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Bad Rectifier?

MoldTheClay said:
Got the new stator (it was blackened and fried) in as well as the new r/r.

checked battery voltage after charging it for a day and it read I think 12.7v. Started her up and the battery is at 14.34v at idle and it goes down to 13.78v when revving yo 4k rpm.

Sounds like I am all good to go to me, but if somebody can confirm to me that everything sounds normal I would appreciate it!
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No, it's not ideal. Voltage should not drop from 14 to 13.7 as when revving to 4,000. The opposite should occur.
 
afm199 said:
No, it's not ideal. Voltage should not drop from 14 to 13.7 as when revving to 4,000. The opposite should occur.
Click to expand...

My thinking is that since the battery was fully charged on a tender the R/R might sense a near fully charged battery and step down to a slightly lower 13.8v vs the full 14.4v charge rate.

An interesting test might be to turn the key on, let the bike sit for 5 minutes, then start the bike and re-test the voltage. With the battery mildly run down from the 5 minute drain see if the R/R is putting out 13.8v or 14.4v when the bike is recharging the battery.

And what multimeter are you using, a top shelf Fluke or Harbor/RadioShack version?
 
I didn't think that the RR did anything of the sort - my understanding is that it has a target voltage, and outputs that whenever it can (if you're drawing enough power, it might droop but that doesn't seem to be the scenario).
 
mototireguy said:
My thinking is that since the battery was fully charged on a tender the R/R might sense a near fully charged battery and step down to a slightly lower 13.8v vs the full 14.4v charge rate.

An interesting test might be to turn the key on, let the bike sit for 5 minutes, then start the bike and re-test the voltage. With the battery mildly run down from the 5 minute drain see if the R/R is putting out 13.8v or 14.4v when the bike is recharging the battery.

And what multimeter are you using, a top shelf Fluke or Harbor/RadioShack version?
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+1

Also.... when ever someone says they replaced a battery I always wonder; "Chinese or Japanese ? " 'cause imo you just wasted your money if you bought a Chinese battery.... I've chased my tail trying to fix a charging problem only to figure out that, "yes" you can purchase 3 defective Chinese batteries in a row
 
mototireguy said:
My thinking is that since the battery was fully charged on a tender the R/R might sense a near fully charged battery and step down to a slightly lower 13.8v vs the full 14.4v charge rate.

An interesting test might be to turn the key on, let the bike sit for 5 minutes, then start the bike and re-test the voltage. With the battery mildly run down from the 5 minute drain see if the R/R is putting out 13.8v or 14.4v when the bike is recharging the battery.

And what multimeter are you using, a top shelf Fluke or Harbor/RadioShack version?
Click to expand...

RR should always charge at peak and shunt the current if not needed.
 
Could be a HF multimeter bouncing around on top of the bike being vibrated.
 
Alright got home after a day of working to see what it looked like after a day of use.

Got home and used my handy itty-bitty-shitty HF Multimeter to check the battery again and found the following.

Voltage at idle with high beams on: ~12.42-12.5v
Voltage at 4k RPM with high beams on: ~14.2v

Voltage at idle after turning high beams off: Slowly climbed up to 13.45v
Voltage at 4k rpm with high beams off: 14v-14.1v

After returning to idle again with the high beams off it stabalized out to 13.55v

That seems a lot better, and might match up with mototireguy's theory. Or so I hope?

This battery was brand new after warranty last monday but was drained by riding to work on a dead stator. Since then I put it on a battery charger with an automatic cut off for 24hrs and then left it disconnected until finishing the installation of my new stator and new rectifier. After installing my new parts it went through a normal commute to work, riding around oakland for 45 min on my lunch break, and then being flogged like a red headed stepchild on my way home from work to give the bike an opportunity to do some real work. When I got home and tested the battery with the bike turned off, the thing read 13.2v, I am guessing because it just got done getting ran hard almost immediately before. Putting the key in and setting it to the on position with all of my electronics dropped it down to 12.5v

Then I turned it on and performed the above tests and measurements in my garage.

Sound like the battery and charging system are good to go now? I could probably still warranty this battery again as it is a megaboost and has a pretty forgiving lifetime warranty. But it doesn't really seem necessary to my untrained eyes. What say you, folks who know better?
 
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MoldTheClay said:
Got home and used my handy itty-bitty-shitty HF Multimeter to check the battery again and found the following.

Voltage at idle with high beams on: ~12.42-12.5v
Voltage at 4k RPM with high beams on: ~14.2v

Voltage at idle after turning high beams off: Slowly climbed up to 13.45v
Voltage at 4k rpm with high beams off: 14v-14.1v
Click to expand...

These off/on/running voltage numbers look ok to me.

14.4v when running is the optimal target number but anything close to that like 14.1v will do the job.
 
Junkie said:
12.4-12.5 at idle is awfully low. is the lighting all factory?
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the lamps are but I have brighter bulbs. also fairly sure I have some malfunctioning accessories that are adding to the drain. my hand warmers stopped working as has my 12v jack.
 
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