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11-11-2019

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Lenovo c940 - Charging via USB-C?

2019-11-11, 10:50 AM

Can the C940 be charged via USB-C?
What values does the charger need?

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11-11-2019

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Re: Lenovo c940 - Charging via USB-C?

2019-11-11, 14:29 PM
Which model? 14" or 15"?

Still waiting for my 15" to arrive and i'm a bit concerned that charging using usb c wont work. I have a stardock usb c docking with a powerbrick that delivers 65W (and is compatible with Lenovo it says) so I hope it will charge (does'nt have to be quick but enough to keep it running).
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07-22-2010

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Re: Lenovo c940 - Charging via USB-C?

2019-11-11, 15:41 PM

Welcome to the forums.

 

Based on page 3 of manual I would say no if its the 15 inch.  If its the 14 inch then yes.

 

Per manual it supports the below.

 

Connect external display, storage, or data devices. Note: An appropriate adapter may be needed for connecting external devices. • Support data transfer rates up to 40 Gbps for Thunderbolt 3. • Support DisplayPort 1.4. • Provide up to 5 V, 3 A power output

 

https://download.lenovo.com/consumer/mobiles_pub/lenovo_yoga_c940_15irh_ug_en_201907.pdf

 


 If a post answers your question, please mark it as an”Accepted Solution“!
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 I do not work for, nor do I speak for Lenovo. I will not respond to unsolicited private messages. Questions belong in the forum so it may   help other forum members as well.
 T490, TP 25 Retro, X1 Yoga 3rd Gen, W510 850 EVO, A30p
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22 Posts

11-06-2019

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Re: Lenovo c940 - Charging via USB-C?

2019-11-19, 23:54 PM

I've used two of the 14" versions Best Buy carries (swapped out one due to defective digitizer). Both did not take a charge from several different 60W chargers that provided max 3A output (20V-3A). I've monitored battery charge rates through HWInfo, and it was not slow charging either (dropping battery output when connected, but not showing charging). Turning the machines off and connecting them to 60W chargers also did not induce charging.

 

The only chargers I've gotten a charge result from are the included charger, and a few third party chargers offering 65W or higher. It seems the charging circuit will only recognize 3.25A or higher output, Voltage did not make a difference (the 65W chargers outputs 20V-3.25A, 60W chargers put out 20V-3A).

 

If you have docks offering 100W PD or at least 65W it's probably ok. Not sure if this is a firmware lock for some reason or Lenovo cheaping out on the circuitry required for converting between difference charging voltages/amps, but that's what I've encountered so far.

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8 Posts

11-21-2019

FI

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Re: Lenovo c940 - Charging via USB-C?

2019-11-21, 18:37 PM

Unfortunately, it seems that the 15" model doesn't charge via USB-C. I've tried it only with a "zendure supertank powerbank", which has a 100w USB-C PD output, and it does not charge. 

 

When I was looking for a new laptop USB-C charging was one of the main criteria on my list. When looking at the c940 15" it stated everywhere that the USB-C ports are Power delivery or PD compatible, which I understood that meant that they can give or take power according to the PD standard. Apparently I was wrong?

 

Any idea why Lenovo has opted to leave usb-c charging out?

 

It's pretty disappointing to find this out now and I'm considering returning the laptop.

 

Although the competition in the 15"/ dedicated GPU 2 in 1 segment isn't exactly spoiled with options right now. I guess the HP Spectre x360 is the only competition in town?

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11-11-2019

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Re: Lenovo c940 - Charging via USB-C?

2019-11-21, 19:25 PM

I'm in the same boat as you, also bought this laptop so I could charge over usb c (although slow charge). Maybe it can be possible with a future update. 

 

Lenovo are you are reading this too?!

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8 Posts

11-21-2019

FI

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Re: Lenovo c940 - Charging via USB-C?

2019-11-21, 20:19 PM

This has really thrown a wrench in my plans, which is a shame, as I started to like the laptop.

 

I have until next week to decide whether to keep the laptop or not and would appreciate it if someone from Lenovo could confirm if the USB-C charging is not possible. 

 

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11-21-2019

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  • Message 8 of 47

Re: Lenovo c940 - Charging via USB-C?

2019-11-22, 20:58 PM

I contacted the local Lenovo support today about the USB-C charging and the claim they have on the spec sheet of the 15" model that it has 2x USB-C PD ports.

 

They just quoted the online manual of it having 5V, 3A output and that because it has 135W charger it doesn't support 100W charging, which to me seemed nonsense. After some conversation about the USB PD standard they promised to elevate the ticket to the next level and get back to me.

 

After some more looking into the USB PD specification, I'm even more confused as USB-IF states that:

 

USB Power Delivery offers the following features:

  • Increased power levels from existing USB standards up to 100W.
  • Power direction is no longer fixed. This enables the product with the power (Host or Peripheral) to provide the power.

 

https://www.usb.org/usb-charger-pd

 

But then again this TI training video states that:

 

"How do I know if I need a USB Power Delivery Controller? You only need power delivery if you require more than five volts, more than 

three amps, or more than just USB data, such as DisplayPort or Thunderbolt via an alternate mode."

 

https://training.ti.com/usb-type-c-vs-usb-power-delivery-whats-difference

 

So just having the Thunderbolt means that it's USB PD?

 

These different USB versions and standards are starting to get a bit confusing.

 

My conclusion to this is that because of the Thunderbolt Lenovo is stating them to be USB-C PD ports and that for some reason have decided to not include the two way (and higher than 5V 3A) charging. And that makes me sad :(

 

 

 

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31 Posts

08-30-2018

SG

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  • Message 9 of 47

Re: Lenovo c940 - Charging via USB-C?

