1 #+TITLE: 12V Lead-Acid battery changer and terminal
2 #+AUTHOR: Svjatoslav Agejenko
5 * (document settings) :noexport:
6 ** use dark style for TWBS-HTML exporter
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16 + DISCLAIMER: I DO ELECTRONICS AND 3D DESIGN SOLELY AS A HOBBY. THERE
17 COULD BE ERRORS THAT CAN RESULT IN ALL KINDS OF DAMAGE. USE THESE
18 DESIGNS AT YOUR OWN RISK.
22 - Homepage: https://svjatoslav.eu
23 - Email: [[mailto://svjatoslav@svjatoslav.eu][svjatoslav@svjatoslav.eu]]
26 - [[../../index.html][Other physical projects in this repository]]
27 - [[https://www.svjatoslav.eu/projects/][Other projects hosted at svjatoslav.eu]]
32 [[file:make,%202.png]]
34 Simple charger and terminal (front-end) for 12V lead-acid battery.
36 Idea is to distribute power from rechargeable 12V battery to various
37 appliances (soldering iron, radio transmitters, etc..) while also
38 providing use-charging in the background.
40 Single on/off button disconnects battery and up-step voltage source
41 from front panel terminal connectors.
43 [[https://www.amazon.de/gp/product/B07G4KWV6S/ref=ppx_yo_dt_b_asin_title_o08_s01?ie=UTF8&psc=1][Tecnoiot MT3608]] voltage up-step is used. 3V DC external power supply
44 is used to feed voltage up-step. Up-step is tuned to ~14.4 V.
46 [[file:schematic.png]]
48 Current design is rather of blog (experience sharing) value. It has
51 - Warning: Circuit has dangerous instability. Requires low voltage
52 ~3V but relatively high current external power supply. Using
53 higher voltage but low current power supply could easily lead to
54 situation where step-up generated load pushes power supply output
55 voltage down too much. This leads to too much power being lost
56 within power supply and easily leads to power supply overheating!
58 - There is no dedicated current limiter. 3V external power supply
59 and up-step are acting as current limiters.
61 - While RCA connectors do work as DC power connectors, but are not
62 intended to be used this way and are not very reliable.
72 + [[file:body%20and%20cover.FCStd][body and cover FreeCAD file]]
73 + [[file:body.stl][body in STL format]]
74 + [[file:cover.stl][cover in STL format]]