Originally Posted by jonnyvtec
It just boosts the system voltage by inputting at the power socket like adding another battery in series. You'll hear the click if the contractors are closing for HV. 10.8v sounds right based on my experience with a weak battery.
This was my experience. Seems like all of a sudden, my car wouldn't start on the IMA (but it did spin the 12V starter). Checked voltage, and IIRC, it was 10.8V. Tried charging it back up to 12V, but it wouldn't hold the charge any more.