+++ /dev/null
-<!doctype html>
-<html lang="en">
-<head>
-<title>Battery charger and dual power supply unit</title>
-<!-- 2020-07-12 Sun 02:52 -->
-<meta charset="utf-8">
-<meta name="viewport" content="width=device-width, initial-scale=1">
-<meta name="generator" content="Org-mode">
-<meta name="author" content="Svjatoslav Agejenko">
-<link href="https://bootswatch.com/3/darkly/bootstrap.min.css" rel="stylesheet">
-<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.min.js"></script>
-<script src="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.5/js/bootstrap.min.js"></script>
-<style type="text/css">
-footer {background-color: #111 !important;}
-pre {background-color: #111; color: #ccc;}
-</style>
-<style type="text/css">
-/* org mode styles on top of twbs */
-
-html {
- position: relative;
- min-height: 100%;
-}
-
-body {
- font-size: 18px;
- margin-bottom: 105px;
-}
-
-footer {
- position: absolute;
- bottom: 0;
- width: 100%;
- height: 101px;
- background-color: #f5f5f5;
-}
-
-footer > div {
- padding: 10px;
-}
-
-footer p {
- margin: 0 0 5px;
- text-align: center;
- font-size: 16px;
-}
-
-#table-of-contents {
- margin-top: 20px;
- margin-bottom: 20px;
-}
-
-blockquote p {
- font-size: 18px;
-}
-
-pre {
- font-size: 16px;
-}
-
-.footpara {
- display: inline-block;
-}
-
-figcaption {
- font-size: 16px;
- color: #666;
- font-style: italic;
- padding-bottom: 15px;
-}
-
-/* from twbs docs */
-
-.bs-docs-sidebar.affix {
- position: static;
-}
-@media (min-width: 768px) {
- .bs-docs-sidebar {
- padding-left: 20px;
- }
-}
-
-/* All levels of nav */
-.bs-docs-sidebar .nav > li > a {
- display: block;
- padding: 4px 20px;
- font-size: 14px;
- font-weight: 500;
- color: #999;
-}
-.bs-docs-sidebar .nav > li > a:hover,
-.bs-docs-sidebar .nav > li > a:focus {
- padding-left: 19px;
- color: #A1283B;
- text-decoration: none;
- background-color: transparent;
- border-left: 1px solid #A1283B;
-}
-.bs-docs-sidebar .nav > .active > a,
-.bs-docs-sidebar .nav > .active:hover > a,
-.bs-docs-sidebar .nav > .active:focus > a {
- padding-left: 18px;
- font-weight: bold;
- color: #A1283B;
- background-color: transparent;
- border-left: 2px solid #A1283B;
-}
-
-/* Nav: second level (shown on .active) */
-.bs-docs-sidebar .nav .nav {
- display: none; /* Hide by default, but at >768px, show it */
- padding-bottom: 10px;
-}
-.bs-docs-sidebar .nav .nav > li > a {
- padding-top: 1px;
- padding-bottom: 1px;
- padding-left: 30px;
- font-size: 12px;
- font-weight: normal;
-}
-.bs-docs-sidebar .nav .nav > li > a:hover,
-.bs-docs-sidebar .nav .nav > li > a:focus {
- padding-left: 29px;
-}
-.bs-docs-sidebar .nav .nav > .active > a,
-.bs-docs-sidebar .nav .nav > .active:hover > a,
-.bs-docs-sidebar .nav .nav > .active:focus > a {
- padding-left: 28px;
- font-weight: 500;
-}
-
-/* Nav: third level (shown on .active) */
-.bs-docs-sidebar .nav .nav .nav {
- padding-bottom: 10px;
-}
-.bs-docs-sidebar .nav .nav .nav > li > a {
- padding-top: 1px;
- padding-bottom: 1px;
- padding-left: 40px;
- font-size: 12px;
- font-weight: normal;
-}
-.bs-docs-sidebar .nav .nav .nav > li > a:hover,
-.bs-docs-sidebar .nav .nav .nav > li > a:focus {
- padding-left: 39px;
-}
-.bs-docs-sidebar .nav .nav .nav > .active > a,
-.bs-docs-sidebar .nav .nav .nav > .active:hover > a,
-.bs-docs-sidebar .nav .nav .nav > .active:focus > a {
- padding-left: 38px;
- font-weight: 500;
-}
-
-/* Show and affix the side nav when space allows it */
-@media (min-width: 992px) {
- .bs-docs-sidebar .nav > .active > ul {
- display: block;
- }
- /* Widen the fixed sidebar */
