Upgrading the Charging System & Battery Questions

[Geo2008]

Hi Guys

I recently bought a 17' Procraft boat that, as I understand it, has two batteries. I think that one is for cranking main motor and one is power for the trolling motor.

I am not sure which one runs the bilge, aerator, lights, radio, sonar etc..(Do you happen to know?)

Yesterday I went out to the lake and right off the bat the boat would not start even though I had charged both batteries the evening before. I mention the batteries because that is what it sounded like was the problem to me and I noticed earlier that the second battery caused my charger to show the "fault" light. That being said it cranked it in the yard with the muffs, no problem.


With a boat ramp full of people and my wife looking at me like "what are you going to do now?" I decided to try swapping the batteries and wallah! the boat started perfectly, what a relief!


I decided not to try the trolling motor yesterday because I was not sure how the batteries work on the boat and did not want to risk being stranded.

I have now decided to shore up the possibility of this ever happening again by

1. Purchasing the strongest, longest lasting, batteries available.

2. I would like to add a third battery if possible so the trolling motor and accessories can run off the two and the motor has a dedicated battery.

3. Also, it is a pain to charge the batteries one by one, is there a system that charges them all by just charging one?


I am hoping for some advice from some experts on the viability of my plan, but all is welcome to chime in ...

Geo

 

[Silvertip]

Re: Upgrading the Charging System & Battery Questions

You have given us a lot of detail but not much of it is useful. But here goes! Generally -- All of the accessories (lights, bilge pump, live well, radio, etc) operate from the starting battery. That battery is charged by the engine whenever it is running. If your boat has a voltmeter, it tells you if the charging system is working or not. The trolling motor operates from a "deep cycle" battery and is generally the only thing on that battery except for a fish finder that may be mounted up front. Yes -- you can buy a dual output on-board charger to charge both batteries simultaneously. Or a three-bank if you insist on three batteries (which I don't happen to feel is necessary). You plug the unit in at the dock and the two (or three) batteries charge automatically and you can leave the charger plugged in indefinitely. Since you probably don't have room for a third battery, nor do you need the extra weight, buy a jump start unit to carry for emergencies. Now then -- as for batteries, you need a "marine starting" battery for the engine and a "deep cycle" battery for the trolling motor. My recommendation is a group 24 for the starting battery and a group 27 or 31 deep cycle for the troller.

 

[Geo2008]

Re: Upgrading the Charging System & Battery Questions

You have given us a lot of detail but not much of it is useful.

Forgive me Silvertip, doing the best I can for now but give me a few years and I will be fielding questions like a moderately educated boat enthusiast!

I will take your advice to heart, thank you.


BTW - I took my wife out on the lake yesterday for the first time and she really loved it, I think I have a new lake buddy which is very cool indeed!

Geo

 

[Geo2008]

Re: Upgrading the Charging System & Battery Questions

Does the trim run off of the starting battery also?

Geo

 

[fishmen111]

Re: Upgrading the Charging System & Battery Questions

Yes.

 

[redfury]

Re: Upgrading the Charging System & Battery Questions

If your battery charger shows a fault in the battery, then you either have a bad cell in the battery, or there is something screwing up the charger. Usually it means what its saying...bad battery. It may hold a charge and show 12v on a multimeter, but it won't have the amps for anything to draw from...such as you found out.

If you don't want to go through the process of manually charging your batteries, then yes, an onboard charger is the way to go. They aren't cheap, but having the ability to just "plug it in" wherever you are is certainly nice-especially on a weekend trip where your dock has power to plug into.

Beyond that, I agree with all the advice above. Never scrimp on batteries unless you want to try and rope pull your engine

 

[Geo2008]

Re: Upgrading the Charging System & Battery Questions

Does the trolling motor get charged by a alternator or just by a manual battery charger?

 

[darrklim2]

Re: Upgrading the Charging System & Battery Questions

Does the trolling motor get charged by a alternator or just by a manual battery charger?

Unless it is connected in parallel with the starting battery no it will not be charged by the alternator. If it is connected in parallel with the starting battery the two batteries will act as one large 12V battery therefore if one is dead they both are dead. Thats why it is recommended that you don't connect them together.

 

[evilratgirl]

Re: Upgrading the Charging System & Battery Questions

Hey GEO, when running a dual battery system I believe in keeping it as simple as possible. Marine starting battery for starting and deep cycle for the trolling motor. Obviously to get the most out of them they need to be in good shape.

It sounds like your charger pointed you to a possible battery problem. There's no substitute load testing to get a real idea of a batteries condition. The cheap 100A ones at Harbor Freight, Fleetfarm, ect are worth the small investment.

Knowing what battery runs what is really helpful. Especially for troubleshooting. Simple enough to make a list of all your electrical demands. Disconnect each battery one at a time and see what works or not.

DO NOT connect the 2 batteries in parallel without some kind of isolation between them. Totally wastes the benefit of 2 batteries. Some people like the big isolation switches and some the old style diode isolaters. I personally like prefer the combiners. The combiner allows charging both batteries from a single charging source, be it alternator or battery charger as well as the isolation benefit.