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Weird battery behaving (Power Commander?)


nick13

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Hi, I was wondering maybe someone can help me to figure out battery's weird behaving...
I bought used 2015 with 4K miles on it, in mint shape. With Power Commander V, Yushimura exhaust, fender eliminator, Woodwork clip ons, all LEDs and so on, real showroom condition...
The question is, often the battery acts like it's being discharged, even though, the voltage is 12.6 and with running engine is 14.3 Volts. Seems OK. But still, I did change the battery, put new OEM battery from Revzilla... First week it was great, then the problem came back.
The strange thing is that it may do cold start good, but after short stop it will hardly spin the starter... Looks counter-intuitive, it should be the other way around... right?
Also I noticed if I revv the engine a bit, to enjoy the sound, then shut it off, the battery feels weaker after that... Also I notice a few times it was stuttering during low RPM moving in 1st or 2d gear, then it comes normal again, I don't feel save riding this bike anymore :(
So I was thinking maybe it's a Power Commander glitches that kills the battery? I can't really establish any connection, like what is triggering what exactly :(
 
Any help is greatly appreciated.
 

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You need to do some generic electrical testing of your bike's generator and reg/rec, google these tests then grab a multimeter.
 
Unlikely that the pcv is drawing current when the ignition's off in my opinion.
 
Do you have an alarm or other powered accessories fitted?

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Do your basic electrical system checks with a good digital multi-meter.
 
With the bike off, it should show about 12.4 - 12.6 volts on the meter. If OK, check cranking power or do a load test, shouldn't fall below 9.5-9.6 volts at it's lowest point while cranking the bike over. While the bike is running, you should see the battery reading about 14-14.5 volts. This indicates the battery is getting replenished. If not, you most likely have a bad regulator / stator - test each of those using a meter.
 
If you notice the battery has low resting volts but it's charging adequately once the bike is running , check to see if you have a parasitic drain issue. That is, some electrical component is drawing power from the battery while the bike is off. Excessive drain could cause sluggish starts after the bike sits for a few days or so. These bikes will have a very small amount of draw for the clock (maybe some other things?) but I'm not sure what the normal draw # is. If you have more draw than normal, start pulling fuses until you notice when the draw drops. Once that happens, you at least know what component is giving you fits. Further diagnosis will be needed from there.
 
You say you replaced the battery and the battery is showing 12.6 volts resting and 14.3 volts running, which indicates it has good charge and charging volts. If the battery consistently shows 12.6 volts after sitting for a few days (prior to running the bike of course), I wouldn't suspect a parasitic drain issue. If you are getting 12.6'ish volts to the starter and you are having starter issues, I would suspect a defective starter.
 
I'm not quite sure on the specific power commander setups and wiring as I've never installed one, but I could see how it could cause issues if not installed right or is malfunctioning. When the bike is sluggish or stuttering, do you notice the lights / cluster dim? You could always do away with the PC briefly to see if the problem is resolved.

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You need to do some generic electrical testing of your bike's generator and reg/rec, google these tests then grab a multi-meter. 
Unlikely that the pcv is drawing current when the ignition's off in my opinion.
 
Do you have an alarm or other powered accessories fitted?
The weird thing is that PC is not plugged to battery, I'll have to trace the wires to see where the previous owner connected it, unless it should not be connected to battery at all and only to injectors... Maybe he didn't plug it to the right place and it cause malfunctioning... Thanks for your help.  
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Do your basic electrical system checks with a good digital multi-meter.  
With the bike off, it should show about 12.4 - 12.6 volts on the meter. If OK, check cranking power or do a load test, shouldn't fall below 9.5-9.6 volts at it's lowest point while cranking the bike over. While the bike is running, you should see the battery reading about 14-14.5 volts. This indicates the battery is getting replenished. If not, you most likely have a bad regulator / stator - test each of those using a meter.
 
If you notice the battery has low resting volts but it's charging adequately once the bike is running , check to see if you have a parasitic drain issue. That is, some electrical component is drawing power from the battery while the bike is off. Excessive drain could cause sluggish starts after the bike sits for a few days or so. These bikes will have a very small amount of draw for the clock (maybe some other things?) but I'm not sure what the normal draw # is. If you have more draw than normal, start pulling fuses until you notice when the draw drops. Once that happens, you at least know what component is giving you fits. Further diagnosis will be needed from there.
 
