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[greg]

Hi, wondered If you could give me some advice.

I charged a flat battery on my bullet and connected positive and negative back wrongly. The bike is positive earth and I improperly connected to tradtional negative earth.

I rode it for a few miles and noticed no brake light.

I eventually realized I had connected the battery wrongly and on connecting it right (positive earth) the battery is being badly drained when running..

Any advice would be much appreciated.
Thanks.
Greg Mort.

P.s. I find it amazing the bike worked perfectly with the battery the wrong way, apart from no brake light......

[Dennis C]

Greg. You have almost certainly destroyed the rectifier/regulator, unless you are very lucky and just blown a fuse.

[Alan R]

Hi DENNIS,----- OOps !!----Anything that is "Polarity concious" may well have been effected eg }--- Electronic ignition, regulator, rectifier, power box, the capacitor in a points ignition system.... The bulb in the stop light is not effected as such by incorrect connection though it might have been blown because the regulator is possibly U/S ??..... And as DENNIS C says, the fuse may have gone as well.........

[Norm]

What I do on these bikes is regardless of polarity I use a red wire for positive and black for negative. In pos earth bikes the red goes to the frame and the black into the loom. On neg earth bikes it is reversed so that regardless of who sticks a battery in any of these bikes the red wire always goes to pos on the battery. reduces the chance of making a mistake

[Les H]

Just to add a small anecdotal fact. If your bike has a dynamo and mechanical regulator (No rectifier in this set up) then you can swap polarities just by swapping the battery connections and re-energising the magnets residual magnetism by flashing the battery into the dynamo...often done by pushing down the cutout contacts for a second or two when the engine is not running. When running, the dynamo will produce current with the new polarity...although the ammeter connections will have to be reversed to indicate a charge/discharge correctly.

[Alan R]

Hello LES, Goodness, that takes me back a while------polarising a dynamo (I ran several Morris Minor vans back in the early '70s.)....And yet only this Summer (?) as well....My mate Tim runs a 1938 Enfield 350 and had some major repairs done to his dynamo which needed re-polarising before use....... Ironic that GREG called Negative earth "Traditional"...... it's within living memory that Positive earth was the norm.... (Sorry mate, no pun intended !!!).

[Les H]

Hi Alan...yep, nice mechanical things dynamos and just to keep up my tradition ...here is another correction for my post above: "You can swap polarities just by swapping the battery connections and re-energising the DYNAMO'S residual magnetism by flashing the battery BACK into the dynamo"...