12v batteries hooked up wrong??

[gemert]

First this is not something you want to screw up! You can do a lot of damage to electrical items in your coach depending on the system. The theory is simple. All cables should be as close to the same length and as short as possible. In parallel your neg terminals should be connected together and the positive should be connected together. That keeps the voltage at your load the same and increases the usable current. In a series configuration, your cables go from negative on one battery to positive of the other. The load will have a positive from one battery and a neg from the other. But don't listen to me either. Read up on it, make sure you understand the theory and then lay it all out so you don't make any mistakes. There was at least one post above that made me go "HUH!" I have 20 years of experience working with electronics in the Navy and I break out the theory all the time just to be sure.Good luck.

[2ndramtd]

The PDF shows the correct hook up. This ensures that both batteries share all of the loading and charging. Because of a battery's internal resistance the other way cause one battery to fail earlier than the other. That's one of the reasons for replacing them as pairs. Internal resistance is why your cell phone is warm when it has just finished charging.

Also the word "starting" on the top would lead me to hope that is just marketing hype.

Dar
37 years marine electrician for the D.O.N.

[garbonz]

Originally Posted by xrated

Do you seriously believe that mis-information? It's totally wrong, so you may want to rethink what you just said.



Electricity only flows when there is a voltage difference between two or more points in a circuit. Obviously in a battery system like we are talking about here, there is a 12V pos and a 12V negative terminal. Apply a load of some sort between the those two terminals and current will flow.



Now, just for the sake of this discussion, what do you think would happen if you applied the load (let's say a simple 12 volt light bulb) between the two positive terminals of the two batteries.........or if you applied the load between the two negative terminals of the battery? I'm hoping you will say....nothing, no current will flow, the light bulb will not light up, there is no current flow if the bulb's two wires are hooked up to the two positive terminals of the battery.



Let's take it one step further.....what do you think the voltage difference or voltage potential is between the two positive terminals or any point along the jumper that connects the two positive terminals.....I'm hoping that you will say ZERO volts....remember, current can ONLY flow when there is a potential DIFFERENCE.....and there is no potential difference between the two positive terminals since the are both hooked up to the same positive terminals

Geeeez, I was kidding, why don't you lighten up a bit. I SAID LONELY!

For a two battery system it probable doesn't matter, but the mfg clearly indicate that in large parallel and series battery banks the leads should be at opposite sides of the banks and the inter battery jumpers should be identical lengths.

What you say about voltage and resistance differences do to the wires is true, so I think it must be psychological.

[xrated]

Originally Posted by garbonz

Geeeez, I was kidding, why don't you lighten up a bit. I SAID LONELY!

For a two battery system it probable doesn't matter, but the mfg clearly indicate that in large parallel and series battery banks the leads should be at opposite sides of the banks and the inter battery jumpers should be identical lengths.

What you say about voltage and resistance differences do to the wires is true, so I think it must be psychological.

I'll tell ya what, I'll lighten up if YOU learn to use a smiley when you're kidding.....Deal?