Got my hands on trickle charger to help with some battery problems. I also got this battery health indicator which has a special plug adapter that can also connect directly to the charger. Purpose is that you have a permanently connected charging plug that is easy to connect to the charger http://www.ctek.com/EN-AU/consumer/comfort-indicator-eyelet.aspx Im not understanding the instructions correctly. The CHARGER instructions says the following for a battery MOUNTED in a vehicle. "1. Identify the grounded pole. If ground is negative, connect red wire to positive pole, and black to the vehicles chasis" (and vice versa for positive pole) I understand connecting the red to positive. But its the connecting black to the chassis I dont get. I understand the chasis is the ground, and is connected to the negative pole (in this circumstance). But why do i connect the black charger cable to the chasis, and not the battery pole? And where exactly is a good place to attach the eyelet to the chassis? The instructions for charging a battery NOT connected to a vehicle say attached both cables direct to the battery poles. Why is it different? To complicate further, the battery health indicator i linked too above, shows a diagram with both black and red eyelets connected straight to the battery terminals. No mention of connecting black to chasis or ground, like the charger instructions. This indicator is basically just an adapter for the special charger plug, so shouldnt it need to be attached to the bike in the exact way as described in the charger instructions? Can anyone clear this up for me?