The Motronic is stingy about giving up its secrets, that's for sure.
The Motronic is stingy about giving up its secrets, that's for sure.
Getting the ABS out isn't really a bad job but to get to the voltage regulator you've got to:
--remove left and right fairings and fuel tank
--I chose to pull the battery
Still not sure I can get to the vreg without
--remove alt belt cover
Then add a diode, a couple bucks. This is a lot of work for the PC680 battery ...
If I pull the alternator, I have a spare HES so I'll replace it. I'm this far maybe I just will.
The other thing I could do is pull the throttle cable and Bowden box to get the battery/ABS box out. That would let me swap the 3 bar regulator for a 3.5 I have. Maybe that's over my time limit.
Last edited by Roger 04 RT; 11-09-2013 at 03:57 AM.
I got to the "diode" project over the weekend. The alternator is now charging at 14.75 volts. Many thanks to GSAddict for his valuable help, often on a moment's notice at the crack of dawn.
While the project seems a success, it is a bear of a job. At this point I can't say for certain that it won't be bad for the bulbs, or other electronics. Nor do I know for sure that the higher voltage won't be bad for the ABS or Motronic. I don't know that I've selected the best diode, and I don't know how long the diode will last. If the diode fails, the alternator will stop charging. (But often overloaded diodes short out in which case the alternator will operate but at its original voltage.)
The first time I reassembled, the diode interfered with the alternator body causing two internal pins on the voltage regulator to touch. This happened because I attempted to do the work without pulling the alternator. You really have to remove the alternator to do a good job, which I did the second time. (It would be better to find a voltage regulator that was adjustable or a higher voltage, then swap regulators. I haven't found one yet.) Removal of the ABS system takes a great deal of care.
If I haven't scared you off from trying, and you're willing to take all the risk yourself, and you want to install a diode, here is a brief outline of what I did:
Remove the alternator by removing:
-Seats, left and right fairing and fuel tank
-Alternator Belt Cover
-ABS (requires bleeding all circuits afterward)
Remove the Voltage Regulator from the Alternator by:
-Removing the black cover on the alternator
-Drill out the spot weld on the ground lug
-CAREFULLY remove Ground Lug. (Note in the photo below that I have started removing the ground and it is bent upward.)
-Save ground lug to shim the underside of the regulator when you reinstall it.
Boost the Voltage by Adding:
-One NTE 5812 Diode in series with the internal ground
-Reinstall fuel tank and battery
-Test alternator output
-Pull fuel tank and battery again
-Reinstall and Bleed ABS system
-Reinstall everything else
There are a lot of steps and skills needed for this project. It would be easy to do it wrong and cause serious damage. This outline and the photos should be sufficient if you have the right skill set to take this on. Otherwise, if you have an Odyssey PC680 battery and want to keep it 100% charged, consider charging your battery with an approved Odyssey charger every few weeks. Or at your next battery change consider a regular lead acid or Gel battery, both of which are fully charged with the standard alternator.
Nice work, easy pathway to follow, despite the locations and challenges.
You've presented a strong case for others to investigate the "happiness" of their AGM's, so I am going to test mine. Although it has an open circuit voltage of 12.9 since removal this fall, I had previously reduced my alternator output to 13.8v subsequent to concerns on overcharge from my HO modified charging system (900W) where an ambitious internal regulator was pushing values north of 14.5v (was probably on the eve of failing I suspect).
Being a PC925, the numbers are substantially higher, and I dare say all the rules are bent somewhat, with 380CCA's plus a voltage correction table that allows for normal fueling on crank even when the battery might drop off.
Regardless, if the slow drain test confirms less than full capacity I'll look into raising the voltage again. And yes, the 925 is somewhat of a monster (26lbs compared to 15.4 for the 680) but I wanted a longer rating for the tuning/ logging lap top I carry occasionally, and she actually fits nicely in the standard tray with stock tool kit on top.
It will be interesting to hear how many amp-hours you get on the first discharge cycle. Once you get to 11.2 volts it drops very quickly to 10.2.
