23:14 · Plugged in
Your charger doesn’t know when to stop.
This one opens the circuit at 100%.
ChargerGuard
Charging · 18%
A normal adapter
—
23:40 · Charging
Smaller than the plug it feeds.
29 mm across. 11 mm thick. It lives on the cable.
01:02 · Cut
100%. The relay opens.
Not a slower trickle. A physical break in the circuit.
03:30 · Nothing happening
This is the part you’re paying for.
Five hours a normal adapter spends pushing current into a full battery.
05:40 · Still cut
No app. No account. No firmware.
It reads voltage and opens a switch. That’s all.
06:41 · Morning
Full, cool, eight hours younger.
The same 100%, without the heat.
How it works
Three parts, one decision.
There is no intelligence to explain.
-
Voltage sensing IC
Reads the battery, not a timer. A full one stops pulling.
-
Overcharge protection MOSFETs
Carry the load safely up to the moment the relay opens.
-
Safety cut-off relay
A mechanical switch. Open means an air gap, not a setting.
The dead hours
What a full night costs.
Most phones finish in three hours. The rest is holding full at full.
5hours
Already full, still plugged in.
—cycles/yr
Every return from 99% to 100% spends part of a cycle.
—kWh/yr
Current paid for and spent entirely on heat.
The dashes go in once a unit has been on a meter. Not before.
Specifications
What you’re buying.
| Connector | USB-C in, USB-C out |
|---|---|
| Cut-off | Relay, opens at full charge |
| Pass-through | Up to 30 W |
| Size | 29 × 29 × 11 mm |
| Body | Polished zinc alloy |
| Indicator | Single LED — lit while charging |
| App required | None |
| Subscription | None |
| In the box | Adapter only |
Order
One adapter. One job.
Then it gets out of the way.
Does it work with fast charging?
Yes, up to 30 W. Above that it limits the rate rather than blocking the charge.
What happens in the morning?
Unplug, plug back in, the circuit closes. Nothing to press.
Will it work with my phone?
Anything that charges over USB-C. It reads the line, not the phone, so there is no compatibility list.
Is it safe to leave in?
That is the point of it. An open relay is a gap in the circuit — safer than a charger left carrying current.