Need Advice re-wiring Pontoon

[Jchandler5008]

My step-father recently purchased a used Play-Craft Pontoon with a 90 hp Mercury 2 stroke outboard. We have had a fish/ski boat for years so I'm somewhat familiar with boats but I have very little experience with wiring them. The wiring on the Pontoon needs overhauled (in my opinion). It looks like someone wired it with spare parts from their garage after finishing a case (or two) of beer. I searched through the forums and have gone through several wiring diagrams for Pontoon boats with two batteries. I have a diagram drawn out for this pontoon but I have several questions about the components.

1. The boat came with two deep cell batteries that had sat for awhile. One was located in the rear compartment adjacent to the motor and the other was 'jimmy rigged' behind the captain's chair. Both were dead on arrival however i was able to charge them enough to start the motor, operate the trim/fishfinder/stereo/lights. The starter battery was wired to a fuse block (see picture) and from what I can tell powers the starter/trim/gauges. Battery #2 was wired to a switch panel that is seperate from the fuse block, that operates the fishfinder/stereo/lights/CB. I took both batteries to AutoZone to have them charged and luckily for me they accidentally sent them out with the deposit truck.. So I now have two brand new deep cell RV/Marine Batteries. My question is should one of the batteries say "Starter" on it or is it okay that they are both 12V deep cell marine batteries?

2. I plan on building a small shelf in the rear compartment to hold both batteries up off of the floor and in place. I would like to replace the ancient fuse panel in the console. Does anyone have suggestions as far as what kind of fuse block or panel would be appropriate for this type of application? Is there one that is made to connect two two batteries?

3. I plan to wire one battery to the starter/gauges/nav lights and then be able to switch to the "house" battery for the accessories. I've seen several diagrams on how to do this and all of them are a bit different. Has anyone done this and if so can you please describe what/how you did it and the results?

4. I've read several conflicting posts about the motors ability to recharge one or both batteries. I have included a picture of the motor (Merc 90 hp 2 stroke). If anyone knows anything about the recharge capabilities of this motor and could give me some information I would greatly appreciate it. From what I've read, it is best to have the motor wired to the starting battery only because wiring to the starter and house can cause problems with recharging. Again any info would be great.

5. And my last question (for now) is in regards to types/gauges of wire to be used. What I've read suggests 10 gauge wire from the battery to the fuse block however I haven't found anything from the fuse block to the accessories.

Thank you in advance, sorry this is so long. Trying to avoid several different posts and give a good description.

 

[Silvertip]

Re: Need Advice re-wiring Pontoon

I know of no fuse panels that are intended for use with two batteries unless the two batteries are permanently wired in parallel. You intend to use a dual battery switch so here is what you need to know. A dual battery switch DOES NOT require that you wire accessories individually to the separate batteries. Look at the terminals on the switch and identify the one labeled COM (common -- and that does not mean ground). COM is the terminal that feeds the one and only fuse panel you will need. You wire everything to the fuse panel. You then wire battery #1 POSITIVE to the BAT 1 terminal on the switch. Wire battery #2 POSITIVE terminal to the BAT 2 terminal on the switch. You then connect the NEGATIVE terminals on both batteries together and then to the ENGINE block. Event the positive battery cable from the engine goes on the COM terminal. You can now start the engine on either or both batteries, charge either or both batteries, run all accessories on either or both batteries or kill all electrics depending on what switch setting you use. This is how a switch is intended to be used. Your engine likely has a 15 amp alternator and since neither battery will likely ever be deeply discharged, it will up with demands (assuming you do not add a trolling motor or a gazillion watt amplifier to the boat). Check right here on IBOATS for fuse panels. They have whatever type, size, and style you need. A covered unit with room for 6 - 8 circuits should be plenty. You would also want a panel that has a built in ground buss so you don't have to run ground wires all over the boat. The +12 volt feed from the COM terminal on the switch to the fuse panel, and the black ground wire from the ground buss on the fuse panel to the NEGATIVE terminal on either battery should be a #10 gauge minimum which will provide a 30 amp service. #8 gauge would allow even higher current draw but on your boat, that is not necessary but certainly doesn't hurt anything except your wallet. All branch circuits (accessories and instruments) can be wired with 16 gauge. Instruments are powered from the engine harness (the "A" terminal on the ignition switch). They are not fed from the fuse panel. Yes -- there are many dual battery configurations. The setup just described is the simplest and least expensive. Yes - you can use a deep cycle battery to start the engine (regardless what others may say). Some on this forum are using deep cycles to start 454 big block inboards.

 

[Jchandler5008]

Re: Need Advice re-wiring Pontoon

Check right here on IBOATS for fuse panels. They have whatever type, size, and style you need. A covered unit with room for 6 - 8 circuits should be plenty. You would also want a panel that has a built in ground buss so you don't have to run ground wires all over the boat.

Thank you for the advice. What you described is very similar to what I have drawn. Forgive me if this is a dumb question but like I said I'm not really an electrical guy.. I was looking here on iboats and they have a few different categories.. "Marine Fuse Blocks/terminal blocks" and then there is "Marine Electrical Panels". My guess is that I'm looking for something like the Screw Terminal Blade Fuse Block ATO/ATC 6 Circuit with Ground - Blue Sea Systems but some advice here would be greatly appreciated!

Also, the trim motor is currently wired directly to the starter battery. Is there a benefit to this other than being able to raise and lower the trim without the ignition in the on position? Thanks again for your help!

 

[Silvertip]

Re: Need Advice re-wiring Pontoon

That fuse panel will work although the same thing is likely available with spade terminals that simply push on. Either will work. Are you certain the trim motor is wired directly to the starting battery? That would mean there are two wires coming from the motor (one large red battery cable, and another smaller wire for the trim motor). I doubt that's the case. The large red battery cable provides power to the engine. The trim motor wire is simply connected at the engine to power the trim. If there really is two wires from the engine to the POSITIVE terminal of the battery then someone has mucked with the wiring. That is simply not necessary. The trim would work without the key being on anyway. With a dual battery setup using a dual battery switch, nothing changes. If the large red battery cable is connected to the COM terminal on the switch, either or both batteries power the engine circuits so everything still works the same as if you had a single battery. The only difference is that you have two batteries to select from: #1, #2 or BOTH.