Where the original battery was a hard black rubber type PU7E there are 3 choices of replacement.
1. A new battery just like the original. The good point is that it is original but when you forget to keep it charged over the winter lay up it is expensive to replace. At the time of writing these are not available, we supply a dummy box and new batteries. See #2.
2. A dummy battery box. This is the same as the real thing but without any lead plates or compartments so that a modern battery can be fitted inside. This is slightly cheaper than the first option even when the modern battery is included but is also a lot cheaper to replace the battery the next time. Ref PU7D for the dummy battery; BAT2A (6N6-3B) for the modern 6 volt battery; BAT6 (YB3L) for a 12 volt battery. The 6 volt battery is 6 amp/hour, which is slightly lower than original and the 12 volt one is 3 amp hour. A larger 12 volt battery can be fitted by removing the rear of the dummy battery (usually not visible) ref BAT5 (12N5.5-3B); this is 6 amp/hour. More information about converting to 12v, see here ‘Electronic Regulators’ article
3. A modern battery of the same size as the original black rubber one. This is the cheapest option but does not look very original. Ref BAT3 (B38-6A), this is a whacking great 13 amp/hour.
Batteries are sent out ‘dry charged’ as the Post Office does not like battery acid leaking out of parcels, they can be filled with acid at any place that sells batteries for a nominal fee. If you buy a battery from us in person, we will fill it for free!