My charging voltage is at +15V!!

[bikemaniac]

Hi,

I have a Toyota Hiace from 1983 with an L engine with 60000 km on the clock. Everything original. I have made some tests with my multimeter and a cigarette plug voltage meter and made the following measurements:

1 When driving with low RPMs the average charging voltage is 14,7V.
2 When driving on highway with high RPMs, the charging voltage increases to an average of 15,5V. It stays there for maybe 1-2 hours before it drops to maybe 14,5-14,7V.
3 As a result I can conclude that the system is somewhat RPM dependent.
4 The charging voltage is not dead steady - it always changes some 0,2V up and down.
5 The alternator is 35 years old but has only "done" 60000 km.
6 The battery is brand new (Yuasa 110Ah).

Can anyone make some conclusions on my readings? I think that 15,5V is too much.

Lucas

 

[120mm]

That's not crazy bad.

But if it bothers you, change out the alternator, or rebuild the alternator, while changing out the voltage regulator. (assuming it is an internally regulated alternator).

 

[Jeremy9A]

I had an 83 pickup that was about the same voltage you are seeing. I never fixed it, just drove around with headlights and blower motor on to drop it down a bit.
I would lean toward the voltage regulator causing the issue though.