I have a Dell Precision 7510 with a USB-C port.
If I don't have a cable to test it with, is there a way to determine if my computer can charge through this port?
If I do have a USB-C cable that I can connect to a power source and I plug it into my laptop, will simply plugging it in give me a definitive answer, or is it possible that it won't charge through it until I configure it on my computer?
Most certainly, you won't. Although you won't get any confidence unless asking the dell support or trying it out, since I couldn't find any information regarding USB-C charging in the manual of your laptop. But here's how I come to my conclusion:
At first, if your laptop was enabled to be charged over USB type C, it most certainly would be mentioned in the manual. But the only two hits when searching the manual for "USB C" mention USB C for data transfers.
Then, Charging over USB type C is done using the USB type C Power Delivery specification. According to that specification, the maximum power that may be supplied over USB type C is 100 Watts (5 Ampere at 20 Volts). The output of your laptop's power supply is way higher than that, 180 Watts. Not surprising, regarding the hardware of your laptop. So you definetly won't be able to charge your laptop over USB type C while using it. And while it might be possible to charge your laptop over USB type C while turned off, the manufacturer probably didn't include this feature: If you can't charge your laptop using USB type C while in use, manufacturers tend to leave this feature out, even for the shut-down mode.
Of course, you'll only get confidence by trying out or asking the dell support hotline. But don't be surprised to get a no.
This can be a confusing topic because the port is Thunderbolt 3, the shape of the port is USB-C, and the charging protocol is USB PD (power delivery), and Thunderbolt 3 ports are also capable of communicating via USB 3.x in addition to the much faster Thunderbolt speeds.
In this case I'm happy to let you know I also have a Precision 7510 and it can be charged via the Thunderbolt 3 port, and despite Dell's recommendation that you use a power adapter in addition to their TB15 or TB16 docks, the 130w the docks output if powered by a 240w power brick is usually sufficient to power the laptop if you aren't running 64 GB of RAM fully utilized and rendering crazy 3D models.
I have a wide variety of chargers available and in my experimenting I've found that it can actually charge from all the way down to about 65 Watts via a standard Dell charger or USB-C, but using anything less than a 65 watt USB-C typically requires your laptop to be in a suspended state otherwise it's using more power than it's receiving.
One thing to be aware of when using chargers that are less than the recommended size for your system is it will typically limit system performance due to throttling. You can override this with some applications to force "Performance mode", but in doing that your battery may discharge even though you are attached to a charger because it can use more then you are receiving as mentioned above.
Another thing to note is there are multiple voltages and amperages that are defined as Power Delivery compatible so even though you might be plugged into a charger that supports USB Power Delivery if it doesn't match what your device understands you won't get a charge. I noticed this when using a mid range USB-C power adapter that the 7510 simply ignored it even though a smaller one worked fine. Using the same adapter with a Precision 5510 or my XPS13 (9360) it works just fine.
I don't have enough reputation to comment on dragon788's post, but I have partially reproduced his success with my Precision 7510 using two different (one 65watt one 90watt) USB-PD chargers. The battery charging indicator does not light, however, and does not seem to charge. I am able to boot the laptop and run it for at least an hour on a dead battery using Type-C and Linux indicates it is plugged in and charging, but at an unknown rate. The laptop shutoff immediately when the power was disconnected with a battery that was dead at boot. I have not tried to power-off charge the battery in this manner yet, I just got my charger and it's a car charger, so I'll try it next time I'm on the road.
Edit: after a roughly 40 minute round trip, laptop powered off, there was no substantial change in battery (dropped 2%, probably in boot up / shut down loss and whatever margin of error. So it appears that for me, the laptop can be type-C powered, so long as there's a battery in the system, even if that battery is very dead, but it cannot charge the battery using type-C.
