12.8v-13v+ at idle, but less as RPMs rise...

[Shuriken]

12.8v-13v+ at idle, but less voltage as RPMs increase. When I increase throttle, the voltage drops to under 12... like 11.5v. I suspect a bad battery, but before I just go and replace it with an expensive one, what comments do you guys have?

I can charge the battery and it appears to hold a charge. I charged the battery a week ago and can go out and start the bike, but if I take a ride or two, I have to push start the bike. Of course the headlight runs and I use the signals, but a 15-20 minute ride is all it takes and she won't start.

Because I have seen over 13 at idle, I don't think the charging system is at fault and the battery is 2 or 3 seasons old now and has been discharged pretty low at times. Should I update my wiring and/or regulator first and then check voltage or just try a battery first?

I had a hot start issue last year once that left me walking, but otherwise, the bike has been quite reliable for 2 seasons.

 

[maleko89]

Disconnect red wire that comes from R/R from it's connector. Measure voltage coming off that wire. If it does the same thing, then something is up with R/R, stator, and/or connections in between them. You can take your battery to Walmart and have them load test it.

 

[Buster Hymen]

I'd say it was a charging system issue and not a battery issue as 13v is not a proper charging voltage.

 

[atVMAX99]

12.8v-13v+ at idle, but less voltage as RPMs increase. When I increase throttle, the voltage drops to under 12... like 11.5v. I suspect a bad battery, but before I just go and replace it with an expensive one, what comments do you guys have?

I can charge the battery and it appears to hold a charge. I charged the battery a week ago and can go out and start the bike, but if I take a ride or two, I have to push start the bike. Of course the headlight runs and I use the signals, but a 15-20 minute ride is all it takes and she won't start.

Because I have seen over 13 at idle, I don't think the charging system is at fault and the battery is 2 or 3 seasons old now and has been discharged pretty low at times. Should I update my wiring and/or regulator first and then check voltage or just try a battery first?

I had a hot start issue last year once that left me walking, but otherwise, the bike has been quite reliable for 2 seasons.

Your charging system is not working, the battery is simply a storage device, a properly functioning 12 volt charging system should be 14 to 14.5 volts.

 

[Thevmaxrider]

It seems to me that the battery is the culprit. An older battery will take a "surface charge" and indicate that the voltage is fine until it is placed under load. At that point it drops off fast and will require more output from the charging system in an attempt to keep up with the demands of the electrical system. Remember that the system is in parallel with the battery as far as the charging system is concerned. Electrically the bike can draw from either the charging system OR the battery which means that the battery can also draw on the charging system while running. If your battery is weak it will not only take most of the output of the charging system just to attempt to keep it charged it will also suffer draw down from the electrical system as well. The charging system for any vehicle is not designed to charge a battery continuously, just when it needs it due to startup or, in the case of the Vmax, long periods of idling. Of course as with anything else I could be wrong. Just think that the easiest thing to check is the battery and work from there.

 

[atVMAX99]

It seems to me that the battery is the culprit. An older battery will take a "surface charge" and indicate that the voltage is fine until it is placed under load. At that point it drops off fast and will require more output from the charging system in an attempt to keep up with the demands of the electrical system. Remember that the system is in parallel with the battery as far as the charging system is concerned. Electrically the bike can draw from either the charging system OR the battery which means that the battery can also draw on the charging system while running. If your battery is weak it will not only take most of the output of the charging system just to attempt to keep it charged it will also suffer draw down from the electrical system as well. The charging system for any vehicle is not designed to charge a battery continuously, just when it needs it due to startup or, in the case of the Vmax, long periods of idling. Of course as with anything else I could be wrong. Just think that the easiest thing to check is the battery and work from there.

The charging system is in parallel with the battery, however, the reason why the charging system puts out 14 to 14.5 volts is to push positive current flow into the battery overcoming it's surface voltage while suppling the vehicle with it's electrical needs. This is the case with a car, tractor, motorcycle, etc., the voltmeter across the battery while it's running is the indicator to go by. The battery would be to blame if despite the proper voltage being present across the battery while it's running (14 volts) and it were shut off and the battery was still dead then the battery could be suspect as it would appear not to be holding or taking charge.

"The charging system for any vehicle is not designed to charge a battery continuously, just when it needs it due to startup or, in the case of the Vmax, long periods of idling."

This is not an accurate statement, the charging/electrical system of any vehicle is designed to hold 14 to 14.5 volts under varying loads, it's the state of the battery itself which will pull more or less current. To the charging/electrical system the battery is just another load like lights, blower motor, ignitors, whatever.

 

[Thevmaxrider]

I stand corrected.

 

[atVMAX99]

I stand corrected.

:cheers:

 

[Shuriken]

I do appreciate the help on this stuff. I really don't want to mess with the rotor. I need to check some things and get back to you guys.

 

[davidon]

It's your R/R or connections with it

 

[RaWarrior]

Have you done the "crimp fix"? When I first got my Max, I never had any issues with the battery going flat, but voltage across the battery at idle was only like 12.8 volts, and it peaked out at a bit over 13 when revving. I did the crimp fix, but I just cut out the old connector and re-crimped it with a blue butt connector. Voltage at idle rose to about 13.2, and to about 13.7 when revving. Still a bit low "by the book", but I've never had any problems with slow cranking, even on hot days with a hot engine. I have the Odyssey battery as well.

I've noticed that just off idle the voltage drops and "flickers", it's most noticeable if you watch the headlight brightness.....it'll pulse a bit in a certain range just off idle. Past that and it rises up to normal.

I'd guess your R/R is going south. Might as well replace it with a R1 unit, since it seems the Max's R/R just tends to suck and not work quite as well as it should.

 

[davidon]

Also worth it to do a Heavy Duty ground kit

 

[88Vmax]

I havent had any responses to the last posts i put on another thread, but when i was testing my r/r ohms said .4-.5 is this good. also tested my stator and 2 wires tested 38.9vac and 1 tested 7.5vac. is it obvious that the culprit is the sator or is there any other tests. can 1 bad wire off the stator cause no charging?

 

[Shuriken]

I found some loose wiring. That might have done the trick.