Quick Headlight Question

[raptormeat]

I have sorted (most) of the electrical gremlins on my bike..turns out they all were due to rusty/bad connections. (5 Ohms resistance in the Y-wire connectors to the coils! Atrocious!)

NOW:
Battery at 12+ Volts, bike is NOT running, but ignition is ON.
When I keep the lights off the battery stays near that.

Turning the headlight on (35W H4), my voltage drops to 5V and drains the battery within 15 seconds...I dont think this is normal?
The issue is definitely in the headlight circuit. High beam does the same.

I understand this isn't that important as the bike will always be running when I turn the headlight on, just was wondering what anyone else's battery voltage is with headlight on, bike off.

 

[Hoosier Daddy]

As you found, the condition of connctions plays a big part. Ohm's law says if you have a high Resistance you will need more Amps to get the same Voltage. So a dirty connect could drain your battery faster than normal. To me what you descibed says battery is good (12V) but in a low state of charge. Depending on it's Amp-hour rating, it should not drop that fast with the draw of the headlamp (35W). I recommend putting your battery on a long slow charge and retest again.