Hi,
there have been a few topics recently regarding batteries failing or just getting low,
due to reduced use (Covid19)
or the colder weather
or Both

If you have a 13 pin or twin sockets for towing then you can check the cars battery with a volt meter via the socket,
while it is still Sleeping (dont unlock it first ) as there is a perm live in a 13 pin and the white S plug with twin sockets, both of which should be fused.
12.7v should be a good healthy figure
12.2v its getting low and you could fine stop/start has not been working and possible another turn or two of the engine before it starts
It could just be wanting a charge or good long run 20+ miles and over 1/2 hour minimum or a new battery is looming.
lower than 12.2v and your on borrowed time

you can charge the battery via the tow socket as well, Martin sells many types of leads in the SHOP ^

https://fnltd.co.uk/shop/tow-electrics-cha...c-p45.html

PS>
happy for voltage figures to be amended they are the figures I have found right
The car needs a good run of 20+ miles or around 1/2 hour just to get all the oils up to operating temp your water temp gauge may be showing normal after 2-4 miles and 10 minutes but for the oils to get up to temp takes a lot longer  .
my first ever FL2 and I did keep it longer than most other cars!
But its now gone way up Norf

This is a good thread to read on charging thru the 13pin tow socket.

https://www.freel2.com/forum/topic34903.ht...battery+13