Battery Problem

[h2omaiden]

My 2005 Honda Transalp battery keeps on losing its charge very quickly, i.e had stopped today and inadvertently left lights on for 3 minutes, unable to start. Also if the bike is not ridden for about 3 days then the battery is flat. Battery is reading 12.85volts and 14volts at 2000rpm. The only mods are a bleeper for the indicators and Accumate connection. Any ideas?
PS. Bring back kickstarts!

[Aubrey]

I have had almost exactly the same problem for a while now and I have discovered that there are a number possible causes:

1. Your battery is buggered! Either from a prolonged period of de charge during which time the battery has frozen, or from repeated charge and discharge.

2. Your alternator is not recharging the battery, although this does not seem to be the case if your getting so many volts at only 2000rpm.

3. Your regulator/rectifier is not regulating or rectifying effectively thereby cooking the battery. Check what Haynes states your input should be at what revs. My 01 transalp is around 14v at 5000rpm.

4. You have a wire which has been pinched and is earthing or a poor terminal (this can be a bugger to find). Perform a continuity test while removing fuses which should highlght the area where the problem is.

It would appear that after many trials my battery was at fault although only time will tell. Honda regulator/rectifierers are, I'm told, notoriously unreliable. Haynes should provide all the advice necessary to pinpoint this problem which of course means you'll have to spend a bit of time revising high school physics and then a lot of time applying those lessons to your bike. I have decided that if my problem arises again I'll simply put a switch inline with the negative terminal and switch it off everytime I leave the bike a poor mans immobiliser if you like.

[Mabels Old Man]

Welcome to the forum. I'm going to move this to bike tech where it will get more exposure.
Afraid I'm a bike electrickery numpty but I'm sure someone who knows will be along soon