Dual Battery Switch

[AJFishin]

I've got confused regarding the dual battery switch and what position it should be in to be used.


- I've been told to start the boat with the switch in the 1&2 position and cruise like normal, so that both batteries are getting charged.

- Then I was told, NO, only start it in the #1 position.

- But then I heard, run in the #1 position at the start of the day. Then at the end of the day when you're heading back, use #2.

- Then I hear both batteries will be charged no matter what position the switch is in, while the engine running?



Now what I have done, without issues, is start with the #1, then switch to #2 while anchored (for the electronics)  I have the "Arima" old battery switch, not the Blue Sea switch.

I just want to make sure I use this whole dual battery switch correctly and eliminate the confusion.

Thanks

[First Cabin]

IMHO the correct way to use that switch is to use either #1 or #2, but not both at the same time unless it is an emergency where both batteries on their own are not strong enough to start your motor and your fingers are crossed that by combining the batteries you can find just enough energy to get the motor started.

When I had that switch I would run #1 one day and #2 the next, etc....  Then when I got home, I would charge each battery individually so they were both fully charged for my next trip.  While charging and storing, the battery switch was always off.

Now, if for some reason, you're using the batteries a lot and not charging....say a long weekend with lots of trolling.... Then I can see that you may want to temporarily put the switch to both while you run the main motor either out to the fishing grounds or back from the fishing grounds....  But while you are draining the batteries, you want the switch on 1 or 2.

Again, the whole idea of the switch is to always have a fresh battery in reserve.  The more often you run them in the "Both" position, the more likely at some point in time one battery will go bad and since they are connected, it will take out the second battery and you will be dead in the water.

If someone thinks that "both batteries will be charged no matter what position the switch is in while the engine is running", they are either very confused or they have a very unusual wiring schematic.

[AJFishin]

First cabin thanks for the information, I appreciate it.
What you wrote makes sense and I think I'm going to follow your way in using the battery switch.

Thanks

[whale]

It all depends on which battery you have downrigger and everything else is running off of.(house battery)
You should be charging your starting battery with your motor. Charge your house at home.
This way your starting battery is always topped off unless your motor has charging issue.
If you go out with house battery, drain it during the outing. You rely on what ever you had charged previously. If your starting is dead, it's better to know when your are heading out, not on return.

[First Cabin]

It all depends on which battery you have downrigger and everything else is running off of.(house battery)
You should be charging your starting battery with your motor. Charge your house at home.
This way your starting battery is always topped off unless your motor has charging issue.
If you go out with house battery, drain it during the outing. You rely on what ever you had charged previously. If your starting is dead, it's better to know when your are heading out, not on return.

Your system as described is different than a standard 1,BOTH,2 switch.  You are describing a system with a dedicated starting battery and a dedicated house battery.  If this is the system you have, you should at least have a different switch and an ACR(automatic charge relay).

At the end of the day, we all have to understand exactly how our boat is wired and make the best decision based off what we KNOW is true about our specific boat.  NEVER TRUST AN INTERNET IDIOT!  There's no way he can know how your boat is wired.

[AP]

AJ, my system is similar to yours (I have yet to move to an ACR with a dedicated start and house battery).

You probably want to dig in and figure out a little more.  For example, do you have a distribution or fuse panel?  If so, where does its source power come from?  From the common hot post of the switch?  Or directly from one battery? 

I assume the main motor is connected to the common hot post of the switch, meaning that switch controls which battery starts the motor (only use "both" during emergencies if a single battery packs the power to start the engine) and also determines which battery is being charged by the main.  Because of that, I tend to do go from 1 to 2 on every other trip.  That way, I use and charge both batteries regularly and almost never charge at home.  I also have a kicker that starts/charges from battery 2, regardless of switch position.

[AJFishin]

I do charge my #1 battery after every outing on my marine battery charger that also has an auto shut off when it reaches it's max charge.

I'm guessing mine is still hooked up in the original way from the factory. The only thing the #2 battery has hooked up to it, is my fishfinder, with the exception of the battery switch.

Here's a picture I took when I was cleaning the fuel tank area. You can see the previous owner must have wrote "1, 2, & C" on the back of the switch, but not sure what "C" would stand for.



As of now this is the only shot I have of my fuse panel.

[Browneye]

"C" seems to be for 'common' for the ground.

The kind and type of battery makes a difference as well. A 'starting' battery should only be used for starting and then allowed to be recharged by the alternator/stator. Note that these smaller outboards don't put out much juice - nothing like your car. The Honda and Yamaha's are some 25-35amps. Once that battery get's near full charge they're putting out way less than that, also at idle - much less. It is VERY difficult to peak up a battery with an outboard motor - batteries should ALWAYS be put on a smart charger. It could take a dozen hours of running to replace what juice was taken out - amps out must equal amps in.