- .bs-docs-sidebar.affix,
- .bs-docs-sidebar.affix-bottom {
- width: 213px;
- }
- .bs-docs-sidebar.affix {
- position: fixed; /* Undo the static from mobile first approach */
- top: 20px;
- }
- .bs-docs-sidebar.affix-bottom {
- position: absolute; /* Undo the static from mobile first approach */
- }
- .bs-docs-sidebar.affix .bs-docs-sidenav,.bs-docs-sidebar.affix-bottom .bs-docs-sidenav {
- margin-top: 0;
- margin-bottom: 0
- }
-}
-@media (min-width: 1200px) {
- /* Widen the fixed sidebar again */
- .bs-docs-sidebar.affix-bottom,
- .bs-docs-sidebar.affix {
- width: 263px;
- }
-}
-</style>
-<script type="text/javascript">
-$(function() {
- 'use strict';
-
- $('.bs-docs-sidebar li').first().addClass('active');
-
- $(document.body).scrollspy({target: '.bs-docs-sidebar'});
-
- $('.bs-docs-sidebar').affix();
-});
-</script>
-</head>
-<body>
-<div id="content" class="container">
-<div class="row"><div class="col-md-9"><h1 class="title">Battery charger and dual power supply unit</h1>
-
-<div id="outline-container-sec-1" class="outline-2">
-<h2 id="sec-1"><span class="section-number-2">1</span> General</h2>
-<div class="outline-text-2" id="text-1">
-<ul class="org-ul">
-<li>DISCLAIMER: I DO ELECTRONICS AND 3D DESIGN SOLELY AS A HOBBY. THERE
-COULD BE ERRORS THAT CAN RESULT IN ALL KINDS OF DAMAGE. USE THESE
-DESIGNS AT YOUR OWN RISK.
-</li>
-
-<li>This design is released under Creative Commons Zero (CC0) license.
-</li>
-
-<li>Authors:
-<ul class="org-ul">
-<li>Svjatoslav Agejenko
-<ul class="org-ul">
-<li>Homepage: <a href="https://svjatoslav.eu">https://svjatoslav.eu</a>
-</li>
-<li>Email: <a href="mailto://svjatoslav@svjatoslav.eu">svjatoslav@svjatoslav.eu</a>
-</li>
-</ul>
-</li>
-
-<li>Valeria Agejenko
-</li>
-</ul>
-</li>
-
-<li>See also:
-<ul class="org-ul">
-<li><a href="../../index.html">Other physical projects in this repository</a>
-</li>
-<li><a href="https://www.svjatoslav.eu/projects/">Other projects hosted at svjatoslav.eu</a>
-</li>
-</ul>
-</li>
-</ul>
-</div>
-</div>
-
-<div id="outline-container-sec-2" class="outline-2">
-<h2 id="sec-2"><span class="section-number-2">2</span> Project description</h2>
-<div class="outline-text-2" id="text-2">
-<p>
-I needed dual voltage power supply for my lab that runs on mains
-electricity (wall power) and slowly charges attached 12V Lead-Acid
-battery. Lead-acid battery in turn provides high current when needed
-as well as power in portable situations or when mains electricity is
-not available.
-</p>
-
-
-<figure>
-<p><img src="make.png" class="img-responsive" alt="make.png">
-</p>
-</figure>
-
-<p>
-Power supply provides about 13 Volts and 5 Volts simultaneously.
-</p>
-
-<p>
-!!!WARNING!!! I use USB-A connectors for power output, but IT IS NOT
-COMPATIBLE WITH USB DEVICES AND POSSIBLY WITH EXISTING USB CABLES.
-</p>
-
-<p>
-Normal USB devices and cables should not be plugged in! It would
-damage device/cable and likely power supply.
-</p>
-
-<p>
-I found USB-A connectors to be easily available, cheap, reliable and
-functional, so I re-purposed connector for my own needs but I'm using
-totally incompatible electrical wiring.
-</p>
-
-
-<figure>
-<p><img src="connector%20terminal/USB%20hack.png" class="img-responsive" alt="USB%20hack.png">
-</p>
-</figure>
-
-<p>
-As seen, it has dual voltage output. Additionally one wire is
-dedicated to data transmission and can be used with <a href="https://en.wikipedia.org/wiki/1-Wire">1-wire</a>
-protocol. Power supply simply passively links all data wires together
-but does not participate in communication.
