Dual Batteries
 

What purpose does running dual batteries serve? If one goes down will the other crank the motor? I am just wondering as I have this setup and can't think of the advantage. Both of my batteries are currently "flat-lined" at the moment. And over the last few weeks of the boating season, the batteries would discharge during the week and be dead when the weekend came. I would have to put the charger on them for a little while in order to go out. Is something possibly draining them?

Any thoughts?

RickerTX,

Are you turning the battery switch off when not using the boat??
If your boat is only 2yrs old, your batterys should still be good, although if you have let them drain completely a few times, they may not be!
If you are not turning off the main battery switch, maybe a stereo amp or some other accessory is draining it down.
As far as running two batteries, it doesn't hurt to have a spare!
Although if you don't have a lot of accesories in use when the boat isn't running, and you check the battery on a regular basis you should be fine with one.

If everything is off and they still drain, touch your merccathode and see if it is warm or disconnect it and see if the batteries still goes down.

The main benefit of dual batteries is as a "safety net". You can cook your stereo all day long and not worry about starting up to go home.....provided you charged batteries in the "both" position and then switched to #1 or #2 while stopped and cookin' the stereo.... or overnight fans, tv's etc. Of course there is always the "safety switch" to prevent discharging too far. Available from West or Boaters world or an auto store. It works for me!! :cool:

Antother advantage of the two is that if you do drain your battery all the way down then when you start up you can run the boat on the both position so that you do not spike your alternator with the dead battery. You should have one starter battery and the other should be deep cycle or house battery

Jon

Thanks guys! Great input. I have never thought about turning the battery switch to "OFF" at the end of use each week. It makes sense to turn the switch to #1 or #2 while cranking the stereo. I will pull the batteries this weekend and have them tested. Thanks again!

Rick

Also check your stereo for the memory circuit. This keeps the preselected chanels in memory so you don't have to reselect your favorite stations.
If that is the case, then set the memory wire to run off 1 battery direct....RUN A FUSE or CIRCUIT BREAKER!!! and expect just the 1 battery to be low.
Another caution in the wind. Unless your battery switch has field protection built into it.........
DO NOT switch the battery switch to any position other than what it is on with a motor running. Shut down both motors BEFORE switching the battery switch position!
The voltage spike will fry alternators, regulators, stereo amps, refrigerators, etc. if you do.
It has the same effect as removing the battery cable with your car engine running or switching the power switch off then on real quick. NFG, "thats non functional gear" when Mom's listening or no F------ good in the real world.
I've seen others get by with it a few times but they eventually end up with electrical problems somewhere.
Good luck

NEVER leave a battery in a discharged condition (This means anything less than full charge). This is where most battery damage/failure will occur. Use an onboard charger/float whenever the boat is not in use