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<p class=MsoNormal>Hi to all,<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>I am new on the lists but using nut on megatec for last two
and half years.<o:p></o:p></p>
<p class=MsoNormal>Looking at archives I saw that there is a lot of people
confused about battery voltage and I want to help them to clear out some stuff
in their heads.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>This story is based on my experience with UPS devices from
600VA to 20kVA, from single phase systems to three phase systems, with battery
packs from 1 battery to 62 batteries in both technologies interactive (aka
stand-by) and on-line (aka double-conversion) but all of them were “speaking”
megatec. Anyway this does not necessarily relater only to megatec enabled UPSs
this is story for all UPSs and their batteries.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>On one hand we have UPS manufactures which use their own or
OEM boards which are the hart of UPS. These electronics have their battery banks
which enables them to work when mains (ups power supply) is out of specified
value. Battery bank size varies from ups to ups depending on UPS technology
and back up time. How ups electronics sees battery bank is what you get over megatec
driver and this is what I am writing about.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Battery in UPS is in 99% of cases electro-chemical product
made of Pb, Sulphric Acid, Water and some other chemical stuff to give better
performance. It’s sealed, non-spill able in order to make it safer for
manipulation and what is most important its standardized by its physical and
electrical characteristics. Battery is usually made out of three or six cells
in one standardized package – this is what you know as one battery. This
packed battery has two very important electrical characteristics for your UPS:
nominal voltage (V) and capacity (Ah). Usually you will meet 6V (3 cell) and 12
V (6 cell) batteries in UPS. This represents nominal voltage of battery.<o:p></o:p></p>
<p class=MsoNormal>In 70% of ups devices usually is used battery of 12V/7Ah in
some rare cases 12V/9Ah or 6V/4.5Ah.<o:p></o:p></p>
<p class=MsoNormal>Depending on ups power rating in output different number of
batteries is used and common values are:<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal><b>UPS Technology UPS rated
power number of batteries total battery voltage<o:p></o:p></b></p>
<p class=MsoNormal>Interactive 600VA 1
(12V) 12V<o:p></o:p></p>
<p class=MsoNormal>Interactive 1000VA 2
(12V) 24V<o:p></o:p></p>
<p class=MsoNormal>Interactive 2000VA 4
(12V) 48V<o:p></o:p></p>
<p class=MsoNormal>On-Line 1000VA 3
(12V) 36V<o:p></o:p></p>
<p class=MsoNormal>On-Line 2000VA 6
(12V) 72V<o:p></o:p></p>
<p class=MsoNormal>On-Line 3000VA 8
(12V) 96V<o:p></o:p></p>
<p class=MsoNormal>On-Line 5000VA 20
(12V) 240V<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Since battery is electro-chemical element it doesn’t
have constantly rated voltage. It’s voltage is somehow in relation with its
charged capacity and this is usually identified by battery manufacturer but normally
you can have following values:<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<table class=MsoNormalTable border=0 cellspacing=0 cellpadding=0 width=284
style='width:213.0pt;margin-left:-.75pt;border-collapse:collapse'>
<tr style='height:15.0pt'>
<td width=61 nowrap style='width:46.0pt;padding:0cm 5.4pt 0cm 5.4pt;
height:15.0pt'>
<p class=MsoNormal align=center style='text-align:center'><b><span
style='color:black'>per cell<o:p></o:p></span></b></p>
</td>
<td width=61 nowrap style='width:46.0pt;padding:0cm 5.4pt 0cm 5.4pt;
