Charges after start & then stops

[Prestone]

My 99 charges after initial start & then after about 30 seconds it stops or at least decreases significantly. I replaced wiring from R/R, eliminated infamous splice, etc, checked stator & R/R per the book with VOM & all tests are good. It charges way better than it used to voltage wise after all that (14.2V vs 13.2V) @ 3000 RPM but still drops out after about 30 seconds after start up. If I let it sit it will do the same thing, charge fine for about 30 sec to a minute & then drops out. Will not come back until I shut it down & let it sit. It tries to charge a little with some RPM after it kicks out (12.6) but that's it. Any thoughts??

 

[Miles Long]

Did you repeat the stator tests (at the three-wire connector) immediately after the bike shows a no-charging condition?

 

[Prestone]

I did the VAC check with it unplugged & it checks good on each leg even after several minutes of running.

 

[Prestone]

I haven't seen what AC readings would be plugged in, any ideas what they should be

 

[Miles Long]

You should also check for resistance between the three legs, as well as continuity to ground of each leg, after the bike stops charging - with the engine off, of course.
I have no idea how you would check for AC voltage after plugging in, other than stripping the insulation off the wires.
Are you also using the Electrosport fault-finding chart? If not, it can be found in the electrical forum, as a "stickie"
Cheers!
edit - also, this thread contains a lot of info, Q&A's and tips re charging problems.
http://www.vmaxforum.net/showthread.php?t=19108

 

[Prestone]

I have used the electrosport chart & it all checks good

 

[Miles Long]

The last line of the chart reads something like this (paraphrase)
"If all stator and regulator tests are good, suspect the battery"

This info bit me in the ass a few years ago, when I chose to ignore it.

Sure enough, it turned out my battery was slowly failing. It was an AGM, and one of the characteristics of that type is slow failure - an advantage when it comes to perhaps not leaving you stranded, but a disadvantage when judging performance.
How old is your battery, what type, and have you had it load-tested?
Also, the three - wire stator connector often fails on the Max (and other bikes).
If you haven't already, check this puppy out, and assemble with di-electric grease.

 

[Prestone]

Battery is less than 2 yrs old. It a Xtreme 16 AH powersport battery from Batteries Plus. Load tested fine a few days ago

 

[Prestone]

I eliminated the 3 wire stator connector with aircraft grade splices

 

[Miles Long]

And the diode test on the RR was O.K?
As far as I know, that's the only test you can do on the reg, other than the connections.
Did you eliminate the crimp completely, or install a Y on the positive wire from the RR?
If you suspect the RR is failing because of heat, is there a way to cool it for test purposes? maybe a small fan or compressed air?

 

[Prestone]

Diode test was OK cold. I eliminated the splice completely. Gonna bring another VOM home from work tomorrow so I can monitor stator output when it stops charging. Thanks for the advice & I'll keep ya posted

 

[Miles Long]

A few of us on this forum have maintained the original splice, after soldering it up well, but have also piggy-backed into the red wire, and ran this directly to the positive post - with an in-line fuse incorporated.
Kind of a built in "redundancy".
Also, an extra ground wire direct to the negative post.
I gained over 1/2 volt at the terminals after doing this.
Your problem seems to be an RR misbehavin' (providing the stator checks out), but -this is a long shot - what if there is a extra draw on the system cause by a short circuit of some type, just after starting the bike? You could do a battery leak-down test, or just remove all the fuses except the one for the ignition circuit.
Cheers!

 

[Prestone]

I gained about 3/4 of a volt when it does charge so happy in that regard. Great idea pulling fuses, I will give that a shot

 

[Prestone]

OK, pulled all fuses except ignition of course. Charged indeifntely at 14.2 V @ 3000 RPM or at least until engine started to get hot Added one fuse back at a time & all was well until the last one which was the headlamp (15 amp fuse). 30 sec or so after I added the fuse it dropped to 12.4 volts & would get no higher than 12.6 regardless of RPM. Pulled it & voltage climbed back up well over 13V. I will start isolating the circuit tomorrow. Looks like just headlight & some instrument lights best I can tell from schematic. Headlight maybe?? seems to work in normal & bright

 

[Miles Long]

Has your headlight been modified, or still stock?
Perhaps the P.O. replaced the stock 55/60 watt bulb with a higher wattage?
In any event, there's not many components in that circuit (fuse, starter switch, dimmer switch, headlight, high beam indicator ) Good luck with the troubleshooting.
Cheers!
edit - just noticed the "or at least until engine started to get hot" notation in your last post. Is this when the cooling fan kicked in? The operating fan has a notorious effect on displayed voltage, especially when the bike is only idling. Seems every Max is different, but if your idling voltage is at or above 12.6, with both the headlight and fan on, your charging system is about average. Of course voltage should pick up with increased rpm's.

 

[wildweasel_pt]

Yup. Increased draw by the fan. I guess you going to start experience ignition miss and bike stalling not being able to start again until cooled or fan disconnected.

 

[Prestone]

OK, think I got it. With the draw of the headlight removed it did drop after about 45 sec of running from 14.2V at 3K RPM but only to about 13.5. Not bad. Put headlight back in circuit & it went back to it's normal failure mode (12.4V after 30 sec). Taped two ice packs on the R/R for a few minutes & it would run at 14.2V regardless of load & about 4 times longer than before dropping. Left ice packs on for about 45 min. Bike ran for over 5 min before dropping to 12.8. R/R is breaking down when it heats up. Ordering R/R

 

[Bill Seward]

Would be a great time to upgrade to a MOSFET unit...

 

[95spfldmax]

OK, think I got it. With the draw of the headlight removed it did drop after about 45 sec of running from 14.2V at 3K RPM but only to about 13.5. Not bad. Put headlight back in circuit & it went back to it's normal failure mode (12.4V after 30 sec). Taped two ice packs on the R/R for a few minutes & it would run at 14.2V regardless of load & about 4 times longer than before dropping. Left ice packs on for about 45 min. Bike ran for over 5 min before dropping to 12.8. R/R is breaking down when it heats up. Ordering R/R

Nice troubleshooting work , sir!

 

[Bill Seward]

I've got a stock R/R unit (Rick's Motorsport). Wires are cut so you have to solder the 3 connections to stator, and lengthen wires to positive and negative battery. Works great, only about 3000 miles on it. $30.00 gets it to your door.. I've got the long screws to mount it in stock location, and will give you 3 posi lock connectors for the stator connections if you need them.