Run battery switch on all or 1????

[scubayachts]

I am wondering if I should have my betterys on all, 1 or the 2 selection when running my boat? Any help with this? Thanks

 

[northvanwatertaxi]

Re: Run battery switch on all or 1????

A Quote from slvertipThe purpose of the switch is to be able to turn everything off. If you connect loads to either the 1 or 2 terminals you run the risk of leaving something on. Therefore all loads except your bilge pump should come off the COM terminal as thats the "feed" for your electrical system. Your accessories will then run on either 1, 2, or both -- whatever you have selected. Start on 1, run as you please. Park. Switch to 2. Get ready to go switch back to 1 or BOTH. Both batteries will charge. At the dock, set to OFF. You should have a POS and NEG wire running to the fuse panel. The POS wire also goes to the COM terminal on the switch. The NEG terminal goes to the NEG terminal on either battery since you have them tied together. Your stereo probably has two leads that require 12V. You probably don't want that wired so the key must be on to run the stereo so it can go directly to the fuse box. The second lead is the station memory which must be energized all the time. That lead would have to go all the way back and tied to either battery POS. It draws very little current so it can run off either battery.

 

[vipzach]

Re: Run battery switch on all or 1????

The only thing I want to add to silvertip's advice: If you know one of the batteries is low, don't switch to "both" because it will cause the full battery to try and charge the low battery. Switch to the full battery and then start your boat, you can then switch to the both position and charge both batteries, but don't do that if you are making a short trip and will need to restart the boat soon.

 

[rickdb1boat]

Re: Run battery switch on all or 1????

And of course, never set to off when running...

 

[Silvertip]

Re: Run battery switch on all or 1????

And make sure your switch is a "make-before-break" type. If its not, switching changes with the engine running can pop the voltage regulator/rectifier.

 

[ricksrster]

Re: Run battery switch on all or 1????

The addition of an isolater prevents the weak battery from discharging the strong battery. Also it allows the alternator to charge first the weak battery, then switches to the strong battery.
http://www.noco.biz/InstallGuidesPDFFiles/Igm-70 outboard marine.pdf

 

[ricksrster]

Re: Run battery switch on all or 1????

Something left out on the install guide for two battery, off -1 - both - 2 switch. Disonnect the red wire at the rectifier and run new wire from the alternator post on the rectifier to alt post on isolater. The set up in the diagram also protects the rectifier should the battery switch be accidentally switched off.

 

[Chris1956]

Re: Run battery switch on all or 1????

Scubayachts, Normally on a multi battery boat you want to always have one battery fully charged for starting the motor. You therefore use the battery switch to select which battery to run the accessories off of, when the motor is not running. When you stop for the night, switch to battery one on odd days and battery two on even days. The next morning, switch to the other battery to start the motor, and then switch to both, to charge both. Since I cannot tell an odd day from an even day, I would consider a battery combiner, which automatically charges both batteries. I would put all my accessories on a single (or dual if necessary) deepcycle battery. I would put my engine starter on a single starting battery, and in combination with the battery combiner, it would automatically keep my starting battery ready to start, without any manual intervention.d

 

[northvanwatertaxi]

Re: Run battery switch on all or 1????

I got tired of opening the hatch all the time, I leave mine on all and used to just keep a charged battery un hooked to anything. now I have a small 10a @12v yamaha generator in case the engine dies or I need a charge in the morning
when i start there is always tons of power and everything on board cant kill two deep cycle batterys

 

[KaGee]

Re: Run battery switch on all or 1????

The addition of an isolater prevents the weak battery from discharging the strong battery. Also it allows the alternator to charge first the weak battery, then switches to the strong battery.
http://www.noco.biz/InstallGuidesPDFFiles/Igm-70 outboard marine.pdf

Rickster brings up an important point... without an isolator you should not run in the ALL position for any length of time.

 

[Silvertip]

Re: Run battery switch on all or 1????

Running in the ALL position is not a problem. Leaving it in the ALL position while anchored or docked can be -- especially if one battery is weaker than the other!

 

[northvanwatertaxi]

Re: Run battery switch on all or 1????

ok I will switch it over to 2 at anchor good point.

 

[Boatist]

Re: Run battery switch on all or 1????

I really like the battery isolator but have to disagree that wired in with a Battery switch that it will stop the strong battery from charging the weak battery.

Example with a fully charged battery 1 and a discharged trolling battery 2. If the switch is set to position 1, all, or both Then battery one will try to charge battery 2.

With switch in position 1 then the switch short out the diode on isolator for battery 1. Since battery one is shorted to the common lead by the switch battery one voltage is on the common post. The isolator comon is also connected to this post. Now since battery one voltage in on the common post of the isolator the diode for battery 2 will be foward biased and try to charge battery 2.

If you set the switch to battery 2 then battery one will not try and charge battery 2 but now your starter is on the weak battery.

Isolator with out the switch will work correctly and protect the strong battery. When running the weak battery will get most of the charge so if you have a small alternator starting battery may not get any charge for a long time. With big alternator on I/O and new large outboards this is not a problem.

Edit see Rick's wireing below the way he has it wired will work great. Only time strong battery would try and charge the weak battery would be if set switch to all or both.

 

[ricksrster]

Re: Run battery switch on all or 1????

The original red wire is diconnected at the rectifier. A new wire is connected from the rectifer to the ALT. post on the isolator. The batteries will charge from the isolator even if the switch is in the off posotion. The engine stills runs because the stator winings for the ignition are seperate from the charging windings. Refer to this link diagram with the original red wire disconnected and a new wire installed. The rectifier will be seperated from the wiring harness. http://www.iboats.com/bbboard/bbBoa...GuidesPDFFiles/Igm-70%20outboard%20marine.pdf

 

[Boatist]

Re: Run battery switch on all or 1????

Rick
Thanks for that PDF file with a isolator and Battery switch.
That wireing will work great. Both batteries charge thru isolator. Also protects alternator even if switched thru off.
Can still select your starting battery.
Only time strong battery will try and charge the weak battery is if set to both or all.

Again thanks that wireing will work great.