try change the altenator
11.5 voltage on the battery and same when car started should be up to at least 12.5 - 14 volts when started.
with the car running, what voltage is the alternator putting out at the actual terminal of the alternator?
Have you actually measured it?
25-26 volts
25-26 volts
You might need someone who knows the difference between ac and dc voltage to have a look at it.
Seriously?! That's almost double the normal output voltage of the alternator. I'd be glad that, for whatever reason, that sort of voltage isn't getting to the battery terminals.
Does the battery light on the dash stay on when the engine is running?
Have you checked the voltage drop with the engine running, between the positive battery terminal and the B terminal of the alternator? Also between the negative battery terminal and the metal case of the alternator? Were both readings less than 0.2v?
With the negative battery terminal disconnected, have you got continuity with no resistance between the positive battery terminal and the B terminal of the alternator?