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How to set up a CTEK charger 12v passenger footwell - 992
Background:
My 992 C4S arrived 3 days before lockdown started here in the UK. The car had only done about 200 miles in the middle of March, (from the dealership to home), so by the time we got the end of April I decided to buy a battery charger. I have had a few 911's and as with any modern internet connected car they do tend to drain their batteries if left unussed for weeks at a time. I have previously used the Porsche Charge-O-Mat on my 991.1 and 991.2 but after reading this forum and checking the "good to know" manual, I worked out that I had a Lithium battery and that my charger would not charge it. I was then left with two choices: buy another Porsche charger, (my preferred action, I'll explain why shortly) or buy a CTEK charger. Sadly, finding a Porsche charger provide quite difficult. Many dealers where closed and even the few that were manned, either didn't have stock or couldn't get it to me for a month or so. I decided to look at a CTEK charger as they are essentially the same as the Porsche version. Only there are some tiny differences, namely the charging profile. How the charger initiations the charge and I believe a subtle change to the pulse, (but I am way outside of my knowledge here so feel free to correct me). From memory, on the 991 if you wanted to use the 12v charging socket vice connecting direct to the battery, it was easier if you had the smoking package as that gave you a permanently powered 12v socket in the centre console. Even if you opt for the smoking package on a 992 you do not get an additional 12v socket. There is a standard one in the passenger footwell but it is not permanently powered unless you use a Porsche charger or follow the procedure below. The issue is that once the ignition is turned off the car protects itself and disconnects the internal 12v socket after 30 mins.
I ordered my CTEK not realising that it wasn't totally plug and leave like the Porsche system. The first time I used it, it just worked, (I got lucky). Imagine my confusion when after I had moved the car to wash it and then put it back on charge, it kept stopping after 30 mins...... It took me a few days to figure out what was going on, connecting the charger and coming back next day to a green blinking light, (meaning it was disconnected from the car). After a lot of research and speaking to my dealer we figured out that the 30 mins shut down could be overridden quite simply, (see below). I can confirm this works for my car (Feb 20 build) using the kit listed below. Hopefully this will help someone else as I could not find an answer anywhere on how to override the 30 min cut off without resorting to buying a Porsche charger or leaving a wire permanently connected to the battery.
Conclusion:
You can charge the car using a non-Porsche cigarette adapter (CTEK) by using the procedure below.
The Porsche-O-Mat just works and is a true plug and play. (Based only on my 991 experience. Can someone confirm that is true of the 992)?
You can also connect a non-Porsche charger direct to the battery, but most people leave a wire in the boot. (Connect to the battery terminal and the other lead to the terminal post in the car, DO NOT CONNECT BOTH CHARGER LEADS DIRECT TO THE BATTERY - See Porsche "good to know" about batteries for more info). I didn't not want to do this as I found the 12v cigarette adaptor method much simpler.
Setup:
CTEK Lithium XS charger and conditioner 12v 5A
CTEK Cigarette Lighter Lead - 12v
CTEK 2.5 Meter Comfort Extension Lead
My car: Feb 20 Build 992 C4S with rear-steer - LiFePO4 Battery
Procedure to keep 12v internal socket active:
Connect your charger to the 12v socket - Car ignition off, Charger NOT plugged into the wall.
Charger connected to the 12v socket - Car ignition on, plug in (turn on) charger.
Check lights on charger are moving through steps 1/2/3 etc
Turn ignition off - Charger lights should still be lit. You are good to go and the 12v socket should now stay live.
If your charger is flashing green (No other lights just the light bottom left in the photo below), then the car has disconnected the circuit and you need to try again.
The photo below is how your charger should look after a few hours if it's happy.
CTEK Charger - Finished charging and now pulsing/topping up the battery.
good hint thanks, plugging in the trickle charger to the lighter port with car power on and then turning car off seems to work! was struggling with putting my new 992 to bed for the winter! not sure why it had to be this difficult, but hey
actually same with me after taking some time to play around. per my dealer there is no way to get around the timed auto cut-off on the tucked away 12v outlet. initially there was some concern on their part about direct hook up to the battery, but they reversed this after some discussion so now just clips to the frunk battery and working fine.
we also discussed buying the $280 porsche charger, but they finally said my standard auto supply one should be fine as not a lithium-ion battery in the 992.
I don't have all the facts yet, but some battery issues have been popping up so here is a HEADS UP:
Make sure you are CERTAIN that you know whether your 992 has an AGM or a LiFePo4 battery since not all 992s use the same battery. I think 992s with RAS (like the OP's) and the 992 Turbo(S) have LiFePo4 batteries - but don't quote me. Remove the cover and inspect your your battery to be sure.
You can damage a LiFePo4 battery by using the wrong type of battery maintainer - they can run the charging voltage up over 15 volts and the nominal max for the new Porsche LiFePo4 batteries is 14.8v. Thanks to the OP we know the CTEK Lithium US product works on Porsche's new LiFePo4 batteries. Is it safe to use a Porsche-branded maintainer (in Li-Ion mode)?
This might be a good thread to accumulate some more facts.
Getting a new 992- question can you wire the charger connector to the positive and negative of the battery- or did I read that should not be done.
No, do not connect directly to the battery. There is a small post next to the battery that you should use. I recommend downloading the "Good to Know" app, it has a diagram showing the right way to connect directly to a battery.
05-09-2020, 10:30 AM
How to set up a CTEK charger 12v passenger footwell - 992
