Does this configuration look good for a 12s2p? Any better ways of doing it?
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use wire instead of folding?
Have you seen how people isolate P-groups from vibration, it’s a good idea.
Ask some builders with long hair about fixing a lot of batteries with folded nickel.
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Thanks for the warning, I want to do whatever is safest.
This is what I’m thinking now:
What’s a good way of connecting this two sides with wire in this configuration?
This two groups need to be flat side by side so it’s 2 rows high. (green arrow is where the wire would connect)
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do you have fish paper to go between the cell walls where all the series connections happen?
if not the flimsy PVC wrap is protecting you from a battery short.
Yep, I would cover both sides series connections with it and separate all the p groups as well.
EDIT: maybe I can connect them like this? (with fish paper to isolate the positive strip from the side of the battery)
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To the battery builders. What do you think how “easy” it is to upgrade this 11 year old cordless drill. It has a 1.2Ah 14.4v NiCd battery with an output of 5A.
I still want to use the drill but the batteries won’t hold a charge. The tray can easily hold 8x 18650s in a 2 layer config. I only have to remove 2 small pieces of plastic to get them to fit.
So with 18650s it would be a 4s pack. Additionally 4s4p?
On tbe flip side a new one is between 20 and 30€ but only 3-3.5Ah
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put the bent nickel on the negative end of the series connection, that way it can not short to anything.
I was considering doing this as well, let us know how it goes - my version of batteries are 9.6v dewalt ones
Any tips to improve this pack? Have I missed anything?
10s4p split for balance charging. Will be putting bullet connectors on the terminals and heatshrinking the whole thing. I’ve used 0.2 x 10mm nickel, 10AWG wire for the terminals and 14AWG wire for the series connections.
Thanks
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Pack looks really clean and safe 
only thing I can’t see if you did solder wire on nickel under those bent ends? I suppose you did.
Otherwise 5+
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Only thing I can see is fish paper between the nickel and balance leads
I don’t think that’s problem since balance wires are silicone and more important than that, silicone wires for series connections will make sure there is no pressure on balance wire because they are thicker, so they will create some space height-wise.
I did solder behind the bent over nickel:
There is some fishpaper between the balance wire and the nickel tabs, it’s just hard to see. I will be stress relieving the terminal wires with tape or something.
This is my first build and have been through almost all the posts on this thread so I’m glad I got it right first time (other than shorting out a cell with a pair of pliers and having to replace a P-group)
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hey what are some of you seasoned builder’s processes in preparing your cells for welding nickel? What are the order of operations and methods some of yous practice? Line up the cells for the p-groups and hot glue first? Then weld? Would love to hear some tips of the trade!
I sometimes print holders to hold the groups together then weld the packs and silicone them after.
There are some files about where the printed part has a recess to put the nickel in and holes just big enough in the end so you don’t weld off the positive terminal.
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- check for balance
- remove wildly out of balance cells
- bring to constant voltage (close to 3.6v)
- remove nickel
- gind ends flat
- replace damaged sleeves
- insulator rings
- holder/spacer/template
- silicone if flex, hot glue if rigid
- cut nickel to size (leave tab for balance leads)
- clip edges
- tack welds (one per cell end)
- insert insulation?
- beef up welds (planning to do 3 per positive and 4 per negative from now on)
- wrap parallel groups? (kapton or filament tape, fish paper, heat shrink)
- series connections? (Silicone wire or braided copper)
- end terminations
- balance leads
- wrap whole pack
For packs with the big cell holders I got glue the long lines on both sides before inserting them, for the odd rigid packs I use a printed template to hot glue both sides, for a flex pack I would use silicone and a big mould to keep the cells in place. Always secure cells, then tack welds, then final welds
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Damn bro that looks great. Well done 
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Ahhh ok so you chomp round the nickel edges after you weld them on? Was wondering about that. Also, I’ve charged my cells up with a littokala type charger, here’s the voltages:
Can I make a pack with my cells charged up like this or do they need to be at nominal V (3.7V)? Also, is this difference in voltages between the cells within a safe range to create a pack with? Thanks for all the pointers my friends!
just balance them all as close as you can.
then you can charge / discharge them to match the pack