Optimizing battery setup

9

98sanger

Cadet
Joined
May 26, 2009
Messages
10
Hi all,

I've been looking over the various posts on two battery setups and have a couple questions. Quick background on the setup. I have two deep cycle batteries. I know the wiring needs to be looked at because I can only play the stereo in BOTH. Not a single setting. Thus with the boat off and in BOTH position it ends up not having enough juice to crank at the end of the day. So, I've done quite a bit of research to optimize my setup and finally get it right, its all kinds of screwy now. Read over and see any errors or changes I should make. Also the boat is powered by a 96 Chevy 350 small block standard engine.



For a two battery setup, one for starting, one for an aftermarket stereo this is what I've gathered: Get a 1-2-BOTH-OFF switch, which I have. Wire the two negatives on the batteries together to get them in parallel. Install a wire from BATT 1 positive to switch position 1. Wire positive from BATT 2 to switch position 2 and then wire the positive from the engine to the common part of the switch.

From my understanding, in this setup you would crank your boat in switch position 1. Then after you crank you switch to BOTH to get motor and stereo as you cruise. When on shore, turn off the engine first and then switch to 2, thus having all electronics run off the second battery.

Hopefully that is right, I have a question on battery charging though. How and what would I install to make sure that second battery, is constantly charged? Will it get charged as the boat runs because the alternator is hooked to BATT 1 since they are in parallel? All stereo equipment should be hooked to BATT 2 directly?

I'm really looking for a good way to isolate BATT 1 for cranking and BATT 2 for a stereo while maintaining a charge to start the boat after a day of music and not have the stereo go dead at the same time.

You guys have great input and fast responses, thanks for the read.
 
bruceb58

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,587
Re: Optimizing battery setup

Buy an ACR and hook your stereo directly hooked up to Batt2. Then all you have to do is leave the switch to Batt1 and the engine will crank off that battery and both will charge underway. No need to switch to "Both" that way.

If you don't want the ACR, just switch to "Both" while you are running to charge both batteries and switch to Batt1 again when you stop. Since the stereo is hooked up to Batt2, the starting battery(Batt1) won't get discharged..
 
9

98sanger

Cadet
Joined
May 26, 2009
Messages
10
Re: Optimizing battery setup

Thanks for the reply. I've been looking at the ACRs. I'm just tired of battery for my stereo dying due to high power output and it seems like the ACR would fix that. Whats the advantage over my current situation if I currently crank in BATT 1, cruise in BOTH for stereo and motor, and do stereo only off BATT 2? If I have the alternator wire running to the common part of the switch it should charge whatever BATTs are selected via the switch, right?


I understand how the switch isolates batteries and if the alternator is hooked into the common section it should charge everything. What else gets hooked to the common part? I should just have all power from the stereo going to BATT 2, right?


Was also thinking about gutting the switch I have now and just going with
http://www.westmarine.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=10001&storeId=11151&partNumber=8646275&langId=-1

It seems like I can just hook up both batteries via the installation instructions of this switch and then turn to on and play all day and it should charge just fine.
 
bruceb58

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,587
Re: Optimizing battery setup

That's true..you could do that. Just a lot of switching all the time. I understand wanting to have the capability of cutting power to the stereo with the battery switch.

On my boat, I basically have as you described. i just always run off battery 1and just let everything suck off of it. If I know I have discharged it a lot, I would transfer over to battery 2 to start the boat but typically I just have the switch set to battery 1 and the second battery is only there for a backup.

I typically don't have a lot of "house" loads so I would do things different if I had more of a cabin cruiser type boat with more loads. In that case I would have an additional on/off switch from battery 2 to all of my "house" loads along with the 1/2/both/off switch connecting both batteries 1 and 2 to my engine.

Or you can use this switch which basically does what I describe all in one switch.
http://bluesea.com/category/1/products/5511e
 
9

98sanger

Cadet
Joined
May 26, 2009
Messages
10
Re: Optimizing battery setup

Perfect link, I'm definitely going to follow that schematic.

With that setup I should be able to crank BATT 1, cruise in 1+2, and then stereo only on BATT 2 right? Having them charge perfectly with the ACR as well when in 1+2?
 
sasto

sasto

Captain
Joined
Jun 1, 2010
Messages
3,918
Re: Optimizing battery setup

98sanger said:
Perfect link, I'm definitely going to follow that schematic.

With that setup I should be able to crank BATT 1, cruise in 1+2, and then stereo only on BATT 2 right? Having them charge perfectly with the ACR as well when in 1+2?
Click to expand...

Nothing is perfect, especially on a vessel... IF.... I had your setup... without the ACR, I would use 1 batt for cranking and other for "house" (stereo,etc). If motor dosen't crank, I would use "both".... Switch back to "house" (the stereo, etc) and charge that battery upon returning. Personally, we never leave a batt switch in the "both" position at anytime. Charge batterys whenever possible with a "smart charger".
 
9

98sanger

Cadet
Joined
May 26, 2009
Messages
10
Re: Optimizing battery setup

Thank you for the reply. I appreciate the info.

So without the ACR I would just have to charge batteries after a day on the lake then. Also, lets say I head to shore and crank the stereo on BATT 2 with the stereo wired directly to it. If that battery ends up dying towards the end of the day I can always crank with BATT 1 and then move to BOTH to charge via the alternator for BATT 2
 
M

mikphilips

Cadet
Joined
May 4, 2010
Messages
18
Re: Optimizing battery setup

One option is to use your existing 1-2-OFF-BOTH switch to direct power, and install a battery integrator ($100) that will charge both batteries while underway and automatically separate the batteries when stopped. Gives both batts max charging time but keeps your house batt from tapping into your starting batt and leaving you stranded.
I agree with the post about using a smart charger back at the dock. You just need to install a simple Perko ON-OFF switch between the integrator and one of your batts. This will prevent the batts from being combined during smart charging. Each batt will be charged according to its need.
If you install the switch next to your dock receptacle for your onboard charger, then its easy to remember when you plug the charger in.
More power to ya.
 
D

Doernuth

Petty Officer 1st Class
Joined
Jul 6, 2010
Messages
332
Re: Optimizing battery setup

It seems to me that you are making this more difficult than it should be. If your stereo doesn't work in one battery position it is probably wired wrong. Make sure that the stereo is wired to the current system correctly and you should just be able to isolate one battery as a starting battery. Or am i missing something?
 
9

98sanger

Cadet
Joined
May 26, 2009
Messages
10
Re: Optimizing battery setup

Doer, I agree I am making it harder.

The boat is currently in storage and I'm headed out there tomorrow. I know the wiring is jacked up right now, I just wanted to get a good gameplan for what I need for the next couple days to wire it up all correctly.

I plan on keeping my switch and just throwing an ACR inbetween the two lugs of the BATT1 and BATT2 switch. Right now I run off BOTH wayyyy too much and ends up eating up both batteries. Isolation is key... something I put by the wayside until now ;)
 
F

Fed

Commander
Joined
Apr 1, 2010
Messages
2,457
Re: Optimizing battery setup

All the negatives joined together.
Batt 1 positive to Batt 1 on the switch.
Batt 2 positive to Batt 2 on the switch.
All other load wires go to the common on the switch.

1) Start in Pos 1 and start up motor then switch to 'both'.
2) While ever you're driving both batteries will charge.
3) When you stop switch to Pos 2 and play the music.

When you want to start the motor again go back to 1) and repeat.
 
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