2019-11-23, 15:36 PM

May I check if your 60W chargers are Power Delivery certified as well? I am planning to get the C940 but if PD is not supported it will be a deal breaker as I currently use a USB-PD power bank without issues on my IdeaPad 720s.

 

I understand QC 3.0 also uses 20V so maybe your charger is using that instead?

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22 Posts

11-06-2019

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  • Message 10 of 47

Re: Lenovo c940 - Charging via USB-C?

2019-11-23, 16:35 PM

Both the 60W chargers I tried were PD certified. One was an Anker unit, the other was an Innergie. Both had worked on the HP Spectre x360 I tried before I switched to this C940.

It's dissapointing to hear the one poster's 100W pd dock didn't work. I was hoping that maybe it was due to the 3.25A delivery not being present on either of the 60W units. I assumed a 100W or 65W pd unit might have worked.

 

Sounds like it might be a firmware limit then, because the third party usb-c charger (similar to the original charger) does work. Perhaps someone more knowledgable at Lenovo would care to discuss the actual issue here?

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31 Posts

08-30-2018

SG

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  • Message 11 of 47

Re: Lenovo c940 - Charging via USB-C?

2019-11-23, 16:57 PM

Thanks for the clarification and this is upsetting to hear. I briefly had a S740 but am considering the C940 instead. the S740 has a round barrel charge tip but is also able to charge using my Aukey PA-Y10, which is a 46W PD charger with PPS support.

 

Do you have the exact model of the Anker and Innergie?

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11-06-2019

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Re: Lenovo c940 - Charging via USB-C?

2019-11-23, 23:24 PM

Innergie 60C, and an Anker Powerport Speed 1 (A2015). Both put out up to 20V-3A.

 

A PWR+ 65W universal usb-c charger does charge however, it outputs at the same levels as the oem charger. I might try to pick up some 65W or 87W hubs over the holiday weekend if they're on sale to test.

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5 Posts

11-26-2019

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  • Message 13 of 47

Re: Lenovo c940 - Charging via USB-C?

2019-11-26, 18:34 PM

Not sure if this helps, here's the charger that came with my C940 14".  Takes 1-2 hours to fully charge, after I reach about 40% battery status.

 

I am considering docking stations, so would be interested in knowing any required specs to charge from the dock station.  From these posts, sounds like I can't just use my C940 charger with any docking station.

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2 Posts

11-18-2014

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  • Message 14 of 47

Re: Lenovo c940 - Charging via USB-C?

2019-11-27, 12:28 PM

I just bought ICY BOX IB-DK2301-C with USB-C PD up to 85W and it does not charge :(

I have yoga C940 14"

 

 

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01-20-2015

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  • Message 15 of 47

Re: Lenovo c940 - Charging via USB-C?

2019-11-27, 13:17 PM

It's weird how everyone has a different experience here. I have a C940 14 UHD and I have used three different 65w USB-C wall chargers (Acer, Huawei and Verbatim brand) and all of them work perfectly. I have also used two different 87w Macbook Pro chargers. Same deal, works fine. I have tested Xiaomi's 20000 mah Powerbank 3 (45w) charger which does 20v @ 2.2A and that also charges my C940 fine. I've also used a 65w 20000mah powerbank (not sure of the brand) and that works fine too. The only thing that is weird out of all of this testing is that they all seem to charge at the same rate (around 16,500 mW as shown in BatteryBar and Hwinfo) for ALL the different chargers and powerbanks, regardless whether 45, 65 or 87w.

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11-11-2019

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  • Message 16 of 47

Re: Lenovo c940 - Charging via USB-C?

2019-11-27, 13:27 PM

Can it be that the option "fast charging" needs to be off (in Lenovo Vantage) to charge with third party chargers?

 

I'm not sure ofcourse because i have the 15" model which can't charge over USB C which is a pitty .... still don't understand why Lenovo disabled this function. I can understand that the 15" model with a Gerforce 1650 is more power hungry but I don't expect that it needs to keep up charging under full load, but at least make it "slow charging" possible so i can use my dockingstation at home and at work. The 135watt power brick is a huge device to bring along all the time.

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11-06-2019

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  • Message 17 of 47

Re: Lenovo c940 - Charging via USB-C?

2019-11-27, 13:28 PM

Interesting. I have my original hunch regarding the 65w chargers, but you said the 45w powerbank works too. Interesting...

Perhaps its something about the amp delivery of the 45 vs 60? So strange.

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08-30-2018

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Re: Lenovo c940 - Charging via USB-C?

2019-11-27, 13:31 PM

I managed to try on my 30W Aukey power bank at a Lenovo store and the C940 charges just fine too.

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01-20-2015

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  • Message 19 of 47

Re: Lenovo c940 - Charging via USB-C?

2019-11-27, 13:36 PM

I actually only got the Xiaomi Powerbank 3 today. Didn't actually buy it for the C940 but thought what the hell I'll give it a try and it surprisingly worked. I've never tried a 45w wall plug though but really that should also work if it can deliver consistent 20v @ 2.2A

There is no "fast charging" option in my Vantage so can't really say whether this would make a difference or not. I'm on Win 10 build 19033.1, version 2004 if that makes a difference.

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11-18-2014

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  • Message 20 of 47

Re: Lenovo c940 - Charging via USB-C?

2019-11-27, 16:27 PM

https://www.raidsonic.de/products/adapter_multidocking/multi_docking/index_en.php?we_objectID=5019#properties

 

This is a Docking station, not a charger. Obviously chargers work fine but docking stations not so.

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11-11-2019

NL

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  • Message 21 of 47

Re: Lenovo c940 - Charging via USB-C?

2019-11-29, 20:29 PM

Can somebody from Lenovo clarify if it is possible to change over usb c on the 15" c940 and of yes based on what specs? If not, will it ever be possible?

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