Pontoon Boat & Deck Boat Forum

I've been reading up on battery switches and the different opinions here and on other forums has me confused.

To start, I have a 2004 Yamaha 60 4 stroke that only puts out 10 amps and I want to install the Blue Sea 4 position switch. I want battery 1 to be starting only and switch to battery 2 "WHILE ENGINE IS RUNNING" to slow the discharge of the battery.

Will moving the switch while the engine is running to ANY position harm the engine, only the OFF position will hurt the engine, or it will have no effect on my engine?

If any of the above will harm my engine, do I need a switch with an AFD (alternator field disconect)? And if so, can anyone point me to a How To Guide for my particular engine?

I considered the automatic relay but I think I would rather stay in control of the batteries.

Lots of folks to help you on this forum. I don't have an answer for you, but when I installed my blue seas switch and charging relay, I got lots of good information from another forum as well, called "The Hull Truth". I also called the tech support line at Blue seas, and they were very helpful as well. Good luck on your install.

So far from what I've read , I am seeing three different opinions about using a battery switch while he engine is runing and they all conflict with each other.

Ive always had dual batteries on my I/O mercruiser set-ups and have always switched between batteries and never had a problem. Ive been told the key is to make sure you don't go past the off position whiles its running, just go directly from 1 to 2. One thing I did learn through trial and error of course is you shouldn't run the boat with the battery switch on both except maybe to start it if needed when the batteries are low. The alternator takes an average voltage over both batteries and will charge them both equally so one will overcharge and one will undercharge, kills your battery life. Also if both are low this can easily overwork and fry your alternator.

I'm not running any trolling motor and my radio has no power booster. I see no reason for me to use a second battery or use any battery switch.

I prefer a good ole automotive battery which lasts much longer and costs less than a deep cycle battery. I already have enough cars, PWC's and ATV's to buy batteries for.

If I was concerned about my boat not starting, a battery jumper box with an air compressor (for blowing up tubes) would be nice to carry as a backup.

DO NOT switch while the motor is running, it may very well fry the charging circuit.

I see the opinions vary here as well.

Maybe get two switches that are only ON/OFF so I always have at least one battery connected?

Have you researched voltage sensitive relays? They do basically what you are wanting automatically.

http://www.ezacdc.com/boat-wiring-produ ... h-systems/

I put one on my build (check sig link)

I looked at that one and the one by Blue Sea, but while on a boat in the middle of no where I rather do it manually.

As long as you don't turn the switch to OFF, you can switch between 1/2/both.