Travel Charger for my new laptop

I recently purchased a new laptop - HP ZBook Ultra G1a 14. It's a great laptop that has a powerful CPU/GPU, a big battery and is still light-weight.

Charging issues

I usually don't use original laptop power supplies due to their bulkiness and general inconvenience.

The new laptop is quite picky when it comes to charging it (caveat: the laptop comes in different variants with different TDPs, and variants with lower wattages might be less picky about power supply).

All the laptops that I had before could be charged using a small travel-size multi-port 65W USB-C charger, which could even charge multiple device simultaneously with the laptop. This is super convenient when traveling as I can take just one charger and use it to charge everything.

Unfortunately, the new laptop would not charge using any of the chargers that I had. 65W chargers did not work at all, and the 100W charger only worked in a single-port configuration.

Initially I purchased a UGREEN 160W charger for around 60EUR. Although it technically can charge the laptop, I wasn't fully satisfied with it. The two major issues with it for me were:

1. The charger is bulkier and heavier than I would like.
2. Even though the total available power (160W) is more than enough for my charging needs, the way that it splits the power across its output ports is not ideal. When connecting 3 devices, it allocates too little power to the laptop for it to start charging. This forces me to shuffle and re-connect my devices to keep them charged.

After some research I ended up buying Anker 160W charger for around 100EUR. Its main strengths for me were:

1. It is compact and lightweight. Not as compact as 65W chargers are, but still tolerable.
2. Power allocation across ports is not fixed and can be configured, which enables to adapt the charger to my laptop.
3. According to tests done by others, it should be more efficient and produce less heat, though I haven't had the chance to test it out. My previous 65W charger could get pretty warm when charging at its maximum power.

In the end I am pretty happy with the Anker charger am I going to keep it.

Charging experiments

During the course of solving the charging issues, I've experimented with multiple chargers and collected some data.

Charging in OFF state

The process of charging the laptop is very different depending on whether it's off or on. When it's off, its battery can be charged using any charger at all, even the most basic 5W (5V 1A) USB-A charger. It would charge very slowly, but at least I know that in a pinch it's possible to charge it anywhere. Apparently it can convert input voltage to battery voltage, so I assume that its DC-to-DC converter is too weak to be able to drive the CPU off of it.

Charging in the ON state

After testing several chargers and several configurations of their output ports, I came to the conclusion that the only requirement is that the charger allocates at least 85W to the laptop. If the charger has multiple port, then the port that the laptop uses must be able to provide 85W, otherwise it won't charge at all. The laptop can use either 20V or 28V for charging (its original charger is 28V).

All chargers (except for Anker) have a fixed power allocation between ports. Anker's charger supports several modes:

• “AI” mode, which tries to guess power requirements of each connected device
• C1 Priority, which allocates the largest portion of power to the first port, and the remaining power is split between ports 2 and 3
• Dual Laptop, which allocates 70W to first 2 ports and 20W to the remaining port
• Custom mode, which allows editing exactly how many watts is allocated to each port.

As far as I can see (and I confirmed it with the Anker Support), the voltages on each port are independent of each other, so it is possible to mix and match devices with different voltage requiements.

The following table is a summary of the chargers and configurations I've tried.

Picture		Charger	Port configuration					Outcome
			Mode	Port 1	Port 2	Port 3	Port 4 (USB-A)
		Belkin 65W USB-C PD Wall Charger with PPS Model number: WCH013vf		laptop	-	-	-	❌
		UGREEN 65W 3-port USB-C GaN Fast Charger Model number: X556		laptop	-	-	-	❌
		UGREEN 100W GaN Fast Charger Model number: CD226		laptop	-	-	phone	✅
				laptop	-	phone	-	❌
		UGREEN 160W 4-port GaN Fast Charger Model number: X762		laptop	tablet	-	phone	✅
				laptop	tablet	phone	-	❌
		Anker Prime 160W, 3 ports, smart display Model number: A2687	"AI"	laptop	tablet	phone		✅
			"AI"	laptop	other laptop	phone		❌
			C1 priority	laptop	tablet	phone		✅
			C1 priority	laptop	other laptop	phone		✅
			Dual laptop	laptop	phone			❌
			Custom, 84W	laptop	-	-		❌
			Custom, 85W+35W+35W	laptop	phone	tablet		✅

After the experiments, I've settled on the following custom mode: