Appliance repair ep. 260: vacuum cleaner battery replacement

Repairman Li, ep. 260: a follower sends in a Dyson-style vacuum battery + 6 × 18650 he bought himself (6S); the old nickel is cut leaving the board connections, cells laid + / − and stuck down with double-sided tape, fish paper rings on, AWithZ welder at power 67 sparks too much → 40 is just right, ‘a few extra welds for strength’, main + and − to the board, fish paper insulation, back in with four screws, charge to wake it and it starts; comments: not the original board or it would be locked; no need for rings on the negative

Self-taught repair, ep. 260: a follower brought a vacuum cleaner battery for reassembly, the cells were done and he bought 6 himself. Cut off all the leads and nickel, but not from here — that part stays, there’s no matching part and it still has to be welded again; new cells laid + − + −; they need double-sided tape or they keep shifting, the original had glue too; + and − stuck down; a fish paper ring on every one; cut nickel, one, two, three is enough; ‘soldering iron’ — no, a spot welder, went with the high-power AWithZ and just go hard; power turned up a bit to 67, fine; one weld done, beautiful; he likes a few extra welds so it can’t come loose, two or three would really do; these two are the main − and main +, the rest you weld without thinking; don’t weld those two yet, put it in the case and look first; weld the board legs on directly without removing them; power is a bit high, can’t run it high or it burns through underneath, down to 40 and try again, fine; some welds crooked; weld the remaining + and −; cut the nickel shorter; really, 40 was enough, turned it up too far before, ‘too young, life hasn’t beaten me yet’; at this power the welds are just right, it kept sparking before; assemble, connect the NTC/B2 board and weld; nickel a bit wide, trim; success, beautiful; fish paper insulation, both sides in one go; back in — he took it apart himself and doesn’t know how it goes; + and − leads must not be swapped, swap them and it’s dead, M+ is red; 4 screws; charge to wake it, shows charging; unplug and it starts; a video for the customer, nailed it. 35 comments: always cheerful (6); no need for rings on the negative (3); not the original Dyson board or it would have locked long ago (2); got one backwards again (2); can batteries be posted; how much; how much is the welder; six in series 25V; the insulation is secondary, mostly to hide the mess.

Outcome

Steps10 steps · click a frame to jump

1. 
   1. Background; cut off the old leads and nickel but keep the board connections

   A follower’s vacuum battery, 6 cells bought himself; cut off all the leads and nickel; not from here, this part stays (no matching part, it has to be welded again); take everything off, cells left.

   00:00 – 00:54
2. 
   2. New cells laid + − + −; double-sided tape; check + and −

   How the new cells go: first one positive, then negative positive, negative positive, negative positive; double-sided tape or they keep shifting, the original had glue too; stick a negative next to a positive; check it’s right; stuck down.

   00:57 – 02:46
3. 
   3. Fish paper ring on every cell; cut three pieces of nickel

   The fish paper rings bought earlier go on every cell, beautiful; confirm the groups; cut nickel, one, two, three is enough.

   02:46 – 03:33
4. 
   4. High-power AWithZ welder, just go hard; power 67; he likes a few extra welds for strength

   Not a soldering iron, a spot welder — the high-power AWithZ, just go hard; the nickel is a bit long; power turned up a bit to 67, fine; one weld done, beautiful; he likes a few extra welds so it can’t come loose, two or three already hold, more welds add strength.

   03:33 – 04:52
5. 
   5. Find the main + and −; don’t weld those two yet, put it in the case and look; weld the legs on directly

   These two are the main − and main +; the rest are joined, weld without thinking; don’t weld the main + yet, put it in and look first; weld it on like this without removing the legs, three welds should do.

   04:52 – 05:54
6. 
   6. Too much power burns through underneath → 40 is just right; some crooked; other side

   Power is a bit high, can’t run it high or it burns through underneath; down to 40 and try again, fine; some cells welded crooked; this side OK, do the other side; + and − left.

   06:00 – 06:37
7. 
   7. Weld the main + and −; cut the nickel shorter; 40 is enough, too much before and it kept sparking

   Main − and main +; the nickel needs cutting shorter; really, 40 is enough, turned it up too far before, ‘too young’; at this power the welds are just right, it kept sparking before; OK, assemble, connect the NTC/B2 board.

   06:43 – 07:38
8. 
   8. Weld the board legs on; trim the wide nickel; fish paper both sides

   Weld the board legs on like this and test, holds; the nickel is a bit thick and too wide, trim it; basically a success, beautiful; insulate, fish paper both sides in one go; fit the other parts.

   07:38 – 08:50
9. 
   9. Back in: don’t swap + and −, M+ is red; 4 screws

   He took it apart himself and doesn’t know how it goes; the + and − leads must not be swapped, swap them and it’s dead; M+ should be red, M− negative; fit the battery and the case; 4 screws, the small one at the front, leave the two big ones for now.

   08:52 – 09:57
10. 
    10. Charge to wake it, shows charging; unplug, it starts; a video for the customer

    Charge first to wake it and see if it works, all or nothing; plugged in, shows charging; unplugged, it starts; a video for the customer, nailed it.

    09:57 – 10:44

Bill of materials

Measured on camera

Creator’s tips

• When cutting the old nickel, keep the end that connects to the board — with no matching part you’ll have to reuse it 00:28
• Stick the cells down with double-sided tape before welding, or they shift 01:36
• Start low on power: 40 is just right, 67 sparks and can burn through the bottom 06:00
• Don’t weld the main + and − yet; put it in the case and check the positions first 05:05
• Don’t connect the red M+ lead backwards 09:06

Pitfalls

• Too much power keeps sparking and welds come out crooked 06:14
• Comments: not the original board or it would have locked when opened; no need for rings on the negative; got one backwards again

Li-ion safety

• Too much power can burn through the bottom of a cell 06:00
• Swap the + and − leads and it’s dead 09:06

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