Dual batteries with switch for switch panel and accessories

[79Cobra]

I have an older boat and want two batteries with a switch. One to start the boat and the other battery to work the fish finder, depth finder, radio, lights, bildge, blower, live well pump, etc.... How in the heck do I wire all that???

 

[sschefer]

Re: Dual batteries with switch for switch panel and accessories

It's easy. Your idea is a perfect candidate for the Blue Sea Add A Battery system. You get a switch and a Automatic Charging Relay and easy to follow instructions. Admittedly, I've done this a few different ways in the past so I was pretty familiar with the wiring. I did follow the instructions and the easy to read schematic and had it all installed in a couple of hours.

I did change from fuzes to push button circuit breakers mounted in an easily accessed space alongside the switch. This allowed me to secure everything else out of sight and out of harms way and make a neater job of it.

 

[Fireman431]

Re: Dual batteries with switch for switch panel and accessories

And wire the switch like this:

 

[79Cobra]

Re: Dual batteries with switch for switch panel and accessories

how do i connect a switch pannel to all that? i'm not sure how to connect everything without burning through fuses or burning down the battery too fast while i'm fishing by using things such as a radio, fish finder, and trolling motor. I know how to set up the battery and switch but i dont know where to go from there...

 

[Piece715]

Re: Dual batteries with switch for switch panel and accessories

Do a search of the forums. This has been answered many many times. SilverTip i know has post many explanations of how the set up should work. Good luck to u!

 

[Fireman431]

Re: Dual batteries with switch for switch panel and accessories

You don't need a switch panel for all of that. You need a 12v+ and a 12v- buss bar. Fuse the incoming 12v+ with a 40 amp inline fuse and the appropriate fuse inline to each electrical device. The buss bars + side will be fed from the #2 side of the battery switch.

 

[Silvertip]

Re: Dual batteries with switch for switch panel and accessories

You've now seen two ways to do this. I don't see a trolling motor or any high current draw items on your list of accessories so right away I question the need for a second battery. Paranoia about a dead starting battery didn't seem to be a problem until the dual battery switch, isolators, ACR's and all the "life saving" devices appeared and now everyone with a row boat seems to feel they need a boat load of batteries. OK I'm done. But seriously, for your boat you can leave everything just as it is. Carry a jump start pack or another battery if you wish and a set of jumper cables. Cheap, simple and effective. However, if you really feel the need for a dual battery system then I need to ask the question -- do you want this to be a versatile and inexpensive system, or do you want an automatic, less versatile, more complex and more expensive system? There are a gazillion ways to do this but the simplest, least expensive and most versatile is the simple dual battery switch. However, if you are "switch challenged" and don't know when or why to use BAT 1, BAT 2, BOTH or OFF then perhaps the Add A Battery System is in order. The picture that Fireman431 posted only requires that the +12 volt feed to your console be connected to the COM terminal on the switch. You can now operate all accessories from BAT 1, BAT 2 or BOTH, you can charge BAT 1, BAT 2, or BOTH and you can start the engine on BAT 1, BAT 2 or BOTH. As I mentioned, if you can't determine when or why to use a particular switch position, do it another way. In my view, in your particular boat you could probably set the switch to BOTH, start the engine and leave the switch there. If you have two good batteries you could fish, listen to tunes, watch the locator and have you phone plugged in for days -- probably all season and never have to change the setting except to set it to OFF when you park the boat at the end of the day. If you add some high current draw stuff like high power amps, flood/spot lights, etc, then that's a different story and understanding the switch usage takes on more importance.

 

[79Cobra]

Re: Dual batteries with switch for switch panel and accessories

You've now seen two ways to do this. I don't see a trolling motor or any high current draw items on your list of accessories so right away I question the need for a second battery. Paranoia about a dead starting battery didn't seem to be a problem until the dual battery switch, isolators, ACR's and all the "life saving" devices appeared and now everyone with a row boat seems to feel they need a boat load of batteries. OK I'm done. But seriously, for your boat you can leave everything just as it is. Carry a jump start pack or another battery if you wish and a set of jumper cables. Cheap, simple and effective. However, if you really feel the need for a dual battery system then I need to ask the question -- do you want this to be a versatile and inexpensive system, or do you want an automatic, less versatile, more complex and more expensive system? There are a gazillion ways to do this but the simplest, least expensive and most versatile is the simple dual battery switch. However, if you are "switch challenged" and don't know when or why to use BAT 1, BAT 2, BOTH or OFF then perhaps the Add A Battery System is in order. The picture that Fireman431 posted only requires that the +12 volt feed to your console be connected to the COM terminal on the switch. You can now operate all accessories from BAT 1, BAT 2 or BOTH, you can charge BAT 1, BAT 2, or BOTH and you can start the engine on BAT 1, BAT 2 or BOTH. As I mentioned, if you can't determine when or why to use a particular switch position, do it another way. In my view, in your particular boat you could probably set the switch to BOTH, start the engine and leave the switch there. If you have two good batteries you could fish, listen to tunes, watch the locator and have you phone plugged in for days -- probably all season and never have to change the setting except to set it to OFF when you park the boat at the end of the day. If you add some high current draw stuff like high power amps, flood/spot lights, etc, then that's a different story and understanding the switch usage takes on more importance.

