Heat sink is a great way. Aside from that, quality iron and skill. Also 63/37 solder instead of 60/40
I’ve gotta say, I’m actually incredibly happy with the modularity of this 5.5mm bullet setup Dr. Mike came up with for me. Makes tapping in for power routing later on easy as shit.
1 Like
TL;DR: High heat, Low time, two parts.
a 480C iron and flux core solder. Just tap is at intervals to tin the very edge of the copper. don’t hold it on there. Tap it, tiny spots at a time. Then make a puddle on the nickel per usual, then hold the braid down with a flathead screwdriver and smoosh the iron on the braid quickly. Don’t give it time to wick.
2 Likes
I’m always fighting to balance enough heat for a good joint, vs wicking, and 99% of the time getting great wicking making the braid stiff as hell. 
Horrible. I have a really nice iron (or two or three) too! And I use hemostat when initially tinning. Lol, need to make more ugly packs to practice 
@longhairedboy that’s good shit. Gotta try the tapping. The rest I already do, but ineffectively most of the time I’m usually using the big 100w weller for this step.
Oooh I just remembered, I bought a solder pot for something… I’ll try tinning the braid using the pot.
There are 2 phases, tinning the braid, then making the braid stick to the puddle on the nickel (or the cell because I’m like that). I usually struggle with both I find silicone wire much more forgiving.
Is this “not a BMS” balancer available somewhere? I’m interested.
The ones I’m talking about:
Options for 1A, 2A, 5A, 10A ($$$$), and a breakout board.
This youtuber has made pretty good videos showing how these work
There are more basic on-board pcbs others have tried:
2 Likes
Anyone have advise for putting together a 12s4p staggered brick pack? Due to very limited space I need everything to be as tight as possible and I don’t have leads on my spot welder so I can only weld the very last row of the pack
I am thinking I will glue one p-pack to the main block at a time and weld it once the silicone cures, it’ll take a couple weeks since I can only do a single set of 4 at a time but that’s okay
I have this jig for gluing, I’ll silicone them then plop the rest of the pack ontop. Series welds then parallel welds on the end of the main pack before the next set of cells because I can’t reach them. I’ll run a 10awg with tabs for the ends
Can you make a drawing? Maybe you can use faster curing glue (hot glue, perhaps industrial types) or a fixture (or tape) to hold stuff together while you weld with wet silicone, so you don’t have to wait?
I will try and make a quick CAD model of it, please give me a few minutes. This will go on a eMTB so I’d like as much silicone holding it together as I can, but the problem is I can’t get them to pack perfectly if there is any dried glue on the surface
IMO borrow a corded probe welder. I read suunko lose power with corded probes?
I’ve got a Sunkko 709a, I’d rather not spend another $50 for a probe and foot pedal if I can avoid it
This is the layout I’m trying to achieve. glue 4 cells, weld the series to tabs then parallel tabs, then glue the next 4 cells so they line up with the series tabs
Is there any practical way to do this that’s any easier? I guess I could superglue the cells together enough to glue it at once but then I can’t weld it anyways
1 Like
It’s only 4.5 cells across. If the weld probes can reach 2.5 cells, you can reach everything?
1 Like
Haha so close. Can you bend the copper to get another 1/4 inch?
1 Like
Oh boy that seems sus…maybe? I’ll have to buy some longer 1/8" copper rods, these are pretty stubby
I’m suggesting all this because it seems much much better not to have to sequence the build with 1 day breaks waiting for the glue. Lots of chances to mess up. For bending the probe tips, you’d have to account for the stagger too. Maybe too much.
I probably shouldn’t talk about it because I haven’t done it, but it seems ideal to glue and weld 4s2p subpacks in 1 step, then glue/weld the subpacks together in a 2nd step. Or 3d print a top and bottom plate for alignment, and glue everything in one go.
I think you could use a top/bottom alignment jig to step through the pack as you planned, but if it were me I’d probably mess up at the 85% point…
I’d like to make larger blocks but I can only reach the edge cells…in theory I could make 4 squiggly 12s1p packs but that seems like asking for a failure
I’ve got a guide for the series tabs ready for printing so I can easily make the welds without the cell on the other end
This all seem like bullshit to not deal with. Sell the sunkko and get a boss/malectrics/kweld?
I guess the lipo + charger pushes the price up.
2 Likes
I want to but bank account says otherwise, gotta save up for the Amethystine build…got like another $900 to spend on that (the analog components and the NEO stuff mostly)
2 Likes
Nobody close who would borrow you a malectrics or kWeld for a while? Your problem was one of the reasons I got me a malectrics.
With a bit luck @DerelictRobot still has his welding pen for the sunkko and might want to borrow/sell you, but I have no idea how welds will be after. The resistance in the long wires till the weld point can reduce the strength of the welds by a lot.
2 Likes