Anyone have an Argus Battery Bug on their Hex Head? The back light comes on when the voltage is over 12.8 volts or so. This allows it to go off at the normal static voltage of 12.5V (engine running back light on, engine off, back light off). The problem is my battery puts out 13 volts even with the engine off, so the back light stay on drawing power. I gather AGM batteries put out more voltage than standard wet cells.