USB over Heating - Suggestions?

tunzafun001 on 11/08/2025 - 11:23

Bought a Drill battery converter with USB outlets of Ali X.

Smelt warm in use.

Opened it up and found it was outputting 5v at 2amps (10w). Input side is an 18v Makita battery.

But then tapered off with voltage dropping to just over 4v after 1 min.

I got out an IR gun, and the little IC chip was 70C! No idea how hot they are meant to get. Maybe faulty. But hard to prove to Ali as they will have a sook for opening it up.

Any ideas / tips. Have to be a tiny heatsink?

Thinking of replacing the board with a 25 - 66w USB board, and hopefully it does 10 - 15w much cooler.

  • Note - using it on a heated vest for the missus. Went with a vest with only a small back panel and pockets. Rediculous to have an entire heated jacket via USB.

Specs say it will take up to 4.5A. Obviously drawing max out of this thing..but it's still only 10w.

Next attempt is a 15w Power Bank. Need to get a converter first. Jacket has a stupid USB A male jack.

Electrical & Electronics

Comments

  • jv on 11/08/2025 - 11:27
    +7

    suggestions?

    Run !!!

    • tunzafun001 on 11/08/2025 - 11:34
      +2

      Yes. That also works well..and did actually buy her a treadmill!

  • spackbace on 11/08/2025 - 11:29
    +5

    Note - using it on a heated vest for the missus.

    Next attempt is a 15w Power Bank

    Wouldn't that be the obvious choice, rather than some MacGyver'd shit up against your Mrs's body?

    • tunzafun001 on 11/08/2025 - 11:33

      Figured the drill battery would have a lot better power delivery / capacity than a Powerbank. Tried it on a single cell Powerbank and it wiped it in minutes (and the powerbank was way hotter than the jacket)!

      As for the Magyver version…at least I know it would be made right (ie. Heatsinks etc), and I think I need to so we don't burn the house down!

  • AwesomeAndrew on 11/08/2025 - 11:53

    That temperature seems pretty normal, most chips are rated to operate at 85C to 105C and some go even higher. Although the board is definitely overrated and cannot actually deliver 4.5A without destroying itself. Probably best just to go with a power bank.

    • tunzafun001 on 11/08/2025 - 12:13

      Cheers mate.It's only delivering 10w…until it gets hot, then starts dropping to 5w.
      Just trying charging my phone instead (USB C) and see what happens. Looks like it sits around 75C

      • Jimothy Wongingtons on 11/08/2025 - 13:39

        then starts dropping to 5w.

        dang, prob the best outcome….instead of you know..just catching fire straight up.

  • apsilon on 11/08/2025 - 12:20

    So a super cheap voltage converter doesn't have any inbuilt heat dissipation. Colour me surprised. Where did you think the wasted power was going?

    Anyway, look up the specs for the chip, it's likely 70degC isn't an issue for it. The housing however may not be as happy

    • tunzafun001 on 11/08/2025 - 12:37
      +1

      Yep, yep all true.

      Was just wondering if there is some way to disperse the heat on a USB (actual or a magyver setup). I figure whatever I come up with is going to get warm at 4.5A. I think the Powerbank will be cooking internally (and it's a 10 000mah pouch cell type). A near 100C usb chip near a pouch cell is probably bad.

      What do you think about swapping the usb board inside for a 65 watt board (they are like $4). Hopefully will run cooler at approx 25 watts. Maybe a small fan as well.

      ….Just got tired of hearing how cold it is when I was being cooked by the AC ; )

      Seemed like an easy solution…urrghhhh

      • apsilon on 11/08/2025 - 13:15

        What does the vest actually require? What's doing the voltage conversion in your macgyver version? Hard to say which way to go with only partial information.

  • bazingaa on 11/08/2025 - 13:12

    I use an Ozito official battery to USB adapter ($16 from Bunnings), and I have never noticed any issues like this. I took it for camping for phone charging and lights :)

    This is the new version (I have old version): https://www.bunnings.com.au/ozito-pxc-18v-usb-power-source-p…

    • JimB on 11/08/2025 - 13:54

      What is a Ozito PXC 18V 4.0Ah Battery equivalent to in terms of say a powerbank, e.g. 20,000mAh ?

      • AwesomeAndrew on 11/08/2025 - 14:19
        +1

        Convert both to Wh for easy comparison. To do this, multiply nominal voltage by amp hours (if it's milliamp hours, divide by 1000 to get amp hours). Usually power bank batteries have a nominal voltage of 3.7V, but some models may be different.
        So for the Ozito, 18V * 4Ah = 72 Wh. And for the powerbank 20Ah * 3.7V = 74Wh. So they are almost exactly the same capacity with the powerbank having slightly more.

        • JimB on 11/08/2025 - 14:25

          Many thanks.

          I incorrectly assumed that powerbanks were 5V.

          I have a 30ah powerbank already (along with some other 10ah powerbanks) can't charge my MacBook Air unfortuantely.

          Doesn't seem like I can buy any adapter for the Ozito to charge my MacBook Air either.

          • bazingaa on 11/08/2025 - 16:00

            @JimB: I am pretty sure you need more than 5V for your laptop (I have no idea about MacBooks). Some power banks can do USB PD at higher voltages.

            • JimB on 11/08/2025 - 16:35

              @bazingaa: I was hoping that the adapter could make into a PD charger since the cordless powertool battery is already 18V.

