add a battery protection board

[devdb49]

Hello,

Is it possible to add a battery protection board with an 8205A MOSFET?
https://www.cestore-mm.com/product/18650-li-ion-1s-bms-module-3a/

[devdb49]

And what is the purpose of the TVS DIODE ARRAY ?
What is the value or model of THERM1 ?

[bartkodden]

Yes agreed.
I do have V2 of the design more fleshed out, moved to ESP32 instead of ESP32-C6, but that seemed unnecessary, i did add an XB8089D protection IC on the board: https://atta.szlcsc.com/upload/public/pdf/source/20160810/1470822740356.pdf

The TVS diode array is for ESD protection on the USB port
The Thermistor is part of the reference design of the mcp73871, it should allow for comparing the current (and the expected thermal output) to the ambient temperature (if i understand correctly)

Disclaimer: im not an electrical engineer, i did make a mistake with the LEDs on the V1.0 and V2.0 too, they are 5v and cannot be communicated with well by the esp32.

[devdb49]

Thank you. Can I remove the battery voltage measurement with the bq27441? Le mar. 10 févr. 2026, 14:36, Bart Kodden ***@***.***> a écrit :

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*bartkodden* left a comment (bartkodden/ESP_MKB#4) <#4 (comment)> Yes agreed. I do have V2 of the design more fleshed out, moved to ESP32 instead of ESP32-C6, but that seemed unnecessary, i did add an XB8089D protection IC on the board: https://atta.szlcsc.com/upload/public/pdf/source/20160810/1470822740356.pdf image.png (view on web) <https://github.com/user-attachments/assets/c2c135b5-3a2b-404d-bb09-f2907304b834> The TVS diode array is for ESD protection on the USB port The Thermistor is part of the reference design of the mcp73871, it should allow for comparing the current (and the expected thermal output) to the ambient temperature (if i understand correctly) Disclaimer: im not an electrical engineer, i did make a mistake with the LEDs on the V1.0 and V2.0 too, they are 5v and cannot be communicated with well by the esp32. — Reply to this email directly, view it on GitHub <#4 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ANPYIN7Q236PSJ5K74QCLSL4LHNHFAVCNFSM6AAAAACTNC2SAWVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTQNZXGY3DGMBWGU> . You are receiving this because you authored the thread.Message ID: ***@***.***>

[bartkodden]

Yes if you remove the bq27441 i think you only lose the measurement reports.
I can send you my design files for the V2 if you want. i did add a CP2102 usb serial adapter which turned out to be unnecessary if you go back to the C6, but the files are a bit better for the overall design i think, then you also see the values of all parts.

edit: (I dont know how to send a private message in github yet, will look into it!)

[devdb49]

I am interested in your V2 version. Thank you in advance. Le mar. 10 févr. 2026, 14:51, Bart Kodden ***@***.***> a écrit :

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*bartkodden* left a comment (bartkodden/ESP_MKB#4) <#4 (comment)> Yes if you remove the bq27441 i think you only lose the measurement reports. I can send you my design files for the V2 if you want. i did add a CP2102 usb serial adapter which turned out to be unnecessary if you go back to the C6, but the files are a bit better for the overall design i think, then you also see the values of all parts — Reply to this email directly, view it on GitHub <#4 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ANPYINZA2QS3A4JPKAYXUPL4LHO6FAVCNFSM6AAAAACTNC2SAWVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTQNZXG42DONBYHA> . You are receiving this because you authored the thread.Message ID: ***@***.***>

[devdb49]

I have the ESP32 Wroom. Le mar. 10 févr. 2026, 14:51, Bart Kodden ***@***.***> a écrit :

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*bartkodden* left a comment (bartkodden/ESP_MKB#4) <#4 (comment)> Yes if you remove the bq27441 i think you only lose the measurement reports. I can send you my design files for the V2 if you want. i did add a CP2102 usb serial adapter which turned out to be unnecessary if you go back to the C6, but the files are a bit better for the overall design i think, then you also see the values of all parts — Reply to this email directly, view it on GitHub <#4 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ANPYINZA2QS3A4JPKAYXUPL4LHO6FAVCNFSM6AAAAACTNC2SAWVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTQNZXG42DONBYHA> . You are receiving this because you authored the thread.Message ID: ***@***.***>

[devdb49]

I am interested in your V2 version. I have a ESP32-WROOM-DEV_KIT Thank you in advance. Le mar. 10 févr. 2026 à 14:51, Bart Kodden ***@***.***> a écrit :

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*bartkodden* left a comment (bartkodden/ESP_MKB#4) <#4 (comment)> Yes if you remove the bq27441 i think you only lose the measurement reports. I can send you my design files for the V2 if you want. i did add a CP2102 usb serial adapter which turned out to be unnecessary if you go back to the C6, but the files are a bit better for the overall design i think, then you also see the values of all parts — Reply to this email directly, view it on GitHub <#4 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ANPYINZA2QS3A4JPKAYXUPL4LHO6FAVCNFSM6AAAAACTNC2SAWVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTQNZXG42DONBYHA> . You are receiving this because you authored the thread.Message ID: ***@***.***>

[bartkodden]

I uploaded the easyeda file here: https://limewire.com/d/rDedc#GbTtH3ikwu
The password is your username. it does expire in 1 week (i could not change that unfortunately)
Please let me know if there is any trouble!

[devdb49]

I have retrieved the file, but how do I open it?
What software should I use?
Thank you.

[bartkodden]

Ah sorry! I'm using easyeda pro (free, here: https://pro.easyeda.com/editor )
I believe you can import the file in there.
It's a web app so no installation necessary.

[devdb49]

Thank you very much Le jeu. 19 févr. 2026, 22:02, Bart Kodden ***@***.***> a écrit :

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*bartkodden* left a comment (bartkodden/ESP_MKB#4) <#4 (comment)> Ah sorry! I'm using easyeda pro (free, here: https://pro.easyeda.com/editor ) I believe you can import the file in there. It's a web app so no installation necessary. — Reply to this email directly, view it on GitHub <#4 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ANPYIN2S6JNANDPACP2UQG34MYQGJAVCNFSM6AAAAACTNC2SAWVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTSMZQGAYDKNRSGM> . You are receiving this because you authored the thread.Message ID: ***@***.***>

[devdb49]

First of all, thank you for sharing and for the changes made to V1. I would like to show you my version, in which I have removed the voltage measurement. I have also renamed BATPos to VBAT on the battery power switch. On the BMS SYSTEM section, is pin 16 VBAT_Sense correct with VBAT? Thank you for your help. Le jeu. 19 févr. 2026 à 22:02, Bart Kodden ***@***.***> a écrit :

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*bartkodden* left a comment (bartkodden/ESP_MKB#4) <#4 (comment)> Ah sorry! I'm using easyeda pro (free, here: https://pro.easyeda.com/editor ) I believe you can import the file in there. It's a web app so no installation necessary. — Reply to this email directly, view it on GitHub <#4 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ANPYIN2S6JNANDPACP2UQG34MYQGJAVCNFSM6AAAAACTNC2SAWVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTSMZQGAYDKNRSGM> . You are receiving this because you authored the thread.Message ID: ***@***.***>