Wiring 4 x 6v batteries for 12v

[bobbynell]

I think this should actually be pretty obvious, but after searching the forum to work out if different cable lengths will be an issue I've found some other diagrams that have confused me.

 

I have 4 x 6v batteries, which will provide 12v once fitted. This is what I think it should look like:

 

 

Does this look right or am I being a bit too simple? And do the interconnecting cable lengths matter in this instance?

 

Thanks in advance,

Edited July 21, 2010 by bobbynell

[WotEver]

This is what I think it should look like:

You think right

 

And do the interconnecting cable lengths matter in this instance?

Keep 'em as short as reasonable, keep 'em the same length, but no, not really

 

Tony

[Gibbo]

Under perfect conditions your diagram is spot on.

 

But this isn't a perfect world and you might (in fact probably will) get longer overall battery life if you also link across the 6 volt points between the two battery strings.

[GUMPY]

Under perfect conditions your diagram is spot on.

 

But this isn't a perfect world and you might (in fact probably will) get longer overall battery life if you also link across the 6 volt points between the two battery strings.

interesting, care to elaborate?

It could spawn a whole new way of wiring my 6v batteries to give 24v

Edited July 21, 2010 by idleness

[WotEver]

... you might (in fact probably will) get longer overall battery life if you also link across the 6 volt points between the two battery strings.

Oooh, why?

 

Tony

[bobbynell]

Under perfect conditions your diagram is spot on.

 

But this isn't a perfect world and you might (in fact probably will) get longer overall battery life if you also link across the 6 volt points between the two battery strings.

Do you mean like this?

Edited July 21, 2010 by bobbynell

[WotEver]

Do you mean like this?

Yes. But I doubt that BOTH of those straps are necessary - one of them would do, wouldn't it Gibbo?

 

Tony

[Gibbo]

Yes. But I doubt that BOTH of those straps are necessary - one of them would do, wouldn't it Gibbo?

 

I just typed a full explanation for this then canalworld.net crashed and threw it away. I can't be arsed typing it again.

 

Just a single link across the middle between diagonally opposite batteries.

 

The reason for it is it helps to reduce the imbalance between the top and bottom battery in each string by swamping it with the other one.

 

If one battery internal resistance starts to rise first (which is nearly always the case) that one battery then gets higher voltage across it during charge and lower voltage across it during discharge both of which accelerate its impending death.

 

The link helps reduce the voltage imbalance.

[WotEver]

Soooo.... why don't we see the same effect with cells within 12V batteries? Or do we?

 

Tony

[bobbynell]

Just a single link across the middle between diagonally opposite batteries.

Brilliant thank you Gibbo

[Gibbo]

Soooo.... why don't we see the same effect with cells within 12V batteries? Or do we?

 

We do, that was in the orignal reply that canalworld.net rudely threw away.

 

How many times have you come across a duff battery? And how many times was just one cell that was knackered? It's nearly always the case.

 

If you had 2 batteries in parallel, and could link across between the cells from one battery to the next that problem would become less common. Same applies here.

 

 

Spot on.

[WotEver]

If you had 2 batteries in parallel, and could link across between the cells from one battery to the next that problem would become less common. Same applies here.

Bring back the old batteries with the links on top

 

Thanks for the explanation.

 

Tony

[smileypete]

Brilliant thank you Gibbo

 

Think I'd prefer doing it like this:

 

 

The current for each of the batteries on the left goes through one vertical link, then the diagonal link.

 

The current for each of the batteries on the right goes through the diagonal link, then one vertical link.

 

So it's perfectly balanced.

 

cheers,

Pete.

[Gibbo]

Think I'd prefer doing it like this:

 

 

The current for each of the batteries on the left goes through one vertical link, then the diagonal link.

 

The current for each of the batteries on the right goes through the diagonal link, then one vertical link.

 

So it's perfectly balanced.

 

cheers,

Pete.

 

That's worse. I suggest you delete it!

 

In your diagram, under normal circumstances (ie no imbalance problems with the batteries) the current for each battery goes through 1 extra completely unecessary link.

 

Another way of wording it: In the one Bobby drew all battery currents go through two links. In yours, all battery currents go through three links.

 

The differences are subtle, but Bobby's is better

[smileypete]

That's worse. I suggest you delete it!

 

In your diagram, under normal circumstances (ie no imbalance problems with the batteries) the current for each battery goes through 1 extra completely unecessary link.

 

Another way of wording it: In the one Bobby drew all battery currents go through two links. In yours, all battery currents go through three links.

 

The differences are subtle, but Bobby's is better

 

 

It's NOT the total number of links that the problem.

 

Explain how Bobby's is balanced and mine is not.

 

The differences are subtle, but mine IS better, I'm afraid.

 

cheers,

Pete.

[Gibbo]

 

It's NOT the total number of links that the problem.

 

Explain how Bobby's is balanced and mine is not.

 

The differences are subtle, but mine IS better, I'm afraid.

 

cheers,

Pete.

 

I didn't say yours wasn't balanced.

 

Bobby's is also perfectly balanced.

 

Bobby's has fewer links than yours and, as they are both perfectly balanced, Bobby's is better, I'm afraid.

[WotEver]

Let's see Bobby's nice and big:

Ahh, that's better.

 

Tony

[smileypete]

I didn't say yours wasn't balanced.

 

Bobby's is also perfectly balanced.

 

Bobby's has fewer links than yours and, as they are both perfectly balanced, Bobby's is better, I'm afraid.

Explain how it's perfectly balanced, bet you can't/wont .

 

Personally I don't think it is, the bottom left/top right batts will see a lower resistance to the common points than the other two batss, because of the diagonal link.

 

Anyway I CBA really, if people do it either way it's fine by me

 

cheers,

Pete.

[Gibbo]

Let's see Bobby's nice and big:

Ahh, that's better.

 

Tony

 

The central diagonal link needs to be the other way.

 

Pete, it really is perfectly balanced.

[GUMPY]

The central diagonal link needs to be the other way.

 

Pete, it really is perfectly balanced.

 

Here's a thought

what about connecting as normal plus to minus and then linking both minuses and both pluses as well as two diagonals

 

Would make excellent spaghetti

[bobbynell]

Here's a thought

what about connecting as normal plus to minus and then linking both minuses and both pluses as well as two diagonals

 

Would make excellent spaghetti

looks like fun:

 

 

But does it justify the cable costs?!!

[WotEver]

Cat's Cradle!

 

Tony

[smileypete]

Let's see Bobby's nice and big:

Ahh, that's better.

The central diagonal link needs to be the other way.

So, it's not balanced as it is.

 

Pete, it really is perfectly balanced.

That's not an explanation either.

 

cheers,

Pete.

Edited July 23, 2010 by smileypete

[bobbynell]

On the question of whether it is balanced or not, will it be possible to accurately test it when I'm connecting them?

 

If so, I can test all of these configurations - within reason - and stick to the one that proves best?

 

I can also post back here with any conclusions...

Edited July 23, 2010 by bobbynell

[Gibbo]

So, it's not balanced as it is.

 

No. I assumed the link was the other way without actually looking at it. I didn't have a microscope handy when the picture was posted.

 

With the link the other way it is balanced.