2 battery switch

[rndn]

I have 2 starting batteries on my boat with a battery selector for off, 1, 2, or both. I have seen other threads where someone stated to not keep it on the both battery setting. The suggestion was to run it out on battery 1 and return on battery 2. I have only had the boat for 10 months and when I have used it I have just put it on the both setting for the entire all of my trips. Please give me your thought and opinions on how and why I should continue to use it as I do or take the other suggestion. I also have 2 deep cycle batteries for my electric trolling motor but I keep them separate and charge them in my driveway. The boat in question is in my signature. Thank you in advance for your time to read this and the offering of your knowledge.
This site is the best!!!

 

[cbavier]

Re: 2 battery switch

I have 2 starting batteries on my boat with a battery selector for off, 1, 2, or both. I have seen other threads where someone stated to not keep it on the both battery setting. The suggestion was to run it out on battery 1 and return on battery 2. I have only had the boat for 10 months and when I have used it I have just put it on the both setting for the entire all of my trips. Please give me your thought and opinions on how and why I should continue to use it as I do or take the other suggestion. I also have 2 deep cycle batteries for my electric trolling motor but I keep them separate and charge them in my driveway. The boat in question is in my signature. Thank you in advance for your time to read this and the offering of your knowledge.
This site is the best!!!

The purpose of switching from one battery to the other is so you have your starting battery fully charged. In other words both batteries don't get run down. You start on #1 then stop motor, switch to #2 say your running a radio, Lights and trolling motor all day long on one battery. When you get ready to leave for shore just turn the switch back to #1 and your starting battery will still be fully charged. If you run everything on both you could run both batteries down low enough where you wouldn't have enough power to start your motor. #1 Battery should be a starting battery or dual purpose and ideally the #2 battery would be a deep cycle for running all your accessories. you probably should switch to both after the engine is started off #1 to recharge both batteries.

 

[Silvertip]

Re: 2 battery switch

The whole purpose of a battery switch is to protect the start battery (BAT 1) so it will not be run down due to running accessories. Anytime the engine is running you should be set to BOTH. Any time you are anchored and using accessories you should be on BAT 2. For starting you should be set to BAT 1, unless it has actually taken a dump. You then switch to BAT 2 (if you haven't run it down) to start the engine. If that fails, switch to BOTH so both nearly drained batteries together might get you going. If that fails, call for a tow. NEVER turn that switch OFF with the engine running unless you enjoy buying regulators. Lastly, if you know BAT 1 is up to snuff and BAT 2 is deeply discharged, start the engine and switch to BAT 2 to charge just that battery. Remember, whatever switch setting you use means that that battery is being charged or discharged depending on whether the motor is running or not. The switch is versatile. You just need to know how to use it properly. If you are anchored for just a little while there is no need to fool with the switch. But if you run your troller or other high powered accessories, get in the habit of using the switch.

 

[Boatist]

Re: 2 battery switch

Also if you leave the switch in both and one of the batteries is weak or going bad it will discharge the other battery as well. The good battery would try and charge the bad Battery and it could leave your dead in the water.

 

[cbavier]

Re: 2 battery switch

Hey Silvertip.

Running two batteries with the switch. Would it be feasible to mount that switch on the dash? How heavy of a wire do you think I would have to run? It sure would be a lot more convenient controlling it's operation from the Helm.

 

[Silvertip]

Re: 2 battery switch

Mounting the switch on the dash is generally not advised for the simple reason the wiring for the start battery needs to be the same size or even larger than the battery cables to the engine. That means you would need to extend the batter cables from the engine to the switch. That wire is not cheap and it would be bulky. The best installation is to have the switch and both batteries close to each other to keep cable runs short. Also keep in mind that if you would ever need to start the engine from the auxiliary battery, it's wiring to the switch needs to be the same size as well.

 

[cbavier]

Re: 2 battery switch

Thanks Silvertip;

I just thought a dash switch would be more convenient. But your explanation makes sense. Thanks

 

[bruceb58]

Re: 2 battery switch

Best thing to do is to put in an ACR(automatic charge relay...also called a combiner) and you don't have to worry about switching to the "both" selection.