Bullet battery elimination

**Matt Cartney** · #1 13th May 2008

Hi folks,

Have just pulled the old girl out the garage after a 3 year lay-up with the intention of running her over the summer.

My question is this. I fitted a Boyer Bransden Powerbox in replacement of the Regulator Rectifier unit a while ago as a reliability upgrade for touring. However, I am intending to use the bike for pottering around, doing some easy off-road etc. and want to lighten it as much as possible. My understanding is that the powerbox allows the bike to be run without a battery, however, when I remove the battery from the bike she will not start.

Any thoughts on this?

Matt

**oldbmw** · #2 13th May 2008

What kind of ignition system do you have. if it is electronic it wont work without a stable 12v supply. If the old points system, it might work if you put a big capacitor there in place of the battery. Old Triumphs would start and run straight from the permaneant magnet alternator, with or without battery charge dor flat but don't know Enfield electrics well enough to say if they will run or not.

**DougieB** · #3 13th May 2008

mine appeared to run without a battery. it definitely ran with zero battery acid in it, does that count? it had points, and no fancy electrics. well I think it did. It's just occured to me that in 16,000 kms I never looked at the points. maybe it ran without points too :-)

I didn't really understand how it managed to start with only the energy from my right leg, but it did.

put it back to stock, and see if it fixes the starting? I've only had experience of fitting electrickery to old cars, and it can produce odd-ness. are you getting a spark?

I'm rubbish on electrics, but with the battery removed have you broken the circuit? What about completely discharging your battery, but leave it in the circuit. does the bike start?

how are those electrons (?) going to get down the +ve wires if you've disconnected the big fat one?

**Matt Cartney** · #4 14th May 2008

I still have the original points ignition. Have recently cleaned and adjusted.

The battery is almost completely knackered, holds hardly any charge, but yet the bike runs fine with it installed but not at all without. I'm wondering if turning all the lights off etc. will make the difference to starting?

That's a good point about removing the battery Dougie. I just removed it from the circuit. I wonder if I join the positive and negative wires together I will complete the circuit, solving the problem. Bit worried this might cause some kind of short circuit, but will have a play anyway.

I too am terrible at electrics (can you tell?!) so this is all a bit 'suck it and see' I'm afraid!

Matt

**DougieB** · #5 14th May 2008

yes, turning the lights off will mean less of the current is drawn on the circuit and more will be available to the starting system.

the +ve and -ve are joined normally anyway, by the battery.

wear wellies and marigolds when you connect the wires... :-)

**Robbert** · #6 14th May 2008

Not so sure shorting the battery is a good idea, cause this will give you 0V at the coil. What I've read about enfields somewhere on the web is that, to properly run without battery you should install a condensor (in stead of the battery?).

Google around a bit, I'm sure you'll find something.

**oldbmw** · #7 14th May 2008

Ouch,, so basic i forgot. yes , turn off everything except teh ignition. use a capacitor do not short the wires together.

**BOB UK** · #8 15th May 2008

Hi
I ran a Triumph 500 off road for a while without a battery it had points and a big capacitor in the circuit to give a bit of a stable supply
It didn’t have an ignition switch but to stop it being started all you had to do was switch the light switch on

I don’t think this set up would work with electronic ignition because at tick over with the lights on the whole system would drop down to about 7 or 8 volts OK with points but no good for this new fangled stuff

I have now fitted a very small battery to the bike (I still have the capacitor on there for emergencies) I did this because it makes it much easer to fault find on the bike if it stops and as I do MCC Long distance trials with it I have had a few times when I have been glad of a bit of back up battery power as if the bike stops its very hard to work out if it’s a charging or ignition problem as the system is only live when you are kicking it over

Lots of fun at night in the rain NOT

So my advice would be to fit a small battery
and the best way to save weight is to buy a KTM

Bob

**Matt Cartney** · #9 15th May 2008

Thanks for all the imput guys. I have bought a new battery for the interim (and to get it through it's MOT

) and will experiment with capacitors at a later date.

Now what was that other suggestion? Buying a KTM...hmm...tempting...!

Matt

**Robbert** · #10 15th May 2008

Check the 'Running without battery' on this page:
The Bullet: Mystries & Myths - Improve Your Bullet

**Matt Cartney** · #11 16th May 2008

Good link Robbert! Love the guys writing style!

Matt