height:15.0pt'>
<p class=MsoNormal align=center style='text-align:center'><b><span
style='color:black'>6 cell<o:p></o:p></span></b></p>
</td>
<td width=161 nowrap style='width:121.0pt;padding:0cm 5.4pt 0cm 5.4pt;
height:15.0pt'>
<p class=MsoNormal align=center style='text-align:center'><b><span
style='color:black'>charged state<o:p></o:p></span></b></p>
</td>
</tr>
<tr style='height:15.0pt'>
<td width=61 nowrap valign=bottom style='width:46.0pt;padding:0cm 5.4pt 0cm 5.4pt;
height:15.0pt'>
<p class=MsoNormal align=right style='text-align:right'><span
style='color:black'>1,60 V<o:p></o:p></span></p>
</td>
<td width=61 nowrap valign=bottom style='width:46.0pt;padding:0cm 5.4pt 0cm 5.4pt;
height:15.0pt'>
<p class=MsoNormal align=right style='text-align:right'><span
style='color:black'>9,60 V<o:p></o:p></span></p>
</td>
<td width=161 nowrap valign=bottom style='width:121.0pt;padding:0cm 5.4pt 0cm 5.4pt;
height:15.0pt'>
<p class=MsoNormal><b><span style='color:black'>permanently destroyed<o:p></o:p></span></b></p>
</td>
</tr>
<tr style='height:15.0pt'>
<td width=61 nowrap valign=bottom style='width:46.0pt;padding:0cm 5.4pt 0cm 5.4pt;
height:15.0pt'>
<p class=MsoNormal align=right style='text-align:right'><span
style='color:black'>1,70 V<o:p></o:p></span></p>
</td>
<td width=61 nowrap valign=bottom style='width:46.0pt;padding:0cm 5.4pt 0cm 5.4pt;
height:15.0pt'>
<p class=MsoNormal align=right style='text-align:right'><span
style='color:black'>10,20 V<o:p></o:p></span></p>
</td>
<td width=161 nowrap valign=bottom style='width:121.0pt;padding:0cm 5.4pt 0cm 5.4pt;
height:15.0pt'>
<p class=MsoNormal><span style='color:black'>Empty<o:p></o:p></span></p>
</td>
</tr>
<tr style='height:15.0pt'>
<td width=61 nowrap valign=bottom style='width:46.0pt;padding:0cm 5.4pt 0cm 5.4pt;
height:15.0pt'>
<p class=MsoNormal align=right style='text-align:right'><span
style='color:black'>1,80 V<o:p></o:p></span></p>
</td>
<td width=61 nowrap valign=bottom style='width:46.0pt;padding:0cm 5.4pt 0cm 5.4pt;
height:15.0pt'>
<p class=MsoNormal align=right style='text-align:right'><span
style='color:black'>10,80 V<o:p></o:p></span></p>
</td>
<td width=161 nowrap valign=bottom style='width:121.0pt;padding:0cm 5.4pt 0cm 5.4pt;
height:15.0pt'></td>
</tr>
<tr style='height:15.0pt'>
<td width=61 nowrap valign=bottom style='width:46.0pt;padding:0cm 5.4pt 0cm 5.4pt;
height:15.0pt'>
<p class=MsoNormal align=right style='text-align:right'><span
style='color:black'>1,90 V<o:p></o:p></span></p>
</td>
<td width=61 nowrap valign=bottom style='width:46.0pt;padding:0cm 5.4pt 0cm 5.4pt;
height:15.0pt'>
<p class=MsoNormal align=right style='text-align:right'><span
style='color:black'>11,40 V<o:p></o:p></span></p>
</td>
<td width=161 nowrap valign=bottom style='width:121.0pt;padding:0cm 5.4pt 0cm 5.4pt;
height:15.0pt'>
<p class=MsoNormal><i><span style='color:black'>bat low start <o:p></o:p></span></i></p>
</td>
</tr>
<tr style='height:15.0pt'>
<td width=61 nowrap valign=bottom style='width:46.0pt;padding:0cm 5.4pt 0cm 5.4pt;
height:15.0pt'>
<p class=MsoNormal align=right style='text-align:right'><span
style='color:black'>2,00 V<o:p></o:p></span></p>
</td>
<td width=61 nowrap valign=bottom style='width:46.0pt;padding:0cm 5.4pt 0cm 5.4pt;
height:15.0pt'>
<p class=MsoNormal align=right style='text-align:right'><span
style='color:black'>12,00 V<o:p></o:p></span></p>
</td>
<td width=161 nowrap valign=bottom style='width:121.0pt;padding:0cm 5.4pt 0cm 5.4pt;
height:15.0pt'>
<p class=MsoNormal><span style='color:black'>> 50% charged<o:p></o:p></span></p>
</td>
</tr>
<tr style='height:15.0pt'>
<td width=61 nowrap valign=bottom style='width:46.0pt;padding:0cm 5.4pt 0cm 5.4pt;
height:15.0pt'>