-</p>
-
-<p>
-Power supply uses 3D printed body with lots of holes, for fanless
-cooling.
-</p>
-
-
-<figure>
-<p><img src="body%20and%20covers/body,%201.png" class="img-responsive" alt="body,%201.png">
-</p>
-</figure>
-
-<p>
-Various modules are realized on top of prototype PCBs that slide into
-dedicated rails within the body.
-</p>
-
-
-<figure>
-<p><img src="body%20and%20covers/body,%202.png" class="img-responsive" alt="body,%202.png">
-</p>
-</figure>
-
-<p>
-Like this:
-</p>
-
-
-<figure>
-<p><img src="make,%202.png" class="img-responsive" alt="make,%202.png">
-</p>
-</figure>
-
-<p>
-When cover is closed, it blocks PCB movement:
-</p>
-
-
-<figure>
-<p><img src="body%20and%20covers/cover.png" class="img-responsive" alt="cover.png">
-</p>
-</figure>
-
-<p>
-There is still some empty space inside, so why not add dummy cover on
-top that can be replaced later with add-on functionality/expansion
-board/terminal :)
-</p>
-
-
-<figure>
-<p><img src="body%20and%20covers/cover%20cover.png" class="img-responsive" alt="cover%20cover.png">
-</p>
-</figure>
-
-<p>
-Download:
-</p>
-<ul class="org-ul">
-<li><a href="body%20and%20covers/body.stl">Body STL file</a>
-</li>
-<li><a href="body%20and%20covers/cover.stl">Big cover STL file</a>
-</li>
-<li><a href="body%20and%20covers/cover%20cover.stl">Small dummy cover on top, STL file</a>
-</li>
-<li><a href="body%20and%20covers/body%20and%20covers.FCStd">Body and covers FreeCAD project</a>
-</li>
-</ul>
-</div>
-</div>
-
-<div id="outline-container-sec-3" class="outline-2">
-<h2 id="sec-3"><span class="section-number-2">3</span> Transformer and AC to DC converter</h2>
-<div class="outline-text-2" id="text-3">
-<p>
-This is where high voltage from mains electricity enters the system.
-</p>
-
-<p>
-Schematic:
-<img src="transformer%20and%20AC%20DC%20converter%20board/schematic.png" class="img-responsive" alt="schematic.png">
-</p>
-
-<p>
-For safety I kept high voltage section as minimal as possible. That
-is, wall plug runs straight into transformer. Also I used <a href="https://www.amazon.de/gp/product/B07VGQKM3G/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1">UV hardening
-glue</a> for extra safety and isolation on PCB.
-</p>
-
-<p>
-Power on/off switch operates on already reduced voltage of about 30
-volts. Power switch is located on <a href="#sec-6">indicator panel</a>.
-</p>
-
-
-<figure>
-<p><img src="transformer%20and%20AC%20DC%20converter%20board/make,%201.png" class="img-responsive" alt="make,%201.png">
-</p>
-</figure>
-
-<p>
-DC current of about 30 volts is then routed to <a href="#sec-4">Main board</a>.
-</p>
-
-
-<figure>
-<p><img src="transformer%20and%20AC%20DC%20converter%20board/make,%202.png" class="img-responsive" alt="make,%202.png">
-</p>
-</figure>
-
-<p>
-<a href="https://www.amazon.de/gp/product/B07RLQH5TR/ref=ppx_yo_dt_b_asin_title_o07_s00?ie=UTF8&psc=1">Single sided prototype PCB is used</a>.
-</p>
-</div>
-</div>
-
-<div id="outline-container-sec-4" class="outline-2">
-<h2 id="sec-4"><a id="ID-65d68227-4bf2-4c4f-b4d3-c390bc6a9c34" name="ID-65d68227-4bf2-4c4f-b4d3-c390bc6a9c34"></a><span class="section-number-2">4</span> Main board</h2>
-<div class="outline-text-2" id="text-4">
-<p>
-This is logically main board because it appears to be central hub that
-connects all components. It also houses 2 <a href="https://www.amazon.de/gp/product/B072MQYJ93/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1">adjustable DC-DC Step Down
-voltage converters</a>.
