Morning everyone,
I'm new here and not particularly technical so apologies for that.
I bought my Jaguar XF Sportsbrake (2018, petrol) back in April and being my first Jag I must say I do love it. However I have a small issue with the 'Low Battery. Start Engine' warning light that comes up on the dash center screen, most of the time. That being said the car always starts first time, for which I am thankful. Upon reading lots of posts regarding this issue I am still a little confused. Some say this is a common fault on jags but not to worry. Others say it's the BMS (battery monitoring system) and others say other things and I don't know. Strange this just started after the warranty ran out. I have taken the car to a Jag specialist who fully charged the battery and then when he came to move it the warning came up again and he said he checked the battery and it was still holding the charge and this must be a fault with system. I mean how do I actually tell when the battery is failing with this fault? Can anyone shed any light on this for me?

Also I believe this vehicle has two batteries? Yes, I've still not checked as always busy but am I right thinking the small battery is for electrics when in start/stop mode and the bigger battery handles everything else? I generally turn off start/stop as a rule.

If the above is correct, is it possible to put a bigger mh battery on the car to deal with the excessive amount of power it draws, not that I'm complaining lol
Many thanks,
Badger