Boat wiring question

[tbrown913]

I got a new to me project bass boat. The trolling motor is a 12v. There are 3 battery holders in the boat, 1 cranking, and 2 for trolling motor and other stuff. Where the 2 batteries go there are 2 sets of wires. I was wanting to hook the batteries in parallel with each other to make sure I have plenty of battery for my trolling motor. My questions are:

If I hook the batteries in parallel should I connect one set of wires to one battery, and the other set to the second, or should I put both reds on batt 1 and both blacks on batt 2?

I am thinking about an onboard charger. Would I need a 2 bank and hook both batteries up, or could I use a single since the batteries are parallel?

To use an onboard charger would I need to take the parallel wires off?

What's the best bang for the buck when it comes to trolling and cranking batteries? I'm at best a once a month fisherman. I dont see myself getting optima agms!

 

[Limitless]

Like this:

 

[Tunaman]

Limitless is absolutely right. As far as a charger goes a single bank is all you need, at least for the trolling motors. hook + to one of the + and - to one of the-. That is unless you want to charge the cranking battery then you need a 2 bank.

 

[Taco4x4]

The wiring above is spot on but I might disagree with putting a single bank charger on that setup. It will have to work extra hard to charge both batteries and take twice as long. I would get at least a two bank. One for each trolling battery. You do not have to remove the jumpers for this to work. A three bank would be perfect. Yes your motor charges your battery while its running but if your running live wells and lights and graphs. It probably ain't getting fully charged and your motors charging system has to work harder to make it charge. I learned this the hard way. A three bank charger is a whole lot cheaper than a new Stator and voltage Regulators. As far as batteries its hard to beat Walmart Everstarts 29's

 

[tbrown913]

The wiring above is spot on but I might disagree with putting a single bank charger on that setup. It will have to work extra hard to charge both batteries and take twice as long. I would get at least a two bank. One for each trolling battery. You do not have to remove the jumpers for this to work. A three bank would be perfect. Yes your motor charges your battery while its running but if your running live wells and lights and graphs. It probably ain't getting fully charged and your motors charging system has to work harder to make it charge. I learned this the hard way. A three bank charger is a whole lot cheaper than a new Stator and voltage Regulators. As far as batteries its hard to beat Walmart Everstarts 29's

Timing for charging isnt much of an issue as it would likely have a week or more between uses! I have no idea if the outboard will charge anything other than the cranking battery. There seems to be a totally separate wiring for the outboard than the rest of the boat.

 

[Taco4x4]

The outboard will ONLY charge the cranking battery and how much depends on how much you run the outboard. Yes the motor wiring is separate from everything else. Do what you want but after that single charger burns out and stops working you might re think that one. Good luck getting her ready for spring.

 

[Tunaman]

that was what I was thinking on charging time. If you use the boat every day a two ball would be better but if you use it even every 2-3 days the single bank would ne fine, maybe better because a slow charge sometimes is better than fast.

 

[CPrestridge]

I went to an Academy store in South Carolina this week. They had some onboard chargers on clearance. Each store is different, but may want to check Academy stores near you.

 

[tbrown913]

I went to an Academy store in South Carolina this week. They had some onboard chargers on clearance. Each store is different, but may want to check Academy stores near you.

The one in athens had them on clearance a month before I got the boat. Now they're sold out of the clearance ones. I was 50/50 at the time on whether I would be getting a boat or not.

 

[tbrown913]

The outboard will ONLY charge the cranking battery and how much depends on how much you run the outboard. Yes the motor wiring is separate from everything else. Do what you want but after that single charger burns out and stops working you might re think that one. Good luck getting her ready for spring.

Do you mean a one bank or just a regular old charger burning out? If a 2 bank is what I would need, or would work a lot better, I'm willing to get it. I know nothing about them so I am not sure if I would need wires for each battery since they're connected. I've seen a few RVs with numerous batteries in parallel and one charger, but they tend to go through batteries a lot faster.

 

[bowandgun]

I agree that you should use a two bank charger for the trolling motor batteries or a three bank for all three batteries. Look into a NOCO Genius battery charger, they are the best in my opinion. They will dramatically increase the life of the batteries.

 

[notnksnemor]

Everyone has given good advice on wiring and chargers above.
I'll address your question on batteries.
Starting batteries are rated in CCA's (Cold Cranking Amps) higher the cca the more power the battery has to start your engine and the more expensive it will be. I have 2 750 cca batteries in my boat on a battery switch (it is a center console offshore boat) you probably won't need this much power.
Trolling motor batteries are deep cycle batteries, They are meant to almost fully discharge and then be recharged, not a continuous charge like from an alternator.
Deep cycle batteries are rated in ah (Amp Hours).
Determine how long you will be using the batteries before being able to charge them and you will get an approximation of the ah.

Note: Some deep cycle batteries can develop a memory if only partially discharged and fully charged multiple times.