2 batteries

[Colliemcc]

Can I connect 2 batteries up to my boat the one I have in already is 12v 85ah,

Is there a limit to how much your alternator can charge.

I have a Volvo penta 4.3gl with one 85ah bat and want to put in another.

Thanks Colm

 

[Silvertip]

Re: 2 batteries

Why? What are you trying to accomplish? There are many reasons to use a dual battery setup. Each may have a different implementation. There are dual battery switches, Automatic charge relays, isolators, combiners, etc. All have their unique appications.

 

[HT32BSX115]

Re: 2 batteries

Can I connect 2 batteries up to my boat the one I have in already is 12v 85ah,

Is there a limit to how much your alternator can charge.

I have a Volvo penta 4.3gl with one 85ah bat and want to put in another.

Thanks Colm

The answer is yes, yes.

Your alternator will only put out rated current..... (whatever that is) and can easily charge 2 batteries.

If you use a marine isolator, then it will charge whichever battery is low. If you just connect them in parallel, it will charge both but you'll over-charge the one that doesn't need charging.

You need to use a switch or isolator....

I'll assume that you want a second battery for running your fish finder, stereo, lights, fan, radar, radio, electric trolling motor, etc and you want to have a separate starting battery.



You can use a marine switch to switch them and depending on how you want to charge them you can also use any number of electronic or mechanical isolators.

Since this is not really an I/O specific topic, you might get better response in the Electrics, Electronics etc area



Cheers,


Rick

 

[Colliemcc]

Re: 2 batteries

Its really just so i can sit listening to the radio and not have to worry about the boat not starting and the bat being dead..

 

[HT32BSX115]

Re: 2 batteries

The easiest solution would be 2 batteries and an electronic isolator.

Wire the radio, stereo, and other stuff you want to use directly to the second battery and use the electronic isolator for charging. With this method, you will only start on the "starting" battery and run your other "stuff" on the "other-stuff" battery but both will be charged by the alternator.

Use an isolator that will stop charging when either battery doesn't "want" to be charged.


Regards,


Rick

 

[earlandamys180]

Re: 2 batteries

Its really just so i can sit listening to the radio and not have to worry about the boat not starting and the bat being dead..

I had the same worry as you do but no real good spot for a second battery so I just bought a Jump Start box problem solved!

 

[HT32BSX115]

Re: 2 batteries

Well, that doesn't really "solve" the problem because the problem is having to deal with a dead battery after running it down listening to music till the end of the day!!

You could also get a solar charger but if you ran the battery down until dark you're still in the same boat!! (Pun intended!)


Your best bet is a second deep cycle battery. I am going to add one to my boat. It'll be a sealed Optima or similar type battery.

 

[Colliemcc]

Re: 2 batteries

cheers i will go down my local boat shop and see do the have the stuff i need, do you know were i might get a wiring diagram from.

 

[NYBo]

Re: 2 batteries

Right here. Read the entire thread. You should, of course, follow the directions that come with the battery switch or other device you buy if they differ.

 

[Silvertip]

Re: 2 batteries

Right here -- again. This is a dual battery switch set up. About $35 bucks. You select which battery you want to power the stuff with the switch.

 

[korygrandy]

Re: 2 batteries

Collie: I did the same thing you wanted to do. I bought a second deep cycle 27 battery, and used the BEP 125 amp VSR. I have the radio and amp wired directly to the deep cycle and I have yet to have a dead battery. My 3.0l and altenator charge this setup just fine. Basically if the key is off the VSR turns off thus cutting off the first battery so if you're second battery dies, the radio will stop working but you can start your boat just fine.

http://forums.iboats.com/showthread.php?t=389643

 

[Colliemcc]

Re: 2 batteries

do i still use the same fuse box or do i have to make a new one and run the positive to it and feed my radio and stuff from that one.

 

[Silvertip]

Re: 2 batteries

It all depends on what you use. If you use a dual battery switch you simply switch the feed to the fuse panel to the COM terminal on the switch. The switch setting then determines which battery is powering stuff (1, 2 or both) and which is being charged when the engine is running. If you use an ACR, VSR, etc, you follow the wiring directions that come with the unit.