4 <title>12V Lead-Acid battery changer and terminal</title>
5 <!-- 2020-02-24 E 00:47 -->
7 <meta name="viewport" content="width=device-width, initial-scale=1">
8 <meta name="generator" content="Org-mode">
9 <meta name="author" content="Svjatoslav Agejenko">
10 <link href="https://bootswatch.com/3/darkly/bootstrap.min.css" rel="stylesheet">
11 <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.min.js"></script>
12 <script src="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.5/js/bootstrap.min.js"></script>
13 <style type="text/css">
14 footer {background-color: #111 !important;}
15 pre {background-color: #111; color: #ccc;}
17 <style type="text/css">
18 /* org mode styles on top of twbs */
35 background-color: #f5f5f5;
62 display: inline-block;
74 .bs-docs-sidebar.affix {
77 @media (min-width: 768px) {
83 /* All levels of nav */
84 .bs-docs-sidebar .nav > li > a {
91 .bs-docs-sidebar .nav > li > a:hover,
92 .bs-docs-sidebar .nav > li > a:focus {
95 text-decoration: none;
96 background-color: transparent;
97 border-left: 1px solid #A1283B;
99 .bs-docs-sidebar .nav > .active > a,
100 .bs-docs-sidebar .nav > .active:hover > a,
101 .bs-docs-sidebar .nav > .active:focus > a {
105 background-color: transparent;
106 border-left: 2px solid #A1283B;
109 /* Nav: second level (shown on .active) */
110 .bs-docs-sidebar .nav .nav {
111 display: none; /* Hide by default, but at >768px, show it */
112 padding-bottom: 10px;
114 .bs-docs-sidebar .nav .nav > li > a {
121 .bs-docs-sidebar .nav .nav > li > a:hover,
122 .bs-docs-sidebar .nav .nav > li > a:focus {
125 .bs-docs-sidebar .nav .nav > .active > a,
126 .bs-docs-sidebar .nav .nav > .active:hover > a,
127 .bs-docs-sidebar .nav .nav > .active:focus > a {
132 /* Nav: third level (shown on .active) */
133 .bs-docs-sidebar .nav .nav .nav {
134 padding-bottom: 10px;
136 .bs-docs-sidebar .nav .nav .nav > li > a {
143 .bs-docs-sidebar .nav .nav .nav > li > a:hover,
144 .bs-docs-sidebar .nav .nav .nav > li > a:focus {
147 .bs-docs-sidebar .nav .nav .nav > .active > a,
148 .bs-docs-sidebar .nav .nav .nav > .active:hover > a,
149 .bs-docs-sidebar .nav .nav .nav > .active:focus > a {
154 /* Show and affix the side nav when space allows it */
155 @media (min-width: 992px) {
156 .bs-docs-sidebar .nav > .active > ul {
159 /* Widen the fixed sidebar */
160 .bs-docs-sidebar.affix,
161 .bs-docs-sidebar.affix-bottom {
164 .bs-docs-sidebar.affix {
165 position: fixed; /* Undo the static from mobile first approach */
168 .bs-docs-sidebar.affix-bottom {
169 position: absolute; /* Undo the static from mobile first approach */
171 .bs-docs-sidebar.affix .bs-docs-sidenav,.bs-docs-sidebar.affix-bottom .bs-docs-sidenav {
176 @media (min-width: 1200px) {
177 /* Widen the fixed sidebar again */
178 .bs-docs-sidebar.affix-bottom,
179 .bs-docs-sidebar.affix {
184 <script type="text/javascript">
188 $('.bs-docs-sidebar li').first().addClass('active');
190 $(document.body).scrollspy({target: '.bs-docs-sidebar'});
192 $('.bs-docs-sidebar').affix();
197 <div id="content" class="container">
198 <div class="row"><div class="col-md-9"><h1 class="title">12V Lead-Acid battery changer and terminal</h1>
