Duel battery troubleshooting

[Drewmusician_electrician]

Howdy, now I’m an alternating current electrician, so don’t give me too much crap. I have 2 batteries. When I test I get 23.5 volts on each battery. Now when I got to my selector switch battery 1 won’t work, if I switch to 1+2 it works and it also works on 2. I’ve checked the fuses. I followed the ground, I’ve checked all the connections. I’m thinking it’s the selector switch? Anyone have this problem? It’s a duck boat. Pretty much a tank on water. It’s duck season I need help.

 

[Scott Danforth]

first, welcome aboard

got a pic of how you have it wired?

because going across just the +/- of the batteries should be between 13.7 and 14.4 volts on a charged 12 volt battery

do you have an on-board battery charger?

if you are reading 23.5 volts on a 12 volt battery, be prepared for an explosion or fire.

a typical battery switch is for two 12 volt batteries in a 12 volt system. the grounds are all common (think of it as the white neutral). the + from Battery 1 goes to the B1 terminal (think of it as a black wire). the + from battery B goes to the B2 terminal (think of it as a red wire). then the output common from the switch is either off, B1, B2 or B1 tied to B2 for double the current capacity

 

[tpenfield]

23.5 volts sounds like marginal 12 volt batteries connected in series rather than in parallel. . . . it would be good to see a diagram though . . .

 

[Drewmusician_electrician]

first, welcome aboard

got a pic of how you have it wired?

because going across just the +/- of the batteries should be between 13.7 and 14.4 volts on a charged 12 volt battery

do you have an on-board battery charger?

if you are reading 23.5 volts on a 12 volt battery, be prepared for an explosion or fire.

a typical battery switch is for two 12 volt batteries in a 12 volt system. the grounds are all common (think of it as the white neutral). the + from Battery 1 goes to the B1 terminal (think of it as a black wire). the + from battery B goes to the B2 terminal (think of it as a red wire). then the output common from the switch is either off, B1, B2 or B1 tied to B2 for double the current capacity

 

[Drewmusician_electrician]

View attachment 392625

Oh wow, I had a blond moment. I’m so used to switching my volt meter to AC. I got it switched to DC. Battery 2 is now measuring 12.7 and battery 1 is 6.72

 

[Drewmusician_electrician]

View attachment 392625

 

[Drewmusician_electrician]

View attachment 392625

 

[Drewmusician_electrician]

View attachment 392625

And yes I plug it in when I park it in the garage to charge the batteries.

 

[Drewmusician_electrician]

Howdy, now I’m an alternating current electrician, so don’t give me too much crap. I have 2 batteries. When I test I get 23.5 volts on each battery. Now when I got to my selector switch battery 1 won’t work, if I switch to 1+2 it works and it also works on 2. I’ve checked the fuses. I followed the ground, I’ve checked all the connections. I’m thinking it’s the selector switch? Anyone have this problem? It’s a duck boat. Pretty much a tank on water. It’s duck season I need help.

 

[Scott Danforth]

your one battery is iffy, the other is toast

 

[Grub54891]

Ya, I’d say replace both of them at the same time. That way you know where you are at with it.
those meters,,,,, been there before myself. I just don’t make it public ! Lol

 

[Drewmusician_electrician]

Ya, I’d say replace both of them at the same time. That way you know where you are at with it.
those meters,,,,, been there before myself. I just don’t make it public ! Lol

Ha well I give zero F’s what other people think. 2020 made me realize that the masses are incredibly unintelligent.

 

[Grub54891]

So are you saying that advice you get here is useless?

 

[QBhoy]

Sounds like you might have cross wired your batteries in series, to give 24v. As a result and after connecting things correctly, one of your batteries might have suffered ? That said, I and many others have done just this very thing deliberately, to give some extra juice when required in an emergency, without damage. Not sure around your circumstances though.
Long story short, you need either a new battery (and keep that and the other battery that’s only just bonding on, always separate) or ideally, two new identical batteries.

 

[airshot]

Ha well I give zero F’s what other people think. 2020 made me realize that the masses are incredibly unintelligent.

As I am part of the masses and can fully understand that a 12 v battery cannot hold 24 volts, guess I shouldn't waste ny time offering a solution. If it worked I would be considered unintelligent, so I will pass.......

 

[rallyart]

Not sure how the charger is set up but it needs to go to both batteries. If it goes through the selector switch it would only go to one unless the switch is set to both. If it bypasses the switch and goes directly to the batteries it may provide a circuit that stops the selector switch from isolating the two. With one battery so dead, it may be that the charger is only going to battery 2 and not charging 1. Also, running the alternator charge to the batteries can be a little tricky when they are isolated.