Eight Port USB Charger with Power Meter

How many different USB powered electronic devices do you have?  And, more to the point, how many ‘wall wart’ or ‘brick’ type chargers are you also accumulating?

Sure, with some planning, much of the time you can allow your devices to take turns at being charged, but particularly if you’re traveling (and doubly so if traveling with a companion), you’ll find occasions when you need to charge a combination of phones, headsets, tablets, music players, eBook readers, and potentially other devices too, all at the same time.  You’re not ‘only’ wanting to charge two or three devices at once, the two of you might be needing to charge six or eight devices.  Quite apart from the other problems, your hotel room might only have one or two spare plugs.

The solution of course is a multi-port charger.  I’ve written about six and seven port chargers before, but should I be proud or embarrassed to say that even seven ports is starting to get inadequate!

Happily, technological solutions are keeping pace with technological problems, and you can now find multi-port chargers with as many as ten or even twelve ports, and costing as little as $20.  That is impressive, but perhaps foolishly, I ended up choosing one with ‘only’ eight ports, and which cost more than the twelve port charger.  But I preferred the eight port charger – let me explain why.

These days the concept of ‘charging’ a device via a USB style connection has become a very nuanced thing.  In the early days, one simply connected the device to the charger, waited until a light went on or off or changed color or something, and that was that.  Chargers would charge at a rate of 0.5A max, while devices, if you left them on, might have been using power at a rate of 0.1A max, so it didn’t really matter if the device was on or off while charging.

But ever larger batteries have called for, in turn, ever faster chargers.  And, ever more power-hungry devices (particularly large screened tablets) quickly reached the point where they would use power as fast as a 0.5A charger could deliver it, with nothing left over to top up the battery.

The USB standard specification upgraded the charging current from 0.5A to 0.9A in the USB 3.0 definition, but increasingly devices and their chargers have grown to want and potentially provide considerably more – up to sometimes 2A or more.

The problem is that different devices now use different ways of signaling to chargers that they want and can accept more than the standard rate of charging current, and different chargers communicate in different ways, too.  It has become a modern-day electronic form of the ‘Tower of Babel’ problem and we never really know if our devices are charging quickly or slowly, other than by watching the battery level change over time.

So I am always very interested to know exactly how fast my devices are charging, and recently I’ve started to think that my seven port charger is charging more slowly than before.  But how to test and confirm this?  You can get nifty devices that will display the voltage and charge rate that plug into the middle of your charging circuit, but sometimes these themselves create new problems by interfering with how the devices and the chargers can communicate with each other.

What appealed greatly to me about the eight port device is that it has an LCD screen that shows the voltage it is providing to all eight ports, and then shows, individually, the rate that charging current is being supplied to each port and the device connected to it.

Which means there are no mysteries.  You instantly can see the charge rate on all eight ports, just by looking at the screen.  While it hasn’t told me what my old charger may have been doing, I sure can tell now what my new charger is doing and will immediately know if it mysteriously slows down in the future.

The unit will provide up to 8A of current (ie 40W) of current in total across all eight ports, and I’ve had devices taking as much as 2.5A per port.

Which brings up one more relevant item on its display.  It shows the total wattage it is supplying.  It would be easy, if taking 12.5W per port, to quickly exceed the 40W maximum, so it is helpful to keep an eye on how much it is providing in total.

I managed to have devices charging on all eight ports, and consuming 40W of power simultaneously.  But as soon as the unit tried to supply more than 40W, a safety breaker tripped then reset, tripped then reset, limiting the current.

I adjusted the devices so they used a little less than 40W, and noticed the device got very hot indeed on its underside while providing almost its maximum 40W, and after about 15 minutes, it cut out.  Fortunately, this wasn’t a permanent failure, it was simply another safety measure – a thermal overload sensor.  After a few minutes, it reset and started charging again.

It seems that if you have air flowing under the unit, it cools much better and can provide almost 40W long-term, but if there is no air flow underneath, it seems to max out at maybe 37W.  With the heat being generated, the thermal cutout seems like a sensible feature to include.

So in round figures you can average almost 1.0A per port.  If you just have a few devices plugged in, there is no problem if they are drawing 2 or more amps each, as long as the total current is just under 8A (ie just under 40W).

Testing confirmed that the unit was accurately displaying both its voltage and its current draws (and therefore, also, its wattage).

Update

The unit I purchased is no longer offered on Amazon.  So now I’m recommending a better unit (the picture at the top has been updated to show it, and so too have the links) – still with eight ports, but now with a total wattage capability increased from 40W to 60W.  This is a practical improvement – as you can see from the picture above, it was possible (but rare) to max out the earlier charger with just five of its eight ports in use.  The replacement unit retains the same display showing charging rates on every port, which we suggest to be an essential feature.

Summary

The eight-port multi USB charger is a great device that gives you a lot of information about what the units you are charging are doing and how much current they are accepting.  While you can probably live without this information, for only a few dollars more than a generic charger that tells you nothing, there’s no need to do so.  The unit is light and portable and so great to travel with.

Priced at $35 on Amazon, it is a good price and a great way to charge up to eight items simultaneously.