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My adventures
Today my heavy soldering iron arrived.

I also prepared the four packs for my mobile power pack. I arranged and taped together the necessary cells for the four packs.

I think I'll do the soldering tomorrow. I'll keep you guys posted.
jdeadman, Shade, neilmc And 1 others like this post
Fuses are an absolute necessity!!!!

I'll elaborate. Yesterday while putting solder on the cells, I must have damaged one cell in such a way that it had turned into a short. And suddenly when I wanted to solder on the fuse it turned bright yellow instantly and burnt off...

So the fuses I'm using are working (I bought a couple of Thousand very low wattage resistors on aliexpress and clipping of the wires to use as fuses, works flawlessly).

For the rest I noticed that while you're soldering, you get better at it. The first cell realy looks like shit, but the second one already looks a lot better. I'll continue soldering them and when I'm done, I'll post some pictures.

But in the mean time:

Wattsup and 100kwh-hunter like this post
Exactly the reason for fusing on cell-level, beside protection against a cell short, it protects (to some degree) also against us, humans, making mistakes...

Thanks for sharing... this is realy important information to keep in mind.

Great progress btw Smile
18x 300Wp solar off grid and 10x 180Wp solar tracker grid-tie
10KW 3phase hybrid inverter. 40Kwh 18650 storage (for now)
My setup:
Did you check voltage before soldering or was it sitting on the table for some days or week so it had self-discharged?
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Daromer, I followed the procedure as should be and it was a good cell. I messed up the cell though while putting solder on the positive side. I think either a blob of solder arrived inside the cell, or I heated it a bit too long, but it started fissing and it had that typical sweet smell suddenly.

And when I tried to the fuse wire, it immediately glowed red/orange and broke.

At this moment the iron is heating up and I'll take some step by step pictures for the process I'm following to solder the fuses and wiring to the battery pack. I'll post it later on then.


Ivo S.
Finished the battery pack. I'll show step by step how I went along

First a general overview of the stuff I'm using

First step: soldering the resistors to one side of the cells

Next step: clip the resistor and solder the reminder of the resistor to the other row of cells

Next step: clip off the resistors and wind the wires two by two together

Next step: solder in the wires and clean it all up

Do the rest with the other cells and then attach it all together. The 4s10p pack ends up looking like this:

It's certainly not a work of art but I think it'll do the job
It certainly will get the job done!

To consider on your next attempts:
You are using quite a lot of solder on some terminals and using solid copper busbars makes building the batteries easier Smile
Another thing to note is that you are not staying on the small POS raised part. On several cells the plastic is melted around the terminal and on the edges. This is what can lead to shorts.
I agree that you are using a little too much solder on the POS end. Especially with those cells I mentioned first.
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Check this:

My score for this evening.

How did it go:

This evening after work I asked the misses: "Give me a name of town in the vicinity"

She said: " xx "

I opened google and typed: bike repair shop xx

I took the phone and asked: " For a personal project I need e bike batteries, can I help you get rid of them? "

He said: I have tons Smile

Et voiila Smile
Very nice!

I actually talked to the people at the nearest shop about batteries as well. This is a big shop, they have several employees alone for their workshop. Turns out they don't keep the batteries. They send over 90% of the batteries to the manufacturer who then decides whether this battery will be repaired or a new one is needed. And then they send the repaired battery (or a new battery) back to the shop where they put it back on the bike and tell the customer that the bike is fixed.
No ebike batteries for me Sad At the day when I was there they had several ebikes standing around with no batteries, waiting for the return of their batteries.

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