The Demon Razor that Wouldn’t Turn Off
What do you do when a battery-powered appliance won’t turn off? And when it’s a sealed unit, so removing the batteries is impossible? And when its body starts to grow disturbingly warm? That’s the situation I found myself in a few days ago.
Riddles in the Dark
I was working at home one night, and gradually became aware of a strange buzzing sound. Initially I thought the sound was outside, but when I went to investigate, I discovered it was coming from the bathroom. My skull shaver, plugged in and recharging, had mysteriously turned itself on and the blades were spinning away. Pressing the on/off button had no effect. Unplugging the charging cable had no effect. The body is a single piece of molded plastic, so there was no non-destructive way of opening it. Nothing could stop the whirrrrrrrrrr of the blades, and the shaver was noticeably warm.
I started to panic that the razor would explode. The internal battery is likely lithium polymer, and from my days with RC cars and aircraft I know that defective or damaged LiPos can fail catastrophically. Like literally go boom and eject flaming molten goo everywhere that burns down your house.
I quickly took the razor outside, and set it on the concrete patio, blades whirring this whole time. A couple of minutes later, I began to fear that it was still too close to the house if it exploded, so I moved it to the street. Thankfully it didn’t explode, and those blades kept whirring for 90 minutes, during which two people stopped to ask what the horrible noise was.
A Tale of Two Chargers
So what caused the skull shaver to go crazy? Bad charging. Besides this manly pink skull shaver, I also own a more conventional Norelco cordless shaver. I’d never noticed it before, but the chargers for the two shavers have the same plug at the end of their cords:
A quick check confirmed that yes, I’d accidentally plugged the skull shaver into the Norelco charger. Is that bad? You might think that the plug shape is standardized, and that all charger plugs with this shape are designed for the same voltage. Let’s check. Here’s the skull shaver charger, which is nicely labeled. 5V output, max 1000 mA:
And here’s the Norelco charger. Instead of a label, its specs are molded into the charger body using impossible to read tiny-sized black-on-black lettering. Yuck.
But if it’s tilted at just the right angle to the light, and you get your reading glasses, here’s what emerges:
15 volts! Ouch! I charged a 5 volt device with a 15 volt charger.
I’m suddenly nostalgic for the days when real on/off switches physically disconnected the power. Many of today’s electronic appliances have a soft on/off switch that’s really just an input to some controller circuitry. When soft switches work, they’re great. But when something goes wrong with the control circuit you suddenly have a zombie appliance that can’t be shut off. In the case of this razor, the 15 volts apparently killed the control circuitry before the LiPo battery could be damaged to the point of explosion by over-charging. And the failure mode of the control circuitry was to fail ON.
Have you ever made a similar charging mistake, or exploded a battery through mistreatment? Leave a comment below and tell your story!
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I’ve now had similar issue with the Freedom-Grooming shaver. Unfortunately, it’s just a defective unit(s), as I only have the one charging cable to use.
One end into the shaver and one into USB. I’ve had two now go fritzy like yours.
My freedom shaver does the same thing. It decides to start running whenever it wants.
Just had this happen with a 26-month old Skull Pitbull Gold Pro. I’m reasonably certain that I have _always_ charged it with a 15-volt shaver charger so I guess props to that battery for taking the abuse for so long.
What’s interesting about those charger plugs is that they are not identical. One of my 15-volt shavers will not accept either 5-volt cable I have handy, but IIRC I have another 15-volt shaver that will (but not charge from it).
Just walked into the bathroom and discovered my husbands skull shaver had turned it’s self on. The only charger we have is the factory supplied charger. Various attempts to default turn off to no avail. It sits in the drive-way spinning it’s life away. Thankfully I work from home and was able to take care of it and our house won’t burn down. It’s at 54% battery life. It was be interesting to see which comes first. Dead battery or flames.
My Wahl 9818A just started doing this at 3 A.M. in my hotel room. I didn’t bring its charger, nor do I have a screwdriver! I MacGyver’d my way down to the outer case using a pair of mustache scissors (which are now pretty mangled) but the screws securing the plastic inner case are preventing me from opening it up completely and doing something like snipping the battery lead wire, so I currently have in the bathroom with the door shut, wrapped in 3 towels. It’s now 4:45 A.M. and quiet enough for me to go back to sleep now… at least in theory, because now I’m wondering what will happen if the batteries explode… in my D.C. hotel room a few blocks from the White House.
Oh, and in the future, if it doesn’t have some kind of switch that can physically cut power, I’m not buying it!
My Babylise shaver turn on 11:55pm. I tried to turn off but switch is not turning off. I took shaver in my garden as my parents are sleeping and I am worried its might blast of flame. Now waiting to see in the morning what happened with shaver.
My Pitbill gold has just started on its own,
won’t turn off,
i’ve put it outside after reading this
only ever charged it once when new and used twice.
will call them in morning
it’s whizzing round outside in the driveway at 76 percent