Getting sick fed up of "Low battery, start car" RR Sport my2015. Car not used much, usually on Ctek & both batteries changed earlier this year. Latest example, Saturday past did about 160 miles. Sunday, put on Ctek which did its stuff, yellow & green lights came on after the usual charging time. This morning, Thursday, disconnected Ctek got in car to the dreaded message.
Cteck has comfort connecter which is connected to the two posts in engine bay. Noticed when disconnecting that it was still flashing red on comfort connector although when I switched it of at the mains prior to disconnecting all yellow & green lights were on. Car started ok
This is driving me around the bend. Anyone have any suggestions

The auto stop/start battery hates cold weather! I had this regularly in the last RRS and both Evoques when it was below 2-3C overnight. 2020 Pangea Green 1st Edition D240 New Defender 110 is here and loving it
2018 Melting Silver Mini Countryman PHEV - soon to be replaced
2015MY Corris Grey SDv6 HSE Dynamic, the best car I have ever owned, totally reliable only a cou0le of rattles in 3 years, now no longer in my care
Also in my garage is a 1996 TDi300 Defender 90 County HT made into a fake CSW

Ok, but why would the comfort connecter still be flashing red after 4 days & the dreaded warning comes on when the Ctek says its fully charged

A fault on the battery conditioner? 2020 Pangea Green 1st Edition D240 New Defender 110 is here and loving it
2018 Melting Silver Mini Countryman PHEV - soon to be replaced
2015MY Corris Grey SDv6 HSE Dynamic, the best car I have ever owned, totally reliable only a cou0le of rattles in 3 years, now no longer in my care
Also in my garage is a 1996 TDi300 Defender 90 County HT made into a fake CSW

That comfort connector indication is a waste of time, I've them on my Sport and Wife's Evoque. I had the Evoque in my garage with heating on (cold affects batteries a lot) during a couple of days detailing, and within an hour of removing from charge the indicator was flashing red (I didn't check voltage as I was pushing on with the detailing). But on startup there was no issue's, messages or anything. Same with my Sport, it flashes amber or red pretty soon after removing from charge especially in colder weather.

Just re-read - do you mean the indicator is still red during charging? If so then check your battery volts before, then during turning on the charger and see if the charger is actually working. 13MY Range Rover Sport Autobiography SDV6 - mine
14MY Range Rover Evoque Dynamic SD4 Black Pack - wife's
99MY Defender 90 TD5, Soft Top Conversion - my toy, and bairns favourite

As this issue relates to mine and seems to point to the Stop / Start battery - which won't work during the winter anyway. (Start - Stop), is this anything to flag up when the car goes in for a Service within the next couple of weeks?
Or should it just be left to slide until warmer conditions arrive, although for me that won't be until about June of 2019.

Cheers
Steve 2019 RRS P400e Autobiography
2014 RRS 3.0 TDV6 HSE Dynamic
2006 RRS 2.7 TDV6 HSe
Alfa Romeo Guillietta 2.0 JTDM 2011
Mazda 3 1.6 2010
Subaru Impreza 2.0 WRX 2005

Hi,

Remove the spare wheel and battery cover.

Check the connection between the battery earth cable and the body.

That’s what LRA did to mine when I had a similar problem - poor ground, OK to charge but causes fault when drawing starting current.

Scrumps Somerset - Where the apples do grow and the cider do flow!
2021 Defender 90 D250 HSE in Tasman with white roof.
24MY D300 AB - Verasine Blue - 😀
19MY SDV6 AB - Byron Blue - Gone
17MY D5 SDV6 HSE - Firenze Red - Gone
16MY SDV6 AB -Aruba Silver - Gone
13.5MY SDV6 "HSE Black" - Baltic Blue - Gone
10MY TDV8 HSE Galway Green - Gone
14MY D4 HSE in Scotia Grey - Gone
05 TD5 D90 CSW in Cairns Blue

Battery conditioner is working. Tried it on spare battery, its delivering about 14.8 v. Comfort connector flashed green on startup, then changed to amber. Just had a look after about 30mins & its flashing red. Looks like there may be a problem with it.
Will try just connecting ctek to the posts with croc clips bypassing the comfort connect.
Also I am using 2 extension cables (total length 5m) maybe getting a volt drop. Have emailed Ctek to see what length I can use

Answer from Ctek (very fast reply) only one 2.5m extension cable should be used

Just out of interest, have you tried charging without the extra 2.5m extension? Any difference noticed?

I'd considered a 2.5m extension but don't think I'll bother now, at the moment I use an extension on the 240v side with waterproof socket so I'll just keep using that. 13MY Range Rover Sport Autobiography SDV6 - mine
14MY Range Rover Evoque Dynamic SD4 Black Pack - wife's
99MY Defender 90 TD5, Soft Top Conversion - my toy, and bairns favourite

Can't see there being any effect of two 2.5m cables over one. Which Ctek do you have? 

I have Ctek MXS 5. The longer the cable, the more volt drop you get. Ctek are saying one, so for an experiment I will put the ctek under the bonnet then I wont even have an extension. The reason I had my setup was that I would not have to open the bonnet, just a quick connect/disconnect at the front of the car onto the comfort connector

While I always put the charger unit under the bonnet, largely due to not having the extension and with comfort connector right at the battery box (L320, probably different to L494), from memory the unit is IP65 rated so fine for rain if left outside although I'd try to tuck it under the car as far as I could.
This was my intention if getting a 2.5m extension. Of course the 240v plug needs protected though but that's why I have a waterproof extension socket, I tend to put it under the bonnet on my sport but that's due to the Ctek power lead being a few inch too short which would cause the cable to rub on the car if windy. On my wife's Evoque it sits outside on the ground just fine. 13MY Range Rover Sport Autobiography SDV6 - mine
14MY Range Rover Evoque Dynamic SD4 Black Pack - wife's
99MY Defender 90 TD5, Soft Top Conversion - my toy, and bairns favourite

I use one of these with my MXS 5;

https://www.disco3.co.uk/shop/tow-electric...c-p45.html

I use the same towing electrics adapter with a genuine 2.5m extension and have never had any problems with it or the car. i am convinced the car behaves so much better because i keep the battery topped up. we don't do a huge mileage in it hence why I started using the Ctek. MY16 3.0 SDV6 Autobiography in Aleutian silver, stealth pack and toys.