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Discussion Starter #1
Can a battery test good when on the bench at room temp but lose volts when heated up?

Currently when riding around, when the bike temp is low, the bike shows 14.1 volts but when it gets hot, 200+, the volts drop to 12.3 or lower causing the bike to die at low RPMs.

Battery or something else?
 

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That is not right. It was cool today in Dallas, well ... comparatively.

With the bike running you should be getting something like 13.5 to 14.5 volts. Check it while it is running at 3000rpm or more and the rectifier should be putting out enough voltage to charge the battery.

Do you start out with the bike on a charger, then go for a ride, then find your battery flat?
 

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Do you start out with the bike on a charger, then go for a ride, then find your battery flat?
Same rail of thought here as bpracer is asking. JHodge, confirm your charging system works as it should. I live in a desert country where it gets seriously hot and high temperatures definately do not have an effect on how much charging voltages are being produced. Charging voltages is a function of engine rpm and nothing to do with ambient temp.

SF
 

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Can a battery test good when on the bench at room temp but lose volts when heated up?

Currently when riding around, when the bike temp is low, the bike shows 14.1 volts but when it gets hot, 200+, the volts drop to 12.3 or lower causing the bike to die at low RPMs.

Battery or something else?
If your battery is really old, you should just replace it anyway or risk being in the middle of nowhere when it fails. Industrial lead acid batteries have a transparent case for maintenance purposes. We don't have that luxury.

You need to look at the rectifier/regulator most likely.
 

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Discussion Starter #5
Yes, I have the bike on a trickle charger all the time and the battery is one year old. The system works and mantains the battery well. This is a new problem that just started in the past month or so. When I start the bike it will read 14.1 volt and stay right there for the first 20-30 minutes. But when the bike temp gets over 200 the volts drop while at idle but if you keep the RPMs up then they system is charging and it holds 14.1 volts but the second you let off they drop.

Could the regulator be affected by temp?
 

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A bad regulator could be affected by temperature, for good measure check the wires coming from the alternator as well for heat damage.

SF
 
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