Just curious for those of you who have dual battery setups with a selector switch for battery1, batt.2, both, and off. Do you also have a negative battery cable to connect both batteries?

Thanks for the help!

Dave

I go from engine to first battery, then from that to the second battery with the negative

Dave,

Do you have twin engine set up or single? Usually with twin engine set ups a ground is run from each engine to a battery and on carburetor engines a ground is linked from bell housing to bell housing. If the engines are fuel injected and/or have a computer you shouldn't link the grounds together. On a single engine application you can parallel grounds but I prefer to run a second ground to a stud on the bell housing just in case of corrosion or loss of ground.

Good luck,
John

I have a single with dual batteries...just wanted to know if I need to connect the negative connections of each battery together or if it's ok to keep them separate. One battery grounds to the block and the other will just ground to itself? That's my question, do I tie both negatives to the block ground or do I leave the batteries completely separated?

Thanks again for the help!!!

Better To Ground Each Sep To Block But Neg To Neg On Battery Will Work

i would run a ground strap from each battery to the bellhouse and the pos to #1 and #2 on your battery switch. you can't have too many grounds in a marine application!

OSO Rules!!! Thanks guys.