Just purchased a CTEK Mullti MXS 10 for my F Type.
Battery is fine; I've been using another conditioner on it that I'm now using elsewhere. Battery showing full.
When I connected the CTEK it quickly went up to light 4, ready to start engine. Then went to 5, checking. Then went to 6 which I understand should be for a max of 4 hours, but 18 hours later it's still on 6. I expected it to move on to light 7 (fully charged) then 8 (maintaining) Why stuck on 6? Can't be saying battery is no good, that is a different message, and I know the battery (new) is ok. I selected the AGM battery mode.

Any one else get this?

SORRY GUYS, I'm an idiot. Couldn't see in the sun (yes, sun in the UK!) but it had moved on to light 7, a green light. So showing fully charged, and I think will stay there for about a week until going to 8, float?

 

I have had two different CTEK'S that seem to do the same thing. But the batteries have always stayed charged. I called CTEK about this and they informed me I need to contact the ( Jaguar, Chevrolet, Bentley, etc dealer direct ) Talk about crappy service. So I did away with CTEKS and went with the "Battery Tender" brand and have never had any crazy lights or problems.

 

I have used the CTEK units for years. The CTEK goes into the long-term mode when the second green light comes on and that, in my observation, occurs around the two week point. No matter. These units are super reliable and don't require monitoring.
Using these battery maintainers I have had batteries last as long as 15 years (yes, 15) but that was in a 90’s Jaguar with nowhere near the power requirements that the F-Type (or any modern luxury make) has. In fact, hold on, the battery in my 1966 Mk 2 is now 18 years old and is still strong, or strong enough for requirements. The only battery drain on it is from the clock (and yes, the clock works)…perhaps I am tempting fate.

 

Thanks for the answers, yes, I think it's working fine. I just hadn't noticed (as per my edit!) that the first green light was on.

 

I had a Battery Tender on my Miata and it cooked the battery dry. The CTEK for the lithium battery on my motorcycle hasn't given me any trouble so I ordered one for the new battery, which is the proper AGM type, not the wet cell that was in there. We'll see how it behaves. The Battery Tender I've got is pretty old, so I'm sure is all analog. Perhaps the newer ones have better control over maintenance charge levels.

 

I have the CTEK MXS-5. I have not started my 2021 F Type R for over two weeks but I glance at the CTEK whenever I am out in my garage. Most of the time it shows the first green LED lit up (LED number 7, Float) but occasionally the green LED number 8 (Pulse) is illuminated. The manual describes the functions and says that after about 10 days, the CTEK will go into the Pulse mode.

 

I have a less complicated CTEK for both my cars, never had a problem. Maybe use a couple times a year for 2-3 weeks.

 

What is everyone's personal threshold for "plug in the CTEK" vs. just leave it off? 1 week without driving it? 2 weeks?

 

For me it's if I won't drive the car for three weeks or more.

 

Same here. 2-3 weeks and I don't bother. Mine holds charge well and fires up fine every time.

 

If my car is going to sit for a week or more I plug in the CTEK. Now that spring is here I expect to be driving it a lot more although with gas being above $6.50 in my town I'll be keeping a light foot on the accelerator.