Roadster battery.

A year would help as the tray did change, 850 mk2 to mk2a was one change.

There is a Motoblatt with 4 terminals used as an upgrade on the MK3 which uses the same tray. I will try to post the number tomorrow.

CT14-A2

https://www.nortonownersclub.org/noc-chat/technical4-commando-forum/130224675

CCA is more important than AH, CCA is the peak amps that drive the starter, AH is how long it will give the CCA out.

A great coincidence as I was just considering the very same question! My 2A is a 1973 and I had a bit of a worry when I saw the Alton video and how the monster battery was fitted fore and aft in the battery tray rather than across the frame as mine currently is!

I enclose (hopefully) a snap of my existing battery box which hopefully somebody will recognise as pre or post mod and then tell me what battery I need to buy if I go the Alton route?

As you can see I have modified my bike to fit a Mikuni carb so the original big plastic air filter box is currently in the loft. At the same time I took the opportunity to fit the ignition switch in a better position - now it doesn't fill up with water as it did when facing forwards! The result is that there is not much spare room beyond the confines of the originally designated battery space.

In your case you can put with no problem at all DEKA ETX15, it is what I have on my 850 MK3 for 6 years.