Bought a AGM battery for my stock 85 FXWG, listed as direct replacement battery, fit perfectly. When I was reading the owners manual it says if you have a stock 32 amp alt that the battery will run out of charge after 150 miles riding. i ride a lot more than that on a given day. vendor recommended battery tender, i have no problem with that, tenders are a good idea. battery tender will not help me if I am 155 miles from home and my battery is dead.

I contacted the manufacturer same story, use tender or change to 3 phase 40 amp alternator. details are the AGM is a 13 amp hour battery the stock battery is a 19 amp hour battery????

Has anybody used a Odessey AGM on a stock out put bike? Does it crap out after 200 miles? I ride usually about 50 miles every day and 3-400 hundred on weekends.

 

My only thought is that it draws so much current charging that it drops the voltage below the level it will charge. I think you need about 13.6V to charge so you might try checking with a volt meter. It might switch so rapidly between charging and discharging that you need a scope to tell what's going on though.

Take the wife along and have her get off and push if the bike won't start

 

I think if you take a voltage reading of the battery while the bike is off then compare it to the voltage when the bike is runninf at idle. The voltage should be higher at idle if it is your battery is charging not discharging. I don't think a bike draws anywhere near 32 amps. The 32 amps is at a certain RPM so if it is charging at idle it shouldn't have any problem on the road. Also does your bike have an altenator light? If its off the battery is not discharging.

 

I would agree with a regular battery, I'm not so sure with an AGM battery though.

 

- sorry , but i don't understand this post.

- if your charging system is healthy , and can produce enough Voltage (.v)
to overcome the batteries internal resistance , then the battery will be
charged.

- But the rate (amps) of charging will depend on your charging system's
output.

- your battery will only be drained flat if the current drawn from the battery
to run the bike exceeds the charging rate of the alternator (which is very
unlikely on motorcycle - unless you're running a crazy set of accessories , etc,
or have a fault somewhere).

- i hope the above makes some sense.

.

 

+1. Something's not adding up here.

 

Should have nothing to do with the battery if it maintains a full charge normally. Either the altenator/regulator is not putting out enough voltage and amps or the bike is drawing more than it's output. 32 amps is plenty of reserve in the charging system. Charging system checks and draw checks are in order.
Ron

 

With a design I'm unfamilar with I would allow for the possibility there's something I don't understand. It's a battery though. Worst that happens is you have to jump it or push it. I would ride the bike and if the battery failed to start the bike I would replace it. I wouldn't use a tender except to maintain the battery when I'm not riding it for long periods. I'm not interested in making a battery work. If a battery doesn't work then I'm going to replace it with one that does. Live and learn, too bad you're out the money.

 

Put it a different way. If the battery manual is right, then you should eventually run out of juice on a 32 amp alternator even with a higher capacity battery, even with a car battery. It would just take more miles to drain it. This is crazy.

 

I never heard of a bike being able to outrun a battery. As long as you don't have any accessories hooked directly to the battery, once the bike is started the alternator will replace the current used to start the bike, then provide current to run the lights. This is why you can jump start a bike or car with a dead battery and the lights will still work.