I'll bite... how do you know? SDV8 AB MY 2020
MINI Cooper S Cabrio
Kit: Jaguar XK140 (in progress - the website is link to build)

Measure the battery at the jump starter connection, order nre one and now i have two batteries😂

For me I was measuring under the hood it was more to see what the charger was doing. I am thinking of getting a battery sensor to attach directly so I can see the real level.

As I use the remote heating every morning at the moment. It is zero degrees here. I want to make sure the battery is good. SDV8 AB MY 2020
MINI Cooper S Cabrio
Kit: Jaguar XK140 (in progress - the website is link to build)

Aldogt3 wrote:

Measure the battery at the jump starter connection, order nre one and now i have two batteries😂

Sorry to resureçt an old thread but I also now have 2 batteries. I don't understand why the readings are different under the bonnet. My original battery is 9 years old so probably due for changing anyway

The moral of the story is 'research on FF before splashing the cash......not after'

The dual battery system is complex - and it's not clear (to me) which one is connected to the under bonnet posts - when the car is turned off. I expect it's the larger one under the spare, but don't know.

As soon as the car is 'on' the batteries may (or may not) be connected together, so all bets are off.

If you really want to know the batteries individually, then you need to check them directly.

A bit of info here, but not sure it will help - https://www.fullfatrr.com/gallery/albums/u...cables.pdf