Balancing LiPo Cell Wired in Parallel

[agran1021]

I've read a lot about the importance of balancing LiPo cells while charging. Makes good sense to me. But when I look at chargers or balancers, they all seem to make a point that they balance cells wired in series. How is a cell that's in parallel (i.e., 4s1p) get balanced?

[henryd123]

the charge plug on a 4s lipo will have 5 wires,one is minus and the other four are the individual cells,the charger monitors each cell and makes sure they all charge evenly. I hope I have explained that correctly,someone will correct if I have'nt !

henry

[grnbrg]

Handy lipo wiring calculator (http://scriptasylum.com/rc_speed/_lipo.html).

It looks like packs with parallel cells (ie: 3S2P - 4S1P has no parallel cells, as indicated by the "1P" part) do not individually balance them. Each set of parallel cells within the pack are balanced as a group.

IANAEE*, but this may mean it is not a good idea to balance charge each group at a higher C rating than each individual cell, as if there is a large difference in charge levels, one cell may be charged faster than is good for it.


grnbrg.

* I Am Not An Electrical Engineer. (But I play one on the internet!)

[osterizer]

The neat thing about charging cells in parallel is that they will level themselves. I haven't seen a lot of prepackaged parallel packs, though-- as grnbrg said, the "1p" part of that is pretty much superfluous, as one cell in parallel with itself is, uh, one cell :).

[agran1021]

Okay; thanks to all. I guess I get it.

It seems to me, one cell wired in parallel to another cell (that's what 4s1p means, doesn't it?), is not, um, one cell. My main concern is that battery balancer instructions seem to make clear that the balancer is balancing the cells wired in series. The instructions I've read are silent on the issue of cells wired in parallel. I could assume that the instructions are silent because cells wired in parallel will be balanced along with the cells wired in series. But since "assumptions are the mothers of all **** ups" I'm trying to make sure I understand what is going on during the charging process.

[osterizer]

Wiring cells in parallel means that you have two or more with their negative poles connected together, and their positive poles connected together. The advantage of this is that you can use multiple cells with a given capacity to deliver more current than a single one could on its own. If you have only one cell, calling it "1 cell in parallel" (what the 1p part says) is meaningless. It contributes zero value, and means exactly the same as "4S," that you have four cells in series, period.

[agran1021]

With egg on my face, I ask that you disregard everything my previous post. I just looked at the link provided earlier in the thread. It explains it clearly.

Again, thanks to all.

-- Art