yea i want a trolling motor, bilge pump, arreator, lights, depth sounder, two fish finders, fuel guage, speedometer, radio, and thinks thats it

 

[Silvertip]

Re: Dual batteries with switch for switch panel and accessories

You didn't answer the question about if you understand how a dual battery switch works or whether you want an ACR along with it, or instead of! Understand that there are generally two electrical systems in a boat 1) the engine system and 2) the boat system. Starting of the engine and operation of the gauges occurs via the engine system. 2) The boat system consists of a pair of #8 or 10 gauge wires that run from the battery to the fuse panel at the console. The rest of your accessories are powered from that panel. Your trolling motor would be wired directly to the second battery. So tell us what you want and how you want it to work. Fireman posted the dual battery switch. All of the other accessories except the trolling motor get wired directly to the COM terminal of the switch. Connect the two negatives on the two batteries together and go boating. OFF = everything off. BAT 1 means BAT 1 is running everything, BAT 1 is being charged when the engine is running. The troller will work with the switch in any setting since it is wired directly to BAT #2. BOTH means everything is powered from both batteries and both batteries are being charged when the engine is running. In the BOTH position both batteries are in parallel so the troller would be running from BOTH batteries. In the BAT #2 setting BAT #2 powers everything and only BAT 2 will be charged when the engine is running. It doesn't get any simpler, cheaper, or more versatile than this. Lastly, you haven't told us what engine you have so we have no idea if the engine has enough alternator output to make any of this worth while.

 

[79Cobra]

Re: Dual batteries with switch for switch panel and accessories

You didn't answer the question about if you understand how a dual battery switch works or whether you want an ACR along with it, or instead of! Understand that there are generally two electrical systems in a boat 1) the engine system and 2) the boat system. Starting of the engine and operation of the gauges occurs via the engine system. 2) The boat system consists of a pair of #8 or 10 gauge wires that run from the battery to the fuse panel at the console. The rest of your accessories are powered from that panel. Your trolling motor would be wired directly to the second battery. So tell us what you want and how you want it to work. Fireman posted the dual battery switch. All of the other accessories except the trolling motor get wired directly to the COM terminal of the switch. Connect the two negatives on the two batteries together and go boating. OFF = everything off. BAT 1 means BAT 1 is running everything, BAT 1 is being charged when the engine is running. The troller will work with the switch in any setting since it is wired directly to BAT #2. BOTH means everything is powered from both batteries and both batteries are being charged when the engine is running. In the BOTH position both batteries are in parallel so the troller would be running from BOTH batteries. In the BAT #2 setting BAT #2 powers everything and only BAT 2 will be charged when the engine is running. It doesn't get any simpler, cheaper, or more versatile than this. Lastly, you haven't told us what engine you have so we have no idea if the engine has enough alternator output to make any of this worth while.

I'm running a 1979 115hp Evinrude 2 stroke. I don't know if ACR is necessary so what do you think? And thanks for the help. It's all making sense now, I'm only a college freshmen so new to the boating world as a owner, but have drivin and rode in them numerous times.

 

[Silvertip]

Re: Dual batteries with switch for switch panel and accessories

An ACR makes the switching automatic. The manual switch makes it inexpensive and versatile. Again, if you don't fully understand why you need one, both or neither, then what I suggest is moot. My suggestion, since you asked for it, is, as it always is, keep it simple. Use a dual battery switch, forget the ACR, and simply learn what you want the switch to do for you. Adding the ACR adds cost, adds complexity. adds other points of failure and since you have a low output alternator, you need to maximize where its power goes to best advantage. Most folks get so wrapped up with having a dead starting battery they build an elaborate electrical system that is simply not necessary. The only deviation from your original wishes regarding running everything off the house battery is that everything should be connected to the COM terminal on the switch. That output receives power from either or both batteries depending on how the switch is set. To protect the start battery when anchored, simply set the switch BAT 2. BAT 1 is then disconnected and therefore protected. Some folks contend that you need to constantly fiddle with the switch which is also untrue. Since you were anchored for a long period for example you set the swtich to BAT 2. When ready to go, simply start the engine. Why not go to back to BAT 1? Because you know that one is topped off already. BAT 2 is the one that was partially discharged and there is a very good chance it will still start the engine. You want BAT 2 to be charged so with the engine running it is getting maximum output from the engine and you didn't have to touch the switch. If the engine didn't start, set the switch to BOTH or BAT 1. My choice would be BOTH. When the engine starts both batteries get charged. You are the master. You simply tell the current where to go, or where you want it come from. Simple as that.