Hitchcocks Forum

If a powerbox can replace the reg/rec with or without a battery does it act as a battery for the pilot lights or horn or flashers or brake lights with ignition on?

Yes, No.
Yes, the bike can run with out a battery but may have problems with starting and poor idle due to low voltage.
No, it does not act as a Capacitor or Battery.

I have fitted these to a number of bikes I have worked on / restored. A BSA Starfire's owner wanted to run without a battery, while using a Boyer electronic ignition, a set up I have seen on numerous unit BSA singles [yes I know about low voltage, full advance, blah blah, but many start and work fine] but starting on this machine could be a pain and it stalled at idle if the lights were switched on, so I talked him in to having a battery and all was well after that. I also added a battery to a similarly equipped BSA B50 MX recently, as you need all the help you can get to start one of those! However, another machine, a Triumph Tiger Cub I restored retained the original points system, with no battery and this would fire up first kick every time and idle with the lights on, but they would brighten a little with some revs applied, as you would expect. I also noticed on this machine that after running and switching off, hours or even days later, I could press the horn button and get one very brief 'beep' from it, so there must be a capacitor of some sort in the powerbox. One thing you definitely DO need, is a good alternator to run without a battery and good wiring, whether you use a powerbox, zener diode, or whatever else. Cheers, Paul.

My Bullet has a powerbox and points, but, as Paul said, starting without a battery is very difficult and idling is non existent. I hoped I could ditch the battery but it's just not practical without it.

Thanks for the replies about the powerbox, just wondered because von 1 papen has posted "wiring fault".

Powerbox does have a capacitor in it. I have never had much luck with starting with a flat battery, though.
It is said to be possible to wire a capacitor in to the bikes electrics and get batteryless starts.

1960s Triumph's had the option of no battery, a capacitor was fitted where the battery would be,also the battery equipped one's had an emergency start position on the ignition switch for if the battery was flat, this in effect turned on the ignition while disconnecting the battery.

John, with a flat battery it is necessary to disconnect the battery (pull the fuse) before trying to start direct from the Powerbox as noted in Dennis' Triumph post.

Thanks Beeza, that's where i've been going wrong!

The old Slo Poke ran batteryless - on a Powerbox with points - and started and ticked over just fine with the lights on and the brake pedal depressed.



However, I had fitted our hosts 120 Watt stator, a SPARX rotor, ran a 35 Watt H4 headlight bulb and an LED tail/stop light, and had no indicators/horn or other such fripperies.



As mentioned by Paul, my (very minimal) wiring was good with soldered joints and all the bit.