-</p>
-
-
-<figure>
-<p><img src="main%20board/main%20board,%201.png" class="img-responsive" alt="main%20board,%201.png">
-</p>
-</figure>
-
-<p>
-High-level schematic of entire device:
-<img src="main%20board/schematic.png" class="img-responsive" alt="schematic.png">
-</p>
-
-<p>
-As seen from schematic, ~30 volts DC from transformer board is routed
-into first step-down converter that reduces it to about 15V. Reduced
-voltage is then directed to <a href="#sec-5">Current limiter circuit</a>. Current limiter
-loses about 2 volts. Now we have current and voltage limited power at
-about 13 volts. This power is used to charge connected 12V Lead-Acid
-battery. Also the same power is routed to <a href="#sec-7">connector terminal</a> to be
-consumed by connected devices.
-</p>
-
-<p>
-As seen from this schematic, device is not meant to provide high
-current for long periods of time. Instead it gets comparatively
-limited current to charge the battery and feed devices with low
-current requirements. Occasional current spikes are backed up by
-battery that stays in use-changing mode.
-</p>
-
-<p>
-Also about 13V output voltage is approximate and depends on connected
-battery charge level.
-</p>
-
-<p>
-Second Step-Down converter reduces voltage even further to quite
-precisely 5V DC. This resulting voltage is also routed to <a href="#sec-7">connector
-terminal</a>.
-</p>
-
-<p>
-Both 13V and 5V lines are also routed to <a href="#sec-6">indicator panel</a> for
-monitoring.
-</p>
-
-<p>
-There is single on/off switch. In off position, it disconnects battery
-and transformer from the system effectively powering everything down.
-</p>
-
-<p>
-On schematic above, some wires are annotated with numbers from 1
-to 13. This corresponds to output pins on the board.
-</p>
-
-
-<figure>
-<p><img src="main%20board/main%20board,%202.png" class="img-responsive" alt="main%20board,%202.png">
-</p>
-</figure>
-</div>
-</div>
-<div id="outline-container-sec-5" class="outline-2">
-<h2 id="sec-5"><a id="ID-afc22d23-9bc4-421c-9cac-e0ce34bd36bc" name="ID-afc22d23-9bc4-421c-9cac-e0ce34bd36bc"></a><span class="section-number-2">5</span> Current limiter</h2>
-<div class="outline-text-2" id="text-5">
-<p>
-Schematic:
-<img src="current%20limiter/schematic.png" class="img-responsive" alt="schematic.png">
-</p>
-
-<p>
-Simple LM317 based current limiter is used. I used 4.7 ohm
-resistor. It provides about 265 milliamps of current. See <a href="http://www.reuk.co.uk/wordpress/electric-circuit/lm317-current-calculator/">calculator</a>.
-</p>
-
-
-<figure>
-<p><img src="current%20limiter/current%20limiter,%201.png" class="img-responsive" alt="current%20limiter,%201.png">
-</p>
-</figure>
-
-<p>
-Thermal paste below and UV hardening glue on top is used to attach
-LM317 to the heatsink. There is also jumper-like solution on top
-right. This is handy to attach multimeter tap to verify/monitor
-current during initial device calibration.
-</p>
-
-<p>
-If attached battery is really empty, significant voltage drop can
-occur in LM317. Heatsink is needed to dissipate that power.
-</p>
-
-
-<figure>
-<p><img src="current%20limiter/current%20limiter,%202.png" class="img-responsive" alt="current%20limiter,%202.png">
-</p>
-</figure>
-
-<p>
-Note: resistor gets hot too.
-</p>
-</div>
-</div>
-
-<div id="outline-container-sec-6" class="outline-2">
-<h2 id="sec-6"><a id="ID-c9a69490-f920-4a31-b32e-b101bfc3d01b" name="ID-c9a69490-f920-4a31-b32e-b101bfc3d01b"></a><span class="section-number-2">6</span> Indicator panel</h2>
-<div class="outline-text-2" id="text-6">
-
-<figure>
-<p><img src="indicator%20panel/indicator%20panel,%201.png" class="img-responsive" alt="indicator%20panel,%201.png">
-</p>
-</figure>
-
-<p>
-Basically 2 digital DC voltmeters and main on/off switch.