If your batteries are identical in brand, type, and age, they can be switched together and used as one, however as has been said they are likely to be different, be at differing states of charge, and you don't want to run them both down together.

Now let's assume it's been done right and you have one starting battery and one house battery that is a deepcycle. This latter you can run down with out killing it, but even so, less than 50% discharge very many times, or left in that state, will ruin it too. They will get to where they won't charge fully and won't hold a charge. Severely shortened life is a result over discharging and improper charging. Again, there's no way your outboard alternator is going to peak up one of those big group 27 deep cycles.

If you switch them together for charging whichever one is less charged will pull more juice from the regulator and can even overcharge the more charged one. Not likely with an outboard, but can be a big problem with a bank of batteries and a couple of 150amp alternators on inboards. So they really need to be used and charged seperately. Start with your starter battery and run everything off that when the motor is running. If you switch off the motor then use the house battery, switch to both to start, then switch back to the house to re-charge it.

Some outboards like the F150 have two charge leads from the alternator and two regulators so you can keep two batteries topped up. I don't think the smaller motors do this.

My preferrence is still for conventional lead-acid batteries, starting and deep cycle for their appropriate application, and keep them watered with distilled or RODi water and keep them fully charged with a smart charger.

If you're doing a lot of idling around and running abunch of lights and electronics you want to be on your house/deepcycle and keep the starting battery fresh for a hot start.

There ya go...12V battery primer. :)

[Wyrguy]

"C" seems to be for 'common' for the ground.

There ya go...12V battery primer. :)

I gotta jump in... This is completely wrong!

1) The 'C' terminal is NOT a 'ground' ...! It's the common terminal feeding all loads and the positive 'output' of the switch from whatever battery the switch has connected.

2) There is no 'ground' anywhere on a 12 volt DC battery system but there is a negative, the return path for electrons from the positive.

Wyrguy Rick



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[DevMah]

All
Rick is totally correct there is no ground in a marine  floating DC system. Marine system is a floating 12 or 24 v system. Floating means that nothing is tied to ground.

Tight Lines

Dev

[Browneye]

Call the word ground wrong, it's still the negative pole. Fussy...

[Wyrguy]

Call the word ground wrong, it's still the negative pole. Fussy...

No it's not... What you are 'spouting' is completely wrong and WILL cause a catastrophic accident (dead short) if anyone connects a NEGATIVE conductor to the common terminal and then switches that switch from off!!!

Wyrguy Rick


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[diodon]

Rick is so right if you do this you will most likely start your ARIMA on FIRE.  :nono:

[Browneye]

That's just silly, then it's not the negative pole, just switch for the plus side. Don't get too excited. Lol
We're talking about two different things.

[Wyrguy]

That's just silly, then it's not the negative pole, just switch for the plus side. Don't get too excited. Lol
We're talking about two different things.

What you have posted is DANGEROUS...!
Your complete lack of any electrical knowledge is going to hurt or kill someone!!! A battery switch, usually located right next to a lead acid battery and connected to the switch as you say WILL cause a dead short and the battery, if the switch isn't  bursting into flames and opening the circuit, will very possibly EXPLODE with acid spraying everywhere...

How dare you say " Don't get too excited"

Wyrguy Rick


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[Browneye]

Yes, that is all on the plus side, agreed, I didn't realise that was the selector switch. I mis-spoke on it being ground. My comment was about the batterirs not the wiring. Please carry on.

@wyrguy:  my apologies, I was trying to read and post from a phone now got to a real keyboard. I'll try not to be so incoherent, you try not to be so dramatic. Deal?  :bowdown:

:applause:

[croaker stroker]

Now I'll throw in my 2 cents...

1. Don't change the switch position while the motor is running.

2. Replace all of those OLD battery cables with proper sized Marine grade TINNED wire with lugs professionally installed and with the proper insulation color.

3. Get a new switch.

Now I'll go away.

[StreamFixer]

While the above discussion between Browneye and Wyrguy appeared to be getting a bit tense, I am glad to see they are now pretty much in agreement.

When it comes to wiring safety on our boats, I would suggest we listen carefully to a person who makes his living dealing with boat wiring safety (that would be wyrguy).  He has been consistently very, shall we say generous, with his wiring knowledge, some times painfully so.  However, that does not suggest he has ever lead us astray with his recommendations.

This is an excellent example of where mis-understanding terms can indeed hurt, or even kill, you.

Thank you for patiently hashing this out guys.

StreamFixer

[AJFishin]

Thank you for all of the information and wyrguy I appreciate the input on proper wiring.
I will look into getting some new parts and updating the system if that is what needs to be done.

I will say this was an interesting read though.

Thank you again