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468 Posts

01-30-2012

United States of America

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  • Message 21 of 27

Re: Thinkpad Tablet Battery Took Long Time To Fully Charge

2012-04-28, 15:53 PM

Fast charger, besides being more versatile, has the potential to charge around twice as fast as the dock with the TPT on. Same rate when TPT is off. Lenovo handicaps both the dock and wall charger to less than half their capacity when the TPT is powered. This came to light in this thread;

 

http://forums.lenovo.com/t5/ThinkPad-slate-tablets/Charging-via-USB-analyzed/m-p/724779#M13227

 

Here are two graphs (charge/time and current/time) for the fast charger while TPT is in standby. Battery was charged from 8% charge to 100% charge, took 105 minutes (0 to 52 minutes is not to scale). Similar would apply to the dock with TPT off;

 

 

 

tptchrg.png

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12 Posts

04-28-2012

Germany

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  • Message 22 of 27

Re: Thinkpad Tablet Battery Took Long Time To Fully Charge

2012-05-01, 21:44 PM

Okay now seriously... this is kinda getting ob my nerves. Now I'm really thinking about creating my own charger.

I have a versatile professional balance charger, the kind of chargers people use for model airplanes for example. I could create a cable to connect the tablet to that charger. I would just need to know what kind of battery there is inside this tablet. Lithium Polymer? Lithium Ion? How many cells? And what's the capacity? If someone has these infos, please tell me!

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12 Posts

04-28-2012

Germany

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  • Message 23 of 27

Re: Thinkpad Tablet Battery Took Long Time To Fully Charge

2012-05-01, 21:50 PM
Here's the answer to my question: 2 cell Li-ion (24 Wh)
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294 Posts

09-24-2011

Rhode Island

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  • Message 24 of 27

Re: Thinkpad Tablet Battery Took Long Time To Fully Charge

2012-05-02, 0:23 AM
Here's something that irritates me I have my TPT in the keyboard folio...I left it in standby mode. 98% battery life. I go to use it 24 hours later, and it's EMPTY battery. YES, I did in fact wait the 10 seconds to see if the screen was actually off. I opened it a couple times to make sure the screen did not come back on. This kind of battery stuff is really starting to get on my nerves. I want to love it..I REALLY do. But between all the battery issues and force closes in the browser, constant lag between screens, and now this parsing error trying to update gmail, I am starting to HATE it. What gives Lenovo? Does anyone from Lenovo read this stuff? I went back and looked and it's funny because you have almost everyone having to come up with some 1/2 baked solution to make sure the screen is off. When you have it docked in the folio, it should act normally. Why would Lenovo even release the folio if there was going to be some issues with severe battery drain? I just don't get it. If I am an engineer, one would think you'd want the best possible experience available to get people to stick to your products. That's where Apply dominates...Simplicity, Ease of use and adoption, and reliability...And it drives me nuts because I do not want to adopt to that platform. Ugh
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12 Posts

04-28-2012

Germany

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  • Message 25 of 27

Re: Thinkpad Tablet Battery Took Long Time To Fully Charge

2012-05-02, 9:21 AM

Yeah... There are good engineers and there are bad engineers. Some want to deliver a perfect, beautiful solution and some just want it to work and then go home at 5 o'clock... More importantly however, there are finance departments, that force engineers to work quicker. There are other factors as well. So, like usual, it's not just black and white...

 

Edit: By the way: Think positive. If we're lucky all of this stuff is adressed in the Android 4 update later this month =)

 

Enough off-topic now.

 

So, once again, I'm thinking about building my own charger cable and using my professional charger. With this one, you can specify the amps, the volts and the charge thats going in there. However, after reading about the differences in USB charging and charging with the Dock, which uses the dock connector, I'm wondering wether I should just buy a micro USB pin or start my research on getting the dock pin and using this one.

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468 Posts

01-30-2012

United States of America

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  • Message 26 of 27

Re: Thinkpad Tablet Battery Took Long Time To Fully Charge

2012-05-02, 12:25 PM

wrote:

 

So, once again, I'm thinking about building my own charger cable and using my professional charger. With this one, you can specify the amps, the volts and the charge thats going in there.

~


 

What your charger can do is somewhat irrelevant in terms of optimal performance. The TPT firmware is going to limit current via the dock connector to 1A maximum (load plus charging current) and if you exceed 20V at the dock connector you probably risk damaging the buck converter (or whatever is used to step down from 20V) in the TPT. IMO, the most you'll probably achieve is a less aggressive charging profile than what I indicated.

 

Forget charging via the micro-USB connector, that's a dead end based on the connector itself. All you need is 20V at the dock connector (it uses two pins for the positive) controlled by what seems to be an internal interlock (probably to prevent charging if the battery is removed or defective). Fancy voltage/current source is a waste of time and money.

 

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2 Posts

06-09-2012

vietnam

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  • Message 27 of 27

Re: Thinkpad Tablet Battery Took Long Time To Fully Charge

2012-06-09, 5:11 AM
Can someone summarize? Is it a hardware problem? Can we just buy a new wall plug? Is it a software problem? Can we just wait for next update (I have done all already all existing one)? Is there some app to shut down? I noticed that when I amcharging in standby mode the screen turns on regularly for 1 second.
Thanks inadvance.
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