Series, then Parallel or Parallel then Series?

BB_TX wrote:

wnjj wrote:

KD4UPL wrote:
It doesn't matter. Either way will work. The first way uses 1 less cable.

x2

Also, the 2nd diagram isn't drawn correctly. The trailer wires come from the smaller jumpers in between each pair of batteries. In that drawing they are connected to each other.

Correct. As shown the trailer wires are essentially connected together. Trailer negative should come from the right side batteries negative posts and trailer positive should come from the left side batteries positive posts.

This is the pic I was looking at that I started this thread about. And you're right about the conductors coming off the posts that don't series the banks together. It takes a bit to figure out which is positive and negative in the pic.

KD4UPL wrote:

Dusty R wrote:
I always looked at it this way.
Two 6v batteries is series may give a you more power but if one battery dies while you are out in the boonies, you are out of power.
But if you are using 2-12v batteries in parallel and one dies, you can keep going, you just need to run your generator more often.

Dusty

I'm not trying to pick a fight, I'm genuinely curious about this view I've heard from others.
The way I see it, if you have 2 12v in parallel and one dies (which I guess you mean develops a shorted cell) the bad battery will be 2v lower than the good battery. This will cause the good battery to try and charge the bad battery which will kill it in the process.
I've often wondered if people operating with this theory periodically disconnect their parallel sets of batteries to test them individually to make sure one isn't shorted. The thing is, I don't know how long it would take for the shorted battery to take out the good one but I'm thinking not very long at all, maybe a matter of a few hours?

I think the difference is you can recharge the remaining 12V battery and be up and running even if one shorts out which you cannot do with a pair of 6V. That’s what Dusty was suggesting by running the generator more often.

KD4UPL wrote:

Dusty R wrote:
I always looked at it this way.
Two 6v batteries is series may give a you more power but if one battery dies while you are out in the boonies, you are out of power.
But if you are using 2-12v batteries in parallel and one dies, you can keep going, you just need to run your generator more often.

Dusty

I'm not trying to pick a fight, I'm genuinely curious about this view I've heard from others.
The way I see it, if you have 2 12v in parallel and one dies (which I guess you mean develops a shorted cell) the bad battery will be 2v lower than the good battery. This will cause the good battery to try and charge the bad battery which will kill it in the process.
I've often wondered if people operating with this theory periodically disconnect their parallel sets of batteries to test them individually to make sure one isn't shorted. The thing is, I don't know how long it would take for the shorted battery to take out the good one but I'm thinking not very long at all, maybe a matter of a few hours?

Well, there is the constant disagreement about 2-12v.......4-12v.......2-6v..........4-6v. I'm after larges amp/hr storage with smallest foot print. If one fails.....one fails. I may think that's an easy thing to say now, but that would cost about 4 batteries worth if one did fail, since good practice to replace them all at once. I'm going to do my best to carefully maintain and not discharge them below 12.4 volts and equalize them once a month. I think all the guys with the 12v batteries should run 12v batteries. All the guys with 6v batteries should run 6v batteries. I've had 6's for 4 years now and no problems.....yet!

BB_TX wrote:

wnjj wrote:

KD4UPL wrote:
It doesn't matter. Either way will work. The first way uses 1 less cable.

x2

Also, the 2nd diagram isn't drawn correctly. The trailer wires come from the smaller jumpers in between each pair of batteries. In that drawing they are connected to each other.

Correct. As shown the trailer wires are essentially connected together. Trailer negative should come from the right side batteries negative posts and trailer positive should come from the left side batteries positive posts.

So, if the second diagram were used, you'd bring the positive and the negative off the posts that are paralleling the two banks? Sounds right now that I look at the drawing. I sketched it out kind of quick at lunch hour today. But really only going after the Paralleling the banks prior putting them in series or putting them in series then paralleling the banks.

Dusty R wrote:
I always looked at it this way.
Two 6v batteries is series may give a you more power but if one battery dies while you are out in the boonies, you are out of power.
But if you are using 2-12v batteries in parallel and one dies, you can keep going, you just need to run your generator more often.

Dusty

I'm not trying to pick a fight, I'm genuinely curious about this view I've heard from others.
The way I see it, if you have 2 12v in parallel and one dies (which I guess you mean develops a shorted cell) the bad battery will be 2v lower than the good battery. This will cause the good battery to try and charge the bad battery which will kill it in the process.
I've often wondered if people operating with this theory periodically disconnect their parallel sets of batteries to test them individually to make sure one isn't shorted. The thing is, I don't know how long it would take for the shorted battery to take out the good one but I'm thinking not very long at all, maybe a matter of a few hours?

Dusty R wrote:
I always looked at it this way.
Two 6v batteries is series may give a you more power but if one battery dies while you are out in the boonies, you are out of power.
But if you are using 2-12v batteries in parallel and one dies, you can keep going, you just need to run your generator more often.

Dusty

I will never run my generator unless there is an emergency. Like three feet of snow overnight. Or I wake up from 30 degree night to 130 degree morning @ 0900hrs. See, no generator.

My favorite:



https://www.usbattery.com/info-center/configuration/configuration-2/

Dusty R wrote:
I always looked at it this way.
Two 6v batteries is series may give a you more power but if one battery dies while you are out in the boonies, you are out of power.
But if you are using 2-12v batteries in parallel and one dies, you can keep going, you just need to run your generator more often.

Dusty

Dusty has a point, but what he has not seen is that if one of the 12 jars develops an internal short (a very common failure) the (was) good jar will pour power into it until one or both explode. Even single multi-cell jars can explode, but it is much rarer than it is for hard parallel sets.

Matt

wnjj wrote:

KD4UPL wrote:
It doesn't matter. Either way will work. The first way uses 1 less cable.

x2

Also, the 2nd diagram isn't drawn correctly. The trailer wires come from the smaller jumpers in between each pair of batteries. In that drawing they are connected to each other.

Correct. As shown the trailer wires are essentially connected together. Trailer negative should come from the right side batteries negative posts and trailer positive should come from the left side batteries positive posts.

wnjj wrote:
Also, the 2nd diagram isn't drawn correctly. The trailer wires come from the smaller jumpers in between each pair of batteries. In that drawing they are connected to each other.

I don't follow. I see that now... thanks.