In English if you had a limited amount of space to write "4 days, 22 hours, 5 minutes" you could shorten it like this, and it would be clear:
4d 22h 5m
In German the equivalent would be "4 Tage, 22 Stunden, 5 Minuten".
What is an acceptable way of representing this in shorter form?
I have seen this used; a couple of native speakers confirmed this is common:
4T 22H 5M
I believe the "H" comes from the Latin hora.
However I've also heard someone complain about this format, saying it should be:
4T 22S 5M
Is there a standard, or are both equally understandable and accepted?
Is the capitalisation important too in this case?