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XPS 13 and TB16 proper usage
Hello. I have an XPS 13 9360 and a dell tb16 dock. Should I remove the dock every time I shut down my laptop? I think if I don't remove the dock, it will damage my battery over time. If I keep on removing it, it would wear out my usb c port. Any insights on this? Also when I plug in my 180w tb16 to my xps 13 it says it doesn't charge my laptop but the battery doesn't decrease as well even when the laptop is in use. If I want the tb16 to charge my laptop, I need to restart the laptop and enter BIOS then exit again for it to normally charge my laptop. I know that the extra step of entering bios on start up shouldn't be needed but it's the only way the tb16 charges my laptop. any idea how to fix this issue as well?
jphughan
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November 25th, 2018 10:00
I'm well aware of the 9365's port configuration, but since the OP is asking about the 9360, I don't know why you felt the need to bring that system into this discussion. The 9360 supports charging over its USB-C/TB3 port, even though it also has a traditional barrel-style power connector. So does the older 9350 if we're going to talk about other systems. That's why they're listed in the TB16's FAQ page here. You're welcome to go do all the checking you want, but that's not just something I've read; I've actually tested those and other systems with the WD15 and TB16 docks, results detailed below. Anyway, the TB16 can provide up to 130W to an attached Dell system when the TB16 itself has a 240W power adapter attached (Dell is doing something proprietary there to stretch the USB Power Delivery spec beyond the 100W max), and it can provide either 65W or 90W to Dell systems when the TB16 is powered by a 180W adapter; I can't remember which. When used with a non-Dell system, the TB16 provides at most 60W. You may have seen that maximum listed frequently with USB-C chargers and cables because it's 20V at 3A, and all USB-C/TB3 cables must support at least 3A. The next step up for cables is 5A, which enables 100W max, but those are less common. That cable requirement plus the fact that many systems don't require more than 60W is why most chargers on the market don't offer more than 60W, and even the ones that do will only deliver it when used with an appropriately rated cable because cables that support more than 3A and/or USB 3.1 Gen 2 (10 Gbps) have to have an "E-marker chip" in them to advertise that capability.
Of course none of that means that every system will always request that much power when negotiating USB-PD. When I connect my XPS 13 9350 to a TB16 with a 240W adapter and check the Battery Information area of the BIOS, the XPS just shows a 45W power source, even though the same dock registers as a 90W power source on my Latitude 7480 and a 130W power source on an XPS 15. The XPS 13's normal AC adapter is 45W, so apparently it won't accept more than that over USB-C even when more is available.
As for your "2.5W power share type port" comment, first 2.5W is the minimum spec for USB 2.0; it's 4.5W for USB 3.0 (5V at 900mA). Second, Dell's proprietary PowerShare functionality has absolutely nothing to do with the industry standard USB Power Delivery spec. Third, even some systems that support USB-PD only support it in one direction in order to provide extra power to peripherals (typically 7.5W or 15W max) rather than being able to receive power from a charger over that port, so even seeing USB-PD support doesn't confirm charging support. You're really mixing up concepts that shouldn't be mixed up while also leaving out a lot of key information here.
jphughan
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November 25th, 2018 07:00
For the charging issue, make sure you've updated all of the following, and update them in this order if you haven't:
- System BIOS/firmware
- Thunderbolt software/drivers
- System Thunderbolt 3 controller (not part of the BIOS update)
- TB16 firmware
If you still have trouble with getting the system to charge, it sounds like the system isn't reliably identifying the type of power source. When Dell systems can't detect the type and wattage of the power source, they default to only drawing enough power to run rather than trying to charge the battery. If that's what's happening here, it could be an issue with the dock or the 180W AC adapter. If you bought them together, as I assume you did, then unless you happen to have access to another dock and/or AC adapter where you're located, you might just need to exchange the whole thing.
In terms of your other questions, the short answer is that you're not likely to see any actual negative side effects either way. The USB-C connector should long outlast your use even if you disconnected at each shutdown, and battery longevity is not going to be meaningfully improved by disconnecting from the dock all the time. If you REALLY want to improve battery longevity, go into the BIOS and configure custom charging behavior so that your battery doesn't charge all the way to 100%, which reduces longevity. Li-ion batteries don't like to be maxed out on charge level all the time, which is why Tesla cars for example default to only charging to 80% unless you specifically select a Max Range charge, and even that has to be selected every time rather than being configurable as a default. And then even better, configure a minimum battery charge level so that the battery doesn't even start charging again until it drops to that level. Since I use my laptop at my desk frequently, I have my max set to 80% and my minimum set to 50%. In this configuration, my AC adapter charges my battery only up to 80%, then it essentially disconnects the battery and continues running the system on AC (not the battery) and allows the battery to slowly drain over the next several days rather than keeping it topped up to 80%. When it has self-discharged down to 50%, the system charges it back up to 80%. This is the best strategy of all for battery longevity, but the downsides of course are that a) you only ever use 80% of your battery's capacity, and b) depending on when you disconnect your laptop from AC, you might only have 50% charge. I think newer Dell systems have a utility called Dell Power Manager that allows you to perform one-time overrides of this behavior, such as "Charge to 100% once" if you know you'll need a full charge soon, but I'm not sure since my system doesn't have this capability.
Of course the above makes the battery less useful in day-to-day situations, so you have to decide whether you're willing to accept some possible short-term inconveniences for long-term life. If so, then great. If not, then no problem, since most people aren't willing to do that. But just disconnecting from the dock while the system is shut down won't do much.
Saltgrass
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November 25th, 2018 10:00
There are some things I don't understand regarding the use of the TB 16 and charging or particular systems. To understand you should be aware the XPS 13 9365 uses the USB C Thunderbolt port as the normal charging port on the system. The normal charger has a USB C connector as does the TB16.
There are specs regarding a Thunderbolt port and USB C port but obviously, the internal wiring with reference to normal system charging is different between the two systems. Some, but not all, USB C ports can support up to 100W but is your USB C/Thunderbolt port one of those or just a 2.5W power share type port?
I suppose I will need to check what you read that supported the TB16 would actually charge your system as a normal power adapter would do, unless you already have a reference.
Saltgrass
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November 25th, 2018 12:00
@jphughanmy post was not intended for you ………………………………………….
jphughan
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November 25th, 2018 14:00
Ok, in that case I don’t understand why you’re here questioning whether the 9360 supports charging over USB-C when the OP already said that he can get that working; the issue is that he’s having to go through hoops that should be unnecessary, and he also asked about general battery best practices. If the 9360 didn’t support charging over USB-C, then charging that way would never work because the system’s USB-PD controller would never attempt to negotiate charging.