What’s In A Name For A Tool Battery Pack?

Power tools have come a long way. It used to be you needed extension cords or a generator for your tools, but now you can get just about anything with a nice rechargeable battery pack. As it turns out, most of those packs are made by the same company, and [syonyk] wanted to see how similar two different Makita packs and a Rayovac pack were. What he found was surprising. The outsides were very similar, but what was on the inside?

The Rayovac pack was easy to open and had a controller, a thermal cutoff device, and two layers of 18650 batteries. The similar Makita pack looked identical from the outside until he tried to take it apart. The maker had plugged one screw hole and used security screws instead of the Phillips heads like on the Rayovac.

Once open, the insides looked totally different. The battery management board was larger, potted, and connected to the battery using nickel strips instead of soldered wires.

A smaller Makita pack should be about the same with a single layer of batteries. Makes sense, right? It does make sense, but it isn’t true. There was a much cheaper board inside and the cells used didn’t even match the published spec which is decidedly naughty.

Despite the markings, not all of the packs met their rated specs. The Rayovac pack for example may have had a slightly higher output voltage. The small Makita didn’t meet its Wh rating. Even two packs from the same company didn’t have anything near the same innards, and while the larger pack was well constructed, the smaller pack looked a little slipshod for many reasons covered in the post.

Maybe these toolmakers should hire [Timothy Economu]. If you want to see the guts of a much bigger battery, take a look at this Tesla Model 3 pack teardown.

17 thoughts on “What’s In A Name For A Tool Battery Pack?

  1. Remember when every brand of cell phone (and often different models of the same brand) used a different charger? It took the EU to say ENOUGH! and tell the industry that they had to come up with a standard that was used by all phones. This is what we need for power tools.

      1. You are being fooled with. You have to remember that all USB-C cables are not going to be equal.
        Some ex. Apple C’s will more then likely not run all devices, And some cables will have usb-2 N not sub-3, some will only deliver 5v only. And so on.
        if you want to learn more you should take a look at the spec’s.
        We will still have a bag of cables. they are misleading us.

        1. I only have 10 or so USB Type C devices, but I have never had a cable incompatibility. I’m curious what devices you’re having this experience with (Disclaimer: I do not own any Apple products)

          1. A common one is using the cable provided with a MacBook charger to connect an external screen. It is a power delivery only cable so it does just that.

            As long as you buy full featured USB-C cables everything works. You have power-only cables with Micro USB as well so this is not new.

        2. I got one of those USB-C dongles with gigabit ethernet and three USB ports, those USB ports work great with everything on my MBP. Full power and bandwidth to a SATA hard drive adapter. Sleep, wake, no problem, unlike my Dell. If there is a problem here I certainly don’t see it.

          My bag of USB cables is in the pile of junk to be recycled.

  2. prompted by this, I decided to take a peek inside a $20 Harbor Freight Warrior 18v pack. Follows:

    https://cdn.discordapp.com/attachments/351827386037174274/692986590120771654/20200327_023823.jpg https://cdn.discordapp.com/attachments/351827386037174274/692986591672795157/20200327_023900.jpg https://cdn.discordapp.com/attachments/351827386037174274/692986592356204544/20200327_024012.jpg

    Inspection of a Harbor Freight Warrior 18v Lithium battery pack
    Findings :
    Fully balanced
    Onboard charge controller
    Thermal sensor
    Spotted nickel intercell straps with weld-helper slots
    Balance wires soldered to the straps, not the cells
    Cells marked as 1.3Ah HIGHSTAR, manufactured 04/2018
    ABS (probably) battery bracing
    Fiber rub-protection washers under the nickel straps
    Fishpaper covers over the ends of the cells
    16AWG load wires
    Power traces on controller have numerous ampacity vias

    All in all, a high-quality pack

    1. Just shows that Chinese companies will build *exactly* the quality you’re willing to pay for. Apparently Harbor Freight is willing to pay more for their top line tools and less for their lower priced line.

    2. Is there a way to check the circuit board. The charger is showing around 24 output. When trying to charge battery, the light doesn’t come on. My meter shows batteries at 9.7. But will not charge.
      Any ideas?

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