Battery question...

[TacomaCouple]

Here is a pic of the two batteries. In the pic you will see one battery that is not being used (because the guy we bought the boat from just threw one in there) and one battery that IS.

Question:
The battery that is not hooked up...what DOES get hooked up to that one?

I notice a difference between the two batteries and the terminals on each of them. The one that is being used has a sort of "V" thingy on the terminals where things (I have no idea WHAT things) are hooked on to.

Question:

Should that other battery, that is not being used BE used for something AND have the "V" thingy on the terminals?

If you notice, on the left side of that boat compartment, there is a Red switch to go between the two batteries and an off switch. That second battery needs to be connected to that, somehow, correct?

Maybe, after we get these batteries hooked up CORRECTLY the existing fishfinder and radio will work?

[Randygh]

What are the settings on the front of the battery switch? Off-1-2-both or On-Off?

[TacomaCouple]

What are the settings on the front of the battery switch? Off-1-2-both or On-Off?

I wil need to answer tommorrow after I look at it again. I should have taken a pic but didn't. I believe it's 1-off-2 but won't swear to it.

[TacomaCouple]

Ok, here (see pic) is what I have on there. Shouldn't BOTH batteries be attached to it? What attaches to the second battery?

[Randygh]

Before you disconnect wires from the one battery, I recommend you follow each POSITIVE (+) wire to see where it ends. Then wrap a masking tape label around the wire next to the battery. For example, there will be a large gauge wire that goes to the engine starter. Label that wire "starter." (Use a felt-tip marker to label the masking tape.) Does you boat have a fuse buss? It is probably hidden near the dash and should feed your house circuits. A large red wire should feed the buss. I think it is a good idea to know the "target" for each red wire that is attached to the current battery.

Your boat has a good battery switch. Unscrew the Perko switch from the bulkhead and look at the back side. There should be bolt posts labeled "1", "2" and "Out" (or something similar). I think it would be best to keep your wiring simple. Others on the this board will probably have different ideas that may be better than mine.

I would designate each battery. #1 could be your starter battery, #2 your house battery. I would wire the starter cable directly to the + post on battery 1. I would then run a large red wire from the positive post on battery 1 to post number #1 on the back of the switch. Then run a large (starter wire size) red wire from the #2 battery + post to the post labeled #2 in the switch. (In order to have continuous uninterruptable power to your bilge pump, I'd wire the positive lead DIRECTLY to the positive post of battery #1.)

All the other wires that are currently attached to the positive post of the existing battery in the picture would be attached to the "out" post of the switch.

With the above wiring remember:
1. The starter battery #1 will always be recharging when the engine is running. (The alternator charges the battery through the lead to the starter)

2. When the switch is in the #1 position or #2 position, all the electrical house circuits are feeding from that particular battery. If the switch is in the "both" position the house circuits will be feeding off both batteries.

3. When the switch is in the #2 position and the house battery is run down, the starter battery (#1) will still be strong. You don't ever want to run down the #1 battery.

4. In order to recharge both batteries at the same time the switch has to be in the "both" position. When running, I'd always have the switch in the "both" position. If you are anchored or moored switch over to the #2 position to use your house battery.

5. If the switch is in the "Off" position, you'll still have power to the engine starter because the #1 battery is wired directly but you wouldn't have any power to the house circuits.


The black wires on the negative post of your battery are the ground wires for all your circuits. Ground wires are just as important as the positive (hot) wires. They should be free of corrosion and not too small. Currently, your battery has a large black wire from the negative post to the engine block. You can run a large black jumper wired from the negative post of battery one to the negative post on the second battery. You can connect all the other black house leads to either battery's negative post.

As mentioned, others on this board may have more suggestions.

[TacomaCouple]

Before you disconnect wires from the one battery, I recommend you follow each POSITIVE (+) wire to see where it ends. Then wrap a masking tape label around the wire next to the battery. For example, there will be a large gauge wire that goes to the engine starter. Label that wire "starter." (Use a felt-tip marker to label the masking tape.) Does you boat have a fuse buss? It is probably hidden near the dash and should feed your house circuits. A large red wire should feed the buss. I think it is a good idea to know the "target" for each red wire that is attached to the current battery.

Your boat has a good battery switch. Unscrew the Perko switch from the bulkhead and look at the back side. There should be bolt posts labeled "1", "2" and "Out" (or something similar). I think it would be best to keep your wiring simple. Others on the this board will probably have different ideas that may be better than mine.

