Thanks Sam! it was certainly used during wartime, and the reason the C number was painted on there, was that Mr. Lucas was not very good at charging their batteries on the bike, so they had sometimes to be charged of off the bike, by mobile charging units, now, to make sure all batteries went back to their respective bikes, they painted the C number on them! Story from a veteran I spoke to many, many years ago.
Also note the earlier brown, and later green on top of that!
Cheers,
Lex
I was always under the assumption the batteries were painted at the Lucas factory and then distributed to bike manufacturers. I painted my battery at a slightly different shade of green to emphasize that. I suppose the painted c numbers on the batteries were done at unit or workshop level once the bike was in service and not at the manufacturing plants?