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Laptop is EVGA SC17 Usb-c 3.1 (non thunderbolt) Battery 3.7v 550mah

Ok so i stupidly was hotwiring a battery to charge via my laptops usb-c port, I know i should have used my powersupply or even a usb hub but I was lazy and stupid.

What i did was hooked up the positive to the negative and the negative to the positive (reversing the polarity) did I just fry the laptop by pumping the 3.7v 550mah into the usb-c port?

I immediately unplugged it after the laptop shutdown, the laptop is now not powering on and there is no lights from plugging in the power cable etc.

Is it fixable? There is no smell of smoke and i would assume the laptop has a reverse polarity safety protection.

Any advice is greatly appreciated.

Edit add- the laptop was on battery power only at the time of the reverse polarity incident.

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    What you did is basically short circuit the USB port.
    – Daniel B
    Commented Mar 19, 2023 at 14:40
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    @DanielB worse, a battery connected to the system ground via the USB port could essentially reverse-voltage everything in the system that is on a voltage lower than the battery voltage. It is common in electronics for the 0V/GND to be universal and connected across all components and so anything running at less than 3.7V would have had its ground raised up above its power supply and see a reverse current.
    – Mokubai ♦
    Commented Mar 19, 2023 at 14:43
  • @Mokubai: Seems like poor design of the laptop if true. Otherwise if most USB ports are that vulnerable, why do “USB killers” go to the trouble of using voltage multipliers to generate thousands of volts before dumping the capacitor? Plus some devices have been known to resist even such attacks
    – James P
    Commented Mar 19, 2023 at 14:53
  • I will open it up and report back with my findings.
    – WherEmEweeD
    Commented Mar 19, 2023 at 15:12
  • @JamesP USB killers do it for thoroughness. There may be better protected devices, or they are trying to overload better designed systems with layered power defenses. If you want a device guaranteed to kill anything you plug it into then you are inevitably going to over-engineer it. Not every device is designed as well as you'd hope and engineers are only human and do make mistakes with this kind of thing. They may have protected the data lines and not the power ground, or designed in all the protection and left it off in the final design to save costs.
    – Mokubai ♦
    Commented Mar 19, 2023 at 15:17

2 Answers 2

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A bit arm-wavy, but as first guess…

You wouldn't imagine 3.7V to be enough to kill any circuit… but had it been diode-protected nothing at all would have happened. So, fried or not, something was badly upset by it. First test would be to disconnect that USB bus from the mobo & test again. Otherwise, repair shop.

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    The problem is more that the battery voltage was reversed. It could have done something very weird to the ground in the system, potentially pushing a large current through it and exposing components to some current going in very wrong directions. Components on a 1V supply, like the CPU and its related power supplies, suddenly seeing a voltage of potentially around -2.7V might fail horribly.
    – Mokubai ♦
    Commented Mar 19, 2023 at 14:39
  • I will open it up and report back my findings also attempting to disconnect the usb component thanks for the advice.
    – WherEmEweeD
    Commented Mar 19, 2023 at 15:13
  • postimg.cc/YhSWp9Yp and postimg.cc/ygBD2Y7C iam no rossmann but i see no physical damage to any small components. Theres no apparent way to disconnect the usb as it is built into the motherboard unfortunately. Its looking like a laptop repair specialist is required any recommendations?
    – WherEmEweeD
    Commented Mar 19, 2023 at 16:35
  • I feel like the guy louis rossmann openly mocks blowing ppbus g3hot lol
    – WherEmEweeD
    Commented Mar 19, 2023 at 16:45
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So I opened it up and unplugged all components from the motherboard, and then I checked for blown diodes, capacitors, etc and removed the CMOS battery it started up fine I replaced the CMOS battery put it back together, and it's working fine.

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  • Could be a resettable fuse protecting the battery was triggered then. Glad it was something relatively minor.
    – Mokubai ♦
    Commented Mar 19, 2023 at 19:57

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