Sudden battery power lose

[vaacietis]

Hi

I have an interesting problem with my battery on my 2003 BMW F650GS DAKAR.

I can ride the whole day and no problems and then suddenly when I stop and turn it off, I can not start it, no crank nothing 0 response, then I take off the + from the battery and put it back - everything works perfect. Battery is very fresh, I did a test on it in my buddies shop - checked out good. I cleaned the terminals on the battery and the connecting cables.
Did use the circuit tester too, it gives out what is needed.
Even after a week of not riding starts with no problem, just sometimes this odd situation happens.

Just a mystery, no idea what it could be!? Appreciate any help.
____________________
F650GS DAKAR

[carpe_diem]

Have you considered the possibility that your bike might be possessed by Satan?

[uberkron]

Poor battery to frame earth. Replace the factory earth cable.
The one from battery negative to frame.
____________________
i ride a zip 50 2smoke. It overtakes a hundred times a day.

[vaacietis]

[ZebraDriver]

I have had two car batteries do something similar. Both would fail from time to time and then "recover" again. They both had similar faults in that they would internally disconnect themselves and if left for a period would reconnect themselves. One of the symptoms was that the lights would suddenly get brighter (as the battery disconnected itself while the engine was running)

The first time it happened it took me ages to find. I had to wait for the car to not start and then check the battery voltage - without moving anything or bumping the battery. It showed the battery to be down at six volts, leaving the car alone for 20 minutes and it recovered to a normal 12.5 volts

I suspect your battery is doing something similar. Carefully check the voltage next time it plays up !!

[vaacietis]