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22 Posts

10-11-2015

DE

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  • Message 21 of 25

Re: Charge P52 over USB-C or with a lighter power brick

2019-11-25, 19:48 PM

Thanks for the long reply and your understanding ;-)
First I guessed you are an crazy idiot, but obviously you thought the same of me :-D
But fine that it finally solved that we got some proper understanding...

Actually the major issue is, the P52 will - like the P50 too not "run" on a 90W charger (at least I think so - from the P50 I know for sure!)
It will only charge when powered-off.
It will just draw the battery and ignore the charger, which is the point that I consider extremely stupid.
BTW: I just got one even WAY simpler idea than all the "reduce and adjust power"-stuff... Why not run the P52 in battery-mode when connected to any "small" charger and draw any power from the battery and at the same time just pump the power of the PSU right into the battery? Then there is no need for big adjustments, the battery will buffer and the PSU will do what it can do.
It is well enough to show a simple message like "the PSU is not big enough, the notebook will run on battery-performance".
Then people will know what to expect in terms of performance and will be also happy if the battery will not drain / if it will even charge.
And it requires almost no controls beyond the existing circuits and the existing BMS.

But my approach is much different, I'll use my existing 80 (or 8X) Watt charger and then add the following:


PSU::: Female slim-tip --> resistor --> male slim-tip ::: P52 Notebook
My idea is to adjust the resistance to the 135W PSU's 1kOhm (the cable should have less, so adding is fairly simple, easier than bridging another one to reduce the total resistance).
The notebook will recognize a 135W PSU, which will be most likely not draw the current for 135W, but 60-80W during normal use, which will charge the P52 and power it with normal speed. Only when there is a high-power demand, it may draws more than the PSU is willing to supply. But no problem - in this case the PSU will just drop the connection. Then my battery will kick-in.
This seems even more easy than the PCB you posted the link for (which I still like a lot!).

For you understanding, if you look at the power-supply I posted some pages before - this does not connect to the USB-C with the lenovo-adaptor but instead it has a (I know, weird...) USB-A connector on the other side. So it is USB-A to Lenovo slim-tip.

Actually I've paid only about 5€ for the male-slim to barrel and the female-slim to barrel adapters in total.(aliexpress)
I'll just cut the barrels off and solder a bit.
In addition I've also purchased an USB-C to Lenovo slim-tip adaptor from Aliexpress. Maybe it will work - maybe not.. but it is worth a try...

Let's see what works..

BTW: this is the stuff I ordered...

https://www.aliexpress.com/item/DC-Square-USB-Plug-Female-To-7-9x5-5mm-Male-Power-Adapter-Converter-Connector-Cable-Cord/32976006025.html?spm=a2g0s.9042311.0.0.10c74c4dcQaAEI

https://www.aliexpress.com/item/7-9-x-5-5mm-to-Square-Pin-Plug-Converter-Dc-Laptop-Power-Adapter-Connector-Cable/4000016035643.html?spm=a2g0s.9042311.0.0.10c74c4dcQaAEI

https://www.aliexpress.com/item/USB-Type-C-Charging-Cable-Cord-Plug-Connector-Laptop-Power-Adapter-for-Lenovo-G400-G500-G505/33051116163.html?spm=a2g0s.9042311.0.0.10c74c4dcQaAEI

https://www.aliexpress.com/item/Laptop-DC-Power-Adapter-Connector-Plug-Converter-Cable-Cord-USB-Type-C-Female-to-Square-Plug/4000056652773.html?spm=a2g0s.9042311.0.0.10c74c4dcQaAEI

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421 Posts

07-08-2019

CA

583 Signins

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  • Posts: 421
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  • Location: CA
  • Views: 7398
  • Message 22 of 25

Re: Charge P52 over USB-C or with a lighter power brick

2019-11-25, 22:07 PM

Hi maeffjus,


 wrote:

Thanks for the long reply and your understanding ;-)
First I guessed you are an crazy idiot, but obviously you thought the same of me :-D
But fine that it finally solved that we got some proper understanding...

Actually the major issue is, the P52 will - like the P50 too not "run" on a 90W charger (at least I think so - from the P50 I know for sure!)
It will only charge when powered-off.
It will just draw the battery and ignore the charger, which is the point that I consider extremely stupid.
BTW: I just got one even WAY simpler idea than all the "reduce and adjust power"-stuff... Why not run the P52 in battery-mode when connected to any "small" charger and draw any power from the battery and at the same time just pump the power of the PSU right into the battery? Then there is no need for big adjustments, the battery will buffer and the PSU will do what it can do.
It is well enough to show a simple message like "the PSU is not big enough, the notebook will run on battery-performance".
Then people will know what to expect in terms of performance and will be also happy if the battery will not drain / if it will even charge.
And it requires almost no controls beyond the existing circuits and the existing BMS.

