overcharging?

[theo305]

Hello
I have just replaced a dead rotor and my 1981 cb750f is charging again.
The problem is that i have 14volts on idle 1000rpm.
On any other rpm 1500-full throttle it gives 14.5 maximum.
Is this normal?

[rich]

14.5 is good and about as high as you'll get. 14 at 1000 RPM is unusual but won't hurt anything. I guess you got a really good rotor this time.

[theo305]

Does the battery play any role on this?I mean if battery is low maybe rectifire gives more voltage to charge it.
I have checked the voltage and after a full charging it keeps about 12.7 volts after one day sitting in garage.

[LukeM]

Moved this to a more appropriate topic.

Luke M

[Lucky 1]

A 12 volt battery is not really 12 volts.

A 12V battery has 6 cells and each sell is 2.3 to 2.7 volts.
So a 12 volt battery is really 13.8 volts. Surprise!

That is why people get so confused.

The voltage regulator decides how much current to put into the battery.
When it is charging it can vary a lot depending on how much the battery needs.
If you just started the motorcycle it could charge more until the battery is fully charged.
It might not need anything. But it does not mean the battery is not charging when it is supposed to be.

Turn on your lights and then hit the high beams. Did the charging rate go up?
See what I mean?

When you test the battery when at rest (engine not running), do the test after you have gone for a ride.

[sgtslag]

If your battery is at 12.7 Volts, resting, it is in excellent health, at 100% charge.  This is what you should get on a flooded battery, in good condition.  The resting voltage for an AGM is 12.8 Volts.  Here is a link to a site which lists the proper voltages for flooded, Gel, and AGM batteries:  Battery Information.

In order to check the health of a battery, it should be tested no sooner than two hours after a ride, which gives it time to reach its actual voltage; after a ride, it will read much higher, initially, from being charged by the alternator, but this is temporary, and it will drop as the plates and the electrolyte settle to their 'resting' state (the chemical charging process needs to calm down).  Cheers!