Zendure X5 Charging MacBook (USB-C)

Following up from the lackluster results I got with the Anker PowerCore Fusion 10000, I tried again with a Zendure X5 Portable Charger (still using the Anker cable). I topped it off overnight using the PowerCore Fusion, and did a quick instrumented test with the early-2015 MacBook 12" Retina. Success!

Zenure X5 charging MacBook (measured by Klein ET920)

I had high hopes for this power pack, since it advertises “USB-C: 5V/3A, 9V/3A, 12V/3A, 15V/3A, 20V/2.25A, 45W Max.” Sure enough, connected to the MacBook they negotiate (according to the Klein) 20.02V at 1.38A (a little better than what I expected), which my calculator says is 27.7W and the MacBook reports as 30W. coconutBattery shows the MacBook charging at 1.4-10W depending on what the computer is doing (in regular use on battery only, it typically shows 8-10W discharge). This is acceptable.

MacBook % system_profiler SPPowerDataType
    ...
    AC Charger Information:
      Connected: Yes
      Wattage (W): 30
      Charging: Yes

Next up: How much capacity do I really have in the Zendure. (Can it recharge a ~4100 mAh battery from below 10% to full?) I just topped off the battery pack and I’m running the laptop down... Film at 11.

Charging While Using

For my first test, I hooked up the Klein inline between the Zendure and the MacBook and proceeded to use the laptop. It spent some time copying files over WiFi and streaming music to an Apple TV, while I caught up on email via GMail and Apple Mail. The Zendure X5 was full (four solid lights and the Klein - inline between a wall charger and the battery pack - was showing 14.76V and 0A). I started off with the laptop at about 10% charge - 423 mAh - according to coconutBattery (though right before showing those numbers, it was reporting 9.3% charge, 378 mAh); call it about 3.2 Wh. It had just popped up the low battery warning:

Over the course of about 1 hour 32 minutes, the battery charge climbed to 83.2% (3451 mAh) before the Zendure was exhausted and stopped providing power. coconutBattery generally reported the system charging with ~16W throughout, system_profiler saw a 30W adapter connected (the Klein reported ~20V and ~1.38A consistently). At the end, the USB multimeter reported 2123 mAh and 42.8 Wh total; by my estimates, about 23.24 Wh ended up stored in the MacBook’s internal battery (26.1 Wh stored):

This wasn’t the best raw capacity / efficiency test, as I was using the machine with a variable load while charging. I’m going to re-run this with an idle machine (sleeping, lid closed), and with the MacBook shut down completely. But back of napkin math says the internal storage of the Zendure should be about 54.45 Wh (assuming the 15,000 mAh capacity is accurate, and that it’s using 3.63V batteries). If it actually sent 42.8 Wh over the wire, that’s about 79% efficient, which is a little lower than I’d expect (but maybe efficiency drops at 27.7W ... But for a charger rated at 45W ...?), but within the realm of the expected.

The Mac’s internal battery (degraded over ~7 years and ~300 cycles) is down to a reported 4146 mAh, or 31.44 Wh (7.55V). The Zendure should be able to bring it back up to 100% charge, at least when shut down, but I don’t know how much loss I’ll see as the Mac charges.

(To get the battery back to 100%, I hooked the MacBook up to the factory 29W USB-C charger through the Klein, and measured another 592 mAh (8.88 Wh), which brought the battery up to 100% reported by Apple’s menu bar icon, 99% (4102 mAh) reported by coconutBattery.)

These numbers mostly align. If the battery pack was sending 27.7W and the machine was charging at 16W and using about 10W average while running, all of which match my not super scientific observations, then I’m very happy with the recharge capacity of the X5.

Charging at Idle

Update: Had an opportunity to charge the MacBook from approximately 1% to approximately 97.4% (exhausting the fully charged Zendure). That took about 2.25 hours, though it was mostly done (last white light blinking, and charging slowed to a ~3W trickle) at the 2 hour mark.

11:05, 63 mAh, 1.5% (reported by coconutBattery), charging with 11.4W (screen on)
13:05, 4013 mAh, 95.7% (ditto), lid closed for 2 hours, charging with 3.26W (screen on)
About 15 minutes later the Zendure was empty and the MacBook was up to 4140 mAh (97.4%). A charge of about 30.8 Wh. 

coconutBattery showing the charge state, starting, at 2 hours, and final

I didn't have the Zendure connected through the Klein (long story), will have to repeat the test with more observation to really get a feel for efficiency. But knowing I can basically go from zero to essentially fully charged with the Zendure and this MacBook is good enough for now. Though it really does highlight how essentially worthless stated capacities are on these battery packs; 15,000 mAh should be able to fully recharge a 4140 mAh device once with capacity to spare. But in reality ... Not so much.

Charging the Zendure

Hooked up to the PowerCore Fusion through the Klein USB-C to USB-C, I’m seeing just under 20W (~9V at ~2A) when recharging the Zendure X5.