I added one in my car because I have a large stereo system. I'm noticing very odd behavior in the hybrids electrical system most of it I assume is normal but I did notice that at a stop light my voltage can sometimes drop to 11.9V. I though all batteries put out about 12.6V when not being charged.

Anyone know if this is normal?

Other stuff that I found interesting was:

When accelerating your voltage drops (obviously the car cant charge the battery while the motor is driving the wheels. since the motor doubles as the alternator).

The max voltage I read on my my car when charging is only about 13.7v. (I hear this is pretty typical of hondas).