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Discussion Starter #1 (Edited)
Does anyone know if the power output from the Rectifier/Regulator should be even when the battery is fully charged? My Yamaha manual shows 14.1-14.5 VDC whiling revving the engine, but makes no mention if this is normal under the condition I mentioned.
 

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Voltage really depends on a number of things such as saturation level and rpms. If the battery is fully charged and everything else being the same the voltage will be higher than when the battery is charging. The real world range of normal can be outside the narrow range listed and should be used to only as a metric to diagnose issues. In and of itself it's just an indicator that you use to help make decisions rather than something that is telling you the problem.

Point is not to freak out if voltage is outside the normal range. It doesn't necessarily mean there is a problem. It just means that current conditions place it at that level. You have to decide if it's because something's wrong.
 

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Discussion Starter #3
Gr8! That's what I suspected but needed some confirmation. This illiminates the battery from the charging issues I've been having. I've done the diode test on the rectifier/regulator and found a failed/shorted diode. The battery still gets charging voltage (at much lower level, 12.3-12.7) but I'm concerned that this may send AC voltage to my battery.
 

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Discussion Starter #5
My Ride

Thanks Sick Mick and here are the vitals stats concerning my bike.
2000 V-Star 1100, Equipped with windscreen, hard bags, ORK, and road lights. The rest is all stock. I've reviewed the information you posted in the link, but it lacks the specifics I was looking for. Specifically, will the burned out diode in the rectifier/regulator pass AC voltage from the stator directly to the battery? I understand that DC batteries don't handle AC voltage well and can cause serious problems for the electrical system on my bike.
 

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I can tell you that a faulty reg/rec will take out everything electrical on the bike. I've seen it far too often. It always starts with a charging issue, either low or high. My advice is always...if something is not right with reg/rec, don't ride with it until you get a new one.

Tim B at metric Magic sells a HD reg/rec that pretty much solves the problems....but the stock one has always been a weak link on the 1100. I carry a spare with me, when the original goes, I'll get the HD one.

A word of caution....use only OEM Yamaha ones... the aftermarket ones can cause some real issues.
 

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Hey, Sick Mick, that link is spot on. Nice reference.

One interesting note about motorcycle charging systems with permanent magnetos is that they run hotter with LESS load. They generally produce the same output at all times and must dissipate any energy NOT consumed by the bike. So, while it's good to keep the regulator cool (the cooler the better), there should be no fear of adding lights and things so long as the maximum output isn't exceeded.

A side effect of this is that a fully charged battery may cause the regulator to dissipate additional heat that would normally go to charging the battery. Poor grounds and connections can have the same effect if they are causing the bike to draw less energy then normal. Not a problem if your regulator has good air flow to keep it in a good operating range.

So, the next time a cop stops you because your high beams and driving lights are on with you stereo blaring and carnival lighting on, just tell him your regulator was running a little hot and you were cooling it down.
 

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LOL...no kidding!

Yup..running the full regalia of lighting is not a bad thing like you say as long as the system can keep up.
 
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