Discussion on question by animesh : LiPo battery sparks when used with DC step up convertor

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1:32 AM

The OP is worrying about risk/protection of his ESP32 on using boost converter MT3608. Me hobbyists know very little about risks, so I searched this forum and found the following the good: Boost converter with overvoltage protected output - Olin Lathrop, EESE, 2018
https://electronics.stackexchange.com/questions/355557/boost-converter-with-overvoltage-protected-output.

2 hours later…

tlfong01

3:13 AM

I found MT3608 interesting, but not too many forum discussions around. So I googled, and found a couple of discussions in Chinese. Below is a discussion by poor hobbyists like me.

MT3608 Boost Converter Tutorial - Tai Wan Hobbyist Shop
https://www.ruten.com.tw/item/show?21502221425703

tlfong01

3:30 AM

I read a couple of negative comments on MT3608. The following is an example" The alternative is to go ahead and buy cheap stuff from the surplus or China market, and test everything as it comes in the door. For instance, I'm pretty sure those power supply modules that are so ubiquitous are just copied from vendor's data sheets, without any characterization or testing. – @TimWescott 2020sep02

Me poor hobbyist always worry that the cheapie stuff I bought Up North are fake goods, so I usually do a fact check. I found one possible reason that those cheapy (MT3608 in this case study) are cheapy is that they are like ex-startups Uber: selling services or products at a losing money price, with a short term goal to grab market share, with an ambitious long term goal to become a Unicorn and more, ...

5 hours later…

tlfong01

8:32 AM

So I googled further for more MT3609 info. Then I found XL6809 boost converter which is more powerful than MT3608.

XL6009 Replace LM2577 Power Boost Module Adjustable Converter - US$0.4
https://aliexpress.ru/item/32355892507.html?spm=a2g0o.search0302.0.0.44ad7d18P8FZl8&algo_pvid=8d70be32-bd7b-4015-8547-2734935b96f1&algo_expid=8d70be32-bd7b-4015-8547-2734935b96f1-17&btsid=0b8b036316028369060971466ef4f2&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_

XL6019 180KHz 60V 5A Switching Current Boost Converter - XLSemi
http://www.xlsemi.com/datasheet/XL6019%20datasheet-English.pdf

I read the XL6809 datasheet and found it operation is similar to MT3608, except bigger current capability. I also found both has an inductor coil across input and output. So I think it is the reason that the OP sees the spark when (I guess) disconnects the circuit of the inductor load and the back EMF creates the spark. Anyway, I decided to give up MT3608 and switch to XL6009.