You are right, now I that think of it. The P52 already needs to take the Slim Tip power and charge the battery and take the battery power to feed the system. USB-C PD in would add another branch (bi-directional), let's ignore that for now. You are right that the P52 should already have everything needed to use a lower power input in combination with the battery, unless they did run in some design problem with the  power conversion circuits. Obviously, the power circuits can handle 170W, but why it cannot handle less is really wierd. I mean, the computer does not use all that power, so the Slim Tip or the battery power conversion circuits can pass less than the full 170W. The machine can detect the available power from the Slim Tip! It just needs a link from hardware (EC?) to Lenovo Vantage/PM driver. All I can think of is that was a choice. But Why?!? I now see what you mean.

 

Maybe Lenovo chose not to tie all power inputs together for some reason and keep them somewhat isolated. Maybe it's a safety reason (battery?), maybe ground loop prevention, or RF compliance reason (that's my bet ;-), or something else. Again, we don't know!

 


 wrote:

But my approach is much different, I'll use my existing 80 (or 8X) Watt charger and then add the following:


PSU::: Female slim-tip --> resistor --> male slim-tip ::: P52 Notebook
My idea is to adjust the resistance to the 135W PSU's 1kOhm (the cable should have less, so adding is fairly simple, easier than bridging another one to reduce the total resistance).
The notebook will recognize a 135W PSU, which will be most likely not draw the current for 135W, but 60-80W during normal use, which will charge the P52 and power it with normal speed. Only when there is a high-power demand, it may draws more than the PSU is willing to supply. But no problem - in this case the PSU will just drop the connection. Then my battery will kick-in.
This seems even more easy than the PCB you posted the link for (which I still like a lot!).

For you understanding, if you look at the power-supply I posted some pages before - this does not connect to the USB-C with the lenovo-adaptor but instead it has a (I know, weird...) USB-A connector on the other side. So it is USB-A to Lenovo slim-tip.

Actually I've paid only about 5€ for the male-slim to barrel and the female-slim to barrel adapters in total.(aliexpress)
I'll just cut the barrels off and solder a bit.
In addition I've also purchased an USB-C to Lenovo slim-tip adaptor from Aliexpress. Maybe it will work - maybe not.. but it is worth a try...

Let's see what works..

BTW: this is the stuff I ordered...

https://www.aliexpress.com/item/DC-Square-USB-Plug-Female-To-7-9x5-5mm-Male-Power-Adapter-Converter-Connector-Cable-Cord/32976006025.html?spm=a2g0s.9042311.0.0.10c74c4dcQaAEI

https://www.aliexpress.com/item/7-9-x-5-5mm-to-Square-Pin-Plug-Converter-Dc-Laptop-Power-Adapter-Connector-Cable/4000016035643.html?spm=a2g0s.9042311.0.0.10c74c4dcQaAEI

https://www.aliexpress.com/item/USB-Type-C-Charging-Cable-Cord-Plug-Connector-Laptop-Power-Adapter-for-Lenovo-G400-G500-G505/33051116163.html?spm=a2g0s.9042311.0.0.10c74c4dcQaAEI

https://www.aliexpress.com/item/Laptop-DC-Power-Adapter-Connector-Plug-Converter-Cable-Cord-USB-Type-C-Female-to-Square-Plug/4000056652773.html?spm=a2g0s.9042311.0.0.10c74c4dcQaAEI


Nice project, I hope it works! Of course, make sure to test it thoroughly, after all you might be lying to the P52 ;-) I would hate to have you lose data because of a crash! So you know, the third and fourth links might be very close to what I would try to build (but not as pretty ;-).

 

Keep us informed!

Martin

Using Browser Search to find your answers in Lenovo and Moto Community

I'm a volunteer, NOT a Lenovo employee.
If I solved your issue, please click Accept as a Solution.
If my post helped, consider giving me a Thumbs Up.

Main: P52 (I7-8750H P1000 FHD 16GB 2TB-SSD 1TB-HDD)
Also, 2x M820z, 1x P520c, 1x ideaCentre 300S-11IBR

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1 Posts

04-09-2020

CH

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  • Message 23 of 25

Re:Charge P52 over USB-C or with a lighter power brick

2020-04-09, 21:45 PM

 

This only works to charge the device while it is powered off - While it is under use, I am not aware of any USC-C solution to provide an adequate power source to keep up with the demand. 

