Power Interruption with Multi-Port Wall Chargers (GaN & Non-GaN) When Plugging in or Unplugging from Another Port

johnwickspuppy on 30/04/2024 - 11:45
Last edited 30/04/2024 - 16:22 by 1 other user

This is a PSA for people researching wall chargers that don't exhibit power interruption. There seems to be a bit of confusion on this.

You may require uninterrupted power for devices like:

• Raspberry Pi
• USB fan
• Baby camera monitor

Here is a conversation on the need for uninterrupted power if you want to be entertained.

There are claims that all GaN chargers are unable to deliver uninterrupted power. It has been called a feature of GaN but I found this to be false.

Another claim is that all non-GaN chargers are able to deliver uninterrupted power. This is also false.

Here is a Reddit discussion looking for GaN chargers that deliver uninterrupted power. The newest comment claims that such a charger does exist and provides evidence.

It seems that manufactures don't clearly specify whether their charger can deliver uninterrupted power. Maybe because this is not a big issue for most people? But it is to some and it would be nice if they could find out before purchasing.

One workaround is to plug in your device to a separate USB wall charger for devices that require constant power.

I am not a techie or wall charger expert. Feel free to add your knowledge on this topic if you know more.

• 

  bio on 30/04/2024 - 12:48

  One workaround is to plug in your device to a separate USB wall charger for devices that require constant power.

  …or a small powerbank between the charger and the device? There is a reason we invented something called "Uninterruptable" Power Supply decades ago.

  I would do that for a Raspberry Pi anyway, with or without a GaN charger.

  • 

    johnwickspuppy on 30/04/2024 - 12:52

    Great idea! I haven't heard of this one. Do all powerbanks supply power while charging? I'm guessing most modern ones would but I'm not sure.

    • 

      bio on 30/04/2024 - 13:05

      Not all of them can do. It needs to support pass-through charging.

    • 

      trongy on 30/04/2024 - 13:46

      Raspberry Pi users may want to look at a UPS designed specifically for the Pi.

      example 1

      example 2

• 

  trongy on 30/04/2024 - 13:43

  What you are talking about is the difference between a USB (battery) charger and a power supply designed for continuous power delivery.

  Most battery powered devices can tolerate short interruptions when charging the batteries.

  The interruption occurs due to the connection being reset as the maximum charging rate on the primary port is lowered when the a second device is connected (or disconnected). This is done so that maximum power can be delivered when only a single port is in use, while also allowing for safe charging of multiple devices on the same charger.

  Since most chargers are not suitable as continuous power supplies a simple strategy would be to use separate chargers - one for devices that are never removed and one for temporary battery charging.

• 

  CodeXD on 30/04/2024 - 16:14

  It sounds like the lesson here is if you require uninterrupted power for devices on a multi-port charger, make sure that all the devices on that charger requires it. In which case there shouldn't be any power re-negotiation as you won't be constantly plugging/unplugging into the port. Ofc this means you'll need all your devices in a central location which might not be the case.

• 

  Namidairo on 30/04/2024 - 19:50

  I've seen a couple of the pricier ones being reviewed wherein they don't do the PD renegotiation if conditions are met, but it's quite obviously in the minority and limited to… not cheap ones.

  Eg. https://youtu.be/qKY5SLwCwd0?t=166

• 

  Prong on 01/05/2024 - 22:21

  USB-C PD is still a bit of a mess, because there is enough variance in the possible implementations that it can cause issues.

  The USB-C PD spec doesn't actually require charger disconnection for power level renegotiation. But many chargers do so because it is the surest way to make sure the renegotiation works as expected every time. But as the electronics get smarter, we should see more in the future that don't disconnect.

  If you have a low power device like a Pi etc then Limeta EB40 is a great 10,000 mAh UPS power bank option for $30. It does 5V 3A, 9V 2A, 12V 1.5A.

  https://www.ozbargain.com.au/node/836987

  Each USB-C input / output is fully independent, so you can use it to do pass through charging and it works as a UPS with zero interruption. It also has a Bluetooth app that allows the max capacity to be set to 80% for longevity. Plus it uses Samsung INR21700-50E cells.