I got several good power banks with 18w, 12v
My laptop requires at least 45w, 20v (up to 100w)
Is it possible to bundle and boost voltage?
Laptop is LG Gram 17, 2021 model
Yes, in theory. But many new laptops have the ability to identify the power supply connected to them and may decide that it doesn’t want to play nice with the power supply. How? FM (Frelling Magic?)
As a side note, the IT guys upstairs have about 60 LG Gram laptops deployed to their users. These are a few years old now.
Many of them have hinges that are starting to get loose. The way the WiFi antenna is routed through the hinge, is right at the area that flexes. Soon after the hinge starts to get loose, the WiFi antenna wire is pulled in half. These are way finer wires than the typical WiFi setup found in most laptops.
It’s basically not user fixable.
So if you notice your screen plastic starting to flex open at the hinge. Fix the joint PDQ (this is covered by warranty) during the warranty period.
Hopefully they have fixed this problem on your newer model.
All the Best,
Jeff
Just re-read your question. I’m not sure you can “Bundle” a pair of PS. That would depend on how the PSs are designed.
But Watts is Watts, and you could, perhaps put a few in parallel and use a boost to end up with what you want.
But, I’d be real hesitant to plug $1700 worth of laptop into something like this.
Better to find an aftermarket PS that is known to work.
All the Best,
Jeff
Maybe you can use the YZ926 boost module (https://nl.aliexpress.com/item/4000553268600.html) to boost the voltage coming from the powerbanks to 20V for your laptop. I tested the module with my Dell XPS 13 and it charges just fine, although I hear some audible coil-whine from the adapter. The 100W rating also seems about right, I tested the module with 12V in and it could deliver about 65W to charge my laptop.
You’ll need to make an “aggregation-cable-assembly” or something yourself, with “PD decoy modules” so they can ask the highest voltage possible from your powerbanks. Cables like this (https://nl.aliexpress.com/item/32999479210.html) could work, they have internal trigger chips. Additionally you’ll need a (good, with thick wires) Y-splitter going to the YZ936 module, and I think it’s also good if you’ll have diodes after each trigger cable to prevent power from flowing between the powerbanks.
So my proposition is this (although I have no idea if the power will flow correctly/if there’s going to be “load balancing” of the powerbanks etc):
Powerbank 1 -> Trigger cable -> Diode (on positive side) -> Y-cable -|
Powerbank 2 -> Trigger cable -> Diode (on positive side) -> Y-cable —-> YZ926 -> Laptop
Powerbank 3 -> Trigger cable -> Diode (on positive side) -> Y-cable -|
It’s going to be expensive/a hassle to set up though, but you could give it a try 
I know almost nothing about this stuff, but isn’t there some sort of communication between the PS and the laptop?
If so my laptop may get confused if it asks a question and 3 power banks reply that they only supply 12v (while the laptop sees a boosted 20v)
I share your hesitation Jeff…
Not what I really want but now I’m considering a PB that can deliver the required 45watts or more and then use my other power banks to recharge that PB.
Currently I’m testing the efficiency of 7 of my PBs and plan to post my results here. Anyway the PB with the best efficiency doesn’t support powering a device while it’s being charged itself.
I have my eyes on the 65w and 100w Baseus PBs. But I don’t know it supports the charging while being recharged itself.
At a certain point it might be better to take my loss.
A once time hassle isn’t the biggest problem, but after that it should be easy to uses and not a mile of cables all over the place.
And to be honest, when I look at those cables I don’t even understand, which of the 20v cables I need