Grounding issues

[cleanmerc01]

aright i have few questions and would appeciate some help please. i have installed a 2nd battery for my audio and i have voltage drops. i think i have figured out the shorting problem it was the screw we used to install the fuse holder it went into frame and the was touchin the positive wire connector.

the ? i have is i hooked my test light and volt meter to the grond wire to frame and positive side of battery and get nothing. do i have to have the ground hooked to battery to get a reading

and i am i right that the back battery should read 14.7 with car on like the front??????

[sly]

both terminals of the battery should be connected to get a proper reading from it. as for the fuse holder... definitely don't want to bolt that down to anything except maybe a plastic bracket to prevent the shorting issues.

as for the voltage... if you have the batteries in parallel (positive to positive), both batteries should read the same voltage at all times (+/- a little for length of cable... probably no more than 0.1V difference). The battery should be around 12.6 with the car off and anywhere from 13.0 to 14.7 with the car idling (depends on the alternator and it's condition).