battery question

[ripnlip]

Can any of you please have a look at this diagram. Am I making bacon here, or spinning my wheels? the shop wired it like this. just doesn't make sense to me. it's a crude drawing, but I was in a hurry. wired like this, would i be the same as a single battery?

thanks guys.
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[albinotrout]

Attaching a - to a + I would think you would have a short in the system.
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[BearLakeFishGuy]

No, not the same as a single battery. This is "series" wiring, which means double the voltage but same capacity. Two 12V batteries wired like this makes 24V output. However, you should use the negative off the battery in your picture without anything attached to it. Not the way it is shown.

If you're after a "parallel" connection (same voltage..i.e. 12 volts, but double the capacity....i.e. how long it will take to run them to discharge), then you would need to hook positive to positive and the neg to neg.

In any case if its wired exactly like you have shown its not correct.
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[BearLakeFishGuy]

Here is some help for you.


Connecting in Series
When connecting your batteries in Series you are doubling the voltage while maintaining the same capacity rating (amp hours). This might be used in a scooter, Power Wheels kids vehicle, or other applications. Just use a jumper wire between the negative of the first battery and the positive of the second battery. Run your negative wire off of the open connector from the first battery and your positive off of the open connector on your second battery.

Connecting in Parallel
When connecting in Parallel you are doubling the capacity (amp hours) of the battery while maintaining the voltage of one of the individual batteries. This would be used in applications such as laptop batteries, some scooters, some ups backups, etc. Use a jumper wire between the positives of both batteries and another jumper wire between the negatives of both batteries. Connect your positive and negative wires to the same battery to run to your application.

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[Kent]

I would be careful trying to charge two batteries simultaneously. I have a hunch that the extra demand would burn up many chargers that don't have the needed capacity to handle two batteries.
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[mojorizing]

[quote ripnlip]Can any of you please have a look at this diagram. Am I making bacon here, or spinning my wheels? the shop wired it like this. just doesn't make sense to me. it's a crude drawing, but I was in a hurry. wired like this, would i be the same as a single battery?

thanks guys.[/quote]
That diagram is what is called series hookup- Almost. If you would put your negative of your trolling motor to the right side battery negative you'd have 24v, assuming they're both 12v batteries. The way your diagram is you're only running off one battery. The left one, since the negative terminal isn't hooked up to anything.

If you have a 12v trolling motor using two batteries, run the positive+of battery 1 to the positive+ of battery 2. The red/positive+ of your trolling motor will go to that + post.
Run another jumper/cable from the negative - of battery 1 to the negative of battery 2 and attach your black/negative - of your trolling motor to it. Doesn't matter which battery you use. That's called a parallel circuit.
If you put your trolling motor red clamp on battery #1 and put a cable from the negative of battery #1 to the positive of battery #2 and put your black/negative clamp
on the negative terminal of battery #2 you will double your voltage- 24v. That's a series circuit.

Using the flashlight analogy.
Flashlight use a series circuit. Your flashlight bulb tit it the positive+ and the bodyof the bulb is the negative or -. You drop a 1.5v D cell in it and drop another battery right behind it you'll be at 3v. One more battery will be 4.5v. So on and so on. Battery nipple is +. So you're putting a positive of the second battery to the negative of the first one, doubling your first voltage.

Clear as mud now?

Putting + to + and - to - will stay the same voltage but up the amperage.

Bearlakefishguy has a good diagram. Not as fast as he was.........
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[albinotrout]

I have a friend that had the battery system setup like this and he was able to charge both batteries at once. He had an 18' Bass Tracker.
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[WET1]

Walt, you need to be + to + and - to - on those batteries to have 12 vdc. If you go + to - you will get 24vdc. The other thing you can do to verify is to take a multi meter and go from gnd to the hot wire going to your trolling motor and see what you have. Get with me tomorrow at work and let's scratch it out.
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[fairwayphilly]

everybody is right UNLESS they installed 6 volt batteries. 6 volt batteries are used to increase run time. You can tell by counting the number of cells on the batteries. Pull the caps, each opening is a cell and each cell is 2 volts. 3 cells = 6V; 6 cells = 12V.
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[Kent]

[quote albinotrout]

I have a friend that had the battery system setup like this and he was able to charge both batteries at once.

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Come to think of it (wish that I would have thought of it earlier) Lee, from Lee's Marine, recommended that while running my outboard, that I leave my Perko switch set to both batteries -- so that my outboard would charge both of them simultaneously.
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[addicted2fishin]

A lot of good replies here. That set up won't work at all if nothing is hooked up to the other neg. on the battery.

The question I haven't seen posted here is what you are powering with the pair of batteries. If it is a 24v trolling motor, then you want it set up to put out 24v from the pair. If it is a 12v motor then you DON'T want to be putting out 24v to the motor. Use the diagrams already posted here. It isn't too tough.
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[walleyebob]

If it is wired that way, the extra battery is doing nothing. And if you hook up the ground, you end up with 24 volts. You want it hooked up in a parallel circuit, which means you hook + to + and - to - .Any time you hook up + to - and have the first battery grounded and the second battery + to positive, you will have 24 volts and blow everything up.
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