Opinions Needed:

I replaced my Bosch unit which was putting out 12.8-13.0V to the Battery at idle, with Hella Solid-State Unit which is putting out 13.9V at idle. Is this OK, or too High?

I have an Optima Battery.

Thanks,
Jim

I think you will be fine. 13.9 is what new cars charge their batteries at. and you have a newer battery too. The only downside I can imagine is it might wear your alternator out quicker,,,,, but I doubt it.
-Rob

That's 100% right.

Let's see it

I had a Hella solid state in my 912E which also had an Optima installed.

The Hella failed and the battery was grossly overcharged, filled the front trunk with Sulpherous vapor. I had to have the car towed home after I gave the front trunk a Baking soda water bath.

I replaced the regulator with a Bosch relay contact style and replaced the Optima.

This happened back in 2000.

The 912E engine and alternator are very similar to my 914 components. The regulators are also interchangeable. The alternator mounting ears are slightly different, and the 912E is slightly higher output, but otherwise very similar.

I do not have any desire to ever use a solid state regulator on my 912E again, or on my 914 race car.

The solid state didn't work in my 912E either. I think the charging light would not go out.I had to use an old style. The recommended alt rebuild shop came to this conclusion.

Pics attached.

So far, very happy with the unit, Bosch would go sub-12 with lights and heater on, Hella is right at 13V with lights and heater, 13.9V without.

Jim

Click to view attachment

Click to view attachment

......I also use them(elect.,VR) on my classic U.S cars (mostly Ford's)
no issue's & they last in tandem with ALT. for years&years!