Mine are a bit contrary to the battery charging obsessive fetishist evangelists, I dont think any vehicle with a minimum of a 90 amp alternator probably a lot more will have any problem recharging the small extra capacity of an 096 battery, once fully charged it is not going to need any more recharging after a start than an 027 battery, the starter motor will not have drawn any more current, the difference in the overnight self discharge will be de minimis.
And on that subject the starter motor will be a 1.7kw geared starter lets say 2 kw, these engines start in less than a second of cranking but lets say 3 seconds, that equates to 166 amps at peak, at lot less having got the engine rotating, this equals 0.14 AH.
Throw in the glowplug preheating say 5 seconds and the heating while cranking 3 seconds, post start heating will be covered by the alternator, lets say 40 amps for 8 seconds = 0.09 AH
So a total starting discharge of 0.23 AH which we will round up to 0.25 AH
Lets say you drive off using heated rear screen, heated seats and anything else you can think of, lets say that half of the alternators output is used to cope with the running load, it wont be anywhere near that but I am being very conservative with all these figures, lets say that there is only 45 amps remaining output from the alternator.
You would need to run the engine above tickover speed to get the full alternator output ie driving but recharging will have commenced as soon as the engine starts even at tickover but I will also ignore that, you need to replace 0.25 AH from the spare alternator capacity of 45 amps = 45 AH.
You would need to be driving for 20 seconds to recharge the battery from a normal cold start.
Lets say that you crank the engine for 2 minutes which is a very long time but maybe you have air in the fuel system, even using the above very exaggerated current figures you would only need to drive 13 minutes.
I'm afraid the "your battery will discharge on short journeys" has been an old wives tale since the introduction of alternators as standard fitment some 50 years ago over the preceedin dynamos that did not give enough output to cover a full electrical load with the then new heated rear screens and which did not charge at idle speed.
I would appreciate it if someone else can cast an eye over my figures and tell me if I have made a mistake 👍