How long to discharge battery?

jpcollinsworth

jpcollinsworth

Joined
Apr 22, 2008
Messages
28
Location
St. Albans, Vt.
Bike
BMW R1200 GSA
STOC #
7440
Twice I've shut down the engine by lowering the sidestand while in gear and left the ignition on. Both times after about 15-20 minutes the battery discharged.

I've got an '06 that I bought new last April and generally keep it on a battery tender when not riding. Out side of these two incidents, I've not had any battery issues.

Can anyone tell me if discharging in that short of time in normal or should I look at replacing the battery before too much longer. I've heard that continuing to use a battery that's almost on its last leg can ruin the starter.
 
Turn the key off is the key :smile: to not draining the battery. Why would you not? Why do you use the side stand to stop the engine? I would never test a battery that long, just me :wink:
 
I have never run my battery dead, so can't answer the first question.

As for the battery being on it's last leg... if the battery is cronically low on charge, yes it will shorten the life of the starter. Low voltage will cause much more heat generated in the starter (and the rest of the starter circuit) and cause premature failure. OTOH, if there is no hesitation when you hit the button, the engine rolls right over every time (except when you leave the ignition on for 15 minutes:D) then I wouldn't think the battery is on it's last legs. If there is any hesitation, though, it would be worth the peace of mind to go ahead and replace it.

I may be the odd man out here... and I hope I don't start a flame war... but I have never been a big fan of battery tenders. I either ride it enough to keep the battery up, or if I don't ride for an extended period, then I will charge it before riding it. I've seen to many bad things happen with tenders. They are definitely not all created equal! And even the best have the ability to overcharge your battery if left for too long, especially on a battery that is already weak or may have a shorted cell. YMMV
 
My 03 is still on its original battery. Shows no signs of failure. I am one that uses a battery tender that only cycles when the battery drops below a certain voltage. Once it brings the battery back to top form it "floats" Is it because I use the "tender" or do I have a great battery? I will keep using the Tender during the off season.

Many have commented on how fast the battery will drain down if you leave the key on for even a short period of time.

Kevin
 
My 02 is still on the original battery and shows no signs of degradation. The bike is used about 2x per week and on a battery tender when it sits for more than 1 week. I have seen a new fully charged battery on my 05 drained in less than 10 minutes, if the ignition is left on.
 
My '03 is on it's original battery and still going strong after 46,000 miles. I did the same as you twice, lefty the key on when the bike was fairly new and it didn't hurt the battery. I have never owned a tender and when the snow is flying I just start the bike up every few weeks to charge.

Ed
 
That's normal. It's rated a 11.2 AmpHr battery at a 1.1amp load.
At an 8amp load (like when the oem head lights are on) it won't be a 11.2AmpHr battery.
Depending on how dead dead was and how long it sat discharged you may still be ok with the battery.
Does it crank ok?

Try to get yourself in a routine when shutting the bike down.
 
st1300r said:
Try to get yourself in a routine when shutting the bike down.
Click to expand...

I've always been surprised that Team Oregon or MSF doesn't teach a shutdown routine given how big they were on FINE-C. I stop the engine with the switch and do FIGS-Farkles:

Fuel off
Ignition off
Gear (As in "in gear")
Sidestand down
Farkles off​

--Mark
 
Thanks everyone for your responses. Up the other day, I always killed the engine via the ignition switch.

But, in reading a post the other day regarding dropped bikes, a couple of people touted the practice of always leaving the bike in gear when parked. Therefore, I thought I'd form a new habit of using the sidestand interlock switch to kill the engine. This way I would always park the bike in first gear as well as validating that the sidestand interlock switch is working. Because of what happened and realizing that I must be a prime example of the old adage about not being able to teach an old dog new tricks, I'll find other methods to my maddness.

Just wasn't sure if it's "normal" for the battery to discharge so quickly with the ignition switch in the on position without the engice running. I now have my answer.

Thanks again everyone.
 
I would say it's NORMAL. I did it twice when I first got my bike. 10 minutes was enough to drain the battery to a "no start" condition. The same battery has since gone another 1 1/2 years and 24,000 miles so I believe it was not a bad battery.
 
It's normal. When I first got my '06 I left the ign on while showing a few friends how cool the electric windshield worked. After a few minutes, I hit the starter, the headlights went dim and all I got was a click out of the starter. I charged it up, never did that again, and 3 years later still have the same battery.
 
Jerry55 said:
It's normal. When I first got my '06 I left the ign on while showing a few friends how cool the electric windshield worked. After a few minutes, I hit the starter, the headlights went dim and all I got was a click out of the starter. I charged it up, never did that again, and 3 years later still have the same battery.
Click to expand...


Sounds exactly like my story! Battery seems to have survived.
 
7-8 minutes and the battery will be DOA...I did it twice..I now carry a cheap set of jumper cables from autozone 12.95 in their own little plastic case. By the way for anyone not familar with the ST workings you should always have a spare key to use to jump the ST.
 
I leave the bike in gear in various situations, but I turn the bike off with the key. Never use the kill switch for that as I have to take the key out anyway, so may as well use it.
 
Strawman said:
Geoff,
What do you mean needing a spare key to jump the st??
Click to expand...

You need the key to put the bike back together after getting the jump.
Thereby requiring another jump LOL.

It's a good idea to use the kill switch as it keeps both hands on the controls until the motor is stopped.
 
The headlights alone draw nearly 8 Ah and the battery in perfect shape is only rated at 11.2 Ah. With Peukerts Law in effect a load in excess of 70% of the battery capacity means a perfect battery is toast in a few minutes. It might recover from a few episodes like this but each one takes a toll on capacity. They never recover totally.
 
saaz said:
I leave the bike in gear in various situations, but I turn the bike off with the key. Never use the kill switch for that as I have to take the key out anyway, so may as well use it.
Click to expand...

One reason not to do this is if the motor temp is up (as in the fan should be running) and you shut off with the key you kill the cooling fan also. I will use the key if I am coming off the open road and the temp is down. If I am in town and the temp is up I will use the kill switch. The fan will stop by the time I have my gear off, then I switch the kill button back on, turn off the switch and remove the key.
 
I often use the sidestand switch to shut off the engine but I have formed the habit of turning off the key after that. I haven't worked out what to do about the fan turning off when the key is shut down. I was suprised :eek: that the ST did that as my previous Kaw Vulcan cruiser left the fan running after the keyswitch was shut off. :confused: As do most other vehicles.

:06biker: :06biker: :06biker:​
 
Phartz said:
I was suprised :eek: that the ST did that as my previous Kaw Vulcan cruiser left the fan running after the keyswitch was shut off.
Click to expand...

The engine temperature goes through the roof right after you shut it off because it's still trying to pour heat into the coolant, which is no longer circulating. Above certain temperatures, running the fan for a bit after shutting off helps dispose of enough of the extra heat to avoid damage.

Think of it as a self-preservation measure.

--Mark
 
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