Author Topic: Absolute bear minimum.  (Read 343 times)

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Offline Sgtbiro

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Absolute bear minimum.
« on: 20 Feb 2020 at 20:11 »
Hi all after recently receiving my Dragonfly engine back from re-build i need to test fire it so what i need to know is whats the absolute bear minimum electrics i will need to fire it up, as in can i just attach a battery charger to one wire going to the coil and and the other going to the condenser on the side of the distributor or am i living in cloud cuckoo land and it a lot more complected than that, as you might of guest i know nothing about electrics.

Cheers Kevin..     

Offline EW-Ron

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Re: Absolute bear minimum.
« Reply #1 on: 21 Feb 2020 at 01:44 »
Didn't we cover this before, but with a battery ?

A battery charger may or may not have enough ummmph to drive the points and coil,
depending on its rated output and if you are getting half wave or full wave rectification.
All you can do is try it and see  !!

Polarity likely doesn't matter if thats all you have in circuit, so one side needs to go to earth, and the other side to the coil.
The other terminal of the coil goes to the points, and presumeably the condensor somewhere there will look after itself.
Note that coils are slightly polarity sensitive, so best if you match that up,  +ve to the +ve terminal thank you...
Don't leave it all on for long periods doing not much.
Tell us how it goes...

Offline yosemite

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Re: Absolute bear minimum.
« Reply #2 on: 21 Feb 2020 at 19:48 »
 A modern battery charger may probably not work at all as they are designed not to put out current unless  they are connected accross  a battery of the required voltage,  many won't even charge a completely drained battery, I had to connect a second battery in parrallel to the BSA'S to start the charger reading the battery was there after I left the lights on over a weekend.  After a couple of minutes with both in circuit I disconnected the second battery and the charger continued charging the BSA without a problem. Old non "digital" chargers may work, depending as Ron said on the rated output and rectification.