dntlvet

OK ..... In the tools and equipment thread of 991 GT3; I asked about this as well.
The NOS 1500 and the Battery Minder were recommended.

I like the fact CTEK can charge using the cig lighter. Is the main unit also plugged into a 110 v outlet or is the power supply strictly from the cig lighter? How does that work?

Can multiple cars be connected to the CTECK as is possible using the battery minder?

GreenLantern

3300 vs 7002 is more modes, and faster charging. No idea about the 4.3.

I went with the 7002 because I wanted the additional modes, and the faster charging is nice when you need a battery charged in a pinch (~day vs. days).

Mike in CA

One battery per CTEK charger. You can't charge multiple batteries with one charger.

WSH

Thank You !

bronson7

Thanks for all the responses. Snowflake it is.

golfnutintib

Ctek, Noco, Battery Tender are all fine. Higher models charge faster, have a few bells and whistles. For battery maintaining all work with no issues. Brand wise better to stay away from Schumacher...used to be good, now sh-t...

Some have different or flexible adapters for pigtails connected to battery posts, SAE connections, cig lighter input etc etc...Porsches can charge via cig lighter fine in maintenance mode.

dntlvet

Thanks everyone. Good thread!

W8MM

I wish I knew how Noco and Battery Tender were internally constructed. I'm an EE and have my own (possibly peculiar) ideas about what makes a good battery maintainer, or not.

1) Old school (i.e. Porsche wall-wart-style) battery maintainers were made by using a wall-voltage AC step-down transformer and a semiconductor rectifier circuit filtered by an electrolytic capacitor. This circuit performed just fine for as long as the crappy capacitor held its "capacity". Electrolytic capacitors sometimes "dry out" or otherwise lose their "capacity" to function over time or from power-line surge abuse.

2) After the capacitor lost some portion of its function, the 120 Hz (or 100 Hz depending on local power specs) rectified AC waveform caused ripple currents to appear in the charging current. It turns out that large values (you get to guess the critical amount) of ripple current cause all sorts of nasty chemical actions in the battery chemistry and the internal resistance of the cells begins to rise. After a sufficient amount of time of being charged in this high-ripple-current manner, the battery begins to resemble an anvil in its ability to hold a charge. Kaput!

3) I experienced many battery failures in my stored-for-the-winter vehicles during the time I was ignorant of the AC ripple-current battery destruction mechanism. I took "perfect" care of the batteries with impossible-to-know imperfect or failing battery maintainers. They seemed to charge the battery, but the battery failed anyway. I was really pissed.

4) The C-Tek method does not use a conventional transformer/rectifier that can output 120 Hz (or 100 Hz in Eu, etc) ripple currents if imperfectly reliable. C-Tek uses a 10's or 100's of KHz switching regulator that samples the incoming AC wall-plug voltage at this very high frequency and filters it with a small, but effective, inductor. This system cannot excite the same destructive chemical reaction if something goes slightly amiss. The inductor filter is much easier to guarantee its function over time and, if it failed, the frequency of operation is less molecularly active in the battery if the failure goes unnoticed. Ripple-current battery destruction is sooooo much less likely.

5) After changing to the C-Tek high-frequency switching-regulator battery maintainers, I have NEVER had a subsequent over-the-winter battery failure in any of my cars.

6) Anyone using anything BUT a C-Tek (or equivalent) battery maintainer is ignorant or a fool!

991 3Turbo

I have used Battery Tender products for the last 20 plus years. Never failed me. Always work. I have also restored batteries that wouldn't otherwise hold a charge with convention chargers. CTEK is nice but not at all necessary especially for the expense. I have Tender brand on every jet ski, car, motorcycle, and garden tractor as well as my cars and they work perfectly. I also like to see the lights on the wall plug to monitor state of battery. CTEK is not the only product that works. A correctly maintained and desulfated batter is what counts.

W8MM

Of course, you are correct.

Now, just how do you know if your charger of choice is putting out AC ripple currents?

If you don't have a clip-on AC/DC current probe for your oscilloscope, how would you know?

Plus, $59.60 including 2-day shipping from Amazon doesn't seem extravagant to me:

sccchiii

Not sure about anyone else but I check for AC ripple currents with my flux capacitor?

bronson7

When using a CTEK 7002 with the cigarette lighter attachment, which should get plugged in first, the power cord in the wall outlet or the cigarette lighter adaptor? Or does it matter? It doesn't specify in the CTEK manual. I believe with my previous Porsche battery charger, they recommended the power cord in the wall outlet first, then when finished, always remove the cigarette lighter attachment first, so the opposite.

GreenLantern

To be honest, I've never been a fan of using the cig lighter as the charger connection. I always prefer to plug into the positive contact on the battery, and to the ground point of the frame (whatever it may be).

Mike in CA

Page 5 of the CTEK 7002 manual says to connect the charger clips to the battery and ground first and then plug in the AC cord. It doesn't specify for a cig lighter connection but I'd infer from this that you would be safest to plug in the 12V connector before plugging in the charger.

bronson7

Thanks Mike. I might go the "clips" route eventually vs the cigarette lighter, just need to get more info.