<p class=MsoNormal align=right style='text-align:right'><span
style='color:black'>2,10 V<o:p></o:p></span></p>
</td>
<td width=61 nowrap valign=bottom style='width:46.0pt;padding:0cm 5.4pt 0cm 5.4pt;
height:15.0pt'>
<p class=MsoNormal align=right style='text-align:right'><span
style='color:black'>12,60 V<o:p></o:p></span></p>
</td>
<td width=161 nowrap valign=bottom style='width:121.0pt;padding:0cm 5.4pt 0cm 5.4pt;
height:15.0pt'></td>
</tr>
<tr style='height:15.0pt'>
<td width=61 nowrap valign=bottom style='width:46.0pt;padding:0cm 5.4pt 0cm 5.4pt;
height:15.0pt'>
<p class=MsoNormal align=right style='text-align:right'><span
style='color:black'>2,20 V<o:p></o:p></span></p>
</td>
<td width=61 nowrap valign=bottom style='width:46.0pt;padding:0cm 5.4pt 0cm 5.4pt;
height:15.0pt'>
<p class=MsoNormal align=right style='text-align:right'><span
style='color:black'>13,20 V<o:p></o:p></span></p>
</td>
<td width=161 nowrap valign=bottom style='width:121.0pt;padding:0cm 5.4pt 0cm 5.4pt;
height:15.0pt'></td>
</tr>
<tr style='height:15.0pt'>
<td width=61 nowrap valign=bottom style='width:46.0pt;padding:0cm 5.4pt 0cm 5.4pt;
height:15.0pt'>
<p class=MsoNormal align=right style='text-align:right'><span
style='color:black'>2,30 V<o:p></o:p></span></p>
</td>
<td width=61 nowrap valign=bottom style='width:46.0pt;padding:0cm 5.4pt 0cm 5.4pt;
height:15.0pt'>
<p class=MsoNormal align=right style='text-align:right'><span
style='color:black'>13,80 V<o:p></o:p></span></p>
</td>
<td width=161 nowrap valign=bottom style='width:121.0pt;padding:0cm 5.4pt 0cm 5.4pt;
height:15.0pt'>
<p class=MsoNormal><span style='color:black'>Fully charged<o:p></o:p></span></p>
</td>
</tr>
</table>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Just for info, charging and discharging of batteries are not
linear functions in voltage vs. time.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>When your UPS tells you battery voltage over megatec driver
he tells you actually charged value of its battery bank. This information can
be told in two ways: as a voltage sum of whole bank or as average value per
battery cell. In first case you may get 38.6V in a second case 2.14V for the same
on-line 1kVA UPS. This depend on how manufacturer implemented it.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>This gets me to megatec driver and how it see battery
voltage. I think that this is job for someone to improve megatec driver in
order to look at some table to see battery charged value or to create it with parameters
to driver.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Since I think I am becoming boring if you are interested how
to determine charge level I can continue writing… but this involves real
time clock inside of driver, some counters… lots of work for someone.<o:p></o:p></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:black'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:black'>All best,<o:p></o:p></span></p>
<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:black'><o:p> </o:p></span></b></p>
<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:black'>Željko Baralić</span></b><span style='font-size:12.0pt;font-family:
"Arial","sans-serif"'><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:blue'>Pakom Computers doo<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:blue'>SST Service Center Nis<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:blue'>Serbia<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:blue'><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=DE style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:blue'>zeljko.baralic@pakom.com<o:p></o:p></span></p>
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