Battery repacking experiences

Discussion in 'Electronics & Electrics' started by metamorphosis, May 18, 2021.

  1. metamorphosis

    metamorphosis Member

    Feb 25, 2002
    Wanted to know about other's battery repacking experiences (either doing it yourself or through an external company) before I write an article about it.

    My own experience so far has been getting a mower battery repacked, got it to 3AH (from 2AH original), but started cutting out toward end of run and also the charger kept showing a red flashing light (indicating a dying/dead battery) despite charging ok. this was through an external company.

    I was wondering what the success rates are that people have seen. I've previously talked with a guy who's built his own battery bank setup for his home solar power (like the tesla one), and is currently constructing an electric truck (apparently it's going to take about 10000 cells).

    Your thoughts?
  2. Lost Property

    Lost Property Member

    Aug 30, 2013
    We've repacked a few older 18v Makita drill batteries that we used on the farm about 8 years ago. From memory one pack needed 2 cells replaced and the other we replaced the lot. Was an easy enough job and when we palmed them off with the drill about 4 years ago they were still working fine. Price of ebay ones pretty much makes repacking them too much of an effort (for us) these days. Also did an old 14v GMC drill battery which I found out came from the factory with a dodgy charger so I fixed the charger and replaced the dead cells, but that's hardly a great job because it was a GMC and worth next to nothing.

    I don't have battery pack at home but I run all my house lights, charge all phones, cameras, tablets and rechargeable batteries, security lighting and camera system from a panel on the roof. When my needs get beyond the 200Ah that I have I'll add another deep cycle to the system but that's not really a battery pack, more a pigeon pair. My old man does a similar thing with his panels but again it's not really a battery pack when it only has a couple of deep cycles connected to it. The jockey wheel for the boat is the same, it's gel cells and charges off a roof panel, but it's not really a pack. My old man did make a battery pack (out of 18650s) for one of those Air Hawk tyre pump things for little other reason that he had spare batteries. He also made a similar pack for his air jack but I don't remember how many cells he put in those, but probably not the same sort of packs you're talking about.
    metamorphosis likes this.
  3. merlin13

    merlin13 Member

    Apr 12, 2003
    back in BrizVegas
    Done well over a dozen packs for domestic 'n DIY-level cordless tools over the past couple of years, to replace sick/dead cells or to beef up the Amp/hr rating in a few power tool ones.

    Haven't heard of any failing to date, but I do give the replacement cells a good thrashing first (especially any used ones) and replace the entire array with cells from the same source, rather than "One cell dead out of 3/5 whatever, just replace that one". Do end up with some orphan cells per se but they get used elsewhere, like grafting them into torches and various other things that normally use non-rechargeables. That counts as repacking as well, right?... :)

    And I am rather naughty in that I solder them in rather than spotweld the tabs to them as well, but I've been trained to seriously solder so Myeh. That and I might get around to sourcing or doing a DIY spotwelder one day.

    I also tend to scrounge replacement cells out of either sick laptop packs, or acquire the cheap 'n cheerful imitation Dyson vacuum ones off evilBay and disembowel those. Those to date have been a reasonably priced source of new Yum Cha 18650s, and putting aside the ridiculous amp/hr claims they advertise them as surprisingly have quite respectable amp/hr rating as well. Genuine Dyson packs I've had the luck to acquire though, Hoo Boy those cells are serious...
    metamorphosis likes this.

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