The battery builders club



Anyone know where to get nickle like this?

1 Like

I was going to suggest @BenjaminF but his website doesn’t have any

1 Like

He completely ignored the tabs used to transfer current from the “jelly roll” to the top and bottom contacts, even slicing apart the bottom tab in his disassembly.

There’s the top contact structure with its protection devices too, something that could also be shown.

At least he identified the jellyroll’s layers…a good thing.

1 Like

This is the best battery builder ever right here watch and learn folks :confused:

yeah I was particularly looking for that bottom connection. you can stil see it if you know it’s there but he chopped right through it.

1 Like

Hello Everyone,

I am building a 12s4p Duck Battery Systems PCB kit with the following components.

I have welded all the molicell packs together and am waiting to be 100% confident before welding and soldering to the PCB.

Here is my wiring diagram, if anyone could verify that it is safe that would be awesome!

I am confused on what to attach to the bolt down BF1 100 A fuse seen on the left of the battery.
What should I connect to the other side of this fuse?

I am using a GX 16 4 pin charging port.

Amass XT90S-F/M
Amass XT30-F/M
150mm 10AWG Silicone Wire
150mm 16AWG Silicone Wire
16AWG Inline Fuse Terminal
Littelfuse MINI 997 15A 58VDC
Littelfuse BF1 100A 58VDC
13p JSH KH Cable
Daly 12s 10A BMS


1 Like


I bought another LLT smart BMS 120A for one of my packs.

The problem: I can’t seem to connect through Bluetooth while charging.

While discharging and idle it connects fine.

Anybody else have this issue?

If a drone designed to explode is using fish paper rings on its cells, then so should you haha

I was flooding pcb pads with solder today that I spot welded and soldered one of my 4p groups in reverse - + in series with the rest of the pack. I took a dremel to the folded edge of the nickel tab and removed it. Im wondering how I can reattach it with solder or nickel tabs. Pics here:

I am thinking of trimming off the rough nickel on the 4p pack, spot welding on top of the nickel with another precut 4p nickel with tab and spotwelding to the pile of solder or if that wont spotweld I can rough up the tab surface and solder to the pile of solder. I could also melt off the solder on that pcb and remove it to try to spot weld to the original nickel tab spotwelded to the pcb. Will that work?

I also screwed up before this and caused a brief short when what I think happened was the slack in the solder wire touched an exposed pad as I was soldering the bus bar at the end of the pcb. Feel like a dunce but a major learning lesson to keep everything insulated and labeled. Hopefully the pack is not fucked.

This is my first battery and the learning curve is so high, but challenging and rewarding to do things safely. Thank you - Lucas

Looking for some guidance on a battery build for my son’s dirt bike, I was planning to build a non flexing brick using .20x30mm nickel creating one solid sheet connecting the parallel groups, this will be 20s8p. Now Im not sure how to calculate the amperage that can pass through the series connections as it’s one solid sheet, or should I use multiple silicone braid from each p group?
For simplicity of building I was hoping to avoid the extra step of wire.

What can I expect from the solid nickel strip across the groups amp capability wise?

Also for the positive and negative wires I was thinking of soldering the wire all the way across the strip like a bus bar what’s the best method of soldering that way? Can it be done with an iron?

On second thought, I can weld the nickel strip to a copper bus bar and use terminated 1/0 wire to connect from the battery to the controller?

So I have the SF12 2 pin female on my enclosure right now. I don’t have a charger yet, so I don’t know which pin will be positive and which negative. If I read the PDF correctly, they are interchangeable? All I would have to do was make sure I wire the charger/connector the same as the female port? Cheers.

Spot welding nickel to nickel just does not work so well. You can try but it’s much harder.

Don’t spot weld to solder. It won’t work and solder will splatter over you.

Best for you is to remove solder from pcb and nickel from P group and start over.

2nd best is to cut sticking out edge from P group and solder nickel strips to create new edge that you can easily attach. I said strips because it is much easier to do flat solder connection instead of wide one pice. You also need to be careful no to solder where bend would be. You need to pretin both surfaces and then quickly join then. It is much more difficult option. You can also spot weld but I never trust this connection. You can test before you start it it’s good enough for you. Put additional fish-paper between nickel and P group when you spot weld.


Black to black - red to red. Best to check with a multimeter or open it up to see because I don’t trust much of anything. When i make my connectors up i always use #1 pin as positive if they arnt marked with polarity just to be consistent.

Most chargers will have reverse polarity protection but here we are, back at my trust issues again :grin:

1 Like

Spot welding nickel to nickel works fine.

1 Like

I hear superglue works well for balance wires too


It did for me when potting lifepo4 and 50miliohm discharge balancers. I don’t recommend it though unless ur willing to drill through and balance manually if it doesn’t continue to work.

This was also done with custom made balance discharger pcbs so felt I had to drill through anyway to make sure they were working correctly.

Thank you so much I will remove solder from pcb and start over

Is there a technical reason why I can’t modify and use a mix of 2/3 1/3 of the different tab width on the same battery?


Nope that’s fine - best practice to leave rounded edges though.