Battery drains while riding.

[Coolbreezin]

My battery drains (sometimes) while I'm riding my bike. I have a voltmeter under my seat and I can slowly watch it go down while idling. I checked for a parasitic drain, stator cks OK as does VR. I was hoping to find a loose or bare wire somewhere under the engine. I only have two wires coming out of my VR and both plug into the stator. Yesterday I needed a jump. Today I'm fine. Any advice you can give me? Thank you

 

[awg]

Is the battery very old? I have seen that a bad battery will not hold a charge.

 

[Reddickracing]

What is voltage not running? and at idle? Should be around 12.5 at idle and increase to 14 at around 2 thou rpm.

 

[Coolbreezin]

Is the battery very old? I have seen that a bad battery will not hold a charge.

New lithium ion 420cca purchased jan2019.

 

[Coolbreezin]

What is voltage not running? and at idle? Should be around 12.5 at idle and increase to 14 at around 2 thou rpm.

Not running is 12.9, idle is same but goes to 13.1 about 1500rpm.

 

[Coolbreezin]

I have only 2 wires on my aftermarket VR.

 

[Reddickracing]

My factory vr had 2 wires, just put a compufire on and it had 3

 

[Coolbreezin]

My factory vr had 2 wires, just put a compufire on and it had 3

And what good did that do? Whats the third wire for?

 

[Reddickracing]

The extra wire on my new unit is a ground.

 

[Jersey Big Mike]

The compufire if same model as mine, puts out 40A max and does 25A at idle.
Had them on both K-9's and love them, never a problem.

 

[Coolbreezin]

The extra wire on my new unit is a ground.

Thank you. I understand its 8 more amps, but what would I gain from an additional ground? Or is the gain simply "Compu-fire"?

 

[Coolbreezin]

The compufire if same model as mine, puts out 40A max and does 25A at idle.
Had them on both K-9's and love them, never a problem.

Thank you. If I have a 32amp stator, will that create a problem with the 40amp VR?

 

[awg]

Seems to me it should be a more than 13.1 at 1500rpm. Cant hurt to put a new VR in. The original one's were prone to problems. Certain years had recalls. If everything else checks out good, I would install a VR and check it again. And yes the third wire is the groung. Just ground it to the frame where the VR mounts.

 

[Coolbreezin]

Seems to me it should be a more than 13.1 at 1500rpm. Cant hurt to put a new VR in. The original one's were prone to problems. Certain years had recalls. If everything else checks out good, I would install a VR and check it again. And yes the third wire is the groung. Just ground it to the frame where the VR mounts.

Thank you for all the good info.
This is my 2nd VR, about 5-7 yes old. I've always understood electronics either work or don't. They don't slowly die like an engine. Am I wrong by thinking like this?

 

[Jersey Big Mike]

Thank you. If I have a 32amp stator, will that create a problem with the 40amp VR?

Can't use the compu-fire 40A VR without the compufire stator -- The 40A system is 3 phase, a normal charging system is not.

You say VR and Stator check out but you only list voltage at 1500rpm, try 2000 or 2500rpm and see what voltage you get. Standard system doesn't produce real power til that rpm range.

I have the old stator and VR from my k-9 when I replaced (by choice not neccessity) the system with the compufire.

 

[Jersey Big Mike]

Thank you for all the good info.
This is my 2nd VR, about 5-7 yes old. I've always understood electronics either work or don't. They don't slowly die like an engine. Am I wrong by thinking like this?

electronics can and do degrade. VR's usually do see catastrophic failures though but it is still possible. As I said check the output voltage at 2000-2500 rpm and we'll have a better clue.

 

[Coolbreezin]

Idle is 12.9
2000 is 13
2500 is 13
3000 is 13

 

[awg]

Should be around 14.5

 

[Coolbreezin]

I have a 420cca battery and started it yesterday with 11.7 volts. It was reluctant but did start. If im producing 12.9 at idle, wouldnt that be ok though? I understand something is slowly dying, but 12.9 be usable?

 

[Jersey Big Mike]

Ok, at this point given my luck with Li-on batteries I'd borrow a decent lead acid/agm battery and install it and see what it does to the voltage.
Or you could disconnect the lead from the VR to the battery and start the bike and see what voltage you get off that lead. If it never goes above the 13 its in the charging system, if it goes to the 14+ side its the battery or some other load issue.
Check your headlight for a bad connector. Disconnect light and do test!