<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<meta name="Generator" content="Microsoft Word 14 (filtered medium)">
<!--[if !mso]><style>v\:* {behavior:url(#default#VML);}
o\:* {behavior:url(#default#VML);}
w\:* {behavior:url(#default#VML);}
.shape {behavior:url(#default#VML);}
</style><![endif]--><style><!--
/* Font Definitions */
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:Tahoma;
panose-1:2 11 6 4 3 5 4 4 2 4;}
@font-face
{font-family:Euphemia;
panose-1:2 11 5 3 4 1 2 2 1 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman","serif";}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
p.MsoListParagraph, li.MsoListParagraph, div.MsoListParagraph
{mso-style-priority:34;
margin-top:0in;
margin-right:0in;
margin-bottom:0in;
margin-left:.5in;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman","serif";}
span.EmailStyle17
{mso-style-type:personal-reply;
font-family:"Calibri","sans-serif";
color:#1F497D;}
.MsoChpDefault
{mso-style-type:export-only;
font-family:"Calibri","sans-serif";}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
/* List Definitions */
@list l0
{mso-list-id:326061373;
mso-list-type:hybrid;
mso-list-template-ids:-1078814772 67698703 67698713 67698715 67698703 67698713 67698715 67698703 67698713 67698715;}
@list l0:level1
{mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-.25in;}
@list l0:level2
{mso-level-number-format:alpha-lower;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-.25in;}
@list l0:level3
{mso-level-number-format:roman-lower;
mso-level-tab-stop:none;
mso-level-number-position:right;
text-indent:-9.0pt;}
@list l0:level4
{mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-.25in;}
@list l0:level5
{mso-level-number-format:alpha-lower;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-.25in;}
@list l0:level6
{mso-level-number-format:roman-lower;
mso-level-tab-stop:none;
mso-level-number-position:right;
text-indent:-9.0pt;}
@list l0:level7
{mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-.25in;}
@list l0:level8
{mso-level-number-format:alpha-lower;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-.25in;}
@list l0:level9
{mso-level-number-format:roman-lower;
mso-level-tab-stop:none;
mso-level-number-position:right;
text-indent:-9.0pt;}
ol
{margin-bottom:0in;}
ul
{margin-bottom:0in;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang="EN-US" link="blue" vlink="purple">
<div class="WordSection1">
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Wrenches,
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">I’m guessing that there is a problem with the battery, or the user just over discharged this bank. I doubt the inverter is at fault here.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Reverse charge batteries are common in two cases from what I’ve seen. You can take any battery, discharge it to zero volts and reverse charge it.. you’ll
lose efficiency but the battery will work… By way I don’t advise doing this just because it might be fun! <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><span style="mso-list:Ignore">1.<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Low Battery Cut Out situations where the system in unsupervised, Low battery is hit and the inverter turns off, but doesn’t isolate from the battery
bank. <o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">LBCO is a great feature, but too often it’s left at the factory defaults which in most cases is way too low. Most inverter/charger
manufactures set this at 1.75 volts per cell. 1.75 vpc is essentially a 95-100% Dead battery. Even a little bit of current load, say the 3-5 watts an inverter, charge controller or any other DC loads connected will quickly draw the battery bank down to
0 volts. Depending on the internal resistances of each cell, this can actually cause the cells when the load is finally removed to reverse charge!
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><span style="mso-list:Ignore">2.<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Excessive parallel string battery banks.
<o:p></o:p></span></p>
<p class="MsoListParagraph"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">This usually happens when you have a dead or bad cell in a parallel string that is not caught for a long period of time. Over time this string acts
like a load to the rest of the stings, and eventually reaches zero volts, at that point there is a possibility that it can reverse charge.
<o:p></o:p></span></p>
<p class="MsoListParagraph"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Best way to avoid these situations, Raise the LVCO voltage to a higher point, (Usually 1.85 to 1.90volts per cell) and instruct the customer to where the status
screen is on their device. Most of these devices out there tell you if it shut off during LBCO or not… If this is a cabin or a site where the customer is away for an extended period of time, have them disconnect the inverter, and only leave the charging
sources connected to the battery bank. <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Installing a voltage controlled breaker, this acts as a back up to the LBCO… in most military applications they needed these installed due to they didn’t want
to kill a combat vehicles battery system. Installing this breaker can be pretty expensive though. An last but not least, avoid excessive parallel strings.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> RE-wrenches [mailto:re-wrenches-bounces@lists.re-wrenches.org]
<b>On Behalf Of </b>Corey Shalanski<br>
<b>Sent:</b> Wednesday, December 17, 2014 9:37 AM<br>
<b>To:</b> re-wrenches@lists.re-wrenches.org<br>
<b>Subject:</b> Re: [RE-wrenches] Magnum System - Discharged Battery Bank<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><o:p> </o:p></p>
<div>
<p class="MsoNormal" style="margin-left:.5in">Clarification and Update:<o:p></o:p></p>
