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Can I use a 8s active balancer for double effect in 4s use?

Seafinn

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Aug 3, 2021
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Basically the question is can I use a 8s balancer and use two leads per cell and use it in a 4s build for double effect?
Backdrop is I was planing 24v but changed my mind and went with 12v in the end.
I already used it on the 4s but only used 4 leads and left 4 unused, but can’t finish the build like that.
 

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I would consider two 4S balancers on one battery before an 8S. If you just want one, than a 4S.

If you had two 8Ss, I’d consider buying them. I have two batteries I’m putting together, 8S Each. If you put in for sale or trade you may get a bite.
 
I’m not to bothered about selling it, shipping from me would probably be same price as buying a new unit.

The reason I’m asking is that I have this balancer in hand and I’m eager to finish the build, I understand I could order a 4s but I’d have to wait for it to arrive.
 
Basically the question is can I use a 8s balancer and use two leads per cell and use it in a 4s build for double effect?
Backdrop is I was planing 24v but changed my mind and went with 12v in the end.
I already used it on the 4s but only used 4 leads and left 4 unused, but can’t finish the build like that.
An emphatic NO.

The balancer will be looking for a consistent voltage between each pair of consecutive balance leads, and will try and correct it if they are not equal. There is simply no way to wire up 8 leads to 4 cells and not have the balancer either burn out or be in a constant mode of trying to move energy around.
 
An emphatic NO.

The balancer will be looking for a consistent voltage between each pair of consecutive balance leads, and will try and correct it if they are not equal. There is simply no way to wire up 8 leads to 4 cells and not have the balancer either burn out or be in a constant mode of trying to move energy around.
Is it only moving from highest to lowest or is it balancing in the mid range also?
I understand if it needs one cell to be the high and another to be the low, it would t work in a 4s.
But I figured it just moved energy from any cell beeing higher than another cell. And if I connected two leads to one cell it would just think “those two cells” and treat them as that.

I’m still not convinced it wouldn’t work.
 
Is it only moving from highest to lowest or is it balancing in the mid range also?
I understand if it needs one cell to be the high and another to be the low, it would t work in a 4s.
But I figured it just moved energy from any cell beeing higher than another cell. And if I connected two leads to one cell it would just think “those two cells” and treat them as that.

I’m still not convinced it wouldn’t work.
I promise you it will NOT work.

Let's try one way to do it. Let's say you put the BC0 lead on the most negative terminal, and BC1-BC4 on the positive terminals of your four cells. Now you still have 4 balance leads. Where do you put the next one (BC5)? I suppose you could put it back on cell 1. Then you would put BC6 on cell 2, BC7 on cell 3, and BC8 on cell 4. If all of your cells were balanced at say 3.25V, balancer would be trying to see 8 cells. It would see 3.25V for the first 4 cells. For the fifth cell it would be measuring relative to cell 4, but what it would see 9.75V (3 x 3.25V) LOWER than cell 4. So the balancer would see these cell voltages:
1: 3.25V
2: 3.25V
3: 3.25V
4: 3.25V
5: -9.75V
6: 3.25V
7: 3.25V
8: 3.25V

My guess is that the balancer would simply burn out, but in the best case it would be trying its hardest to move energy to cell 5 from everywhere else.

Go ahead and try to find some other way to wire 4 cells and make it look like 8 to the balancer. It can't be done.

You are certainly welcome to try it to prove it to yourself, but I hope you don't try and sell it afterwards.
 
I promise you it will NOT work.

Let's try one way to do it. Let's say you put the BC0 lead on the most negative terminal, and BC1-BC4 on the positive terminals of your four cells. Now you still have 4 balance leads. Where do you put the next one (BC5)? I suppose you could put it back on cell 1. Then you would put BC6 on cell 2, BC7 on cell 3, and BC8 on cell 4. If all of your cells were balanced at say 3.25V, balancer would be trying to see 8 cells. It would see 3.25V for the first 4 cells. For the fifth cell it would be measuring relative to cell 4, but what it would see 9.75V (3 x 3.25V) LOWER than cell 4. So the balancer would see these cell voltages:
1: 3.25V
2: 3.25V
3: 3.25V
4: 3.25V
5: -9.75V
6: 3.25V
7: 3.25V
8: 3.25V

My guess is that the balancer would simply burn out, but in the best case it would be trying its hardest to move energy to cell 5 from everywhere else.

Go ahead and try to find some other way to wire 4 cells and make it look like 8 to the balancer. It can't be done.

You are certainly welcome to try it to prove it to yourself, but I hope you don't try and sell it afterwards.
You are right. I didn’t thing about the way it measures the cells. It would have been obvious when measuring the leads before connecting the balancer. Glad I didn’t have to go thru that thou.

Thanks
 
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