Dual Batts??/

[zacs]

What I have described is the standard for wiring dual batteries in small craft (23ft or less) with a single outboard. Typically what most people do is switch batteries durring the day. Some will run out on one, fish, then at some point, switch to two and use two for the run back. I usually alternate between main batteries each trip.

YOU DO NOT WANT TO RUN ON BOTH. If you have a problem battery that is not holding a chage, and you run on both, it will drain the good battery down to the charge of the bad battery. This is a fact. you will then be screwed with two bad bateries. Charge one, and then charge the other. If you are not able to start on one, then try the other. If you can't start on that one, then use both. That is the only time to use both.

You can wire like mike said with an isolator, but that is typically only used on large boats where there is a major drain on the house battery. For small craft it is not necessary.

[beamie]

What Mako Mike said is right on, even for a smaller boat....A battery isolator isn't big or too costly and will charge the battery that needs charging regardless of position.

What Zacs said is true about switching while running. If the switch makes before breaks it is ok. But you really want to avoid this at all cost. I know my switch states not to. If contact points move and things don't make and break good then there is a chance of blowing your isolation diodes in your alternator that convert AC to DC since all induced current is alternating.

Personally unlike what Zacs said I always run on both batteries. There is nothing wrong with this while running. The batteries are always getting charged etc. If your engine is off and fishing using juice well that is another issue,... that is what I do. And I do not have a battery isolator yet but someday will install one.

The only issue with battery isolators is sometimes you'll see a voltage drop accross the isolator.

For battery switches there is allot of choices anywhere from $25 and up. I prefer the more expensive bigger Cole-Hersey switches compared to the $25 Chinese Blue Seas stuff. Although for $25 is looks decent and small in size for a small boat. But I think you get what you pay for too.

Good luck with the install, it is easy to do yourself.

[zacs]

Well, i guess we could debate for hours, but if you are running on both, you are only charging to the voltage of your weakest battery. It is fine for 99% of the time when your batteries are fine, but if one goes and you don't know it you are screwed.

And blue seas is not junk. it is very good stuff. i don't know if it is made in china, but the stuff i have used is very high quality stuff. i have used their switch panels, fuse bars, and batery switches and they are all built real tough and it is all very high end. extra heavy duty made with good materials.

But, you have me thinking on the isolated batery setup. maybe it is a good idea. i am going to look into it, maybe it is the way to go, although I have never seen it on any of the small boats I have had or been on...

[beamie]

Zacs,

Not looking for any debate. Everyrone has opinions etc and I agree with most of what you say. If you say Blue Seas isn't junk I'll look closer at it. When I saw the low price of the switches I assume you get what you pay for.

You are right about leaving batteries on both all the time. They won't charge at the same rate etc. But I choose this way as to not to have to switch while running.