USB Chargers: Pros and Cons

Very new here. From what I’ve seen people either love or hate chargers with USB power supplies. I wanted to learn more about the pros and cons.

I’m interested in the perceived versatility - like being able to plug it into my computer, laptop, or a solar charger, and with only 2 plug adapters (rather than two separate cords) can plug it into a wall outlet or car charger as well.

From what I’ve read, the cons are (1) finding an adequate plug adapter to get sufficient power, (2) li-on charging safety concerns, (3) USB wasn’t intended for a large charging platform.

Any information is helpful.

1) If you want maximal charge speed it can be tricky, but as a start use my list:
2) Not different from any other LiIon charger and you avoid all the mains safety issues with the charger (But have them with the USB power supply instead).
3) Usb has changed over time, to making more power available. In the future you might be able to draw 100 watt from a usb supply, today it is usual in the 10-20 watt range.

These pretty much seems to sum things up! But any other thoughts or considerations are welcome (helps me learn).

My VC4 has a nice display but is not the fastest charger. has a weird cable too, not standard.

surprised someone hasn;t said this - but a CON is “wait time”.

you have to wait for the light to recharge.

If you have a charged cell in the charger, just swap and go.

Of course you can still do this - if you have a charger and spare cell - but then why have USB?

The obvious other CONs are weight, expense, and potential water leakage or damage to the USB port itself (i find it gets clogged with pocket lint, for instance).
Even if it has a plug to cover it up, that becomes something else to fiddle with and break off eventually.

Outside of the first point, this is why I’m a fan of the batteries themselves having a USB port for charging. No worries about the host being more fragile.

problem with that [charger inside battery] is, it reduces battery capacity, because the charger takes up space inside the battery
the smaller the battery [16340], the more reduction is necessary
plus now it makes each battery cost more, not just one charger, or one light, now it’s X number of batteries, all of which are inferior to batteries without charging built in
just saying


Pro for USB Chargers:

  • Lot of power sources worldwide usable
  • Depending on plug every microUSB cable works
  • Independend from AC outlet (charge everywhere, anytime)
  • higher efficency (no own SMPS is needed)
  • longer lifetime (less parts who can get faulty)
  • more flexibility with cable length
  • with USB QC or PD up to 100W are possible

Good examples for USB Chargers:

Please take care with certain USB to micro-USB cables and devices. I've tested the cable which comes with Lii-100 and Lii-202 units, it's a dummy cable with bridged data lines. You can use it to connect the battery chargers to standard USB power supplies (what you call phone/tablet chargers), or to connect the battery charger in powerbank mode to a phone/tablet… but please avoid connecting the battery chargers to computers/laptops with them! There won't be power negotiation if you do this and thus, as the computer ports are only designed to supply a maximum of 0.5A per USB/USB2.0 standard, if you go beyond this it is very likely that the computer will force shutdown the port, there will be current tapering because of voltage drop… or even magical smoke/port burn out (unlikely but possible)!

You're warned!

Cheers :-)

VERY good to know. Thanks a bunch, Barkuti!

USB supplies bus power across VBUS and GND at a nominal voltage 5 V ± 5%, at supply, to power USB devices. Power is sourced solely from upstream devices or hosts, and is consumed solely by downstream devices.

This is not really valid anymore, usb voltage can in some cases be increased to higher voltage and with usb-c devices power can be drawn either way.

With USB QC, voltage can be requested and delivered from 3.6-20V.
USB-C can request/transfer/deliver up to 100W.