Fried Odyssey Battery

[markst1]

I recently went for a 80 mile ride on my '74 R75/6 in 90 degree temps and when I got home, bike wouldn't start. Usually I just use this bike around town for shorter commuting. Charging light on the dash had been behaving normally. I checked the battery voltage, 12.5V. After putting it back on the battery tender, still not enough juice to start the bike. The lights were dim, and faded to nothing when trying to start. Solenoid just clicked. So I swapped out the Odessey PC680 (2 years old) for the older (5 years) PC925 from my other airhead. The /6 seems just fine now. So I guess I will replace the PC680 with a new PC925.
A few questions for the group?
- Is the PC680 too small for the airheads?
-This PC680 did spend sometime in my other bike last year while the bike was having charging problems (diode board) and had spent significant time in a drained state as I limped home from a long trip with no charging happening. Could this have permanently damaged the battery?
-Could the voltage regulator on the /6 be malfunctioning and overcharging the battery? I don't want to fry the new/old battery that I just put in if that is the case. How best to check this?
Thanks
Theo Marks

[20774]

-Could the voltage regulator on the /6 be malfunctioning and overcharging the battery? I don't want to fry the new/old battery that I just put in if that is the case. How best to check this?

Put a good digital voltmeter across the battery terminals and start the bike. Rev the engine and watch the voltage. Shouldn't go any higher than slightly over 14v. If it climbs to beyond 15, then the regulator ain't regulating. Extended periods of time over 15v could even do damage to wiring...I would think that would suffer before a battery would.

[85K100LT]

"Is the PC680 too small for the airheads?"

PC680 is fine for Airheads.

You may have drained it to far and not be able to bring it back. Do check your current bike to make sure charging system is working.


"Charging light on the dash had been behaving normally" The light on dash is either on or off not a good way to troubleshoot your charging system. Even though on Airheads it is in circuit with charging. Use a DVM to check output of charging system.

[stanley83]

After putting it back on the battery tender, still not enough juice to start the bike.

Odyssey's literature talks about only certain charger/maintainers being up to recharging a deeply discharged battery. Perhaps yours has been discharged beyond the capabilities of your battery tender?

[markst1]

Well, I suppose that running that battery low last year for so long probably did it in. The charging system on the bike seems fine. The voltage regulator keeps the charging voltage maxed at 14.3V. Not sure why the battery picked now to die, maybe due to it being a very hot day. Only got ~20 months out of the PC680, but I guess it was was pertty seriously abused. So I am using the 6 year old PC925 from my other bike in the /6 now, with a new PC925 on order. I buy the Odysseys because I expect to get a lot of life from them, and I have for the most part. But I guess no battery could stand up to the abuse that fried that one.
Thanks for the help
Theo Marks
' R75/6
'88 R100RS

[ISAMEMON]

I have been happy wiht odyessy batt's. The 925 has about 150 more cca and 250+ more crank amps. However, in my bike I can not fit the 925 as it is nearly twice as wide as a 680..........if I remeber correct. I think its also about 50 bucks more. ( od's part numbers refer ot cranking amps, thus 680 is 680 ca, 925 is 925ca)

My bike ( 85R80RT) has the extended tool box that goes down next to the battery between the rear fender etc. I would not be able to fit the 925 without going to an earler flat tool box/tray
If you can fit the 925 in your bike, then that is what I would do.

Yes make sure your charging system is working correct.Bikes equiped wiht the "factory" volt meter offer a bit more info , but some are not right on compared to a multi-meter . Just going by the dash bulb is not a fair way to check. Also remeber that the little bulbis a critical part of the charging system.
Motorad used to sell a resistor link that keeps bike charging even if light burns or shorts out, I think he only sells it now when you buy the whole omega charging system, sno-bum does a write up on it as well as how to make it, , adn you can buy it pre-made on fleabay

I also modified my flot charger to a cig plug ( male) instead of the alligator clips it camae with, so I can plug it in to my power outlet and thus not lift the seat to put it on, makes it easy to use. My power outlet is wired direct to battery on its own fuse, so its hot all the time, and thus can back flow foro power without sending the power to other parts of bike. If your doing lots of short trips, you will want to flat charge on occassion. I live 15 miles from town so I dont have a prob with short rides.

[boxerkuh]

I love the PC 680. I have had mine in my RS for over 7 years now, with no issues. One time I thought I had battery issues I took the battery to Auto Zone and had it tested. It tested fine. I even double checked with Odyssey customer service and the numbers I gave them it checked great. It turned out to be broken and weak diode board mounts. I would go through the system, item by item to have peace of mind.

[GeorgeRyals]

Theo,
Don't give up on the battery. Put a 10 amp charger on it and bring it back to life.

14.3 volts is not too much from your charging system for odyessy batteries; it is for lead acid batteries on long rides. Find the odyessy battery manual online and read up on what the manufacturer has to say about charging.

http://www.odysseybatteries.com/file...1_0411_000.pdf

This is a link to the tecgnical manual. It tells how to revive a stone dead odyessy battery.