Thanks for the above. I'm "late to the party" but I found the interview most instructive in terms of the exact function of the second battery and the Ctek120S and what I'd refer to as the "Ctek philosophy" which I hadn't fully appreciated until now. It certainly hasn't been properly explained either by Ineos nor Ctek to date in terms of the Grenadier application.
My uninformed complaint was that the system was not as I had expected in terms of a dual battery arrangement!
My "education" came around the 26 minute mark in the video: essentially the pulse charging of the main battery by the second battery is a form of conditioning which reduces the likelihood of sulphation and amongst other things, where there vehicle has been left standing, keeps the electrolyte from developing layers of non-uniform acid concentration.
Conclusion (mine): The Ineos system has been designed to optimise the life of the (expensive) EFB Molle Stop/start battery, and is best left well alone. Use a separate setup with a DC-DC charger to maintain additional "house" batteries for accessories ...fridges, camp lights etc ....
In the past 9m for various reasons, I've driven less than 1,500km in my Grenadier since the first 12m/15,000 km service, but I have charged the batteries every couple of weeks using a Victron 15Amp IP65 intelligent charger.
Seems that based on the tech. explanation in the video, reducing the interval to once a week to bring the system to float/maintenance mode would be an optimal course of action. (One of the Ctek interviewees uses the example of his 2019 Audi which he implied is "hungry" in terms of power demands, is still on the original battery (Feb2025) because he keeps it regularly charged to float (100%) level , whereas the alternator alone will never reach much more than 90% in day to day use.)
Thanks again
@TheDocAUS for drawing attention to this info. IMHO it goes a long way to explaining the design philosophy of the second battery arrangement in conjunction with the Ctek 120S.
