Deltran: first one @ $39.00 is just a bargain - the other is a tad more sophisticated for $120.00

If you're driving the car every now and then you probably don't need it....if it stays inactive more than a month or so, it's safer to leave it plugged in - be careful not to leave the key inside the car, as that would be a drain on the car battery

https://www.batterytender.com/Batter...tery-Charger_7

https://www.batterytender.com/Batter...tery-Charger_3

rsabeebe

i would say that your experience may be specific to the car(s) in question. some of mine will deplete quicker than others and i think 3 weeks is right on the edge of needing one. if you asked about 'a month' timeframe, i bet you'd be getting far more 'yes, you need one' responses.

they're cheap, unplug with ease, and you will always have a car that starts.

Richard_Wallace

I leave the keys in my car and I do not think it issues wake up calls, as mine has been parked at times for 3-5 weeks, and no issue. If they key caused wake ups (like some of my other cars do) - it would be dead within 2 weeks.

What will drain it faster, if you check the app frequently, as that does send wake up calls to the car.

Also, not sure where I read it - here or another site, but with the alarm on, it is more power draw than off.

drcollie

Which battery do you have in your 992? They come with either AGM or Li-Po depending on your options such as Rear Wheel Steering.

AGM might want a tender in 3 to 4 weeks
Li-Po can go much longer but requires a specialized charger, not the cheapie Battery Tender brand.

This is a photo of the 992 Li-Po battery

photonscience

Because of my busted hip, I haven't driven my 2021 Carrera S for about 4 weeks. Before installing the Porsche (CTEK) battery tender, a friend started the car up for me (just to see if it would start) and it turned over immediately. He plugged the battery tender into the 12 v socket in the passenger well and then connected it to power. Worked fine, started to charge the battery and then about an hour later, it was no longer working. Apparently, that 12 v socket is automatically shut down after 30 minutes. Porsche parts guy says you have to buy a plug adapter with alligator clips for the tender that allows you to hook it up directly to the battery. Wasn't that way in my 991. Don't know if there is a work around for the 30 minute shutoff, but the Porsche parts guy didn't know of any. Anyone know how to get around the 30 minutes shut-off?

My experience tells me that a new AGM battery is not going to let you down after 4 weeks of the car sitting.

drcollie

The12v outlet will shut off if you leave the doors unlocked. Hook it up, then lock the car and it should function.

I see you have never owned a Ferrari ! Their AGM batteries rarely go move than 5 days without being on a tender. High parasitic loss and low quality $ 650 batteries.

997usa

I installed the connectors onto the battery, and using the CTEK Lithium charger. Works perfectly.

photonscience

Hey, thanks. I'll give that a try.

Nope no ferrari here.

markjeansonne

I was told, a long, long time ago, that a battery that is not 100%, say consistently 80% at start-up as an example,
does indeed strain the alternator, at least momentarily. I was told that if you keep your battery at 100%, then there
is always less stress on the alternator, which should extend it's life. I keep all my vehicles on tenders any time
they are parked at home.
(disclaimer: I'm far from being a mechanic, so I'm just repeating what I practice, don't know the actual science here.)