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USB charging cable

Posted: November 29th, 2021, 11:14 am
by 88V8
Looking for a new workshop light. My existing light came with a mains charger, as do all my rechargeable devices.
I see that many new lights apparently come with a USB charging cable, and no charger.
Why??
How is that supposed to work?

V8

Re: USB charging cable

Posted: November 29th, 2021, 11:19 am
by swill453
88V8 wrote:Looking for a new workshop light. My existing light came with a mains charger, as do all my rechargeable devices.
I see that many new lights apparently come with a USB charging cable, and no charger.
Why??
How is that supposed to work?

Because everybody has multiple USB outlets in their home. I know I have tens of them.

(Not literally true but it's the assumption.)

Scott.

Re: USB charging cable

Posted: November 29th, 2021, 11:20 am
by GrahamPlatt
Most people now have an excess of USB chargers. Not providing one is a good thing; less “stuff”, saving the planet. If they provide one, it’d be in the price. If you need another, buy one.

Re: USB charging cable

Posted: November 29th, 2021, 11:40 am
by pompeygazza

Re: USB charging cable

Posted: November 29th, 2021, 11:43 am
by bungeejumper
Stupid question, possibly, but I've always understood that a properly smart charger 'knows' when the device that it's supplying has eaten its fill, so that it's time to stop charging for the benefit of the batteries?

How do you do that when your plugged-in devices have different requirements? Or isn't overcharging really an issue with 5.5 volts?

BJ

Re: USB charging cable

Posted: November 29th, 2021, 11:52 am
by bungeejumper

Can't speak for others, but neither of our home-office desks could manage without one of those socket towers that have ten or twelve mains sockets. And very often they come with an integral USB slot or two. Easier than changing the wall socket. ;)

Incidentally, Pompeygazza, you can generally shorten a long link by deleting everything after the initial question mark. So your link works as https://www.tlc-direct.co.uk/Products/BG822U3.html.

[Edit: It's also a good way of ensuring that your link doesn't include your postcode or other personal information.]

BJ

Re: USB charging cable

Posted: November 29th, 2021, 1:09 pm
by GrahamPlatt
These wall sockets though, I imagine they're "always on" and whilst a fairly miniscule amount, I understand that this still consumes electricity. So I'd prefer one with at least an on/off switch, or simply a separate, unpluggable charger.

Re: USB charging cable

Posted: November 29th, 2021, 1:47 pm
by Urbandreamer
bungeejumper wrote:Stupid question, possibly, but I've always understood that a properly smart charger 'knows' when the device that it's supplying has eaten its fill, so that it's time to stop charging for the benefit of the batteries?

How do you do that when your plugged-in devices have different requirements? Or isn't overcharging really an issue with 5.5 volts?

BJ


It's a misunderstanding. USB chargers, are not in fact responsible for charging any battery. Instead they supply "power" that is used by a charging circuit in the device that charges the battery.

A USB charger could provide a nominal 5V or 20V. The new PD system, older Quick Charge system or Moto's fast charger allow the device to negotiate with the "charger" to use higher voltages on the USB wires, Which allows for more power to be delivered over the same wires.

Even if you use a dumb charger that simply provides 5V, the device is responsible for stopping charging when the battery is full.

Re: USB charging cable

Posted: November 29th, 2021, 1:51 pm
by bungeejumper
Urbandreamer wrote:A USB charger could provide a nominal 5V or 20V. The new PD system, older Quick Charge system or Moto's fast charger allow the device to negotiate with the "charger" to use higher voltages on the USB wires, Which allows for more power to be delivered over the same wires.

Even if you use a dumb charger that simply provides 5V, the device is responsible for stopping charging when the battery is full.

Thanks, UD. Very helpful. :)

BJ