I was really curious about this, and keep in mind that i have the OLED steam deck so it has a bigger battery, if you have a LCD steam deck in theory, it should add another 25% to it. (50/40)

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So I tried a bauses 65w 20000mah power bank for this test. the results will change slightly depending on the efficiency of your power bank but ones with high voltage support are usually better (assuming they use the cells in series with a step down etc)

I managed to charge my steam deck 1.25-1.2 times with this, meaning that for a 20,000mAh power bank:

• 3H total with no power bank -> of total 7.3H of play time~ (steam deck and power bank both at 100%$)
• 4H turns into 8.5H
• 6H turns into 13.4H

for a 10,000mAh power bank (assuming same efficiency, should be slightly lower):

• 3H turns to 4.8H
• 4H turns into 6.4H
• 6H turns into 9.6H

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