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Discussion Starter #1 (Edited)
Hi everyone, I have an '03 Road Star Midnight 1600, and the bike wont charge the battery over 12.5 volts. It needs about 12.9 volts to spin the crankshaft fast enough for it to start, so I have to use an external charger to charge it to full(about 13.4 volts) before I ride, then hope I don't have to stop more than once or twice before coming home ( about 200-250 mile trip). The light is on and bright, and even when it won't start, once it's running the alternator sustains it. Is there an easy fix? Is it just the regulator perhaps? anyone know how to check? Thanks.
 

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First thing I would do is load test the battery. A failing battery will not properly hold a charge. Any auto parts store can test it for free. Just make sure they enter the correct CCA for a true reading. If it tests good hook a test meter to battery and see what voltage its showing with bike running at 2000 rpm. Also double check battery terminals tightness and ground cable to frame. Post your results. Good luck. (By the way, I bet bad battery.)
 

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Discussion Starter #3
I would have thought that, bad battery, but I just bought it last month, and when it has a full charge it will turn over well in excess of 60 times before slowing. Obviously not a continuous 60 times. I'll take it in and have them check though, gotta start somewhere. Thank you for the swift reply.

-d
 

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Hi everyone, I have an '03 Road Star Midnight 1600, and the bike wont charge the battery over 12.5 volts. It needs about 12.9 volts to spin the crankshaft fast enough for it to start, so I have to use an external charger to charge it to full(about 13.4 volts) before I ride, then hope I don't have to stop more than once or twice before coming home ( about 200-250 mile trip). The light is on and bright, and even when it won't start, once it's running the alternator sustains it. Is there an easy fix? Is it just the regulator perhaps? anyone know how to check? Thanks.
the battery voltage is 12.5 with the engine running ?, change the rectifier/regulator
 

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the battery voltage is 12.5 with the engine running ?, change the rectifier/regulator
This may be poor advice.

I would suspect a poor ground at the battery if the bike won't crank well at 12.5 volts and this could also cause the drop in your charging system.

When you put the bike on a charger you are supplying the battery with a new ground be it clamped on or through the battery tender lead. This would allow the battery to charge properly only when on the charger.

Check the connections on the battery first. Clean them well and see if the problem goes away. If not it still could be the ground on the bike causing it so verify that one next before spending money.
 

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^ yes - follow the black wire from the battery - terminal to where it attaches to the frame. That is a very common corrosion point, because you normally cannot see it unless you follow the wire and look for it.
 

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I agree with checking the wires to not only see if they are in good shape, but also clean & seated well to make a good connection.

My last truck would randomly not start. Turn the key & click. Wait a minute & she'd start right up.
Had the battery checked.... In great shape.
Positive to started solenoid.... Great shape.
Negative cable. Good shape but was a little dirty. Cleaned & still kept having the issue.

Turned out to be the positive cable from the starter solenoid to the starter itself had just about rusted through. Replaced with heavier duty & longer cable. Never a problem again.
 

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I'm a big fan of cleaning the battery connection points and ground straps and smearing on a light coating of dielectric grease as a routine maintenance thing like every year, or more if I've ridden a lot in nasty weather during a particular season. I'll also clean the major connectors and use dielectric grease on the individual terminals as well. If the connectors don't have a protective sheath over them I'll make some from cut sections of old bicycle inner tubes and cinch the forwardmost or topmost end onto the harness with a cable tie.
 

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Discussion Starter #10
Ok, I started at the ground cable, and found it was tight at the frame, it was however loose at the battery. I tightened it and the bike fired right up without a charge. I'll take it for a couple rides and see how it acts, I'm still carrying jumper cables for the moment though. Thank you everyone who offered suggestions, I'm a little embarrassed it turned out to be this easy, if this is in fact the problem. I'll report back when I've put a few miles on her.


-d
 

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It's good you asked because you might have overlooked how simple it was until someone mentioned it.. Glad you got it figured out :)

Sometimes we look for the difficult fixes when it's the simple ones in front of our faces..
 
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