You say you replaced the battery and the battery is showing 12.6 volts resting and 14.3 volts running, which indicates it has good charge and charging volts. If the battery consistently shows 12.6 volts after sitting for a few days (prior to running the bike of course), I wouldn't suspect a parasitic drain issue. If you are getting 12.6'ish volts to the starter and you are having starter issues, I would suspect a defective starter.
 
I'm not quite sure on the specific power commander setups and wiring as I've never installed one, but I could see how it could cause issues if not installed right or is malfunctioning. When the bike is sluggish or stuttering, do you notice the lights / cluster dim? You could always do away with the PC briefly to see if the problem is resolved.
Great, thanks. Will try all that. So far I checked the battery resting 12.6 volt and running 14.3 volts. While cranking - it drops to 10 volts. Seems OK. But the weirdest thing is that it can starts cold real good and strong, but after riding for 15 minutes, I stopped at gas station for one minute and then couldn't start engine again! The battery was hardly spinning the starter. Then during OTHER stops it was FINE again! This random battery behaving just killing me... If the battery was bad, it wouldn't start cold, but it would start after riding, right? But it acts in opposite way, which is so unusual...
I'll remove PC and then see what happens without it.
Greatly appreciate your input.
 
 
 
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So, keep in mind that the one thing that draws the most current when used is the starter motor. Every time you hit that button, you take a big whomping chunk of the batteries capacity by comparison to anything else electric the bike runs. So, start it up, run a few blocks, shut it down, start it up again and repeat, the charge system will not run long enough to be able to put back into the battery what multiple starts have removed. It's just a fact of life.
 
Starting a hot motorcycle can sometimes be even harder than when the bike is "cold" at 50F and started the 1st time for that day. And this is especially if the motor was shut down right on a compression stroke. I've had big twins for decades and have experienced this effect - you hit the button and just as the starter gets going, it hits a wall, then hesitates/stops for a second before it starts to crank normally and the engine starts up.
 
Big current loads (that starter motor) need clean and tight connections. Make sure that both cables to the battery are tight/clean and both connections to the starter solenoid are also tight and clean - keep in mind, with the battery completely hooked up, there is 12V on the one side on the solenoid. So avoid touching the frame with a wrench when it's on one of those positive connections - if that's not possible, the ground wire at the battery. You might also want to check the connection at the starter motor as well to make sure there's no corrosion and it's not loose. Then follow the ground wire from the battery to the motor case and make sure it also is clean and tight.
 
The other place that can cause issues is the low voltage side of the starter solenoid- from the starter button (slide in this case) to the small plug on the solenoid. If that voltage is low from weak connection, the solenoid will not slam shut strongly and you'll have a weak connection from battery to the starter motor.
 
If none of this helps - when it's hot, try jumping those 2 big connections on the solenoid with a screw driver you do not care about - that includes the wrenches you use to check for tightness.. You might get a big spark when you do this that will damage (as in burn/melt) whatever tool you use, so don't be hesitant in the application and removal. If this allows the starter to spin up nice and fast, you'll need a new starter solenoid. Seems a bit young for that, but still
 
I don't think the PC has anything to do with it.
 
 
 
 

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So, keep in mind that the one thing that draws the most current when used is the starter motor. Every time you hit that button, you take a big whomping chunk of the batteries capacity by comparison to anything else electric the bike runs. So, start it up, run a few blocks, shut it down, start it up again and repeat, the charge system will not run long enough to be able to put back into the battery what multiple starts have removed. It's just a fact of life.  
Starting a hot motorcycle can sometimes be even harder than when the bike is "cold" at 50F and started the 1st time for that day. And this is especially if the motor was shut down right on a compression stroke. I've had big twins for decades and have experienced this effect - you hit the button and just as the starter gets going, it hits a wall, then hesitates/stops for a second before it starts to crank normally and the engine starts up.
 
