Ask PYS: Power

How Many Battery Connections are Acceptable?, on Mar 29, 2018 asked:

I’ve recently watched some of your You Tube electrical videos and realize I have some no-no’s at my battery terminals. Is it acceptable to have more than one cable ‘stacked’ on each other at the terminal? For example, a starter cable, bus cable and battery charger cable? If not, what is the proper protocol? How do you determine the size of the cable going from a terminal to a bus (add up all the amperage of the devices being serviced)? Is there a schematic somewhere illustrating a typical marine battery hookup? I realize there is probably no typical hookup, but something that could be used as a guideline. - Brent


To answer your questions:

1) You can only stack up to four terminals at a battery terminal or distribution bus.

2) For sizing a cable, more is always better. At the very least you want the cable to be able to handle all the loads, for instance engine starter, inverter/charger, windlass, thruster, heater, etc.  For most installations, we either use wire 2/0 or 4/0.

3) Besides YouTube, another good place to find marine electrical information is Don Casey and Nigel Calder books.

 Thanks for the feedback on our YouTube videos.  - Jeff