Sony US26650VT Li-ion Cells - Need More info

Yea im waiting for my mmm too. Have you had to balance them yet? or are you just running them to lvc, and recharging?
Ohaa thats right i wanted to ask, have you run them on an inrunner yet? or just that outrunner you had on your maxx? Im curious what temps you see on hi amp draws. Im thinking if they hold up to amp draw well. you could run a 6s1p config. Low kv motor, and still have decent run times, while keeping the weight down. Or you could just go all out run 6s2p and run all day

[sikeston34m]

Originally Posted by dubkatz

Yea im waiting for my mmm too. Have you had to balance them yet? or are you just running them to lvc, and recharging?
Ohaa thats right i wanted to ask, have you run them on an inrunner yet? or just that outrunner you had on your maxx? Im curious what temps you see on hi amp draws. Im thinking if they hold up to amp draw well. you could run a 6s1p config. Low kv motor, and still have decent run times, while keeping the weight down. Or you could just go all out run 6s2p and run all day

They are holding their balance well so far, so I've just been discharging and charging.

I haven't ran them on an inrunner setup yet. LOL I'm sure they would do well though. They don't even get warm with my outrunner E maxx.

I may try a 6S1P setup when I get my MMM just to see how well they do.

Also, i have been having a hell of a time finding copper bendable batt bars/strips. I have seen bulk copper all day long in diff. thicknesses. But i have no idea if all copper conducts the same. and how thick. I also saw on ebay battery braid. which im not sure if it would work that well. I think its prob too thick.
thanks

[JERRY2KONE]

Try Tower Hobbies. Duratrax battery bars. I just ordered some last week and they are in stock.

Originally Posted by JERRY2KONE

Try Tower Hobbies. Duratrax battery bars. I just ordered some last week and they are in stock.

ahh those look perfect, but there discontinued

[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.

[MetalMan]

I use copper braid intended for use as solder wick as battery braid on my A123 packs, and the stuff works perfectly. It's maybe 1/4" wide and 1mm thick, so I use two strips of it to connect A123 cells together. I have three packs constructed using this stuff.

[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 .