Topic: Need to Verify Regulator/Rectifier Bad

[zoombyu]

I found a checklist on a thread saying to check voltage across the battery and with it idling and no lights on it sat at around 13V I think.
-idling with turn signals on, they blink very slowly
-low beam on 7.6V
Hi beam on 7.4V

Lights do get brghter if you rev the bike but the turn signals would no come on with headlight on and reving bike(possibly needs a load)

at 2100 rpm the VDC read 8.5 (couldnt go higher as I was doing this in my parent's garage at 8pm and 10* outside lol)

Also, the batter is a crap $40  battery from NAPA and the bike struggles to electric start, usually will after a solid two seconds but would not attempt to click over last night with a full charge. But the battery holds a charge fine

So I want to make sure that its the rect/reg system and not just a crap battery. Dont want to buy a new battery yet since it holds charge and im not sure where I will be going with my build and plan to ride it while building THANKS!

[Jerry Rxman Griffin aka MuthaF'er]

Charge your battery off bike and get it load tested. They can hold voltage but not be worth a #$%*. Trickle charge only. 2A is consider the max charge rate. Once fully charged they'll usually settle down to 12.6V - 12.8V. Advance Auto Parts can do the load test. Not sure about others.

Did you do a FULL charge on the battery before installing it and running the bike?

So you got 13V at the battery at idle. That can be good. What was your idle speed? What voltages did you record at 2000, 3000, 4000, 5000 rpms? That is where you determine whether the charging system actually has output.

[Spanner 1]

I think you just have a corroded/ loose connection(s) at the battery and/or the main ground wire to frame..... if the lights get brighter with rpms, the charging system is working = regulator/rectifier probably good ( rarely go bad )... 90 percent of sudden charge problems are caused by 40 yr. old wiring connections needing attention and cleaning especially that big 8-way connector that goes to the alternator...