Ariel Owners Motorcycle Club

Might be a daft question about dynamos and batteries but I have never had a motorcycle with a dynamo before!
The question is with the dynamo constantly charging the battery and no load taken by the battery unless the lights are on will the battery suffer from overcharging and even boiling?
This is my first Ariel, a 1955 VH500, with a magneto and dynamo set up. I fired up the engine for the first time recently following a full restoration and the dynamo is charging the battery at about 6.9 volts at tick over as measured with a volt meter. I have a solid -state regulator fitted.
Dennis

Not a daft question at all. You should find, once the battery is charged that the ammeter returns to zero - until you hit the brakes, turn the lights on or take some juice out of the battery some other way.

It's showing a charge with the lights on because your lights are probably consuming 40 W or more and your dynamo output at maximum speed is only 60 W.

Simes,
Many thanks for your reply.
Dennis

Hi

It's the job of the regulator to manage the flow to the battery, don't worry about the voltage, look at the ammeter. As Simes says, the ammeter reading will move towards zero as the battery charges, (though I suspect it will never read zero as the regulator will maintain a 'trickle' charge even when the battery is at capacity).

Regards Mick

hi you may have just a 40 w Dynamo, i use Led lights on my bikes and classic cars and the ammeter justabouts moves with all the lights on

Thanks everyone. Good to know that the regulator manages the dynamo output. I have the 60W dynamo with the longer armature as I replaced the original broken one with a new item.
Dennis

hi Dennis ,
with the solid state regulator fitted the voltage output will be limited to whatever the regulator is set to , which will be somewhere just above battery voltage.
you have to have a higher voltage than the battery voltage in order to charge it .
with the VH you will probably find you see a fair positive deflection on the ammeter when you first run it up and ride it but this will usually drop down as the battery charges .
it will reduce the charge rate as the battery charges up .

with the solid state regulators they all draw a small amount of residual current [ in its sensing circuit] ] from the battery when parked up but some draw more than others , this means the battery will eventually go flat over time but it depends on the make/design of regulator as to how much current is drawn and how long it may take to go flat , some regulators will take years to flatten battery and there are others that will do it in days ..

for instance a wassell regulator draws a fair bit of current , typically 60ma , so you can see that a 4ah battery will lose its charge in around 70 hours .

if you had an AO services regulator it draws less than 0.1ma and so in comparison i think it would take 40,000 hours to get to flatten the same battery .

theres other makes of regulator too and many of them are similar to the AO one .

usually the NH VH battery would be around 12ah capacity but unless you actually have one of these fitted then you may find something like a 4ah battery placed inside a reproduction rubber case .
you can get a 12ah battery that fits inside the repro rubber cases but need to use spade end terminals on the cables to it .

led bulbs use less power , but you may need to suss out which headlight bulb is best in which headlight shell you have , ie "catseye lens" or sealed beam type or whatever they are called with that type pattern .

rear tail/stop lamp bulbs are available but some may produce better stop light than others , i had a couple of different ones and picked the one with brightest stop lamp on it .

paul goff sells a range of led bulbs

http://www.norbsa02.freeuk.com/goffyWhyNotLEDs.htm

http://www.norbsa02.freeuk.com/goffyleds.htm

hope you get some good riding out of the VH .
cheers
ian

They don't actually trickle.They wait for a while and flick on at times to top it up. It slightly over volts and cuts out and this repeats. Nev

Ian,
Thank you for the comprehensive reply!
And Nev for further clarification.
Dennis

Many thanks for that information Ian. It explains why the batteries on my AO regulator bikes stay charged and why the one on my KH goes flat all too soon. I must look to see what regulator that one has, but I know it is different from all the rest.