The BSA A7-A10 Forum

Technical => Lucas, Electrical, Ignition => Topic started by: Marqs1979 on 01.11. 2015 17:45

Title: capacitor instead of a battery
Post by: Marqs1979 on 01.11. 2015 17:45
Hello wondering if I should use a capacitor instead of a battery for my Bsa chopper. the only electricity on the motorcycle's lights. Is this possible and it works well, or?

Which capacitor should i buy?
Title: Re: capacitor instead of a battery
Post by: bsa-bill on 01.11. 2015 18:01
interesting one
it's so long ago since I worked with Capacitors, much has changed, we used to call them cans.
are you thinking of using one instead of a battery?, if so then you need to consider if the VCU would be happy trying to control dynamo charge into a Capacitor, I suspect discharge from a Capacitor would be less controllable than from a battery, but as I said much has changed and maybe modern capacitors are more like batteries than previous,Looking forward to some more up to date info then I can provide
Title: Re: capacitor instead of a battery
Post by: Triton Thrasher on 01.11. 2015 18:16
With a dynamo, you're as well using nothing at all, as the charge in the capacitor will only power the lights very briefly.

The lights will go out at under about 1100 rpm.
Title: Re: capacitor instead of a battery
Post by: metalflake11 on 01.11. 2015 18:17
If you buy a flux capacitor you may be able to time travel as a bonus.
Title: Re: capacitor instead of a battery
Post by: morris on 01.11. 2015 18:58
Boyer Bransden claim that they're dynamo regulator don't need a battery.
I have got one on the plunger (6V) but haven't tried to run it without battery yet.
I think it should work though as even with the lights on, at tickover the ammeter needle shows a little charge.
Title: Re: capacitor instead of a battery
Post by: sparx on 01.11. 2015 20:20
I think you'd be better off with a small gel battery.
  With a capacitor you'd want to be thinking in terms of Farads rather than microfarads.
Maybe something like a 500uf would kid the charging system you've got a battery fitted if that's what you're looking for, but it won't run even led sidelights for long at all.
Title: Re: capacitor instead of a battery
Post by: jachenbach on 01.11. 2015 20:48
Well, as you don't  say what BSA it is....... if it's got an alternator, I've been very happy in the past with a Mity Max on my unit construction 12 volt bikes. It replaces the rectifier and zenor diode, and can run ignition and lights without battery. If, however, you're talking A10 with magneto ignition, then I don't know what you can do for lights without a battery.
Title: Re: capacitor instead of a battery
Post by: Marqs1979 on 01.11. 2015 20:52
It is an A10. I guess I must have a battery or headlamp: /