The alternator is installed and the belt tensioned, the ABS reinstalled and all the brake circuits bled (side benefit, my front and rear brakes are firmer). I've reinstalled the add-on pressure regulator but removed the BoosterPlug. The fuel tank and all the plastic parts went back on too. The battery had been disconnected during surgery so it was charged to 100%. As a result of the disconnect the Motronic was reset, so I did the twist-the-throttle thing.
With everything back on and the bike cold-soaked in my garage, I ran a cold-start test. Fast idle lever to mid-dent, press the button, Er, er, vroom--1.5 seconds to start and the idle jumped immediately to 1400 RPM with a stable spark advance and dwell. Just what I was hoping for when I started the thread.
The bottom line to this whole exercise: a bad lower plug, weak stick coils and a 67% charged, sulfated Odyssey PC680. The battery was restored with 6 Odyssey specified discharge cycles and the alternator output boosted by about 0.7 volts with the addition of a diode in the alternator's voltage regulator. I will charge it as needed with an odyssey approved charger.
I choose to initiate the first discharge test a bit late in the day and ended up having to stay up later than intended (& tending to want test to end LOL) to capture the "10.2V" moment.
As you say, the time to get down to 10.2 from 11.2 was rather exponentially quicker than the previous decay behaviour. I utilized a 3.7amp load and found this first test took 7hrs. For the PC925 that is I believe not up to snuff but I'll perform the additional drain/recharge cycles to document changes in capacity.
One thing that looms large relative to this 925 history, I had "accidentally" allowed this battery to decay to a shockingly low state last winter when I guess my storage temps were too high and it was still connected ( and again I hadn't really reviewed or learned all the details on this when I bought this first to the bike AGM item). If I remember correctly, it was down below 8v, took a recharge rather well and I have not been having any issues starting (cranking behaviour is stellar, as well I have voltage correction tables adjusted to satisfy cranking fueling etc.). Guess we'll see.
While contributing to the ABS thread (here) I noticed that the GS-911 reports battery voltage and the voltage at the top of the coils VIGN.
VBAT is 14.56 volts and VIGN is reported as 13.8 volts. That's a pretty big drop across the key. I think I'm beginning to see why they added the second Load relay to later R1150RTs.
Here is what Odyssey says for maintaining a PC680 or other Odyssey AGM battery if your alternator voltage is below 14.5 volts, for example an R1150 which has a 14V regulator that outputs about 13.7 volts much of the time.
The recommendation would be proper consistent charge maintenance when the motorcycle is not in use with an ODYSSEY program approved 12V charger/maintainer from the list of approved chargers linked on the ODYSSEY website Product Support page. Any of the listed maintainer chargers can be used to maintain the battery indefinitely without harming the battery.
We would also recommend turning the headlamp on for 1-2 minutes after parking the motorcycle but before initiating charge to ensure that the voltage reading is fairly accurate and the charger will "see" the true resting voltage of the battery and charge accordingly. If the battery appears to be discharged according to the chargers initial startup testing, it should go through the entire charging profile with maximum constant current initially which the battery will love especially if it is at least 40% of the 10 hour amp hour rating of the battery. The OMAX-6A-1B is a 6A ODYSSEY Ultimizer charger that is manufactured specifically for the powersports industry for up to the PC680 series sized batteries. It is a high enough amperage charger to perform deep discharge recovery (full amp output good for a discharged powersports sized battery) and maintain the battery at a full state of charge at the optimum recommended 13.6V [trickle] charging voltage.
If the battery is not fully charged when any charger goes into float, float voltage charging has to make up the difference to complete the charging process. The required float voltage range is 13.5-13.8V. We would highly recommend leaving any approved charger on the battery from use to use to ensure full charge especially for a motorcycle with an inadequate charging system. CTEK chargers with the snowflake setting (required for ODYSSEY) also work very well for seasonal powersports applications. They are plug and play as well.
AGM, Absorbed Glass Mat. It's a freeeking Lead Acid that doesn't leak when upside down. That's it, that's all.
If I saw a machine, any machine, charge above 14.5V, I would red flag it. 14.7V is damn near a condemn in my opinion. 15.0V pops bulbs at the very minimum.
