Author Topic: Charging the HC-2b from a computer or USB hub, or other devices  (Read 1032 times)

G8B4Life

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Charging the HC-2b from a computer or USB hub, or other devices
« on: February 02, 2018, 09:04:32 AM »
This is not really a guide as such but some general information on what's needed to charge the HC-2b when your don't have the PA-3 charger available.

Charging the HC-2b from a computer or USB hub, or some other device

Despite what's contained in the HC-2b manual, it is possible to charge the HC-2b from a computer or USB hub, or some other powered USB port.

The information contained in this guide is useful if you've gone somewhere and you've forgotten your PA-3 charger, or the charger is broken and you have no replacement. You will need the correct equipment to charge via these methods.

Some background

Ring Engineering's statement in the HC manual that the HC-2b cannot be charged from a computer USB port is true up to a point, plugging in a standard USB cable into a standard USB port will not charge the HC-2b. Standard USB ports on computers and hubs are limited to 500mA each by the USB specification and the HC-2b requires 1A (1000mA, the rating of the PA-3) to charge. Secondly, when a USB cable is plugged in to the HC-2b and the computer the data pair (wires) in the USB cable are connected giving access to the device which the HC-2b software then prevents the HC-2b from charging. When the USB cable is plugged into the PA-3 the data pair are not connected to anything so the device can charge.

About USB cables

A standard everyday USB cable is not usually sufficient for charging the HC-2b. The wires in a USB cable designed for charging should be specified with larger diameter conductors for the pair of power wires. A cable designed for charging may also have a pair of Type A plugs on it though single plug cables are available, such as the cable supplied with the PA-3. A cable with two Type A plugs may be more desirable in using a computer, hub or other powered USB port than a single plug cable. The image below shows a USB cable designed for USB devices that require more than 500mA of current which is useful for our charging purpose. The cable specification shows 28AWG for the data conductors and 22AWG for the power conductors.

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As mentioned, the cable shown has two Type A plugs. The cable is designed to use power from 2 standard USB ports to provide power of 1A (500mA x 2). Out of the box this arrangement of using the two plug simultaneously will not work for charging the HC-2b.

To charge the HC-2b from a powered USB hub

Many powered USB hubs (that means you plug in a powerpack, or wall wart into the hub) contain one or more high powered / charging ports able to deliver up to 1A of current. This matches the rating of the Ring Engineering PA-3 and the ports should be able to be used.

The image below shows a high powered port on a powered USB hub.

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In the case of this hub, the high powered ports are marked with a lightning bolt. If you have a powered hub check the specification for it to see if it has high powered / charging ports.

To use the two Type A plug type of cable plug the "Charging" plug only into a high powered / charging port on the USB hub. If the port does not provide enough power, see the workaround in Charging from the computers USB ports or non powered hub below.

You can also use the USB cable provided with the HC-2b on a high powered / charging port but you'll need to perform the same workaround .

Charging from the computers USB ports or non powered hub

Some computers may contain built in high power / charging ports (check the specifications for your computer to find out). If it does then you should be able to plug the "Charging" plug only into the high powered port on the computer as per a powered hub.

If the computer doesn't have any high powered / charging ports you can still charge from the standard USB ports using the two Type A plug type of cable shown by plugging in both plugs. To do this you need to prevent the data pins in the "Data" plug from connecting. There are as many way to do this as your imagination allows but the simplest is to place some thin tape such as polymide tape (better known as Kapton tape) over the pins for the data pair in the "Data" plug. The Data pins are the middle two pins in the plug.

Charging from other powered devices.

Many things come with high power / charging USB ports these days, powerboards being a good example. The high power / charging ports should be able to be used if they can deliver 1A of current and you use the correct USB cable (such as supplied with the PA-3) however the ports in these devices may not have as good voltage and current regulation as USB ports in hubs and computers so there is increased risk in using these types of devices to charge the HC-2b. You have been warned!

Final notes...

If you have a high powered / charging port available on a hub or computer you may still get a "Fault - Charger under current" warning from the HC-2 when charging from the port. If you have a charging cable with the two Type A plugs you can use both plugs (remember to "blank" out the data pins in the "Data" plug), one in the high powered port and the other in a standard port. This should theoretically give you 1.5A of available current.

- Tim
« Last Edit: February 02, 2018, 09:11:21 AM by G8B4Life »