Monstrous USB Power Bank

At some point, cleaning out the spare parts bin — or cabinet, or garage — becomes a necessity. This is dangerous because it can induce many more project ideas and completely negate the original purpose. [Chaotic Mind], considering the pile of  batteries he’s collected over the past decade, decided that instead of throwing them out, he would recycle them into a grotesque USB power bank.

Inside the bulk of this power bank are an eye-popping 64 18650 Lithium Ion cells, mostly collected from laptop batteries, and wired in a parallel 8×8 pattern with an estimated capacity of over 100,000mAh(!!).  The gatekeeper to all this stored energy is a two-USB power bank charger board from Tindie.

Ah — but how to package all this power? The handy man’s secret weapon: duct-tape!

This brick of batteries is probably unwieldy for most daily use purposes, but we can see it having a place on an extended camping trip or the like. It is still a huge potential danger as there isn’t any charge balancing integrated into the bank, and the potential for catastrophic failure of any of the smaller or older cells is immense considering the amount of time it takes for this monster to charge — it took two hours to charge from 90% to 91% at 1.2A.

At least [Chaotic Mind] has his fire extinguisher handy!

We’ve previously featured a guide on how to hack together your own power bank if you need one, or feel like taking the concept to the limit.

57 thoughts on “Monstrous USB Power Bank

      1. at 1:21, he specifically says “… 8 by 8 arrangement, all placed together in parallel”.

        That many cells in parallel, with some cells of dubious state of health, seems a little dangerous; if one of them has some dendrites (because of being deep discharged previously), and develops an internal short, all of that energy is going to be dumped into a single cell.

        Also, the apparent lack of a fuse can make life interesting.

        1. Yeah your out of order calling him a retard. His idea might not be up to your standard but this is why we share things on here for people’s input. What makes you so great with electronics? Your still working out what a transistor does. Don’t take your crap out on other people only because your mum don’t love you and you have no friends. What a dickhead you are.

    1. That’s what I was about to say: when the cells are wired in parallel, they automatically balance themselves. It’s when the cells are in series where you need an external balance-circuit.

  1. So he’s charging each cell at approx. 19mA? I’d say there is room for faster charging :)

    The real issue here is: If one cell fails, it could turn into a serious fire hazard if there’s no cell-level protection…

  2. Seriously don’t even attempt to think about taking that on a plane… let alone carrying out the task of taking that on a plane… Even if the maker of this don’t get shot if he did try to do so, he probably already made some list of important people already!

    That is how awesomely useful this pack is, now to make it more awesome ny adding more USB charging sockets, maybe a 16 device charging bank for that hack-meet event in the (likely near) future.

  3. Seriously don’t even attempt to think about taking that on a plane… let alone carrying out the task of taking that on a plane… Even if the maker of this don’t get shot if he did try to do so, he probably already made some list of important people already!

    .
    .

    That is how awesomely useful this pack is, now to make it more awesome ny adding more USB charging sockets, maybe a 16 device charging bank for that hack-meet event in the (likely near) future.

      1. I thought it was 100Wh?

        Aah, it’s 100Wh per battery and if you call the airline to ask permission you can take two spares of 160Wh each.

        This is why for instance the Dell XPS 15 has a 99Wh internal battery, and why the bigger external packs intended for charging laptops tend to top out at 26.8Ah or 99Wh at 3.7V.

    1. Li-Ion discharge rate is pretty close to alkaline/low-discharge-NiMh, so yeah, some of them will have lost power, but not much, a couple of percent per year maybe.

      As others have stated, all in parallel means it’ll self-balance, and he at least tested the batteries (says he threw away 3 bad cells) so we know they’re probably ok to charge.

      As for the claim of being the biggest battery pack, that’s probably going to go to a tesla or some other electric vehicle with USB sockets, I’m afraid.

    1. “Student with a history of disruptive behavior and disciplinary issues, whose father is a known drama queen, rips apart a commercially-made clock and puts it in a briefcase. Shows it to a teacher who tells him it’s not appropriate, to put it away in his locker, and not bring it to school again. Instead, carries it into classes and purposefully and repeatedly sets the alarm to go off during classes to disrupt them. Is disciplined.”

      Fixed that for you.

    1. No… you fail.

      Adding a fuse protects the pack from external shorts. With that protection provided the pack is “properly fused”. Sure, it’s still a fire hazard due to the possibility of internal shorts within the batteries. Of course it’s still dangerous. But it is an improvement.

      Your argument is a little like saying that because the pool’s high dive board was mounted at the shallow end one might as well not even put a fence around it.

      1. >”Your argument is a little like saying that because the pool’s high dive board was mounted at the shallow end one might as well not even put a fence around it.”

        The entire pool should not be used as long as the hazard is there, because even if you put fences around some idiot will climb over and jump.

        The entire thing is dangerous whether there’s a fuse or not, because mixing various cells of various ages and makes together means that they have wildly different internal resistances. The cells will discharge at different rates so that once the load is removed the internal balancing currents can set the pack on fire anyways.

  4. Laptop batteries are great source of usable 18650 cells, but it is a good idea to test their capacity and state, some are usable only for proper disposal. I’ve found out that some cells can get very hot while charging, luckily my charger detects that and drops current and I discard those cells immediately. If one such cell finds it’s way into 64cell pack that has no thermal protection you can have very bad day.
    However in this case it looks like charging is happening at 1A divided on 64 cells so that’s no big issue. My suggestion for upgrade would be better module, I doubt that one can provide 2.4A without dropping well below 5V.

