Should I Not Have My Dual Pro 3 Bank Charger Connected To My Starting Battery?

[tcbass]

A friend told me that I shouldn't have my Dual Pro 3 bank charger connected to my starting battery because it could burn out a component of the outboard motor if there is an electrical current that goes the wrong way back to the outboard or some other problem. He said the outboards stator should be enough to charge the battery if I use the boat enough and normally shouldn't need to charge the starting battery.

Is he correct?

I've never heard of this.

[Jig Man]

If you have any accessories running you may not get a good charge especially with today's electronics without a charger.  I'm no mechanic so I can't speak to his statement.  All I can say is I use a dual pro 3 bank charger that is always hooked to my cranker and have been doing it for 12 years with no ill effects.

[Fishing Rhino]

Your friend may be wrong.  It depends on how much you run the big engine.

 

Everything except your trolling motor runs off the cranking battery.  Lights, pumps, electronics, and other accessories are connected to the cranking battery.  On smaller bodies of water, you may not run the motor for more than a few minutes. 

 

As an example, around here, my engine does not run more than a few minutes on most typical days.  I don't run the live wells.  I rarely use the running lights.  Most of the time, the only drain on the cranking battery is the electronics, and starting the big motor a few times per day.  If I don't put the charger on my cranking battery, it will eventually drain down to where it will not crank the motor in two or three weeks.  The motor simply does not run long enough to keep the cranking battery charged.

 

The banks on a multi-bank charger are isolated from each other, unless it is hooked up improperly.

 

Helpful hint:  Most fish finders can display the voltage of the battery to which they are connected.  Pay attention to the voltage when the motor is not running/charging.  If it drops during the day, or over a period of time, your main engine is not running enough to keep it charged.

[B@ssCrzy]

I would disagree, but I am not an expert in that area.  Like previously said the banks on the dual pros are isolated.  I have mine hooked up to my dual pro charger and have for 5 yrs now.  No ill effects.  The only effect is that my battery is properly maintained and is running like a champ. 

[NathanW]

I am expert enough to tell you that your friend is wrong assuming you have fuse protection. Outboards have a main fuse that provides pretty good protection but you should also have a lower amp fuse just off the battery for your cranker.

[lmoore]

Depends how well you can paddle, and how much you like to.

[CJV]

Depends how well you can paddle, and how much you like to.

LMAO!

[Way2slow]

One idiots opinion shouldn't overrule what

probably another million boaters are doing with no problem.

Unless you are doing more running than fishing, it's not very likely your motor is keeping your cranking battery fully charged.

It's highly more likely you will damage your motor connecting a charger to it, from the arc created, than leaving an onboard charger connected.

[FD.]

Your friend is wrong.  If you have a quality onboard charger then you will not have a problem.  As Tom said, if you don't use a lot of aux amps and run your big motor often you will be fine.  In my case, on tournament days, I start with nav lights and then run dual livewells, dual aerators, and dual electronics all day with very little time on the big motor.  If I don't charge my cranking battery I get to paddle like Imoore said.

[Way2slow]

While on the subject of using onboard chargers, I would like to make a suggestion that might save someone some grief one day. This is something I think I learned the hard way but can't swear it was the cause and not just circumstances.

As many of you have probably noticed connecting your onboard charger leads to your battery, you get an arc. This is cause by the discharged filter capacitors inside the charger charging themselves when the battery is first connected, and this arc can generate a several hundred volt spike in the electrical system. Years ago, after taking my batteries out, cleaning and servicing them and reconnecting my onboard charger, getting that little arc, the next time I used the boat it would not start. Hauling it back to the house and checking it out, the SECM was bad, a $600 repair and upgrade on it. I feel pretty confident that arc it what wiped out the SECM, so after that I've changed the way I connect my onboard charger and would recommend you follow this method.

I always want my main engine battery cables on the terminals first. Almost anything between them and the battery will create resistance and I want the best connection possible, so all other connections go on top of the motors battery cable. Now, if you don't have a problem with other terminals under your main cable, then connect the onboard changer first, before you connect the motors cables and problem solved. The onboard charges it's capacitors and the arc can't create a problem since nothing else is connected, then put your other connectors on the battery.

However if you are like me, and want the motor's cables one first, then put the onboard leads on so the capacitors charge, then make a quick switch, taking them off, putting main cables on and then the onboard back on before the capacitors have time to self discharge.

I would not recommend connecting the onboard charger leads to a battery that has the motors and other connectors on it. I had done it many times without a problem, but I'm pretty sure it bit me in the butt that one time.

These same thing with connecting jumper cables or a battery charger, that arc generated can destroy electronics when conditions are right. If I have to connect anything like a battery charger or jumper cables to a cranking battery, since most marine batteries are dual terminal and the motors leads are on the screw stud, I disconnect the positive lead, connect the jumper cables or charger to the lead post and then reconnect the positive cable to the stud, just make sure the key switch is off doing this.

Now, I'm sure some may feel this is hog wash, but I do have a degree in electronics and know more than just a little bit about it. So if you feel it's hog wash just keep on trucking as you always have, but lets not get a debate started in the middle o this guys post.