Power Cover Not Charging 100% 0% 100% ???

I have the same issue on my power cover purchased about a week ago (and reddit seems to have a few people with the same issue). 

Erwin, here's what happens:

• connect the Power Cover to the Surface Pro
• the keyboard operates as a standard keyboard
• both batteries appear in the battery notification area
• battery 1 (Surface Pro) shows the internal battery
• battery 2 (Power Cover) displays either 0% or 100%
• if the Power Cover is connected and the power cord is not plugged in, the battery notification displays "54% Battery 1: 90% and in use, Battery 2: 0% and not charging"
• when the power cord is then plugged in, the battery notification immediately jumps to display "96% Battery 1: 90% and charging, Battery 2: 100% and fully charged"
• when the power cord is removed, the battery notification still shows battery 2 as 100% but the device draws power from the Surface Pro internal battery
• if the Power Cover is removed from the Surface Pro and plugged back in, battery 2 displays "0% and not charging"
• connecting the power cord changes battery 2 to display 100% immediately

There are only states of charge for the Power Cover: "100% and fully charged", or "0% and not charging"

The Power Cover continues to work as a normal keyboard throughout, but it never delivers power to the Surface Pro.

A Surface support person took control of my Surface Pro last week and ensured that all the updates and drivers were correct.  As they could not fix it they asked me to reset my Surface Pro.  I then spent 2 days rolling back through Windows 8, Windows 8.1 and Windows 10.  The Power Cover did not operate as a battery through any of these operating systems. 

Some users on reddit say they've had success by unplugging the power and disconnecting then reconnecting the Power Cover to try to get the Power Cover to accept a charge - their theory is that the Power Covers are completely drained of any charge that was applied at the factory a few years ago and are having troubles in taking a new charge.  I've spent 4 days connecting and unplugging but not had any luck yet.

So I bought a NOS power cover on ebay and had the same issue as everyone here, having knowledge of li-ion batteries I suspected that the batteries self discharged below the cut off voltage (generally the cut off voltage is 2.2-2.9V/cell) in the charging circuitry that then permits the cells to charge. So with my knowledge of electronics and sense of adventure I managed to gain access to the cells and found that they were discharged down to 1.85V, I applied a small amount of current to each cell raising the cell voltage to about 2.8V, put it all back together and it is now working perfectly. Doing this voids all warranties and as some people will tell you that this is risky if you don't know what you are doing.

So in summary, the problems everyone here are having is due to the cells self discharging and the Battery Management System (BMS) is not allowing the battery to take a charge.

More information regarding "sleeping Li-Ion cells" can be found here:  

http://batteryuniversity.com/learn/article/low\_voltage\_cut\_off

Fantastic and relatively easy mod. Just did the same

I used a typical 5V 500mA power supply from my mp3 to wake the cells. I attached the voltage to each cell without detaching the cells. 5 seconds of voltage attachment rose the voltage of each cell from 1.72V to 2.9V. Now it charges like charm. I covered the back with a precision cut piece of thin black pvc and it is even better than new. Now I have more than 10+ hours of battery life in w10 pro2. Before going to surgery I tried everything but nothing worked.

Tanks a lot for the mod.

If you're comfortable with batteries (li-ion can be volatile) and electronics you should have no issue.

With regard to volt/current, I used a current limiting power supply set at 4v and 200mA with a volt meter monitoring it at all times. You will find that they will be in the region of 1.7v and as you apply the power they will fairly quickly ramp up to 3v at which point I stopped charging. I then checked the voltage again after a few minutes, and it was still around 3v, put it all back together, coupled it with my Surface and after 1 or 2 reconnections it started charging, not sure why this was required as but it immediately showed 100% !

Hi.

Can you give us more info about your concern? Have you tried to check for and install the updates? What troubleshooting steps have you tried so far?

Regards,

Erwin