abelia
1 Copper

How to charge with USB-C?

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Hi

How can I charge a XPS 9365 (with USB-C or Thunderbolt)?

So far I found out:

There are just 2 adapters that will charge this device. One is a Dell docking station that functions as a big double power brick. The other one is an Apple USB-C charger (30W).

No other USB-C Charger, no matter how cheap or expensive, no matter if generic or Dell branded, will charge reliably.

They all will charge to some extent, if it is almost full, maybe down to 50%. If it is closer to empty, any adapter except the 2 working ones (and I tested a lot, spent a lot of money on them) will occasionally maybe start charging, then at some point stop charging. If left alone for a longer time, it will not charge.

This applies no matter what port is used, and no matter which one of the not quite working chargers. However, it seems to me when using a particular charger for the first time, it is even less likely to charge. But I may be mistaken about this.

Does the OS matter for USB-C charging? I'm using Linux. However, the 30W Dell charger also does not charge on Windows, so...

If there were a way to charge this reliably, I would buy a few working chargers and a power bank. How to tell?

I tried obtaining information about the actual power requirements (V, A numbers). Linux tells nothing at all, except some estimates that seem to be unrelated. All I found was a PD or QC analyzer that can be bought for USD 2500 (10pcs).

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abelia
1 Copper

Re: How to charge with USB-C?

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Solved, more or less.

Sorry for not following up a long time.

My recommendation is to get chargers that support both 15V and 20V. 30W or more is required.

This applies to the XPS 2-in-1 nnn5 model mentioned above (Exact number always very hard to find, so I stop looking here). I think similar considerations might apply to other laptops.

I got more chargers, semi-cheap but carefully selected.

From a charger with Volt/Ampere display I could see that it mostly charges at 15V but sometimes at 20V. I guess that is the reason for this behaviour - when it is below approx. 40%, it might just stop charging and only restart after a replug, if at all. (Just for some chargers)

I suspect that it sometimes tries to switch to 20V, and when it cannot, stops charging.

I went for chargers and a power bank that support both, and they all work.

This is not definitive information, but from my experience, I consider it a necessary working hypothesis and also in fact likely to be true.

Note the hard part is to find a proper charger. You won't get these by asking experts/salespeople for advice, or by going for a high price. (That is how to get non-working devices) I look into the description, see if it claims 15V and 20V to be both supported (for Power-out), then search for the (seemingly) same device somewhere else, see if the same claims are made, and assess if it is plausible and likely that the claims are true...

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abelia
1 Copper

Re: How to charge with USB-C?

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Solved, more or less.

Sorry for not following up a long time.

My recommendation is to get chargers that support both 15V and 20V. 30W or more is required.

This applies to the XPS 2-in-1 nnn5 model mentioned above (Exact number always very hard to find, so I stop looking here). I think similar considerations might apply to other laptops.

I got more chargers, semi-cheap but carefully selected.

From a charger with Volt/Ampere display I could see that it mostly charges at 15V but sometimes at 20V. I guess that is the reason for this behaviour - when it is below approx. 40%, it might just stop charging and only restart after a replug, if at all. (Just for some chargers)

I suspect that it sometimes tries to switch to 20V, and when it cannot, stops charging.

I went for chargers and a power bank that support both, and they all work.

This is not definitive information, but from my experience, I consider it a necessary working hypothesis and also in fact likely to be true.

Note the hard part is to find a proper charger. You won't get these by asking experts/salespeople for advice, or by going for a high price. (That is how to get non-working devices) I look into the description, see if it claims 15V and 20V to be both supported (for Power-out), then search for the (seemingly) same device somewhere else, see if the same claims are made, and assess if it is plausible and likely that the claims are true...

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jphughan
5 Rhenium

Re: How to charge with USB-C?

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@abelia  I'm not sure why you're having so much trouble with USB-C power sources.  Buying a USB-C power source that supports 20V charging rather than just 15V is a good idea just for the benefit of broader compatibility, and it's not like they're expensive.  I wrote a detailed post here about some USB-C power sources I use frequently, all of which have always worked perfectly with multiple Dell and non-Dell systems I have -- so I'm not sure why you've had so much trouble.  Since then I've also acquired a Nekteck 90W USB-C charger and it works perfectly too, although Dell systems at the moment annoyingly will not draw more than 65W over USB-C from a non-Dell power source, even when the source can provide more and the system would benefit from more (such as XPS 15 models).

But no, USB-C charging would not be related to the OS; it's handled in system firmware.  And a system would not try to switch to 20V charging unless the power source advertised that it supported providing that.  The way USB PD works is that everything starts at 5V for safety and compatibility, then the power source will advertise alternate modes it supports, and the device is allowed to choose from any of those advertised modes -- but only those modes.  It can't ask for 20V if it wasn't offered.

In addition, XPS 13 models are designed for a 45W power source, so if you try to use them with a 30W source, it might work, but you could also end up with side effects like slow battery charging and throttled system performance as the system tries to operate within that reduced power budget.

And fyi if you want a bit more insight into what's going on, you can pick up a USB-C multi-meter like this one to see what voltage your device is using and how much amperage it's drawing at any given time.  I also have one for USB-A just to test the power output/draw capabilities of various ports and devices.  And if you go into the BIOS Setup on Dell systems and select the Battery Information section, under the battery graphic you'll find the wattage of the attached power source.  With USB-C power sources, that figure will be the maximum wattage the system will draw from that source.  Again, on current Dell systems it will never be higher than 65W with non-Dell power sources, but if the system needs less than that, it will only show what it will draw.  So for example if I connect my Latitude 7480 to my 65W USB-C power source, it shows 65W.  If I connect my XPS 13 to that system, it shows as 45W because that's all the XPS 13 draws.

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