OK, so i've been reading on some of the battery topics here and am curious. BOTH my batts died like 2 weeks ago, re-charged them and they didn't hold the charge. So, i'm buyin new ones. anyways...in my boat i have a switch i can change from 1-2-BOTH-or-OFF for my battery juice. Which position should i have this on when i'm starting? And what about when i'm just chillin with the radio on? i DO NOT wanna drain my batteries again on the lake, that sucked big time. I'm just not familiar with this as the boat is fairly new to me. any help is appreciated guys. thanks in advance.

The first thing you need to do is charge the batteries and load test them. Plus you need to see what size you have, you may want to go up a size or 2 depending upon the size of your stereo and amps. The only problem with running the batteries on all is if they are EFI. Mercury tells you to run each engine with its own battery source for a few reasons, if the alternater takes a crap on one motor you dont want the other to have to carry it and try to supply both. That could leed to early failure of that one as well plus the performance may go down do to not enough voltage will be supplied to the ignition systems and computers.
I have a few customers that have installed a seperate battery for the amp and stereo so they can isolate it from the engines when sitting still. Run out with the engine and radio battery on all and switch over to the radio battery or batteries when you get out there. When coming in, switch back over the all position on that bank only. That way you charge the radio battery up on the way back in. If you are running a single engine it gets even easier. Run out or all over with the battery switch in the all position, when you get to the beach just switch one over to the biggest battery or one of them if there the same and use only that one. On the way in switch back over to the all position and run in.

If I am confusing you just give me a call at the shop or email me and I'll give you my cell.

Good luck.

John
c-443-786-2309

Good info, I have also been told NOT to switch from 1 to 2 to all or any combination thereof with the motors running as the momentary "break" in the connection could hurt the electrical system...

I thought my perko switch doc's said it was OK to use the switch with the engine running 1 to both . It was supposed to always maintain some contact. It stands to reason that a momentary break in the circuit could be damaging. I'd like to know for sure. No jucie on the water is a bad thing.

thanks guys...i'm running just a single 496HO. both batteries are the same size. so i guess that means when my engine is going...set the switch to "BOTH". when i'm just chillin with only the tunes...go to "1". correct? now...does it matter WHICH battery i set it to for the radio? 1 or 2.

Most new battery switches you can switch while running no problem.

Jon

Both is for a boost jump start if both are low. Run either on 1 or 2 position randomy as you choose. If you run both, the stronger battery will draw from the weakest eventually expediting it's demise, not to mention one alternator working overtime on trying to charge two battery's. Could havfe a negative effect on the alternator's regulator.

For twins definitely one battery per motor unless both is needed to jump start then immediately back.

If all this confuses you, stay conservative and run one or the other. Typically on single engine setups two battery's are simply for backup, or to assist with your stereo amps etc.

ok...i got it all figured out now. thanks a ton guys!!! just went ond picked up my new batts, gonna put them in shortly. again...i really appreciate it!