As title, does the engine need to be running or will it charge with just the ignition on?

Thanks Black FL2
L200 Warrior

Update: just ordered a new battery

Still be handy to know the answer though  Black FL2
L200 Warrior

As far as I know if the fob is left in without the engine running, it is DISCHARGING. It only charges when the engine is running. My dealer warned me of that and said not to sit for ages listening to the radio without the engine running. Also said to alternate fobs every now and then.

Surely the radio draws its power from the car's battery, not the key's? Series 2A 1961, 1975-78, made to last forever.
Series 3 Lightweight, 1973, 1999 - 2012, still regret selling this car.
Freelander 1, 2005, 2005 - 2008, sold the minute its warranty expired.
Defender 90 200 TDi, 1985, 2012 - 2014, paid far too much for it.
Defender Wolf, 1998, 300 TDi, 2017 - 2019, too expensive to maintain and the Army hadn't.
Defender Puma, 2009, 2014 - 2014, not a sensible family car.
Freelander 2, 2012, current, is this the car to last?

Of course but while the key is in the slot the battery is being drained unless the engine is on. Radio was just aj example of something you may do without running the engine.