-</p>
-
-
-<figure>
-<p><img src="indicator%20panel/indicator%20panel,%202.png" class="img-responsive" alt="indicator%20panel,%202.png">
-</p>
-</figure>
-
-<p>
-Download:
-</p>
-
-
-<figure>
-<p><img src="indicator%20panel/indicator%20panel.png" class="img-responsive" alt="indicator%20panel.png">
-</p>
-</figure>
-
-<ul class="org-ul">
-<li><a href="indicator%20panel/indicator%20panel.stl">STL file</a>
-</li>
-<li><a href="indicator%20panel/indicator%20panel.FCStd">FreeCAD project</a>
-</li>
-</ul>
-</div>
-</div>
-
-<div id="outline-container-sec-7" class="outline-2">
-<h2 id="sec-7"><a id="ID-e33940bd-652f-4ec0-b53b-1c03e16941c8" name="ID-e33940bd-652f-4ec0-b53b-1c03e16941c8"></a><span class="section-number-2">7</span> Connector terminal</h2>
-<div class="outline-text-2" id="text-7">
-<p>
-Schematic:
-<img src="connector%20terminal/schematic.png" class="img-responsive" alt="schematic.png">
-</p>
-
-<p>
-As seen above, most of the USB connectors are used to deliver dual
-power output and 1-wire data connectivity, except one on the bottom
-right. This is used to attach 12V battery. Some capacitors are thrown
-in as well to stabilize against smaller current spikes.
-</p>
-
-<p>
-Electrically schematic is realized using smaller prototype PCBs.
-</p>
-
-
-<figure>
-<p><img src="connector%20terminal/make,%201.png" class="img-responsive" alt="make,%201.png">
-</p>
-</figure>
-
-
-<p>
-Those PCBs are wired to central small PCB that acts as a hub:
-</p>
-
-
-<figure>
-<p><img src="connector%20terminal/make,%202.png" class="img-responsive" alt="make,%202.png">
-</p>
-</figure>
-
-<p>
-PCBs are held together by being sandwiched between front panel:
-</p>
-
-
-<figure>
-<p><img src="connector%20terminal/front%20panel.png" class="img-responsive" alt="front%20panel.png">
-</p>
-</figure>
-
-<p>
-and smaller back-end plate:
-</p>
-
-
-<figure>
-<p><img src="connector%20terminal/back%20panel.png" class="img-responsive" alt="back%20panel.png">
-</p>
-</figure>
-
-<p>
-Result:
-</p>
-
-
-<figure>
-<p><img src="connector%20terminal/make,%203.png" class="img-responsive" alt="make,%203.png">
-</p>
-</figure>
-
-
-<p>
-Download:
-</p>
-<ul class="org-ul">
-<li><a href="connector%20terminal/front%20panel.stl">front panel STL</a>
-</li>
-<li><a href="connector%20terminal/back%20panel.stl">back panel STL</a>
-</li>
-<li><a href="connector%20terminal/connector%20terminal.FCStd">FreeCAD project</a>
-</li>
-</ul>
-</div>
-</div>
-
-<div id="outline-container-sec-8" class="outline-2">
-<h2 id="sec-8"><span class="section-number-2">8</span> Calibration</h2>
-<div class="outline-text-2" id="text-8">
-<p>
-Since device uses adjustable step-down modules, these need to be
-calibrated to provide correct output voltage. It is important that
-battery receives proper charging voltage otherwise either no charging
-occurs or battery starts gassing out and gets destroyed.
-</p>
-
-<p>
-See here for more details: <a href="https://www.powerstream.com/SLA.htm">https://www.powerstream.com/SLA.htm</a>
-</p>
-
-<hr >
-
-<p>
-Happy building! :)
-</p>
-</div>
-</div>
-</div><div class="col-md-3"><nav id="table-of-contents">
-<div id="text-table-of-contents" class="bs-docs-sidebar">
-<ul class="nav">
-<li><a href="#sec-1">1. General</a></li>
-<li><a href="#sec-2">2. Project description</a></li>
-<li><a href="#sec-3">3. Transformer and AC to DC converter</a></li>
-<li><a href="#sec-4">4. Main board</a></li>
-<li><a href="#sec-5">5. Current limiter</a></li>
-<li><a href="#sec-6">6. Indicator panel</a></li>
-<li><a href="#sec-7">7. Connector terminal</a></li>
-<li><a href="#sec-8">8. Calibration</a></li>
-</ul>
-</div>
-</nav>
-</div></div></div>
-<footer id="postamble" class="">
-<div><p class="author">Author: Svjatoslav Agejenko</p>
-<p class="date">Created: 2020-07-12 Sun 02:52</p>
-<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>
-</div>
-</footer>
-</body>
-</html>
projects / physical.git / blobdiff