Symptoms
Here are the various charging behaviors that happen as I plug my Surface 3 to the charger when the battery is not full:
- It shows “Plugged in, not charging”. The battery continues to drop.
- It starts to charge. However, charging stopped after a while showing “Plugged in, not charging”.
- Only in a few cases, my Surface 3 was charging without problem.
This issue drove me up the wall, especially when the battery is low but my Surface 3 still refuses to eat. Solutions I found on the web are:
- Restart your Surface
- Keep your Surface shut down during charging
- Set the low battery limit to 96% in Windows
- Send your Surface 3 back to Microsoft for a new one.
Unfortunately, none of the solutions are guaranteed to work. Luckily, I stumbled upon an article that talks about a light bulb issue in a family where the light is not stable, sometimes the light went dim, and sometimes it
turned very strong. This connected me to the charging problem I encountered on my Surface 3. After some tests, I finally concluded the cause and the solution.
Cause
The power the charger offers is not enough to start the charge when you plug in your Surface 3. The fact is that he charger that comes with Surface 3 provides a charging capability at 5.2V|2.5A which looks powerful enough. My opinion is that the problem
is with the Surface 3 charger (as well as the charger I use for my tests below).
The reasons could be:
- Voltage loss when the power goes through the charging cable, resulting insufficient charging voltage at Surface 3.
- For some reason the charger doesn't respond correctly to what Surface 3 needs.
I used a USB Power Meter to test this. It couldn't detect the charging power at Surface 3 but could detect that at the charger. Please note that the charger I used was not the one that comes with Surface 3 but the one for my Lenovo pad.
Test 1
The battery was at 71% and the charging issue occurs. The USB Power Meter showed the output power is at 5V|0.5A. You see the problem?



Test 2
In test 1, I unplugged and re-plugged in several times until the charge worked. The battery was at 72%, the meter showed 4.92V|1.63A.



Conclusion of the cause
The charger doesn’t respond/provide the charging power that Surface 3 needs. The gap causes the charging issue. Even in Test 2, the charging was not at full capacity of the charger.
Solution
- Use a charger that can respond correctly to the charging power that Surface 3 needs. As far as I know, the charger that comes with Samsung Galaxy Note 3 or S5 is a good candidate.
- Use a tool that helps the charger to respond correctly to the charging power that Surface 3 needs.
I used the second solution. The tool I used was a USB voltage booster.
The result was that the charging issue never comes back. Additionally, the charging power was stronger, at 5.2V|2.18A,
than before, resulting a speedy charge. The golden rule is the stronger the safe charging current is, the faster the charging is.


Is the solution safe?
The electric circuit design of Surface 3 provides good protection during charge. A good charger won’t output more than what the target device needs. It is expected that the charging current will start to decrease until 0 when the battery is close to
full. By the time I finished this article, the battery was at 86% full. The output from the charger had dropped to 5.2V|1.96A, and will continue to drop.
Additional information
The charging process is pretty much like how water comes out of the faucet. The higher the water pressure is, the faster the water flows so you get more water in a given time period.
Side note: Today (Nov 3, 2015) I purchased the wall charger for Samsung S5, it works perfectly with Surface 3. Please be sure to use the original cord that comes with Surface 3 or a cord that can take the current of 2.5A or above.