Surface 3 charging issues

Hello,

I did some further testing given the materials that I had, and here follow my observations & conclusions, after I tested some scenarios.

What I have used for the tests in one or another combination:

• Surface 3 (if in active use then always low Display level (<20%) and not  more than only one simple application running – no gaming, all to keep loading at a low level)
• Package with separate MS power Jack and MS USB power cable (all part of the Surface 3 package)
• 1m USB cable (USB plug <-> Micro-USB connector) for connecting PC to a mobile device, AWG rating for Power: 24 (see also the following excellent  article on why this rating concept may be very relevant here as well: http://goughlui.com/2014/10/01/usb-cable-resistance-why-your-phonetablet-might-be-charging-slow/ )
• 3m USB extension cable (i.e. “Male – Female” with same connector size), AWG rating unknown (will check and add in this post when I back home)
• Samsung USB Phone Wall Charger (came with the package for a Samsung S4 Mini mobile phone) with a longer wire (equal in length to the MS USB power cable)
• Lenove Thinkpad laptop with 4 USB slots of which one is a Power USB port (battery logo included). This is a large laptop  that I have for my office work and is used in this test as a “power bank” option through its Power USB port

Here are the scenarios and the observations I made:

Scen.1 (Surface 3 + MS Power jack + MS USB power cable)

Results: always OK (always charged the battery, in good pace, and always up to 100%)

Scen.2 (Surface 3 + MS Power jack + 1m proprietary USB cable)

Results: Mixed :  1x  OK, but also  1x Power Connected, NO charging, and battery level decreasing

This is in line with observation by others in this thread, suggesting that there may be a too large voltage drop in the USB cable (which has a standard, good AWG spec for its resistance) since the MS Power jack itself is not the problem (Scen. 1)

Scen 3a: Surface 3 (active use) + MS Power jack + 3m USB extension cable + MS  USB power cable)

Results: Power Connected, NO charging, and battery level decreasing

Suggests a too large voltage drop over the extension cable, since after removal of the USB extension cable (i.e. returning to Scenario 1) normal charging resumes

Scen 3b: Surface 3 (sleep / hibernating) + MS Power jack + 3m USB extension cable + MS  USB power cable)

Result: Overnight change from 62% to only 78%, suggesting trickle or interval-based charging

Scen. 4a: (Surface 3 (active) + Laptop in SLEEP mode + 1m USB cable)

Results: almost always OK, charging in good pace

This suggests that the Laptop as a power bank functions generally well (but see Scen. 4b). However when the Surface stays connected to this power source and is then restarted after been shut-down, it tends to reject the source and drain the battery instead.

Scen 4b: (Surface 3 (active) + Laptop ACTIVE + 1m USB cable) 

Results: Power Connected, NO charging, and battery level decreasing

When the laptop takes some power itself (just activated, no programs running, so tiny amount) the Surface rejects this power source

Scen 5: Surface 3 (active) + USB Mobile phone charger

Results: Mixed 

When connecting the Surface to the wall charger it generally did not charge, except for one instance, namely just after it was disconnected from the laptop power and then directly connected to the wall charger. Also, the chance of success seems to increase if one first connects the charger to the Surface before the wall charger is plugged in the wall outlet. In case it is charging, the charging goes well in good pace, the wall charger gets hand-warm (but not warmer than when charging a mobile phone) and the Surface battery gets fully charged.

Of course there are many more possible combinations and resulting scenarios, but from the observations in the given scenarios it becomes quite clear that:

1. The power charging capacity of all of the chargers is not the problem
2. There are very strong indications that the threshold voltage level at which the Surface accepts the charger is too high (and maybe even too close to the MS charger voltage (5.2V) since there are some reports of a non-charging device with the standard MS power supply). In particular scenarios 1, 2 and 3 makes this very clear, since in these scenarios only a voltage drop along the cable can be the source of the problems.
3. Since the MS power supply has a relatively low power level (13W) as compared to Surface 1-2 the consequences are that with loading the voltage drop will also be higher as compared to its predecessors. This, in combination with item 2, may give a possible explanation on why sometimes charging with the "Official" MS power supply package does not work either (as reported here but also eslewhere, see for example here: http://www.lovemysurface.net/after-a-month-with-the-surface-3/ )

For me this is not a deal-breaker, since in most the cases I get a power source that I can use, but it seems that one needs to check whether the Surface actually charges in common scenarios for which this should work (like a standard phone charger or a proprietary USB cable, and – as some reports in this thread suggest – even when just the MS power supply configuration is used). I hope this sheds some more light on the problem. If the threshold voltage can be relaxed a bit in the firmware settings then the problem will most likely be resolved.

Apart from these challenges, I find the Surface 3 an amazingly beautiful, snappy and very well functioning device, so I hope Microsoft is able to fix the power issue as well.