Popping bulbs never happen in a nice warm shop when you are doing a PM but when the machine goes to work and the lights burn out every few hours, who do you think they call at 3:00 AM?
Throw those funky little electronic gizmos that act like fuses on a circuit board into the mixture, there is some Vegas gambling.
Now, at risk of trying the patience of the few that want to slam me, I don't mean to be a smartass but I seem to be perceived that way, if your battery bites, get a new one? Hang the warranty around the vendor's neck?
FLA, VRLA, AGM, GELL are the same!
Roger 04 RT, you are absolutely confidant in expressing your opinions here and you have the full and unconditional support of GSAddict and Happy Wanderer. At times it is very interesting from your perception how some stuff works. I am not taking away that your thoughts are pretty damn smart.
I have had my ticket as an HD Mechanic since 1979, add four years as an apprentice and you know what I take from that? I know I am not the smartest cat on the street and knowing I am right doesn't mean I am always right.
Do you want to tell the readers here that they need to install a Zenor Diode on the brushes of their alternator to own the battery you have?
I'm guessing that isn't your intention. I'm going to take a wild guess that you intended to find a solution to a problem you thought you had and it wanted to share it but it got away from you.
Here is a piece of advice: If you are the guy that puts the duds on at 3:00 AM to get your folks home/working, better to be simple than...................
Aye my boys, Have At Er, eh? Giver gud eh?
Last edited by dieselyoda; 11-21-2013 at 07:30 AM.
1997 R1100RT (Restored Basket Case) , 1981 KZ 440 LTD (Restored Basket Case)
3xR90/6, one running most excellent, two for restoration.
1983(?) K100RS for winter project, 1986 K75S(the beutch)sold, 1993 K1100RS (blown engine)sold,
All I can say to the prior post is, wow! You need to do some homework. Odyssey and others are very clear about the charging requirements of agm batteries. Others who own the pc680 have done discharge measuments and discovered the same state of charge as mine, about 2/3.
I highly doubt that many will mod their VRs by adding a silicon rectifier diode (which is not a Zener diode). That is why I asked odyssey for its guidance on how a user can maintain a 100% State of Charge which is two posts back.
Shortly I will post some follow up comments from odyssey on other considerations for maintaining 100%.
P.S. My average cold-soak starting time, at temperatures as low as 19F, is under 1.5 seconds.
Last edited by Roger 04 RT; 11-21-2013 at 09:04 PM.
Here is some further clarification from Odyssey.
A few additional thoughts.
1. Most PowerSport vehicles have charging systems with relative low operating (charging) voltages because of the fear of boiling out a wet flooded battery and dealing with the acid corrosion issues. Their philosophy is better to under charge the battery and minimize the gassing than charge correctly and out gas the battery. In going to ODYSSEY and not having the corrosion issues, correct charging - operating voltage is critical to getting the long life ODYSSEY has to offer.
2. We don't expect PowerSport vehicle owners to do what you did in correcting the charging system voltage, so a solid alternative is to use a 6+ amp charger - maintainer on a continuous basis when the bike or vehicle is the garage. Continuous float charge will correct under charge from the bikes system.
3. The ODYSSEY Ultimizer OMAX-6A-1B is a great little charger - maintainer if you can live with the continuous cooling fan noise. If not, use the CTEK US Multi-7002 and use the Snowflake battery selection algorithm.
Bruce R. Essig
National Sales Manager
Program Distribution Groups
I've delayed any further Odyssey tests till this weekend when I have more time.
In support, I appreciate a post such as this one, and seek the depth and detail (if I didn't I would simply go do something else).
Last edited by R100RTurbo; 11-21-2013 at 03:56 PM.
PM's sent to a few...C'mon guys, don't make this a long Winter
Food for thought is this lengthy thread with at least one SME on charging systems/batteries/chargers...his background makes his input valuable.Your opinions may differ...but that's another story.
Last edited by henzilla; 11-21-2013 at 04:18 PM.
SABMWRA MOA Club#62's Flat Fixer/ current forum moderator
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