Edit: see comments for clarifications.
I am probably late on this one, but god damn this is one nasty trick by Philips.
Context; I recently decided to upgrade my shaver, from a Philips One Blade to Philips an all-in-one-trimmer-7000. As you can see on the pictures below, they changed the charger for the adapter by maybe 1–2 millimetres, just so the old charger could not be used by the old charger. Now, this normally isn’t a big deal, but with the new trimmer, the charger is USB-A only. Where’s the previous one had the plug on it instead. To me this is mildly infuriating as I know need to get an extra adapter just to charge my shaver in the bathroom. They had the exact same design for the chargers, yet changed it just slightly so they wouldn’t be able to be reused? Why… Philips… why?
Edit: many good points in the comments! I don’t know how to manually check the voltage, but seems like folks figured it out in the comments too. Should have just been USB-C!
A lithium battery needs a charging pattern that reduces voltage as it gets closer to full. And overcharging a lithium battery gets real spicy real quick. You also don’t want to charge them too fast because spicy.
Nicad and nimh batteries (I erroneously said alkaline above) don’t, you just blast it with a steady voltage until it’s done, with some nuance for nimh that’s not worth diving into here.
Makes 0 difference. The charging circuit is in charge of that logic and will accept whatever voltage is supplied (within spec) and step it down to what the battery needs.
thanks!