2 Batteries in parallel

[CFPena]

Can I hook 'em up to the outboard motor to let it charge 'em or do I need to keep 'em separated and put an external charger to the accesories battery?

Is it best to keep the cranking battery by it-self?

TIA.

 

[jtexas]

Re: 2 Batteries in parallel

What accessories, and what is the charging capacity of your outboard?

Generally speaking, it's better to isolate the cranking battery. With a parallel connection, both batteries drain together and recharge together, plus which a bad cell in one will drain the good battery. You could end up with two weak batteries.

 

[JB]

Re: 2 Batteries in parallel

Don't parallel batteries that are not the same type and size.

In your case I would use 2 dual purpose batteries and make damned sure that you don't run them both down with your accessories and/or troller. If you are concerned about draining your starter dual purpose battery simply put a switch between them to isolate it when the engine is not runnning.

 

[CFPena]

Re: 2 Batteries in parallel

What accessories, and what is the charging capacity of your outboard?


Lighting, gauges and a trolling motor in the near future. Doesn't have a power trim. As far as the charging capacity, this is a 79 model Mercury 50 HP and at idle my battery voltage is reading a little over 14V.



Generally speaking, it's better to isolate the cranking battery. With a parallel connection, both batteries drain together and recharge together, plus which a bad cell in one will drain the good battery. You could end up with two weak batteries.

Agree, but I know if both batteries are hooked up in parallel, I'm running the risk of a low voltage if I keep the accesories running too long. Would the engine be able to charge both? Or do I need to keep the cranking battery by it self ?

Thanks for your prompt reply

 

[CFPena]

Re: 2 Batteries in parallel

Don't parallel batteries that are not the same type and size.

In your case I would use 2 dual purpose batteries and make damned sure that you don't run them both down with your accessories and/or troller. If you are concerned about draining your starter dual purpose battery simply put a switch between them to isolate it when the engine is not runnning.

JB,
Would I be able to charge both batteries hooked up this way?

Thanks for your reply

 

[JB]

Re: 2 Batteries in parallel

If they are both connected when the engine is running, yes.

 

[CFPena]

Re: 2 Batteries in parallel

If they are both connected when the engine is running, yes.

Thanks.

As far as a switch to keep 'em separated. Do you have a part #?

 

[PondTunes]

Re: 2 Batteries in parallel

Can I hook 'em up to the outboard motor to let it charge 'em or do I need to keep 'em separated and put an external charger to the accesories battery?

Is it best to keep the cranking battery by it-self?

TIA.

what size / year / type is your outboard? If it's an older engine you probably won't have a charging system that can handle 2 batteries!!!

 

[CFPena]

Re: 2 Batteries in parallel

what size / year / type is your outboard? If it's an older engine you probably won't have a charging system that can handle 2 batteries!!!

Is a 79 model Mercury 50HP. It has the type V ignition system. It's putting out over 14V at idle (measured at the cranking battery). Something like 14.2V or very close to that.

Thanks for your response.