  5. I read somewhere that connecting more than six LIIon/LiPo cells in parallel is a very bad idea. I have a 10-cell pack rated at 18Ah which I never used for anything. Do you have any suggestions other than a powerbank?

  6. Battery pack made in China…

    Homemade soldered… Without fuses or integral protections.

    Neither alternative is likely to be made correctly. Make a dead bug kludge with a couple LoRA radios, a uC of some sort, and a solar cell and you might be able to keep your creation alive in the event of a volcano or nuclear hostilities.

          1. I was looking at boost convertors on eaby from china.
            10-50v in and 12-60v out or something like that.
            They were being rated at 1200W.
            Could handle a max current input of 20A.

            So how did they get to a 1200W figure? Marketing :o)

  7. Creator of the monstrous pack here. I want to clear a few things up.

    First off, the whole load cell charge balancing thing does NOT apply here as these 64 cells are all in parallel. Had I gone series then you bet I would have put a balancing circuit in.

    Second, someone asked how I get 5V from the 3.7 to 4.2 these cells run at. Easy. That LCD thingy is the same type of circuit you find in any other USB battery. For output it boosts the voltage up and for charge it bucks it down. Circuit is a buck/ boost system for 5V and has extra features added in. Custom board from Tindie.

    Third, I know about the dangers of Lithium cells. I’m NOT stupid. Here’s the thing. They are like combustible fuels. Think gasoline. That stuff is always a fire danger but with proper care it is not. None of the 64 cells in my pack are of the dangerously discharged type. I charged them up over a year ago and they all had over 3.5V still so all 64 were good when I started. I threw out 3 cells that were damaged and/ or dead when I checked the cells out over a year ago. Rest are good. When I speak of “dubious quality” I mean those cells looked bad on the outside but were still structurally sound.

    Last, I really should have fuzed each cell but I was getting tired of soldering the cells together so I didn’t bother. I will most likely go back to them in the future and do that.

    Oh. One more thing. I know for sure this would be illegal to take on a plane. I know all about the watt hour limitations and I think this pack is around 400 at minimum. Way over the limit. LOL

    Take care now and thanks for the interest in my project even is mostly useless.

    1. I used the handle Ali and Un-fer-ium (without dashes) above earlier, one to speed up the other because I forgot the latter one has that aproval* delay due to previously being rinsed heavily.
      .
      .
      .

      Anyway back to topic:
      My earlier comment was in a slightly joking form about the plane bit, You and I know the obvious answer here, the joke was directed at the average pleb who may be stupid enough to try this.

      I’m curious as to how you handle caution around battery building… are you like I in the sense that when dismantling and building Li-ION batteries do you treat it like you’re in “Bomb disposal/disarming expert” mode and super cautiously venture in your creation?

      When building, I usually treat the situation as the equivalent to fiddling with a live bomb! Whereas salvage of the cells (as opposed to preserving the pack configuration)… I tend to be a little more straight to the point and just get at them cells. After getting those cells I then treat them as though they’re as safe as a bunch of AA batteries.

      I also presumed that you were sensible enough to have had them all at the same voltage (which is likely as that is how you stored them) as that is the obvious thing to do.

      Thing is, people in general may panic that something that could be dangerous and make out it is fully darwinianly dangerous in their own minds…. to the point that those commenting here who otherwise should know the answer end up confused from fear and forgetting basic physics/ohm’s-law/kirchoff’s-law/common-sense.

      *intentionally misspelled for fylter bi-pass

      1. I treat the Lithium cells like any other battery you just toss in a drawer. Only difference is I make sure to not dead short the cells. Beyond that I take no precautions as these things aren’t like a bomb waiting to explode if you blink wrong at them. All the “bomb disposal” level of caution is good and all but usually unnecessary for the most part.

        I did top each cell off before I Built the pack to make sure they were mostly load balanced. The battery controller LCD showed 90% charged when I hooked it into the pack first time so I think the cells were balanced pretty well.

        As for the comments, I have noticed what you say. Many comment even when they have no idea what they are saying. Most comments are sensible here I noticed aside from a few that are either overly dumb or making assumptions that I can understand but is still wrong.

        Thanks for at least being sensible in giving your feedback on this. I know it is somewhat dangerous especially being housed in duck tape. Point is it’s not ticking bomb level danger. The pack is behind me on my other table now and been there for 2 weeks. No heat from shorts in it, no loss of charge, and no exploding danger.

    2. “I’m NOT stupid.”

      “I really should have fuzed each cell but I was getting tired of soldering the cells together so I didn’t bother. I will most likely go back to them in the future and do that.”

      What is the UL-94 rating for the materials that you used in your pack? Why would you not use such a material given the risks you are assuming?

      Does your pack possess a thermal cut-out, or thermal link, or even a thermistor?

  8. You could do what Tesla does. Use a small size single strand wire link for each cell in the battery of parallel cells. There was a teardown of a Tesla “pack” on HaD. Something more than a dozen cells are run in parallel in each division. 18650″s times a couple of K.

    1. That is a good idea and in fact the YouTube channel “Myplayhouse” did the same thing building a monster pack with 140 cells. He used single strands of wire for a fused link and testing had them fail at around 2.5 amp draw. I should do that to each cell for some sort of protection.

      1. You used to be able to buy ‘fuse wire’ at any corner shop here in the UK, back when there were still a few houses with manually wound-post fuse boards. It’d be specified for a specific current limit per inch/cm. It’s the same stuff that’s in cartridge fuses, just bare and wrapped around a cardboard bobbin.

        You should still be able to find such type of wire, but it’s probably an item you’d need to buy online these days.

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