Adding a second battery - what's on each battery

[amanphoto]

My boat currently has a single battery. I'm going to a dual battery set up. What would I put on the starting battery and what should I put on the house battery? Like where should the bilge blower go?

 

[Bob_VT]

Re: Adding a second battery - what's on each battery

Hey wiring diagrams available in our electronics section.....

Please remain seated until this threads lands in our electornics section

 

[bigskiohio]

Re: Adding a second battery - what's on each battery

Your second would be a spare with a selector switch ?

 

[amanphoto]

Re: Adding a second battery - what's on each battery

Sorry for posting in the wrong place.

 

[amanphoto]

Re: Adding a second battery - what's on each battery

I have a cuddy cabin boat. I was thinking...

Starting battery...
1. Starter
2. Blower
3. Bilge
4. Tilt and Trim



House Battery...
1. Nav lights
2. Cabin lights
3. Radio
4. Sink

Well?

 

[skargo]

Re: Adding a second battery - what's on each battery

I thought the same as you until I learned more.

You put everything on both batteries! In my case I start the boat on 1, then switch over to 2. It's all about redundancy. In your scenario, what if battery 1 dies? How will you start your boat? Sure, you could rewire everything but set up correctly, you just flip the switch to 2. Or if battery 2 dies at night, what are you going to do for lights?

So I start on 1, cruise and anchor on 2, then start on 1 again, and for the ride back, flip the switch to both to top them off.

 

[amanphoto]

Re: Adding a second battery - what's on each battery

My battery switch will combine the batters if one fails. The batteries are separate while the engine is off. When the engine is running the batteries are combined and both are charged.

 

[skargo]

Re: Adding a second battery - what's on each battery

My battery switch will combine the batters if one fails. The batteries are separate while the engine is off. When the engine is running the batteries are combined and both are charged.

So what are you asking? Is it already set up?What battery switch do you have?

You need to make each battery power everything, trust me. Someone hopefully will explain it better than I am

 

[bear_69cuda]

Re: Adding a second battery - what's on each battery

On my Bayliner project (link below) I put everything on my deep cycle house battery, and used the other battery (dual-purpose) only for starting the boat. I also had the option of combining both batteries if needed with Switch. I also had a VSR (voltage sensitive relay) that would separate the system and charge whatever battery had lowest voltage.

 

[amanphoto]

Re: Adding a second battery - what's on each battery

It's not set up yet. Just in my head. I was going to use this switch.


http://www.iboats.com/Dual_Battery_C...view_id.341114

 

[Silvertip]

Re: Adding a second battery - what's on each battery

You don't put ANYTHING on ANY battery. Both batteries connect to a dual battery switch. All loads then connect to the COM terminal on the switch. The only exception might be an automatic bilge pump which would be connected directly to either of the batteries. If it were connected to the switch it would not run if the switch was set to OFF when you were not around the boat. Do a forum search for "dual battery switch". This has been covered at least a dozen times by me and a gazillion times by others.

 

[witenite0560]

Re: Adding a second battery - what's on each battery

I'm setting mine up so the #1 starting battery will run starter only and the #2 aux battery will run starter and/or all accessories. With the usual switch, (Off, 1, Both, 2) should be easy to do. Rationale is that way I should always have starting power on #1, with #2 as a back up.

 

[skargo]

Re: Adding a second battery - what's on each battery

You don't put ANYTHING on ANY battery. Both batteries connect to a dual battery switch. All loads then connect to the COM terminal on the switch. The only exception might be an automatic bilge pump which would be connected directly to either of the batteries. If it were connected to the switch it would not run if the switch was set to OFF when you were not around the boat. Do a forum search for "dual battery switch". This has been covered at least a dozen times by me and a gazillion times by others.

Exactly! There is no benefit doing it any other way. IMO

 

[witenite0560]

Re: Adding a second battery - what's on each battery

Sure there's an advantage and an easy way to do it. The advantage is, if I run accessories off one battery and starter off another battery, chances are I'll always have starting power. The way to do it is use the dual battery switch or Automatice Charging relay to keep the batteries charged. But, for the accessories, directly connect a wire from the positive terminal of your "accessories" battery to a buss bar for the accessories and a wire from your common ground terminal (this would be a large stud terminal that you SHOULD have both battery grounds and the engine ground ganged at) to another buss bar. Now, you've got a positive and negative buss bar for all your accessories, that will only pull from your accessories battery. Even if you run that one dead, you'll still have a full starting battery. The dual battery switch will still charge #1, #2 or Both, whichever you select. It will NOT turn off your accessories curcuit. You can install an "Accessories Master" switch, if you desire or an indicator light that glows when the Accessories curcuit has a draw if you're afraid of having stuff left on or parasitic draw from components with memory curcuits.

 

[skargo]

Re: Adding a second battery - what's on each battery

Sure there's an advantage and an easy way to do it. The advantage is, if I run accessories off one battery and starter off another battery, chances are I'll always have starting power. The way to do it is use the dual battery switch or Automatice Charging relay to keep the batteries charged. But, for the accessories, directly connect a wire from the positive terminal of your "accessories" battery to a buss bar for the accessories and a wire from your common ground terminal (this would be a large stud terminal that you SHOULD have both battery grounds and the engine ground ganged at) to another buss bar. Now, you've got a positive and negative buss bar for all your accessories, that will only pull from your accessories battery. Even if you run that one dead, you'll still have a full starting battery. The dual battery switch will still charge #1, #2 or Both, whichever you select. It will NOT turn off your accessories curcuit. You can install an "Accessories Master" switch, if you desire or an indicator light that glows when the Accessories curcuit has a draw if you're afraid of having stuff left on or parasitic draw from components with memory curcuits.

Maybe you're right, I did leave mine on "both" and kill both my batteries in my driveway once.

 

[Silvertip]

Re: Adding a second battery - what's on each battery

But you can also leave a master switch on as well. You are simply defeating the purpose of the switch and you cannot fully protect against "forgetfulness". You can but it involves adding a relay that turns on when the key is on. That relay becomes the master switch. When the key is off the electrical system is dead. But then one can kill the engine or simply have it die and forget to turn the key off. So you see, there is no ultimate dead battery protection. Just because you have a starting battery connected so it's sole purpose is starting, does not mean it can't die just sitting there doing nothing. It happens with far more regularity than you think. Bad diodes in the rectifier or alternator of an I/O can kill a battery.

 

[skargo]

Re: Adding a second battery - what's on each battery

I am adding one of these to my "start" battery, maybe that will prevent me mistakenly leaving the switch on both.