I did 30 x 26650 for my hummie so it’s not the same, but I laid it out the way you have it, copper braid, and I widened the cavity by like 4-6mm with a router to make it fit. The braid has a bit of flex, but yeah the solder does wick into it, so it’s not good to flex it too much. Holding up great so far though.
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does this approach for the balance wire tabs seem ok for a 10s4p?
Samsung 25r cells
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solder balance wire to 10 x 0.15mm nickel
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spot weld nickel to middle of 25mm nickel
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Yeah that should be fine, but careful welding…if you weld over the can of a cell near the positive terminal the weld may break through the insulation and short the cell out
If you can solder the balance lead to the main series/parallel strip first you’ll be better off in the future
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thanks Zach,
yeh i think next time i’ll solder the balance wires to the 25mm strips, though for some reason i like the idea of the leads connecting on the top of the battery rather than the sides (not sure what that reason was now!)
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Braid is pretty hard to use as a flexible connection that short. Longer connections when you are only soldering from the ends might be ok, but the braid just loves to suck up the solder…
I just did this one and the whole thing is just a solid bar now 
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Didn’t you say not to solder against the cells before? 
Look at the first pic.
There is an aluminium bar behind the tabs that are welded to the batteries. You can see the folded tabs in the second pic.
Pretty much zero heat gets to the cells with this method.
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Was draining a new pack to check capacity and make sure everything stays in balance. I usually go through a couple of cycles on a new pack. Tonight was exciting. While I was right next to load tester(putting inserts in a deck) I hear a pop pop pop and sparks/flames shoot out of the bastard at me. Only for me to find it had this hellish meltdown at 666Wh. Coincidence? Or fate?
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I think that you guys are overreacting about soldering on the cells, yes its not ideal but it seems to me that you are freaking the new guys out about it.
30Q cells get to 80 degree Celsius when you discharge them at 20A, and soldering for a second or two with a proper iron wont even bring the cells close to it, especially if your soldering to a 2nd layer of nickel
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If your really tight in height, maybe get some 14-16awg wire and make 5-6 U shaped connections
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That is a very interesting load tester.
Got any more info?
For a good look of my battery I’d go for some epoxy plates, before I put it in heatshrink.
yeah, I played with it a bit and found that strategic placement of a heat sink (in my case, a lump of tire balancing lead) keeps the solder right where you want it.
in the picture above the one end is fully wetted out and soldered, the other end was fully tinned before cutting (to prevent fraying). the section between the soldered ends was nice and flexible as it came off the roll , right up to the solder joint👍
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You need to get the solder to flow out more, they don’t have a strong bond now. If they aren’t shiny and flow out on the material you are soldering to you need to redo it.
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It’s available on amazon over here. It can only handle about 150W though so it takes forever to drain a pack. It would probably be best utilized on a single cell or P-group.
I just blew up both that I have. Overclocked one of them on accident and then the spontaneous combustion of this second unit.
If you are interested in giving it ago, here’s a link to the tester I’m using:
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https://hobbyking.com/en_us/hobbykingtm-battery-medic-system-2s-6s.html?___store=en_us this does a similar job as well but its a lot slower
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Noted, thanks!
What about getting an inline current meter, a fuse, and a lot of small wire in a bucket of water?
Cut until it’s about 10 ohms and short it out so the power disapates into the water
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How would you guys go about wiring the blance leads for this setup(without crossing). The Black squares represents balance taps (They are on the negative side of the next group)
Orange is bms
I want to order one but im a little unsure why it comes with 2 xt60 connections. Could I connect just one and be fine to my esc?