Altima battery/brake lights

The battery and brake lights on my '98 Altima have been flickering on as the car accelerates (at or around 3000 RPM), especially at high speeds (over 40 mph).

When it first started happening it would only do it above 70 mph. I took it to a mechanic, and they could find nothing wrong with the power system, but we had the battery changed because it was old, and thought maybe it wasn’t keeping up with the alternator. That seemed to solve the problem, but 2000 miles later it started again. This time the lights have been flickering at 30 or 40 mph, but still only while accelerating at high RPM. I took it into a different mechanic, and they could find nothing wrong with the alternator, or the other parts of the power system.

Right now, I’m trying to brainstorm possibilities. The car has been running fine, with no change in performance when the indicator lights come on. My plan at the moment is to continue to drive it, and if it breaks, then hopefully the problem will become more apparent.

That combination of warning lights ususally indicates a failing alternator. You might want to have it tested by a different mechanic in order to rule out that possibility.

I agree. Swap the alternator. Those lights are in the exciter circuit for the alternator.