              However, I've read that you can sloooowly charge a MacBook Air with 10w/2amps.

              But really, you'd only do it if desperate. However, using a non-PD powerbank could extend the MacBook Air's battery life while you're using it, better than nothing during an emergency or long road trip.

              "The 13-inch MacBook Air with the M3 chip typically draws between 9W and 22W of power under load" So technically 10w could sustain usage.

  • joka on 11/08/2025 - 13:19
    +7

    Next time we see an overnight house fire on the morning news, we'll think of you.

  • outlander on 11/08/2025 - 14:08

    Yeah I've encountered this. Not sure I trust those drill battery attachments, but nonetheless it's a common issue with any chinese chip. They are counterfeit most of the time and built to a price, so you never want to use them at their max rating.

    The right way is to use a heated jacket designed for 18v, but you probably don't want to hear that. The second right way is use a board with genuine chips, but you probably don't want to hear that either. Third way is to use a DC-DC converter. If you buy one of the chinese ones rated for 10amps, that should give you enough headroom while still keeping things cheap.

    You can try getting thermal adhesive and gluing the chip to some kind of heatsink. Or a convenient alternative is to hook up a cigarette lighter adapter straight to the drill battery.

    • tunzafun001 on 11/08/2025 - 15:40

      Cheers. The chip is only about 7mm square (with about 4mm clearance between an inductor and cap on the other side). So would be small.

      I use the battery direct out via cigarette plug for an airbed/ paddleboard pump (really gets the 12v pump spinning). But I cant do that here, as the jacket has 3 heating modes and I guess that means there is a chip in the jacket running at 5v. Guess I could do away with all that entirely and just go battery load direct to the carbon fibre stringers inside the vest… might get a bit too warm (she wouldn't admit it even if it was on fire).

      Im thinking adding something like this. But Im pretty sure these are just 3Amp devices (so will do 15w at 5v). To get 65w, voltage increases.
      I dont think there really is a way to get something that puts out 5v at 4.5A (from an 18v source).
      https://www.aliexpress.com/p/tesla-landing/index.html?scenar…

      • outlander on 11/08/2025 - 22:46
        +1

        I was just talking about one of these ones. They are basically just DC-DC converters https://www.aliexpress.com/item/1005005631233546.html

        I dont think there really is a way to get something that puts out 5v at 4.5A (from an 18v source).

        This will do that https://www.aliexpress.com/item/1005005995019785.html. Plus a USB female socket https://www.aliexpress.com/item/1005006069394270.html

        I have a heating vest with 3 heat modes, and it's pretty dumb. As long as the power supply can maintain the 5v, it's happy.

        (Disclaimer: These are just the first listing I found, so prices aren't necessarily the cheapest out there)

        • tunzafun001 on 11/08/2025 - 23:03

          Ahh ..got ya. Good ideas alround here.

          I've got a car charger I could try. Do you think the car cig plug types will handle 18v? I have a 14.4v drill battery I'll try first.

          Like the other options as well. Much better than what it came with. Wonder if a phone will be happy with it. I bought an adjustable DC/DC step down board. Tried 4.9 - 5.5v. Confirmed voltage with a meter. But the phone still wouldn't accept it / charge.

          As for your heating vest. How do you find it?
          With this at 10w - barely on
          15w - starting to feel like body temp..but not much more than a decent insulated jacket

          So guessing it needs a good 20w plus at least..

          • outlander on 12/08/2025 - 11:48

            @tunzafun001: I mean, test it first (this is where having an adjustable current-controlled voltage supply really helps) but I was happily surpised to find out that most car adapters work on either 12v or 24v systems, and anything in between.

            But the phone still wouldn't accept it / charge.

            Yeah phones are smart devices, so they do some back and forth between the charger. At their simplest it's a resistor on the data pins, but when it gets to USB-PD you need one of dummy boards.

            I find them alright. They aren't "clothes straight from the dryer" warm, but I got mine when I was working in a warehouse in winter, and on a 4c day they kept me too warm. Mine is an older one so it draws 10w max, but I got the vest form so I could put it underneath other clothes (I figured the jackets probably weren't much chop and I was better off with a $30 kmart number)

            On the topic, what I was aiming to do but never got around to it, was to use a drill battery to power an electric blanket. Aldi sells a 12v electric blanket, and with a 18v-12v converter I think that'd be perfect for those times when its a cold morning and you're stationary (sitting down at a kids soccer match, camping etc).

    • tunzafun001 on 12/08/2025 - 13:08
      +1

      You just reminded me about the Kogan electric blanket I forgot to pull the trigger on. Great idea re: adding drill battery and making it portable.

      https://www.ozbargain.com.au/node/806441

      Will keep an eye on Aldi and Ali X
      https://www.aliexpress.com/item/1005008268954457.html?

  • hedge on 12/08/2025 - 07:47
    +2

    Not having a go here at all, but for something that's literally going to be up against a family member's body, I think macgyvering AliExpress electronics is false economy (and that's before I ask how much you value your time at).

  • Doug Dinsdale on 12/08/2025 - 15:50

    Buy a Makita vest that is built for purpose and put MacGyver out of a job.
    And avoid having your wife in the first Burning Woman Festival.

    https://makita.com.au/cordless/cxt-12v-max/clothing-lifestyl…

Login or Join to leave a comment
Login Join