Galaxy S10's PowerShare reverse charging speed test with Samsung Buds and Watch Active

You won't get mAh-for-mAh transfer efficiency, of course, as some of the energy will be lost in the process, but still, the batteries of Bluetooth buds or smartwatches are so small, that the feature may actually useful without bringing you a range scare. That's especially true if you are charging from the larger Galaxy S10+ with its 4100 mAh battery pack. Or is it? Let's see what we found out.

We drained the 252 mAh battery in Samsung's wireless charging case by constantly topping off Galaxy Buds until the case was completely dead, turned on PowerShare from the status bar switches, and placed it empty on the back of a Galaxy S10e. The phone was with a case, as that is the most likely usage scenario of Samsung's reverse wireless charging - in our case, the official Pattern Cover. In a short while, the case's LED indicator lit up in red, indicating that the case is charging. 

In a bit over three hours, the light turned green, and the phone beeped, indicating a fully charged case. Indeed, the PowerShare stats showed 3 hours and 2 minutes for Samsung's Galaxy Buds wireless charging case to go from zero to hero. This gives you another 7 hours of listening time, says Samsung, after you charge two completely wasted Buds by placing them into their respective places in the case. 

With each Bud carrying a 58 mAh battery that we drained completely, we then wanted to see how long it will take the case itself to charge Samsung's new wireless earphones to full capacity. Lo and behold, it took the case 1 hour and 17 minutes to transfer its charge to the Galaxy Buds via the cradle pins. Not too shabby, as that gives you roughly another 6 hours of listening time at mid-volume levels. The phone battery consumption during that PowerShare time was also not that terrible - the S10e pack went down about 25% in the process of completely charging the Galaxy Buds' case.

Next in line was the other gadget that we figured will be the most likely to be charged wirelessly, the new Galaxy Watch Active that packs a 230 mAh battery cell. In comparison to previous devices, this battery is quite a bit smaller. However, the display isn’t as big as previously and there is also a much newer processor – the dual-core Exynos 9110 – which is drastically more efficient. 

As a result, battery life isn't taking that much of a hit and we still got a day or two out of it, depending on usage intensity. How long to bring it from a dead state to a 100% charge with just your Galaxy S10's PowerShare? Well, it's again a 3+ hours affair (3 hours and 26 minutes, to be exact) despite that its battery pack is a tad smaller than that in the Buds' case. 

The battery of the phone itself, however, discharged faster than when we used PowerShare to top off the earphones' case. We placed the Galaxy Watch on the back of the phone together with its straps, of course, as that's the most likely scenario someone would slap it on there to charge wirelessly. They prop it up a bit compared to the completely flat bottom of the case, hence the distance from the coil may have been slightly higher. Alternatively, the Watch may simply be able to take in electrons much faster and induce higher efficiency losses in the process. 

In any case, it gobbled more than 40% of the Galaxy S10e battery for the full charge in this real-life test - phone case, Watch straps and all - as you can see from the battery discharge graph here, even though the phone showed 29% PowerShare consumption in the battery stats.