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I have a boost converter that takes 3-5V at input and outputs a steady 5V (This one : https://aliexpress.com/item/33046073847.html). I plugged it to my 18650 battery cell so that I can power an Arduino and also charge some peripherals (earbuds, phone, etc). This boost converter can output up to 3A. I was wondering if I would be able to output 6A if I put two of the modules in parallel? My 18650 cell can output up to 30A according to the datasheet.

I'm quite sure the following would work fine : enter image description here

But would the following work as well? : enter image description here

So my questions basically : can I parallel boosters and expect to earn more current capability? If I put thick wires and put 5 boosters in parallel, will this circuit be able to output steady 5V at up to 15A ?

As far as I know about electronics as a hobbyist, such module is chopping the current (SMPS) and feeding itself a feedback to adapt and output steady 5V. I am wondering if this parallel circuit will (or not) "potentiate" the feedback exponentially and behave erratically.

Musa
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    This has been covered a number of times in the past year on this forum. Bottom line is that you cannot do that unless the supplies are specifically designed to be operated in parallel. – SteveSh May 23 '22 at 17:25
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    Of course, even if you get it working, the battery has to supply quite a lot more than 6A. –  May 23 '22 at 17:40

2 Answers2

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Your first picture will work, but your second is problematic. If there is a small difference in the output voltage between both converters the load current is not equally split, one may have the main burden. Think about a turn on switch in a massive parallel configuration. The inrush current may overload cheap switches and harm them.

Jens
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The input configuration to the converters is not as important as the output impedances of the converters. If there is significant difference in the output impedance between the two converters, then the converter with the lower output impedance will source the majority of the current. You can compensate for this issue by placing resistors (small in value and adequate in rating) at the outputs of the converters so that the output impedances of the converters are dominated by the resistors instead of by the characteristics of the converters.

HypeInst
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