Inherent problem with external batteries

[ProDigit]

Hi,

I wanted to bring to the attention of Microsoft of a problem concerning the plugin keyboards, and external batteries using the down port on the surface 2 tablet.

It seems that after when the tablet is in suspended mode (sleep), that the internal battery is charged by the keyboard/external battery.

This causes unnecessary wear on the keyboard battery.

It would make more sense that the tablet stays in suspended mode using the keyboard battery to get it's minimum power draw, and as soon as it gets unplugged, or is too low in charge, switches over to the internal battery; and leaving charging of the internal battery to be done ONLY by an ac charger.

This to prevent the keyboard to discharge unnecessarily (as the internal battery can get charged the next time the AC power plugs back in).

A second problem is that the keyboard battery is charged BEFORE the internal battery, which also is a software fault or error.
It should be the PRIORITY of the charging system to make sure the internal battery is charged FIRST!!!
And AFTER the internal battery is charged, let the charging system charge the external battery.

This, to prevent the tablet to run out of power as soon as the keyboard is unplugged (this only with battery-equipped keyboards).

When the tablet is pretty passive (just browsing internet, watching a low quality movie, typing text, listening to internet radio, or is on standby), it would make more sense to divide the charge between both batteries, and charge internal and external batteries 50/50%.
That way, the batteries are charged slower, which is healthier for them, while still the same energy is being transferred to the device (only now divided into 2 batteries).
In other words, instead of taking eg: 1 hour to charge each battery, taking 2 hours total, it might be better to have a 50% charge done per hour on each battery.

I'm pretty sure both batteries can easily be charged simultaneously when the tablet is in sleep mode.

 

[malberttoo]

Hi,

I wanted to bring to the attention of Microsoft...

Hi, and welcome to the forum!

If you want to get Microsoft's attention, you might try posting this in their official forum- http://answers.microsoft.com/en-us/surface

 

[jnjroach]

This is by design:

Charging sequence
The Surface and Power Cover batteries are charged and discharged in a sequence designed to keep most of the charge on the Surface battery. Understanding the sequence makes it easier to predict how much charge to expect on each of the batteries.
Which battery gets charged first?
Once Surface is 80% charged, it starts charging the Power Cover. Then, when Power Cover is 80% charged, Surface finishes charging. When Surface is fully charged, Power Cover finishes charging. Power Cover will charge as long as Surface is turned on (sleep is fine) and connected to a power source, and Power Cover is connected to Surface.

How the batteries charge.
Which battery is used first?
When you’re using Surface and Power Cover and the Surface isn’t connected to a power source, Surface draws power from Power Cover first. When the Power Cover battery is drained, Surface switches to its own battery.
Power Cover continues to charge your Surface while it is in sleep or on standby. If Surface is turned off and unplugged, or the Surface battery is completely drained, it can’t detect the Power Cover or draw power from it.
If the battery on the Power Cover is completely drained, you can still use it as a keyboard.
How much charge do you have?
You can check your charge two ways:

• Check the battery icon on the Start screen for a weighted average of the two batteries.

• For detailed info on your battery levels, open the Desktop and tap or click the battery icon in the tray. This lists the charge on each battery.

Battery #1 is the Surface battery. Battery #2 is the Power Cover.

http://www.microsoft.com/surface/en-us/support/hardware-and-drivers/power-cover

 

[ProDigit]

Thanks for the answer to Ms website. I thought I was posting on it, but was clearly mistaken.
As far as charging the tablet goes, it charges the external battery, before charging the internal battery on my Surface 2 with Win RT.

I think it might have something to do with charging whatever battery is emptiest first?

 

[jnjroach]

Thanks for the answer to Ms website. I thought I was posting on it, but was clearly mistaken.
As far as charging the tablet goes, it charges the external battery, before charging the internal battery on my Surface 2 with Win RT.


View attachment 4584

I think it might have something to do with charging whatever battery is emptiest first?

That screen shot is showing it working as designed, It charges the Main Battery to 80% then it starts to Charge the Power Cover to 80% then it charges the Main up to 100% then it goes back in charges the Power Cover to 100%.

 

[ProDigit]

Ok, thanks for the feedback.
Seems like a good way to quickcharge the batteries faster.

The only way to optimize it any better, would be to while charging one battery below 80% of charge on a quick charge, to charge the other one on a slow charge when the tablet is sleeping.

Thanks for the illustrations.

 

[Ann]

the design of jnjroach is great.in fact it is better when battery is full of power.


sony e3 handytasche

 

[ProDigit]

Yeah, it is with almost all Lithium devices, to better stay fully charged, and use AC adapter when in use as much as possible.
Keeping Li charged is a way to save battery in the long term.