[highmiles]

Any common themes on this? Seems to be getting worse. Battery (new) was almost completely drained in a bit over a week.

 

[mlukason]

Is this happening with or without riding during the week, i.e.: is the bike's charging system working correctly? If it's just sitting in the garage, there is a parasitic draw on the battery by the ST series. But you shouldn't have a dead battery in a week, that's too fast. It's not unheard of to have a brand new battery be bad. You could confirm by load testing. I wonder if you have short in the system somewhere, perhaps where every the loom crosses the frame.

 

[HiFlite]

Simple test: With the battery charged up again and ignition in the OFF position, disconnect one of the leads at the battery. Turn to the "amps" setting of a digital volt meter (DVM). Connect one lead from the DVM to the battery terminal and the other to the disconnected battery cable. Current now flows through the DVM. What's the reading? The parasitic current draw (in amps or mAx1000) times the number of hours in a week gives the A*hr drain for the week. If that number is anywhere close to the Ahr rated capacity of the battery, then something in the electrical system is shorted or malfunctioning. If not, there's an internal problem with your battery.

 

[highmiles]

Is this happening with or without riding during the week, i.e.: is the bike's charging system working correctly? If it's just sitting in the garage, there is a parasitic draw on the battery by the ST series. But you shouldn't have a dead battery in a week, that's too fast. It's not unheard of to have a brand new battery be bad. You could confirm by load testing. I wonder if you have short in the system somewhere, perhaps where every the loom crosses the frame.

I'll have to tear into it. It's been sitting for about a week and a half. Weather has been too bad to ride in the tundra.

 

[Quicksilver914]

Lead acid or lithium? My ST4S will drain a battery in 6-8 weeks to the point where it will not start if not on a charger.

 

[Stick]

The normal parasitic drain that I've measured on my ST2 and ST4s is around 2.5 mA.
That's 0.0025 Amps.

With this normal drain, I really don't see any issues, even if the bike sits for 2 weeks or so. But in general, parasitic drains on batteries lead to sulfated batteries. And that's why I use chargers with a 24hr timer on them. The timer gives the charger a fresh look at the battery once a day, and it goes into its charge mode, and into the float, and then off again. Then repeat. Over 12 years on the battery in my Corvette, that sits for long periods.