wwest

Again, it basically does not matter, you can safely use the "snowflake" mode year around. The maintainer's "charge" voltage will then always be at the higher voltage winter setting but it cannot source enough power (~15V x 3.3A = <50W) into a car battery to be of any substantive interest. On the other hand if the car is parked inside in the warm when on the maintainer the summer setting could be used all year 'round.

golfpig

bought the CTEK 3300 for CDN$85.00 but it doesnt have the cigarette lighter attachment. any ideas on where to pick one up where it may easily attach to the unit?

Golf Pigging

axhoaxho

After the OEM battery died just after a couple years on my 997.2, I used a Porsche Charge-O-Matic. I just plugged it in the 12V outlet inside the car, and close the door. It worked pretty well for me so far.

And as folks say, the CTEK 3300 is essentially the same thing, and cost less.

SteveFromMN

Well with a constant 2amps at the end of 3 months storage you wil have probably boiled all the electrolyte away. A maintainer like the Ctek uses a more complicated circuit to back the current off to near zero when the battery reaches full charge. Another problem with your circuit is that with out a step down isolation transformer you may electrocute yourself or worse.
As an electrical engineer I have designed a number of chargers over the years but I just bought a Ctek because it does what I need it to and I have better things to do with my time.

MFank

I just ordered the CTEK 3300 ($55 USD freee shipping) & the cig lighter attachment ($5 + $5 shipping) on amazon.com.

CTEK 56-263 Comfort Connect Cig Plug :

wwest

My point was that it does not take a particularly bright electrical engineer to come up with an automotive battery "maintainer" that works.

If I had wanted to add the complexity of a transformer it would have been a simple 12 volt filament transformer. 18 Volts peak, only ~4 volts at low duty cycle (60 PPS) to "boil" the electrolyte if/when the battery is at full charge.

And finally: Not "dissing" Ctek compicated design by any means, just indicating that the <$10 one at Harbor Freight will work perfectly well, own 3.

jw1977

Two questions. Where are people putting the ground when attaching the ground? Second question is what does the cigarette lighter option replace? I'm guessing you this is so you don't have to plug it into an outlet?

dasams

If you're suggesting to power the maintainer via the cig outlet, then there are a lot of replies that come to mind but you won't like them Connect the maintainer to the car via the battery terminals or the cig lighter. Some prefer the latter due to ease. dave

jw1977

I was just making sure you don't have to connect the leads to the battery if you're using the cigarette attachment. I guess I don't get how it charges the battery if you don't attach leads to the battery?

eflight

Cause the battery is connected to the cigarette lighter

CAVU

Our Porsches are a bit unusual in that the cigarette lighter and accessory connection in the passengers footwell are always "hot". So it makes it a simple matter of plugging in the cig adapter into the cig lighter connection.

USMC_DS1

That's correct... you can just connect the maintainer to the cigarette lighter socket. Make sure to use the cigarette lighter and not the socket at the foot well. Optionally some of us have connected a line directly to the battery terminals... running the line up through the windshield wiper cover.

SteveFromMN

Wwest
I don't want to make a big deal out of this but a continuos current of 2amps will not boil the electrolite away it will none the less turn it into H and O and it will be gone. This is why they designed maintainers instead of trickle chargers to cure this issue for long term storage.
I think if you are going to store your car for a long period it is just good practice to use a good maintainer. There are ones that are as little as $25 that will probably work fine.
However if I'm going to leave something plugged in my garage unattended for 3 months with a typically wet salty floor in the winter, I will opt for a well built unit.

wwest

Provided the cigarette lighter remains "powered" with the ignition key removed the battery maintainer can be connected to the battery via the lighter socket. no need to leave the front lid open.

wwest

Maybe..maybe NOT.