How to wire a blance plug for a custom 2S3P pack?

[Farrell]

I'm trying to make a pack out of three 2S LiPo's, and want to wire them in parallel for increased capacity. The part that I'm stumped with is how to wire the balancing plug. How do you, or is it possible, to wire a balancing plug for parallel packs?

-Farrell

[waterbug57]

i'm not an expert but on the discharge side would be all positive connected on one side and all negitives on the other. as for the charge side you would need to charge this as a 6 cell tap not sure how it is wired. i saw a 2s2p pack and it had a 4s tap

[HeliDan]

I don't think it is possible, as there is no way for the electronics to know one battery from another.

I attached some pictures, but I can't seem to figure out how to make them show, it just comes up as a named attachment.

[spork]

Just wire the balance tap as if you had a 2S pack. Basically, you have 3 of these 2S packs in parallel, so they will inherently stay balanced with one another. You only need to balance the cells that are in series. Make sense?

EDIT: I take it back. It's a tad more complicated, but I'll post a drawing in a minute

OK - here we go.
http://www.helifreak.com/attachment.php?attachmentid=35591&stc=1&d=1200283393

[HeliDan]

Just wire the balance tap as if you had a 2S pack. Basically, you have 3 of these 2S packs in parallel, so they will inherently stay balanced with one another. You only need to balance the cells that are in series. Make sense?

EDIT: I take it back. It's a tad more complicated, but I'll post a drawing in a minute

I guess I misunderstand, I thought he wanted to take apart the packs, and wire them in parallel......

Sorry. My mistake.....

Don't permanently attach the separate packs together. Just leave them as is and plug them in, in parallel.

[HeliDan]

Just wire the balance tap as if you had a 2S pack. Basically, you have 3 of these 2S packs in parallel, so they will inherently stay balanced with one another. You only need to balance the cells that are in series. Make sense?

EDIT: I take it back. It's a tad more complicated, but I'll post a drawing in a minute

If you have the packs permanently in parallel with each other, the current through that balancer will be much higher. How much current can the balancer handle??:confused:

[spork]

If you have the packs permanently in parallel with each other, the current through that balancer will be much higher. How much current can the balancer handle??:confused:

Good question. I don't think the current will be any higher, since the voltage differential shouldn't be any higher. I think it will just take a 3 times longer to balance (for a given imbalance).

[HeliDan]

Good question. I don't think the current will be any higher, since the voltage differential shouldn't be any higher. I think it will just take a 3 times longer to balance (for a given imbalance).

Hmmmmmmm. Thinking about it, if the multiple packs in parallel, have their balance wires in parallel, then they would all self-balance to each other. That does not mean that the 'PACK' is balanced. So cell A in all packs, will all balance with respect to each other. The balancer will balance as usual.......

Does that make sense?

[spork]

Does that make sense?

The three cells on the left in my diagram will self balance with one another. Same with the three on the right. The balancer will balance the left set to the right set.

[HeliDan]

Good question. I don't think the current will be any higher, since the voltage differential shouldn't be any higher. I think it will just take a 3 times longer to balance (for a given imbalance).

Well, since the current is the same, why would it take three times longer to balance? Voltage is voltage and current is current...... Right?

[spork]

Well, since the current is the same, why would it take three times longer to balance? Voltage is voltage and current is current...... Right?

Effectively you now have a battery that's three times as big. Think of the batteries on the left like a big cup of water. The batteries on the right are another big cup of water. The balancer is a hose running between them. If the difference in water height is 1" the balancer has a job to do. But it will take three times as long to level out the 3-cell "cup" as it would if it were a single cell.

[HeliDan]

Effectively you now have a battery that's three times as big. Think of the batteries on the left like a big cup of water. The batteries on the right are another big cup of water. The balancer is a hose running between them. If the difference in water height is 1" the balancer has a job to do. But it will take three times as long to level out the 3-cell "cup" as it would if it were a single cell.

So more current is necessary, but the balancer limits the current.

[spork]

So more current is necessary, but the balancer highly limits the current.

You could balance them in the same time with 3 times the current, or 3 times as slow at the "normal" current.

But for a given voltage imbalance you'd only push the "normal" current. That being said, I suspect balancers always run a fixed current during balancing (when the little LED's are actually on).

[HeliDan]

You could balance them in the same time with 3 times the current, or 3 times as slow at the "normal" current.

But for a given voltage imbalance you'd only push the "normal" current. That being said, I suspect balancers always run a fixed current during balancing (when the little LED's are actually on).

Soooooooo. Like in said in my last post (ya know, before this one) :YeaBaby:

[spork]

Soooooooo. Like in said in my last post (ya know, before this one) :YeaBaby:

Yup. I misunderstood what you meant.

[HeliDan]

Yup. I misunderstood what you meant.

:OK