Dynamo does not charge when battery disconnected

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I have noticed that when an electronic voltage regulator is fitted the dynamo does not charge when the battery is disconnected whereas with a mechanical regulator it still charges and powers the lights. Any ideas why?

On two different bikes this month I have lost lights due to a battery wire letting go - the curse of tiny spade connectors on sealed batteries. Solved with a touch of solder but tricky after dark at the roadside.

Hi Gordon, This is a bit o…

Hi Gordon,

This is a bit of a guess but I would say that the elecronic regulator will check if there is a battery connected and will not prvide an output if not.

I know some electronic regulators for alternators work in this way and also 'clever' battery chargers.

Tony

Gordon, not like you to ge…

Gordon, not like you to get this wrong....how can you 'charge' a battery if it is disconnected? What you really mean to say is 'mechanical regulators' have an output without the battery. But electronic regulators (as I sell) need a decent battery to work with, so if the battery comes adrift certainly at low dynamo revs then there is a cessation of dynamo output, unfortunatly this is an electronic regulator characteristic.

Good to hear from a pedant…

Good to hear from a pedant's pedant! Yes, that's what I meant to say. It did take me by surprise the first time, not that it took too long to track down. In the old mechanical regulator days if the battery disconnected for whatever reason, you only became aware of it when the lights went dim or out at tickover.

Any chance of remedying this in the next upgrade of electronic regulators?

Well sort of. What you are…

Well sort of. What you are really asking for is a dynamo regulator that gives an output with no battery. Some time ago like 20yrs I offered this option through the use of a few extra componants but 2 or was it 3 persons asked for it, ie it wasn't a big demand!

The designer of the regulator-someone you have worked along side once-says he is considering it.

By the way as a bike electrical person, I do not consider Luca spades as particularly good battery terminals, a nut and bolt is what you need. The Luca spades are normally found on sealed 'alarm' batteries, not recommended for Automotive use......

Cary on Gordon.

Wassel are now selling sea…

Wassel are now selling sealed motorcycle batteries, as indeed are Burlen (Amal), with spade connectors. It's getting tricky to buy traditional batteries now that the public can't buy acid separately.

My preference has always been for old fashioned lead acid batteries with proper nut and bolt connectors. When you live miles from a bike shop and rely on mail order, it's all getting a bit tricky.

Still, these minor hiccups once again proved my faith on magnetos. Lose the electrics and the engine keeps turning.

Gordon I had no trouble bu…

Gordon

I had no trouble buying a traditional battery with separate acid by mail order in May. Is the problem just in Scotland or a change to the law that has happened recently?

Alan