Voltage regulator.

Hi. My Norton has a dynamo and a RB108 regulator. I use two modern (dry) 4AH batteries wired in parallel (so still 6v). They fit inside a dummy battery shell. So it looks ok and gives me 8AH.

Doug 

Hi David,

Just a capacitor? Possibly, however, if you have other loads - indicators for example, you need the battery for when you are at idle as few alternators can balance the load then so the battery comes to the rescue. Also, some (if not most?) modern regulators need to see some level of voltage before they start regulating. Not sure if a capacitor would be able to do that?

Regards, George 

Answer to DC above, I recommend 5Ahr as a minimum but 6Ahr will do. No the regulators we all use do NOT regulate battery charge current they only regulate the maximum voltage -hence possible over charging-nothing else. GF observations are also very valid re indicators, but there again if you stop at the traffic lights and stall-you have no rear light! Also you are totally reliant on the magnetism in the rotor for full output from the alternator (Have you measured the alternator full output?). With no battery you are totally reliant on the alternator and the regulator to 'get along' it stops-you stop, with a battery you have up to 100 miles to get home-your choice.

Finally most of the alternator regulators I have seen will generate with or without the capacitor or battery.

Ironic point-some years ago we had a bit of a shout up in the Roadholder to remove the capacitor as it was 'worthless' and now you advocate it as the 'answer to a maidens prayer!'

I fit capacitors and a battery, the capacitor is of the modern type and not prone to ageing like the 2MC. Useful for getting you home at 11pm when your battery goes high resistance, good volts but no amps will not run a motorcycle. Remove fuse and kick, drive home.