Since my new ThinkPad A485 has a USB-C charging port, I was wondering if it would charge with a regular USB powerbank. I read that most standard powerbanks don’t support power delivery and therefore wouldn’t charge the laptop.
After I read that some people had success when the laptop was powered off, I became tempted to try it out, but I am not sure, if it can damage the laptop. So I wanted to ask you guys, if you know more and could tell me, if it’s safe to try it out?
In other words I guess the question is, would it be safe to plug a non-PD charger into a PD-only-device?
Here are the important informations about that. I would adivce against if you’re not using a charger USB PD certified since I think it’s required for the correct negotiation between the power bank and laptop.
I don’t remember exactly where I read it, but between problems with different devices not properly following the spec, and many of the cables also not follow spec, there have been issues with USB-PD. Supposedly they are working on some sort of proprietary communication between devices/chargers.
With the amount of time the idea of USB-PD has been around, you would figure they would have known there would be cheap knock-off chargers and cables and come up with some sort of solution where devices that do properly follow spec could protect themselves from damage without an after-the-fact solution. Adding something in of a similar style to proprietary laptop chargers, negating existing products, sounds like a bad and lazy solution to me. They must be unaware of all of the previous knock-offs and improper usage of USB stuff that has become ubiquitous in the world.
You’ll need a powerbank able to output 19 or 20V and at least like 3A.
The reason it works with the laptop powered off is likely explained by the power the PB is able to deliver. When the laptop is powered off it only needs to charge the battery, not run the laptop at the same time, so the overall draw will be less.
I don’t have any experience with this so take my words with at least a tiny grain of salt. No guarantees.
Very, very few laptops (exceptions being ones that expect a 5-8V input) will charge from the 5V output of a power bank.
If you were to mod the powerbank to output a higher voltage, such as with a boost converter, you may run into trouble…
Most powerbanks use cell(s) in parallel, and none in series (3V lowest charge and max charge of 4.2 for the cell), and just boost the voltage to 12V, when needed for Qualcomm Quickcharge (4.2V ~4.2A, 18W from cell) supported devices.
Pulling 45W (4.2V 10A from cell, boosted to 19V ~2.3A) from a battery designed for higher capacity and lower currents (thin electrodes, but very large surface area), will severely degrading the battery capacity, and risk much worse to happen. Not only that, overcurrent protection will be triggered long before that by the BMS and USB circuitry (if designed properly), so you will be required to use modded-in boost converter to achieve the required laptop charging voltage.
Your best bet to complete this project safely is to read the datasheet of the LIPO/Li-Ion cells inside of the powerbank, and to make your own casing for the cells. Buying an off-the-shelf power bank and trying to mod it to charge a laptop probably won’t go well.