 

Of course, this Lenovo-Deign is (I'm sorry!) very stupid. 

 

As long as the battery has enough power for the Notebook, 

then there is NO technical reason to not charge the battery from a weaker source. 

 

Of course, the weak power source can't run the notebook under full load. 

 

But, of course, with 100W it can easily extend the runtime by 50%.

And that would be a great advantage for a mobile workstation.

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3855 Posts

12-02-2007

US

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  • Message 24 of 25

Re:Charge P52 over USB-C or with a lighter power brick

2020-04-10, 9:52 AM

Hello,

 

Lenovo has to build systems which are powered by power supplies designed to follow engineering specifications and safety standards.  The current USB Power Delivery specification specifies that 100 Watts (20 Volts at 5 Amperes) is the maximum amount of electricity which can be delivered over the USB connection.  If the power required to use the laptop and charge its battery is more than that (135W, 170W, 230W, etc.) than Lenovo has to use a different type of power supply with the laptop.  Otherwise, if a laptop were to try and draw more electricity than a power supply could deliver, it could cause that power source and the laptop to be damaged.  I am sure Lenovo would love to deliver a laptop with the P52's performance that could be powered over over a single USB C connection.  However, the specifications for doing this, not to mention the technologies which abide by those specs, are not yet available on the market to any company.   The Lenovo SlimTip power connector used on the P5x and P7x series is capable of transferring at least 230 Watts of power, so that is a technology Lenovo can use to safely power these workstation-grade laptops.

 

Regards,

 

Aryeh Goretsky

 

 

@ Jehoschua wrote:
 

 

 

This only works to charge the device while it is powered off - While it is under use, I am not aware of any USC-C solution to provide an adequate power source to keep up with the demand. 

 

Of course, this Lenovo-Deign is (I'm sorry!) very stupid. 

 

As long as the battery has enough power for the Notebook, 

then there is NO technical reason to not charge the battery from a weaker source. 

 

Of course, the weak power source can't run the notebook under full load. 

 

But, of course, with 100W it can easily extend the runtime by 50%.

And that would be a great advantage for a mobile workstation.

 



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421 Posts

07-08-2019

CA

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  • Registered: ‎07-08-2019
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  • Message 25 of 25

Re:Charge P52 over USB-C or with a lighter power brick

2020-04-12, 3:25 AM

Hi Jehoschua,

 

To add to @goretsky's post, a power supply who runs at maximum output either has it's voltage drop (constant power limit) or simply cuts off due to a maximum-current sensing safety circuit.

 

Having multiple input power sources requires input power sensing (not to exceed the input power limit), voltage re-conversion (all sources will have a different voltage), and finally load balancing (wasting power as heat). On top of that, you have power management circuitry (Embedded controller) to save as much power as possible.

 

There is a two-input (limited) version of this circuitry already on board (Triangular: Slim-tip, battery, and the battery charger), so it would be possible to add a third input branch with some more parts and software/firmware. The final question is how useful will it be vs. the costs (design, parts, space, programming, support, etc.). 

 

The first big hurdle is that the USB-C can never provide the maximum power required by the machine. Some mechanism must be implemented to "share" multiple power sources, with input monitoring, to prevent having this input overload and shut off. This circuitry is probably already there to protect PD-out, so it would have to adapted to bi-directional usage. Next, you have to build in a switch so it can receive or feed power, like the battery circuit has. That means that the power input circuitry has to be disconnected and the power output circuitry connected, with a power conversion circuit to accept power in. 

 

 

All this should fit in a few inches square of board space, but at what price? Again, think of the design time, parts, space, software, firmware, support, compliance testing, etc. It always comes down to final price, and if Lenovo didn't made some compromises of rarely used, incomplete solutions that could cause confusion, everybody would buy the competition because "They're cheaper". Maybe, in a few years, this won't be an issue if the electronics need less power, but today, with the current limitations, it's not a good idea.

 

@maeffjus , are those diagrams close to reality?

 

Martin

Using Browser Search to find your answers in Lenovo and Moto Community

I'm a volunteer, NOT a Lenovo employee.
If I solved your issue, please click Accept as a Solution.
If my post helped, consider giving me a Thumbs Up.

Main: P52 (I7-8750H P1000 FHD 16GB 2TB-SSD 1TB-HDD)
Also, 2x M820z, 1x P520c, 1x ideaCentre 300S-11IBR

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