I need battery guidance....

just bought a used 2002 sea pro 220 and I've only got 1 set of large cables and 1 set of small cables going to my battery box. I don't believe there is a switch or isolator on the boat at all and I need to find out what I've got to do to get set up my 2 batteries correctly.

Re: I need battery guidance....

You should have a battery selector switch to switch between bat 1, bat 2, both, and off position.

Re: I need battery guidance....

You'll need a 1-2-OFF-Both switch by perko (or some other manufacturer, available right here on iboats) as well as three heavy gauge leads (4 awg or larger) Two red one black.

1) Connect the positives from the single battery to the common post of the 1-2-OFF-Both switch. (It is recommended that you leave your bilge pump connected to one of the batteries!)

2) Connect one of the heavy gauge red wires from your old battery to position #1 on the 1-2-off-both switch.

3) Connect the other heavy gauge red wire to your new battery and to the post on position #2 of the switch.

4) Connect the heavy gauge black wire to the ground on battery #1, run it to the ground on battery #2.


You should now be able to power your accessories / start the engine using either battery via the switch. You can charge either battery using the engine by selecting the individual battery when underway or using the BOTH setting....

NEVER switch the switch to OFF while the engine is running or you will have a fried charging system.

If you use the BOTH setting be sure to switch it back to one of the two batteries or it will be possible for one battery to drain the other!!

Re: I need battery guidance....

Thank you for all the help. I'm going to install the switch this week. I've also found some cables and fuse couplings that need replacing so I'm doing this as well.

The last thing I need to figure out is the fuel gauge. It is not working at all. I'll try cleaning off the connectors at the console first and then work my way back down the wiring to the tank after that.