Sony US26650VT Li-ion Cells - Need More info

[lutach]

This one was meant for the A123: http://www.aircraft-world.com/shopexd.asp?id=5085.

[MetalMan]

Originally Posted by lutach

This one was meant for the A123: http://www.aircraft-world.com/shopexd.asp?id=5085.

That's good to know! However, at least for my A123 packs, those wouldn't work because many of the copper braid joints are folded in half.

Originally Posted by MetalMan

That's good to know! However, at least for my A123 packs, those wouldn't work because many of the copper braid joints are folded in half.

glad you mentioned that because, this is on ebay.
http://cgi.ebay.com/R-C-Battery-Brai...QQcmdZViewItem
so your saying that would work well for assembling packs end to end? Plus it says they are rated 36 amps. Confused a little on how that works. Obviously say a 4 or 6s pack is gonna supply way more than 36amps. but does each cell only put out 1/6 that, If that question makes sense.
What does your average copper bat bar carry amp wise?
Plus on another ? and now we are realy jacking this thread but rather just add to this than start awhole new thread. How would you assemble a 3s2p pack in this https://www.tanicpacks.com/popup_ima...02b9bb555f1d67
configuration. I would do that rather than 2 6s1p config. because my 977 will only charge up to 3s. Plus i can run a 3s2p pack in my other cars and my boat. I know about scriptasylum's site but im confused how to wire them in the 2x2x2 config.

[MetalMan]

That copper braid is similar to what I'm using, except I use two strips to connect the cells together (with a gap in between them to allow the vent to remain unobstructed).
My guess would be that it is rated at 36amps continuous, but it could probably handle much more in peaks. In our vehicles the average current draw is typically around 20amps.

That configuration you linked to is not one I am totally familiar with. A while back I made 3s2p A123 packs into that format, where they were actually 3 x 2p in series. It was pretty complicated to do. This is a picture I drew up that demonstrates the internal connections:
http://img.photobucket.com/albums/v1...pA123short.jpg

I've built many A123 packs into various configurations, so I have enough experience working with them to know what needs to be done. It might not be obvious to you (at least right away) how the construction of that pack would be completed, and it's difficult for me to explain in words.

I know i know its terribly difficult to explain. The picture i linked to is a 6s1p which is easy to wire. Your drawing is good enough, and makes more sense. I drew it up too, pretty much the same way exept. I basicaly would have two sets of 3s were you would have the the 2 negative ends meet and become the negative battery lead. and the two possitive ends meet and become the possitive batt lead. But looking at yours. Im thinking my way would only have two cells wired in parallel instead of 3. If that makes sense. I looked at the wiring diagram on script's site and i imideatly new i was thinking the wrong way. But to wire a 3s2p pack in that 2x2x2 like pictured,is a wiring nightmare, even without the balance leads. your still using a ton of wire and soldering joints. Im thinking maybe it would be better just to make two 6s1p packs and buy a 989 charger or something else that will charge 6s. hmmmm
and regards to your use of braid you wouldnt have a picture would you? because im a little confused. Arent the vents off the center of the cell. So if you used 2 peices next to each other but with a gap inbetween wouldnt they be blocking the vents. Or am i totaly wrong and just dont know were the vent is on the cell. and are these sony cells simillarly constructed?

[MetalMan]

There is a reason why I build my 2p packs that way - I find that having 2p x s (where s is the number of cells in series) is better because there is less balancing required, and it provides an average voltage output for two cells instead of just one, which can help alleviate the effects of single weak cells. To balance 3s x 2 in parallel, there are 6 total cells which need to be balanced individually to be properly balanced, which is a wiring nightmare when it comes to balancing. Granted, A123 cells don't really need balancing, but it doesn't hurt to have the option.

I never did get any pictures of the process I use to build my A123 packs. But I can tell you that it does require a lot of time with a soldering iron (and a good one at that - the outer cans on A123 cells are aluminum and can absorb a lot of heat).

The vents on A123 cells are at the very center, I think on the positive side. But I never really was sure if it was on the positive or negative side because both have circular ports, so I just soldered everything the same way. Here's a picture of how I would make 2s2p:

That's copper braid strips, laid across 4 cells, where the cells on the left side of the dashed line are positive (or negative) and the cells on the right are both negative (or positive, as long as they are opposite of the left). Then I fold the copper braid at the dashed line to make a double-shotgun pack. The image on the right is a view of either end of the pack, where the cells are soldered together as shown.

Good point on the pro's of running parallel. One quick question. On your diagram, the 4 bottom cells. were the 4 ends meet in the middle are all 4 ends soldered together or just the +'s to the -'s Does that ? make sense :P

[MetalMan]

I'm not quite sure I understand. But I edited the picture, hopefully it makes more sense.

Alright, were the 4 bottom cells come together in the middle. the purple line that is connecting the cells, looks like its connecting all 4 ends together. In other words both cells would have there negative ends soldered together as well as the other cells possitive ends. Except wouldnt that short the cells? Make sense? I know im terrible at explaining things. :P

[MetalMan]

Ah, you're referring to the first picture I posted a link to. You are correct, all four bottom cells are connected together in the middle there.

No short-circuits . There would be a short if the positive ends of the bottom-left two cells were connected to the bottom-right two cells. Just remember that the two bottom-left cells are in parallel, as are the two bottom-right cells. So, 2p and 2p, and the top two cells are also in parallel, so add another 2p. All three of the 2p in series gives 3s2p . If you need further clarification, just say so .

Duhhh okay thanks alot, i totaly got it. Its just like a 3s2p config. flat but with the back 2 cells on top. Totaly makes sense. Im def. gonna have to order some because these are gonna be perfect. esp. when i wire up some 2s2p packs to run in my brushless supervee. Now i just need to figure out a way to make them water proof.
Would the plastic caps that come on the 6cells stick packs fit on the end of these or is the diameter that much bigger than nimh? If they worked some good shrink film. those end caps and some shoogoo would prob work perfect.
Metal man thanks again.
and sorry for officialy jacking the thread everybody ;)

[MetalMan]

NiMh sub-c end caps unfortunately won't fit (24mm OD sub-c, 26mm OD A123).
My packs are all built with strapping tape holding the cells together and 2 layers of shrink wrap on the outside.

anyone know were to get these? i cant seem to find any. I even emailed the guy that sells them on ebay, over a week ago and no response. I know there old cells but jeez.

[suicideneil]

Didnt someone say in another thread they could get them in europe? I've search before but only turned up the ebay ones- try googling the part #.

Originally Posted by suicideneil

Didnt someone say in another thread they could get them in europe? I've search before but only turned up the ebay ones- try googling the part #.

I do that on a daily basis. the onlt thing that pops up is it looks like the a123 cells that were dewalt packs were relaced with theses sony cells. I even emailed a company that said they had them and they responded they didnt have them any more.