Boxerworks.com

1984 R100CS
There are times when I would like to disconnect my clock. The battery I have replaced, cost twice what the replacement starter did. Disconnecting the clock requires disconnecting the battery ground, or pulling the positive connector off the clock.

Both methods are inconvenient. As a North American, any inconvenience is unacceptable.

I've actually got some sparking, re-installing the positive lead. This type of behavior would be frowned upon in der fatherland.

I remember seeing quick ground disconnects for sale at BMW ralleys in the distant past, but I haven't seen those in decades. Not sure if they were any good.

I'm thinking, a small in-line (mounted on the positive lead wire) interrupter type switch would be nice, but i can't seem to find one that is light enough (or waterproof) to create a sanitary installation.

Any thoughts? Please don't let my problem delay you from getting your vaccine shot.

ZM - You worry too much
With that 500cca battery you can park your bike for many months (with the clock running) and it will maintain 12.6 v (or more) .
That thing is the absolute King-Kong of bike batteries, bar none. It has roughly the same cca as a stock Honda Civic battery. Power to spare, and then some. It makes every other bike battery look anemic.
A trickle charger can't hurt if it's convenient to use one, but I wouldn't worry about it except maybe for loooong winter storage periods.

Check the current drain of the clock.

When new, the currect drain on the standard BMW clock is very small, probably less than the internal leakage of the battery, and it should make no significant difference to the charge life. The problem is that, when the clocks get a bit long in the tooth, the mechanism gets a little stiff (like humans really ). Like all electric motors, the more energy it has to expend to do it's job, the more current it consumes. The effect is that an old clock might consume 10 or more times as much current as a new one even though the clock is, on the face of it (Hah!) working perfectly. Sometimes, lubing the clock mechanism might make a difference but in reality, a full overhaul or a new clock is the way forward.

As a personal thing, I would find resetting the clock every time I got the bike out more of an incoinvenience than trickle charging the battery.

Rob

Rob Frankham wrote: ↑Sun Apr 25, 2021 4:59 am Check the current drain of the clock.

ZM - Disconnect the battery negative wire and connect your multi-meter (on amps) between that wire and the battery negative post.
This will show clock draw + any other parasitic draw you might have.
Meter should read 0 if clock is disconnected and somewhere around .003 if clock is normal.