Big current loads (that starter motor) need clean and tight connections. Make sure that both cables to the battery are tight/clean and both connections to the starter solenoid are also tight and clean - keep in mind, with the battery completely hooked up, there is 12V on the one side on the solenoid. So avoid touching the frame with a wrench when it's on one of those positive connections - if that's not possible, the ground wire at the battery. You might also want to check the connection at the starter motor as well to make sure there's no corrosion and it's not loose. Then follow the ground wire from the battery to the motor case and make sure it also is clean and tight.
 
The other place that can cause issues is the low voltage side of the starter solenoid- from the starter button (slide in this case) to the small plug on the solenoid. If that voltage is low from weak connection, the solenoid will not slam shut strongly and you'll have a weak connection from battery to the starter motor.
 
If none of this helps - when it's hot, try jumping those 2 big connections on the solenoid with a screw driver you do not care about - that includes the wrenches you use to check for tightness.. You might get a big spark when you do this that will damage (as in burn/melt) whatever tool you use, so don't be hesitant in the application and removal. If this allows the starter to spin up nice and fast, you'll need a new starter solenoid. Seems a bit young for that, but still
 
I don't think the PC has anything to do with it.
 

Great. Will go true all that. Thanks for your help. 
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Gotta say, those symptoms I described are kinda rare in my experience with the FZ. That starter spins up nice and consistent regardless, so what you are experiencing is a bit odd.
 
I've seen this happen with both old BMW twins I owned (the "brown stain" in my avatar had a huge battery but was particularly bad) and even the Aprilia i've now had for 15 years used to do it when new before lots of tightening and soldering happened. Every electric connection on that Aprilia must be perfect for that starter motor to behave. Some guys even replace the starter wires with a heavier gauge wiring to cut down the voltage losses. The starters all ground thru the case where it's bolted to the motor - so those mounts must be clean as well.
 
Worst case scenario - your starter motor is defective and misbehaving when it gets hot - not very likely though.
 
 

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Great, thanks. Will try all that. So far I checked the battery resting 12.6 volt and running 14.3 volts. While cranking - it drops to 10 volts. Seems OK. But the weirdest thing is that it can starts cold real good and strong, but after riding for 15 minutes, I stopped at gas station for one minute and then couldn't start engine again! The battery was hardly spinning the starter. Then during OTHER stops it was FINE again! This random battery behaving just killing me... If the battery was bad, it wouldn't start cold, but it would start after riding, right? But it acts in opposite way, which is so unusual...
I'll remove PC and then see what happens without it.
Greatly appreciate your input.
 
 

  Generally speaking yes, but if the charging system is somehow performing low-normal during riding, it could make for sluggish restarts after only brief riding times. Longer ride times could get the battery charged back up just enough to have normal sound cold start ups. But then again, you are showing 14.3 volts running so I'm not so sure if that is the issue. I know this is a bit tedious and inconvenient, but you should take a multi-meter along with you on one of those short rides. After your 10-15 min ride, test the battery with the engine off and then check the volts when you start it. If you have a Ram or similar phone mount, you could always make up jumper wires and mount your meter on your mount to get constant readings. Anyway, let me know what you find, I'm kind of interested now.   
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I have an idea... when you kill the motor are you just using the key to stop the motor or are you using the red thumb switch 1st then the key?
 
It's my theory that the bike will almost fire up within a few cranks when I use the normal way to kill the motor by using the red thumb switch...tried it the other way for a day by not using the red thumb switch and only used the key to turn off the motor I find it takes more cranks to fire up...
 
If your in California a few ppl had problems with the Fuel Vapor Cannister? - solution is to remove the sucker since the other 49 states don't have it...
 
 

2015 fz-07- Hordpower Edition...2015 fj-09- 120whp- Graves Exhaust w/Woolich Race Kit- tuned by 2WDW
 

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I pretty much only use the key to shut mine off unless I can't get my gloved hand in there for some reason. If it takes an extra crank to fire, I don't care as long as the cranking speed is consistent. My Aprilia's manual clearly states to only use the kill switch in an emergency, so it's the key for  that one as well. 
 
As for carrying a voltmeter - don't leave home w/o one.
 
 
IMG_1207.jpg
 

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