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paulrickards

Question for EE folks:

Background: I have two of these LX-2BUPS units. They're basically a mini DC to DC UPS battery pack using 2x18650 cells. Folks have been using them to power old laptops since they can be used while also being charged.

My question: Can the output of two of these that each provide 5V @ 3A be tied together to provide longer run times?

aliexpress.com/i/3256806788068

aliexpress.15W 3A 5V/9V/12V High Power UPS Battery Boost Charging Module for Lithium Batteries, Dual Power Supply Switching, UPS Function - AliExpress 1420Smarter Shopping, Better Living! Aliexpress.com

@paulrickards I think that might let out the magic smoke unless they were specifically designed for operation with their outputs connected in parallel. They will not agree on what the output voltage should be due to manufacturing tolerances, and the one with lower output voltage might react poorly to having a higher voltage applied to its output terminals.

@paulrickards not an EE but plenty of experience with DC power systems. If you combine their outputs in parallel with equal cable lengths between them and the load, the power draw will be split equally between them and the system will indeed last twice as long.

(Or did I misunderstand the question?)