My wife made an inductive LED, which is just a few loops of wire and an LED. It will light up, or flash, when there is flowing electricity nearby. It’s fun to hold it up to various electrical things and see what energizes it.
The electric toothbrush charger made it flash more consistent and stronger than a much more powerful inductive phone charger. That was the charger for the old and dead electric toothbrush that looked the same as the charger for the new electric toothbrush, so I’d just left the old charger in place. I pulled out the one that came with the new toothbrush, and though it looks the same, it didn’t light the LED nearly as much.
I left the new one in place, and put the old one in my travel bag. I’m sure over the life of the toothbrush I won’t even save enough money on electricity to buy a tube of toothpaste, but it was still interesting that someone at Braun thought it was worth redesigning the inductive charger to be more efficient.
Without any fine tuning by the user, I think they’re only accurate in a statistical, aggregate sense (which can still be useful). The one I believe is most accurate is Sense (https://sense.com/); this includes an app that lets you identify devices it spots but can’t identify. Once the initial tuning is done it’s fairly accurate for larger loads. An increasingly confounding factor is the trend for loads to appear as a generic AC-DC converter to the meter, masking device-specific clues.
I’m not sure. The old one still works to charge the new toothbrush. I don’t know details about how inductive chargers work, so please correct me. They appear to send out pulses of current, and then if they somehow detect that something is ready to be charged, they switch to a state of providing full power.
The LED on a coil made this really obvious. I could set it on an inductive charger for a phone, and there’d be little blips from the light. Then I could set my phone on top, and the light would come on steady. (Or maybe it flashed quickly?)
Anyway, the old toothbrush charger was bright and frequent flashes. The new one was less frequent and dimmer flashes, like on a phone charger.
This also got me to test, could I charge the toothbrush using my phones wireless power sharing feature? I could get the LED on the toothbrush to light up doing that, but it never actually charged.
ETA: related thought to keep this sort of on topic.
Along with the vampire drain threat of 20 years ago, was the more recent minor panic that wireless chargers were supper inefficient and going result in turning back on coal plants or something. It can take twice the power to charge your phone wirelessly as wired, due to losses!
