Reply To: Has anyone done a Dual Battery switch setup – 1979 140 hp Mercury

[Bob Wight]

You can google “marine wire sizing” and find a number of sizing charts and calculators.

Luigi, here’s a link to a supplier of pre-fab marine starting cables I’ve used before.   Just pick the cable size you want, specify the total length of each cable and what type of cable terminations you want and they will make them up for you.   High quality tinned copper wire with heat shrink lug connections, these are very good quality cables and at a reasonable price.

https://www.batterycablesusa.com/battery-cables

Bob

1937 Champion D2C Deluxe Lite Twin
1954 Johnson CD-11
1955 Johnson QD-16
1957 Evinrude Fastwin 18
1957 Evinrude 3022
1958 Johnson QD-19
1958 Johnson FD-12
1959 Johnson QD-20
1982 Evinrude 25hp

“Every 20 minute job is only a broken bolt away from a 3-day project.”
"Every time you remove a broken or seized bolt an angel gets his wings."