Topic: Rectifier/Voltage Regulator

[Bido]

I am having some problems with my 78 F3 charging system only getting about 13.5 volts at 4000 rpms. I am thinking about replacing the voltage regulator and rectifier with a combination unit from Ricks. Has anyone used this unit I could use some info on it. I have a new Big Crank battery which tests good.

Thanks in advance

Bido

[Green550F]

What's wrong with 13.5V? Much more and you'd start cooking your battery on a long ride.  The Regulator's job is to keep the charge voltage limited once the alternator brings the voltage up. Otherwise you'd have inconsitent lights and short bulb/battery life.

[TwoTired]

Are you checking the charging system with a known good battery that is at full charge?

A discharged battery won't show higher voltage until it is at full charge, even if it is good.

If it is fully charged, what is wrong with 13.5V?

What problems are you having?  And, what changes have you made to the electrical system or electrical components?

[Bido]

I am following the shop manual wich states that at 4000 rpms I should be getting about 14.5 volts the battery reads 12.5 volts. I have 2 mods Dyna S ignition and a Halogen head light.

[Johnie]

Nothing wrong with 13.5 volts.  Heck, that is what my meter shows on my 2000 Goldwing.  You are fine.  Ride and have fun...

[TwoTired]

A fully charged battery, after resting for two hours, reads about 12.6V with no load on it. 
A depleted battery, being charged, can read 13.5v on the way to the peak charge voltage of 14.5.
Once the battery reads 14.5 v, the regulator turns down the alternator output to prevent overcharging the battery.
The regulator cycles the alternator on and off rapidly.  And, it is not unusual to average 13.8 V.
The type of meter can make a difference in readings too.  If you have a peak hold function what does that read?  If it is an averaging meter, what is it's sample rate?

The Halogen headlight, if larger wattage than the 40/50 that was stock, will make it more difficult for the alternator to peak charge the battery.
The shop manual assumes you have stock equipment on the bike.

Again I ask.  What problems are you having with the bike?