<div>
<p class="MsoNormal" style="margin-left:.5in">- I believe I may have inadvertently thrown Magnum under the bus in in my initial post. <o:p></o:p></p>
<div>
<p class="MsoNormal" style="margin-left:.5in"><img id="_x0000_i1025" src="https://mailfoogae.appspot.com/t?sender=aY3NoYWxhbnNraUBqb3VsZS1lbmVyZ3kuY29t&type=zerocontent&guid=dab0a56b-2f33-4542-ab89-2eb7e81192f3"><span style="font-size:7.5pt;font-family:"Euphemia","sans-serif";color:white">ᐧ</span><o:p></o:p></p>
</div>
<div>
<p class="MsoNormal" style="margin-left:.5in">While on site yesterday I did speak with Magnum's customer support about my findings and they advised to try to trickle charge the batteries up to the minimum threshold at which the Magnum inverters would turn back
on. From there we will hopefully be able to run some more determinate tests. My question about the low-battery-cutout was more intended to explore whether others have ever experienced any similar issues with this protection feature. I am finding out that the
feature is only relevant during inverting (not charging) mode and so would imply that the utility feed had been cut, which does not appear to be the case.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal" style="margin-left:.5in">- Our battery distributor has lent us a 12-circuit trickle charger - one set of alligator clips per battery. I am planning to re-visit the jobsite later today to put each battery on a trickle charge, which I am
told will take 1-2 weeks for any lasting change to take effect. The distributor advised to reverse the leads on the batteries with negative voltage, hoping that they may be recoverable as "reversed pole" batteries thenceforth.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal" style="margin-left:.5in"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal" style="margin-left:.5in">--<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal" style="margin-left:.5in">Corey<o:p></o:p></p>
<div>
<p class="MsoNormal" style="margin-left:.5in"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal" style="margin-left:.5in"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal" style="margin-left:.5in">On Tue, Dec 16, 2014 at 8:27 PM, <<a href="mailto:cshalanski@joule-energy.com">cshalanski@joule-energy.com</a>> wrote:<o:p></o:p></p>
<p class="MsoNormal" style="margin-left:.5in"><br>
Wrenches,<br>
<br>
I visited a customer today whose grid-tied battery backup system suffered<br>
some sort of catastrophic failure, and now I'm trying to play detective to<br>
figure out what happened and whose equipment/design is to blame.<br>
<br>
Here is what I know so far:<br>
- System is ac-coupled with a Sunny Boy 7000 (7.85kW array), Magnum<br>
MS4448PAE (x2), 3 strings of 4 12v batts (705Ah total)<br>
- Site visit was triggered by the Sunny Boy registering zero output via<br>
online monitoring.<br>
- SPST Solid state relay installed on Sunny Boy output, controlled via<br>
Magnum router, serves as secondary overcharge protection to Magnum's<br>
frequency shift feature. Technician who initially responded claims he<br>
measured 240v across the relay's terminals - relay manufacturer claims this<br>
is "100% impossible". We removed the relay from the circuit, and the Sunny<br>
Boy is again operational.<br>
- On arrival I found the Magnum display showing a "Low Battery Charge"<br>
message with the bank measuring ~4Vdc. The individual batteries were in<br>
various states of charge, ranging from high of 6.3v to low of -2.6v. These<br>
measurements were taken at rest, all battery cables disconnected, and yes<br>
three of the batts were registering a negative voltage.<br>
- Customer reports that he was not aware of any recent prolonged power<br>
outages.<br>
<br>
The three potential suspects would seem to be:<br>
- SS relay: The customer is convinced that this is the weak link in the<br>
system and somehow triggered this failure. I am not so convinced but would<br>
be interested to hear recommendations for properly testing its<br>
functionality.<br>
- Magnum equipment: Since there is low-battery-cutout protection, why would<br>
this feature not have activated and prevented the batteries from draining<br>
so low?<br>
- Batteries: I am not very familiar with modes of failure, but our<br>
distributor suggested that an internal short could be a possibility - what<br>
might have triggered this?<br>
<br>
Clearly I am fishing for potential leads here, so any suggestions are<br>
welcome.<br>
<br>
Thanks!<br>
--<br>
Corey Shalanski<br>
Joule Energy<br>
New Orleans, LA<o:p></o:p></p>
</div>
</div>
</div>
</div>
</div>
<p><font style="FONT-SIZE: 14pt" face="Tahoma"><strong>Steve Higgins<br>
<font style="FONT-SIZE: 12pt">Technical Services Manager</font><br>
</strong></font><font face="Tahoma"><strong></strong></font><font face="Tahoma">P: +1.902.597.4020<br>
</font><font face="Tahoma">M: +1.206.790.5840<br>
</font><font face="Tahoma">F: +1.902.597.8447<br>
</font><font color="#ff0000" face="Tahoma"><strong style="FONT-FAMILY: tahoma; TEXT-DECORATION: "><font color="#d30000">Surrette Battery Company</font><br>
</strong></font><font style="FONT-SIZE: 10pt" face="Tahoma">Exclusive manufacturer of<br>
<a href="http://www.rollsbattery.com"><img border="0" hspace="0" src="cid:rollsd54efe"></a></font></p>
<br>
<p>
This email and its attachments have been scanned by mailWatch E-Mail Firewall for viruses, spam, and malicious content.
The information transmitted in this email is intended only for the entity or person to which it is addressed and may contain confidential/privileged material. If you received this in error, please contact the sender and delete the material from any computer. Any review, retransmission, dissemination, or other use of this information by persons or entities other than the intended recipient is strictly prohibited<p>
</body>
</html>