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Old 11-22-2019, 03:06 PM   #54
cvhsquared
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Join Date: Oct 2019
Location: Richmond VA
Posts: 4
3 yr Member
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After you have completed the rebuild of the cells how do you reattach the cells to the board without burning the circuits up? Do the cells need to be discharged and if so how do you accomplish this? Thanks

Quote:
Originally Posted by dorrington View Post
hi..

right....

i take apart the case, use a heatgun on the back of the case until its really hot(don't spend too long in one spot) the cells either fall out when inverted or use a screwdriver to gently lever (picknthebpositive end of the cell, there is a compression ridge)

once apart I desolder the old cells (having first identified the bad groups), remove the nickel plates..(i just use side cutters and peel rather than rip the nickel strip off....carefully!..) where the bad cells are at and then gently drift the cell out of its sleeve!...easy peasy..no need to split the packs...keep the insulating rings from the positive ends of the cells and make sure you only apply pressure on the circumference of the cell....eventually you have a honeycomb of glued sleeves with no cells in...lol

if i'm keeping the cells I clean both ends with a file..do not short circuit or you'll damage the file!

I then push good sleeve-less cells back in where the bad ones were and reweld with nickel strip.

I try to get a feel for the other cells capacity and try to match as far as possible too.

reassemble the pack (carefull soldering)..charge fully and then capacity test.
(I have made a dummy load and can access the bms registers..the discharge process is automated and terminates automatically...the total capacity is recorded)

so far, worst rebuild is 67%, best is 95% of original.

If i have a really bad pack i cannibalise it for good cells..this is where the automatic machine comes in to play..I de-sleeve all the cells and place them in the machine 6 or 23 at a time..and return after a day or two.check the screen to see what each cell has achieved...

my machines are a jumble of wires and 3d printed parts but they do work..

I hope this is clearer?...
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