When we reviewed Mipow’s original Power Tube 2200 Universal Mobile Charger, we liked its looks but not its performance: the actual charging speed was slow, and there was no remaining charge indicator or even a power button. The company has now expanded the line to include Power Tube 3000 ($49) and Power Tube 4000 ($69), both of which offer clear physical improvements over the original model. New features make these accessories much more practical solutions for on-the-go charging.
As nice as Power Tube 2200 looked, 3000 and 4000 are even nicer. Rather than an cylinder, both Power Tubes are extruded rounded rectangles, stretching the “Tube” name somewhat. They have the same footprint, though 4000 is half an inch longer than the roughly 3.75” 3000, differences attributable to the sizes of the batteries inside.
Rather than separate cables for charging Dock Connector-equipped devices, Power Tube has a pretty ingenious cap mechanism. On the outside is a USB port for plugging in a cable and charging whatever sort of device you’d like; a Micro USB cable and a USB extender are both included. The entire top surface is also a combination power/battery indicator button, with imbedded LEDs showing the remaining charge. Popping the cap off—it’s attached via a nylon-thread covered cable—reveals two plugs: one USB, the other Dock Connector. The USB port is for recharging the battery inside of Power Tube, while the Dock Connector port can be plugged into any supported iPhone, iPod, or iPad. Unfortunately for users of Apple’s tablets, this battery only outputs at 1 Amp, or half speed for the tablet; this is fine for full-speed iPhone and iPod charging.
A bigger disappointment than the charging speed is the actual charging capability.
On paper, 3000mAh and 4000mh batteries are pretty hefty, so we were expecting great results. One of the best battery cases we’ve tested over the past few months, Ibattz’ Mojo Removable Battery Case, packs a 1500mAh battery that delivered an impressive 85% charge, while the very popular Mophie Juice Pack Air with the same size battery delivered 70%. Even extrapolating from the lower-performance model, we expected to get somewhere in the 130-150% range from 3000, and 180-200% from the larger model. Mipow specifically claimed 1.5x and 2x battery performance. Our testing suggested that this was somewhat overly optimistic.
We tested using an iPhone 4S and an iPhone 4, both powered on, with their screens off, no audio playing, and connected to Wi-Fi—the 4S was also connected to 3G. Power Tube 3000 provided a charge of 115%, while 4000 came in at a slightly higher 139%.
