B33 battery size

[SamNorwich69]

Hi people , the BSA b33 I just purchased has a huge battery same size a my Z900 Z1 , my b33 is a dyno mag model I don't see a need for a large battery ..any ideas

[Rog1]

I think the original battery would have been 6 volts, 12 Ah. Is that the rating of your battery?

[neil1964]

Iirc yours is a plunger with exposed battery?
Most people either carve out the old rubber Exide/Lucas case and install a modern type inside.
I converted to 12v years ago to allow QH headlamp bulb but I think that you can get LED bulbs now?
From experience I prefer YUASA batteries as the last much longer in my experience.
If you don't have an old battery to gut you can buy repro shells ready to go.

[Rog1]

From Motor Cycling magazine, 20th December 1951; 72 years ago!

It looks like most medium to large machines had a 12 Ah battery, so that your lights would still be on when you were waiting for the traffic lights to change on dark nights, bearing in mind the low output dynamos most bikes had then. The 20 Ah battery in the ad, for outfit use, would do the same job when there's the sidecar's lights to power as well. I suppose the small bike battery wouldn't be so great; limitations of that time's technology.

[SamNorwich69]

Cheers for the all the advice