I would designate each battery. #1 could be your starter battery, #2 your house battery. I would wire the starter cable directly to the + post on battery 1. I would then run a large red wire from the positive post on battery 1 to post number #1 on the back of the switch. Then run a large (starter wire size) red wire from the #2 battery + post to the post labeled #2 in the switch. (In order to have continuous uninterruptable power to your bilge pump, I'd wire the positive lead DIRECTLY to the positive post of battery #1.)

All the other wires that are currently attached to the positive post of the existing battery in the picture would be attached to the "out" post of the switch.

With the above wiring remember:
1. The starter battery #1 will always be recharging when the engine is running. (The alternator charges the battery through the lead to the starter)

2. When the switch is in the #1 position or #2 position, all the electrical house circuits are feeding from that particular battery. If the switch is in the "both" position the house circuits will be feeding off both batteries.

3. When the switch is in the #2 position and the house battery is run down, the starter battery (#1) will still be strong. You don't ever want to run down the #1 battery.

4. In order to recharge both batteries at the same time the switch has to be in the "both" position. When running, I'd always have the switch in the "both" position. If you are anchored or moored switch over to the #2 position to use your house battery.

5. If the switch is in the "Off" position, you'll still have power to the engine starter because the #1 battery is wired directly but you wouldn't have any power to the house circuits.


The black wires on the negative post of your battery are the ground wires for all your circuits. Ground wires are just as important as the positive (hot) wires. They should be free of corrosion and not too small. Currently, your battery has a large black wire from the negative post to the engine block. You can run a large black jumper wired from the negative post of battery one to the negative post on the second battery. You can connect all the other black house leads to either battery's negative post.

As mentioned, others on this board may have more suggestions.

Wow!! Great info!! Thanks. I will print this out and take it out while I work on that stuff.

[3788sam]

Randy is giving you great advice. Find out where those wires are running and label them.
The previous owner didn't do you a whole lot a favors with that wiring mess.
Redoing the wires with the correct type (Marine grade), gauge, and color should make a great winter project. Electrical problems can spell a quick end to a great weekend on the water.

[Fred P]

Randy is right on, as to how it should be wired. Also disconnect the grounds from the batterys when you are working on and around them. If you do not have battery covers, you will need covers for your batterys. Or at least the + terminal, that way if you drop a wrench on the battery there will not be a spark or fire. It is only 12 volts, but lots of amp.

Fred P......................

[TacomaCouple]

Checking out the wires. Looks like the big Red one goes to the starter...check!

The Red and Black in the next pic should go to the #2 battery? How? Battery terminals too large for them to fit over.

[TacomaCouple]

Here are the pics of the Red and Black wires I found but I also found a loose Black wire...see pic #2 I would think that big Black wire in Pic #2 goes between the neg's of the two batteries, correct?

[TacomaCouple]

Ok, the Black wire goes to the (I'm guessing Bilge motor) then back up around then turns Red then Orange then hooks to battery #1. I find that odd...

[Randygh]

First thing to do--get a vacuum in the boat and vacuum the rust from on top the intake manifold next to the valve covers. Get all the lose rust, dust and debris off the engine and from the floor of the bilge, and on top the fuel tank.

Now the picts. The first pict that shows the starter. It appears there are 2 red wires (one larger than the other) and a black wire. I assume the large red wire goes to the battery and the smaller red wire goes to the alternator. The large red wire should go to the + post of starter battery (#1).

The large green wire is an "add-on" ground wire attached to the thermostat housing. Judging by the looks of the rust on the bolt head, it may be worthwhile to unscrew the bolt, clean the large "eye" of the wire, and remove any rust from the bolt or the thermostat housing. (When you remove the bolt, antifreeze may leak, so you might want to drain the antifreeze from the heat exchanger). The large green wire can be run to a the neg (-) post on either battery. The large black wire in one of the other photos is the jumper wire between the negative posts of the batteries.

[TacomaCouple]

First thing to do--get a vacuum in the boat and vacuum the rust from on top the intake manifold next to the valve covers. Get all the lose rust, dust and debris off the engine and from the floor of the bilge, and on top the fuel tank.

Now the picts. The first pict that shows the starter. It appears there are 2 red wires (one larger than the other) and a black wire. I assume the large red wire goes to the battery and the smaller red wire goes to the alternator. The large red wire should go to the + post of starter battery (#1).

The large green wire is an "add-on" ground wire attached to the thermostat housing. Judging by the looks of the rust on the bolt head, it may be worthwhile to unscrew the bolt, clean the large "eye" of the wire, and remove any rust from the bolt or the thermostat housing. (When you remove the bolt, antifreeze may leak, so you might want to drain the antifreeze from the heat exchanger). The large green wire can be run to a the neg (-) post on either battery. The large black wire in one of the other photos is the jumper wire between the negative posts of the batteries.

Thanks...I feel like I am WAY beyond my limits.