Intermittent flat battery - speed sensor??

Trying to fathom a reason why the bike can be sitting in my garage after a good ride, and within only a few days the battery is virtually lifeless, with <1V showing on my test meter.

Has happened twice now, and with different batteries.  The current battery is not very old.  Managed to charge it back up, and having been off-charge for about 6 hours it's reading 13.08V - with all fuses in.  Whatever had been causing the drain doesn't seem to be doing it now, as idle currents through the main 30A fuses are zero and 1.4mA.

From this Forum, I've picked up on warnings about not leaving the key in the ignition because of immobiliser drain, but it's not something I do.

Beginning to wonder if it's water-related, as this latest time was after having washed the bike.  Sadly can't recall about the first.  I understand the speed sensor can be vulnerable to water ingress and cause a drain.  Would you say the symptoms fit, and is it known for sucking the battery dry so quickly?  I've not noticed any odd behaviour with the speedo itself, but then the bike rarely gets ridden in the wet, and after washing I haven't ridden it before stowing in the garage.

Thanks for any inspiration.

You don't accidentally turn it to Park position before removing the key?

The immobiliser keeps on draining, key or no. Buy an Oxford solariser to top the battery up-ah, you're indoors. Buy an Optimate or similar.

Papa Lazarou wrote:

The immobiliser keeps on draining, key or no. Buy an Oxford solariser to top the battery up-ah, you're indoors. Buy an Optimate or similar.

Historically I've used an Optimate, and now a CTEK charger/maintainer, but only if I've not ridden for more than a week.  I would have thought a healthy battery should be able to cope a week without charging, but these are seemingly isolated instances where it has been drained in 3-4 days, or less.  In between events it can be many months without a hiccup.

Kiwi_Roy wrote:

You don't accidentally turn it to Park position before removing the key?

No, only to the lock position.

I don't remember how I got this info, it was sometime during the 13 years I got my bike...

There was ( is? ) a bug at the dashboard software, that appears randomly. It may or may not happen.

When powered up, meaning when the battery is connected or the fuses inserteted, it may ( or not ) get stuck in the key recognition proccess, thus having the imobiliser antena constantly active, and draining the battery.

This will not happen, the dashboard will not keep the antena allways active, if ....

after the power up, after the dashborad displays the "apgm 0002" thing (or something like this, dont remember exactly)
the key is inserted in the switch and the switch is turned on, for about a minute, withought starting the motor.
After that, the switch should be turned off and the key should be removed for at least one minute.

Done, the dashboard won't get stuck. At least not untill the next power outage (battery or fuse removal)

Well if that works it's very useful information. Well sleuthed!

Thanks for the tip, Petros.  I did come across this while searching the Forum for battery issues - it might've been another of your posts!

So if I understand this dashboard bug correctly, it could potentially drain the battery even if the bike has seemed fine for months, unless I followed that method after the last power outage...?  That's a weird one, but I'm willing to try anything before I start tearing the loom apart (which I sincerely hope not to have to do).

So far no-one is pointing a finger at the speed sensor.  Have I misread previous threads on this being a potential culprit?