200 <div id="outline-container-sec-1" class="outline-2">
201 <h2 id="sec-1"><span class="section-number-2">1</span> General</h2>
202 <div class="outline-text-2" id="text-1">
204 <li>DISCLAIMER: I DO ELECTRONICS AND 3D DESIGN SOLELY AS A HOBBY. THERE
205 COULD BE ERRORS THAT CAN RESULT IN ALL KINDS OF DAMAGE. USE THESE
206 DESIGNS AT YOUR OWN RISK.
211 <li>Svjatoslav Agejenko
213 <li>Homepage: <a href="https://svjatoslav.eu">https://svjatoslav.eu</a>
215 <li>Email: <a href="mailto://svjatoslav@svjatoslav.eu">svjatoslav@svjatoslav.eu</a>
222 <li><a href="../../index.html">Other physical projects in this repository</a>
224 <li><a href="https://www.svjatoslav.eu/projects/">Other projects hosted at svjatoslav.eu</a>
232 <div id="outline-container-sec-2" class="outline-2">
233 <h2 id="sec-2"><span class="section-number-2">2</span> Project description</h2>
234 <div class="outline-text-2" id="text-2">
237 <p><img src="make.png" class="img-responsive" alt="make.png">
243 <p><img src="make,%202.png" class="img-responsive" alt="make,%202.png">
248 Simple charger and terminal (front-end) for 12V lead-acid battery.
252 Idea is to distribute power from rechargeable 12V battery to various
253 appliances (soldering iron, radio transmitters, etc..) while also
254 providing use-charging in the background.
258 Single on/off button disconnects battery and up-step voltage source
259 from front panel terminal connectors.
263 <a href="https://www.amazon.de/gp/product/B07G4KWV6S/ref=ppx_yo_dt_b_asin_title_o08_s01?ie=UTF8&psc=1">Tecnoiot MT3608</a> voltage up-step is used. 3V DC external power supply
264 is used to feed voltage up-step. Up-step is tuned to ~14.4 V.
269 <p><img src="schematic.png" class="img-responsive" alt="schematic.png">
274 Current design is rather of blog (experience sharing) value. It has
275 quite some drawbacks:
279 <li>Warning: Circuit has dangerous instability. Requires low voltage
280 ~3V but relatively high current external power supply. Using
281 higher voltage but low current power supply could easily lead to
282 situation where step-up generated load pushes power supply output
283 voltage down too much. This leads to too much power being lost
284 within power supply and easily leads to power supply overheating!
287 <li>There is no dedicated current limiter. 3V external power supply
288 and up-step are acting as current limiters.
291 <li>While RCA connectors do work as DC power connectors, but are not
292 intended to be used this way and are not very reliable.
298 <div id="outline-container-sec-3" class="outline-2">
299 <h2 id="sec-3"><span class="section-number-2">3</span> Body</h2>
300 <div class="outline-text-2" id="text-3">
303 <p><img src="body.png" class="img-responsive" alt="body.png">
309 <p><img src="cover.png" class="img-responsive" alt="cover.png">
317 <li><a href="body%20and%20cover.FCStd">body and cover FreeCAD file</a>
319 <li><a href="body.stl">body in STL format</a>
321 <li><a href="cover.stl">cover in STL format</a>
328 </div><div class="col-md-3"><nav id="table-of-contents">
329 <div id="text-table-of-contents" class="bs-docs-sidebar">
331 <li><a href="#sec-1">1. General</a></li>
332 <li><a href="#sec-2">2. Project description</a></li>
333 <li><a href="#sec-3">3. Body</a></li>
338 <footer id="postamble" class="">
339 <div><p class="author">Author: Svjatoslav Agejenko</p>
340 <p class="date">Created: 2020-02-24 E 00:47</p>
341 <p class="creator"><a href="http://www.gnu.org/software/emacs/">Emacs</a> 26.1 (<a href="http://orgmode.org">Org-mode</a> 9.1.9)</p>