[arpad_m]

Originally Posted by 2023_ZL1-AUTO

So, car has been on CTEK charger for (2) straight days. I drove to Full Throttle Thursday's at a local car meet up, parked it for 2 hours at the meet, drove straight home. I put it on the CTEK charger right after getting out of the car. Now, the CTEK always take a few minutes to build up the LEDs the current level, and here after 30 minutes, it still shows more than 1/2 to go ??? I'm so confused with what this means, especially after a new 800CA AGM battery just a few weeks ago!

I'm not familiar with this trickle charger, but those steps look like phases, not charge levels, and the unit may be configured to spend a minimum amount of time in each phase before moving on to the next, even if the battery isn't depleted.

Also note that the alternator on our car charges rather conservatively, it takes very long to get back to full charge, a short drive doesn't do much.

If you want to find out about the battery's health, use a tester, here's an excellent, versatile, Project Farm approved one: https://www.amazon.com/dp/B07Z67MMGC

[2023_ZL1-AUTO]

Originally Posted by arpad_m

I'm no familiar with this trickle charger, but those steps look like phases, not charge levels, and the unit may be configured to spend a minimum amount of time in each phase before moving on to the next, even if the battery isn't depleted.

Also note that the alternator on our car charges rather conservatively, it takes very long to get back to full charge, a short drive doesn't do much.

If you want to find out about the battery's health, use a tester, here's an excellent, versatile, Project Farm approved one: https://www.amazon.com/dp/B07Z67MMGC

Thanks !!!

[Gunkk]

Originally Posted by 2023_ZL1-AUTO

So, car has been on CTEK charger for (2) straight days. I drove to Full Throttle Thursday's at a local car meet up, parked it for 2 hours at the meet, drove straight home. I put it on the CTEK charger right after getting out of the car. Now, the CTEK always take a few minutes to build up the LEDs the current level, and here after 30 minutes, it still shows more than 1/2 to go ??? I'm so confused with what this means, especially after a new 800CA AGM battery just a few weeks ago!

The CTEK's state of test/charge shown in the photo is bulk charging (high current, ramping voltage). The little graphics above and below the yellow LEDs are voltage on top and current on bottom. This is where it will spend most of its time when charging a battery. And AGM charging is not "max current for XXX hrs until full." The old school math of 75 Amp-hours / 5 amps = 15 hrs charge doesn't work on AGM. It takes about 5x as long, because the glass mat slows down the ion transport, among other reasons.

In a completely full battery (mine right now, for example) it will move through all the yellow lights in about 30 minutes to a couple hours tops. Then it spends a week at 1st green light before finally getting to 2nd green light.

After a jump, mine took about 3-4 days to completely charge up the dead battery.

Originally Posted by arpad_m

I'm no familiar with this trickle charger, but those steps look like phases, not charge levels, and the unit may be configured to spend a minimum amount of time in each phase before moving on to the next, even if the battery isn't depleted.

Also note that the alternator on our car charges rather conservatively, it takes very long to get back to full charge, a short drive doesn't do much.

I do have one of these CTEK tender/maintainers. The yellow lights are indeed various phases/stages of treatment (desulfation), charging, testing and maintaining/tending. There is no minimum time spent for bulk charging. It will quickly move through the various phases, or spend time at a given stage, based on needs of the battery. If it detects a fault (internal short or open, inability to take/hold charge, etc.) it will stop and throw a red light.

And yes our cars are almost deficient to the point of defective at charging up the AGM after a jump. A 2 hour long top down daytime cruise was not enough for my Z. And this will very much falsely convince you to think your battery is dying/dead and in need of replacement, when it doesn't... if you do not know otherwise.

Learned my lesson the hard way before I got the CTEK. YMMV

[2023_ZL1-AUTO]

Originally Posted by Gunkk

The CTEK's state of test/charge shown in the photo is bulk charging (high current, ramping voltage). The little graphics above and below the yellow LEDs are voltage on top and current on bottom. This is where it will spend most of its time when charging a battery. And AGM charging is not "max current for XXX hrs until full." The old school math of 75 Amp-hours / 5 amps = 15 hrs charge doesn't work on AGM. It takes about 5x as long, because the glass mat slows down the ion transport, among other reasons.

In a completely full battery (mine right now, for example) it will move through all the yellow lights in about 30 minutes to a couple hours tops. Then it spends a week at 1st green light before finally getting to 2nd green light.

After a jump, mine took about 3-4 days to completely charge up the dead battery.



I do have one of these CTEK tender/maintainers. The yellow lights are indeed various phases/stages of treatment (desulfation), charging, testing and maintaining/tending. There is no minimum time spent for bulk charging. It will quickly move through the various phases, or spend time at a given stage, based on needs of the battery. If it detects a fault (internal short or open, inability to take/hold charge, etc.) it will stop and throw a red light.

And yes our cars are almost deficient to the point of defective at charging up the AGM after a jump. A 2 hour long top down daytime cruise was not enough for my Z. And this will very much falsely convince you to think your battery is dying/dead and in need of replacement, when it doesn't... if you do not know otherwise.

Learned my lesson the hard way before I got the CTEK. YMMV

Thanks Gunkk... what you explain seems to be exactly how this is working !!! I appreciate your detail operational description of the CTEK ! Case Closed !!! (for now!!!)

[hawk02]

I just experienced a defective OEM battery with my ’23 Blackwing.

The car sat for 12 days. I opened the trunk with the key fob, but the trunk wouldn’t latch. I hit the key fob again to unlock the car — it was completely dead. I had to pop the cover off the door handle to access the mechanical lock to get into the car.

I was unsuccessful in getting the car started using my low-amp Battery Tender Plus and a low amp CTEK charger, even after several days connected directly to the battery with the negative lead disconnected. I ended up purchasing a NOCO 10-amp charger (https://www.amazon.com/dp/B07W3QT226...fed_asin_title). After approximately 6 hours of charging, I was finally able to start the car.

I took it to the Cadillac dealer, and their 2-hour battery test confirmed a bad cell. I received a new replacement battery under warranty. We’ll see how long this one lasts.