B20 Battery spec

[DavidHill]

I have decided to go back to using a dynamo on my B20 after having used an alternator for some years.  I have had my dynamo refurbished by J Morgan and Sons in Dorking (they did a good job on my Aprilia's dynamo).  The expert there recommended not fitting too high an amp hour capacity battery to the B20 as over time that would wear out the dynamo (he suggested/estimated around 45 amp hours).  Does anyone know the Amp hour specification for the B20's battery??  The manual lists a Marelli battery but not its spec...

[Brian Long]

Hi David,

For what it is worth, both the battery in my Aurelia and that in the Flavia 2000 coupe are 60 amp-hour, 600 Continuous Cranking Ampere (CCA) rated.
I have never experienced any generator problems with the B12; it still has the original M-M regulator.

Brian

[chriswgawne]

I have the same David and far prefer the original dynamo MM  set up to an alternator conversion. The only problem is finding someone to repair a faulty MM voltage regulator ( even in Italy this seems impossible) but they are pretty reliable and if necessary you can replace the internals with a modern solid state conversion.
Chris

[Brian Long]

 A Bosch regulator, as I understand it, has been used provided that the generator's internal field winding connections are changed so that the regulator operates between the negative side of the field winding and ground.