Has anyone tried a battery eliminator (presumably a very large capacitor) ?
Kevin
Kevin
Battery Eliminator
- Thread starter redbloke1956
- Start date
Having discovered them a while ago, standard fitting on Commandos?, I fitted them on Triumphs with crankshaft alternators, where they appeared to assist starting with flat batteries. So I bought one last year for a newly acquired Comet as an alternative to buying a 6v battery and charger. The write up with it said do not use with a battery as it will fool the regulator and stop the charge as soon as it was up to voltage.
It did provide direct lighting but as the Miller dynamo and apparently home made transistorised regulator fitted did not charge until the revs were picked up, I was not happy to ride with it, especially in the dark. Remember that you drop the revs when using the brake light. The regulator didn't last long and I replaced it with a Vreg IIa from Stuart Towner, and as that was easily convertible to 12v I stuck on an old non-bike battery. That was also pretty poor so I bought an exotic bored and stroked comet with a walkenator already fitted. Charging problems cured!
I will be putting the battery eliminator back on the standard Comet as it will run 12v if that is what the generator supplies. If I start riding the standard Comet regularly or sell it on, I will put a battery on it.
Cheers,
It did provide direct lighting but as the Miller dynamo and apparently home made transistorised regulator fitted did not charge until the revs were picked up, I was not happy to ride with it, especially in the dark. Remember that you drop the revs when using the brake light. The regulator didn't last long and I replaced it with a Vreg IIa from Stuart Towner, and as that was easily convertible to 12v I stuck on an old non-bike battery. That was also pretty poor so I bought an exotic bored and stroked comet with a walkenator already fitted. Charging problems cured!
I will be putting the battery eliminator back on the standard Comet as it will run 12v if that is what the generator supplies. If I start riding the standard Comet regularly or sell it on, I will put a battery on it.
Cheers,
I haven't kept track, what ignition do you have? Mag probably OK, points - maybe, electronic probably no. How's that for definitive?
I have bth electronic mag and alton alternator
Hi Bruce, thanks for the info mate, I haven't run the comet with lights etc yet, does the Alton not produce enough output at idle to power the lights?
Kevin
If this device actually works then it has to be more than just a capacitor. The Alton and McDougalator are permanent magnet systems. The ‘Walkernator’, like all other car alternators that I know about, has field coils. This means that it has to have some battery volts available at start up to excite the field coils in order for the system to start and charge. I do not know what system of regulation is used on the permanent magnet types but on the Walker/Sherwin system the regulator has a comparator chip in it which compares the battery volts with a nominal voltage of over 14 volts. If less than 14+ volts is available at the battery then the current to the field coils is increased and the output from the alternator increases. A capacitor, or super capacitor, would only store charge and the voltage available would almost certainly not be stable. Unless one is using an electric starter then with a powerful alternator a large battery is not required so just how much weight is anyone hoping to save by the fitting of one of these. Perhaps either the manufacturer or one of his agents could be approached and asked what they see to be the advantage for road bikes.
I do not know what system of regulation is used on the permanent magnet types
The Alton has an electronic regulator and would most probably use a zener diode of approx 14 Volts as a reference (as used with most 78 series 3 terminal regulator chip circuits).
A capacitor, or super capacitor, would only store charge and the voltage available would almost certainly not be stable.
A very large capacitor can store an extremely high charge and with a relatively low current draw on bikes of this age, with a properly functioning charging system, should be extremely stable.
Kevin
The Alton has an electronic regulator and would most probably use a zener diode of approx 14 Volts as a reference (as used with most 78 series 3 terminal regulator chip circuits).
A capacitor, or super capacitor, would only store charge and the voltage available would almost certainly not be stable.
A very large capacitor can store an extremely high charge and with a relatively low current draw on bikes of this age, with a properly functioning charging system, should be extremely stable.
Kevin