nRFBox Charging Battery released Magic Smoke

I did build a nRFBOX V2 which is working fine so far.

But when I did try to charge a battery, it worked fine at first but after some minutes it released the "Magic Smoked". Can someone tell what I did wrong?

Jun 17 '25 16:06 SunboX

The capacitors C8 and C9 are installed in reverse.

Identifying Tantalum Capacitors

Jun 18 '25 08:06 stonedDiscord

Thanks a lot! I usd the marking on the pcb for orientation. But I will re-check. Thanks!

Jun 18 '25 08:06 SunboX

The markings on the PCB indicate the negative side, the line on the capacitor itself marks the positive side.

Jun 18 '25 09:06 stonedDiscord

I think the marking on one of the caps is wrong. Take a look at one of the "original" photos from @cifertech :

Also, whats about the big cap on the NRF24 GTmini module? Is this needed? If so, why?

Jun 19 '25 08:06 SunboX

hey, where did you get this 'battery holder' pcb ?

Jun 25 '25 05:06 gel3k

@gel3k I made it myself. ;) With KiCAD it's very easy.

Jun 25 '25 12:06 SunboX

anyone can share the kicad pcb or other version, i have already fried almost all my components :)

Jul 17 '25 14:07 gel3k