<html><head><meta http-equiv="Content-Type" content="text/html charset=windows-1252"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;">Hi All,<br><div apple-content-edited="true">
<div style="orphans: 2; text-align: -webkit-auto; text-indent: 0px; widows: 2; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br></div><div style="orphans: 2; text-align: -webkit-auto; text-indent: 0px; widows: 2; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Agreed — excellent discussion.</div><div style="orphans: 2; text-align: -webkit-auto; text-indent: 0px; widows: 2; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br>We (Dave Croker and I) will know more soon, but I certainly agree that more panel and battery and better controllers are a preferable solution in nearly all locations.<br><br>There are a few sites where cost (versus a load of 28 batteries via helicopter) or always-dark conditions (bottom of redwood-lined V-canyon in the PNW) might still argue for a few fuel cell in spite of the initial cost. Fuel is just methanol.</div><div style="orphans: 2; text-align: -webkit-auto; text-indent: 0px; widows: 2; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br></div><div style="orphans: 2; text-align: -webkit-auto; text-indent: 0px; widows: 2; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Suspect thermoelectric has too much fire potential for many locations (used them in Idaho in the way-back-when and they scared the heck out of me so near dry pines).</div><div style="orphans: 2; text-align: -webkit-auto; text-indent: 0px; widows: 2; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br></div><div style="orphans: 2; text-align: -webkit-auto; text-indent: 0px; widows: 2; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Anyone have specific experience with reliability of the SFC cells? Bob?</div><div style="orphans: 2; text-align: -webkit-auto; text-indent: 0px; widows: 2; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br></div><div style="orphans: 2; text-align: -webkit-auto; text-indent: 0px; widows: 2; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">They are mil-spec for the German military (likely though, but even costlier), so might be better for those rare candidate sites if we know nothing else; might be worth one test anyway. Their contact info changed, by the way:</div><div style="orphans: 2; text-align: -webkit-auto; text-indent: 0px; widows: 2; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br></div></div><blockquote style="margin: 0 0 0 40px; border: none; padding: 0px;"><div apple-content-edited="true"><div style="orphans: 2; text-align: -webkit-auto; text-indent: 0px; widows: 2; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">SFC Energy AG<br>Christian Böhm<br>VP Defense and Security Business<br>Eugen-Saenger-Ring 7<br>85649 Brunnthal/München<br>Germany<br>+49 (89) 673.592.364<br>+49 (160) 90.52.74.72<span class="Apple-tab-span" style="white-space:pre"> </span><Cell<br>+49 (89) 673.592.169<span class="Apple-tab-span" style="white-space:pre"> </span><FAX<br><a href="mailto:Christian.Boehm@sfc.com">Christian.Boehm@sfc.com</a><br>www.sfc.com<br>www.efoy-pro.com/page/efoy-proenergybox<br> <br>Björn Ledergerber<span class="Apple-tab-span" style="white-space:pre"> </span>(U.S. Rep.)<br>Bjoern.Ledergerber@sfc.com</div></div></blockquote><div apple-content-edited="true"><div style="orphans: 2; text-align: -webkit-auto; text-indent: 0px; widows: 2; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br></div><div style="orphans: 2; text-align: -webkit-auto; text-indent: 0px; widows: 2; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Dave and I will let you know more when we know it, including at least rough costs and fuel-use rates and costs. We will assume up to 0.6 W at 12 V (500 mA) if no one objects.</div><div style="orphans: 2; text-align: -webkit-auto; text-indent: 0px; widows: 2; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br>Cheers,<br>John<br><br>John R. Evans<br><br>-------------------------<br><br>831-460-7593 direct<br>408-209-6219 mobile<br><a href="mailto:jrevans@usgs.gov">jrevans@usgs.gov</a><br><br>-------------------------<br><br>Normally at (mail or shipping):<br>U.S. Geological Survey<br>400 Natural Bridges Dr<br>Santa Cruz CA 95060<br><br>-------------------------<br><br>Intermittently at:<br><br>Mail ONLY<br>USGS/ASL<br>P.O. Box 82010<br>Albuquerque NM 87198-2010<br><br>Shipping ONLY<br>USGS/ASL<br>Target Rd 10002 Isleta SE<br>Kirtland AFB NM 87117<br><br>-------------------------<br><br>We have found the ground.<br><br><span class="Apple-tab-span" style="white-space: pre; "> </span>-- JPL, Curiosity control room<br><br>-------------------------<br><br><br><br><br><br>--------------------------------------------------<br><br><br><br></div>
</div>
<br><div><div>On 2015-Jan-07, at 10:40 , <a href="mailto:anss-netops-request@geohazards.usgs.gov">anss-netops-request@geohazards.usgs.gov</a> wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite">Send ANSS-netops mailing list submissions to<br><span class="Apple-tab-span" style="white-space:pre"> </span><a href="mailto:anss-netops@geohazards.usgs.gov">anss-netops@geohazards.usgs.gov</a><br><br>To subscribe or unsubscribe via the World Wide Web, visit<br><span class="Apple-tab-span" style="white-space:pre"> </span>https://geohazards.usgs.gov/mailman/listinfo/anss-netops<br>or, via email, send a message with subject or body 'help' to<br><span class="Apple-tab-span" style="white-space:pre"> </span>anss-netops-request@geohazards.usgs.gov<br><br>You can reach the person managing the list at<br><span class="Apple-tab-span" style="white-space:pre"> </span>anss-netops-owner@geohazards.usgs.gov<br><br>When replying, please edit your Subject line so it is more specific<br>than "Re: Contents of ANSS-netops digest..."<br><br><br>Today's Topics:<br><br> 1. Re: solar power problems (Philip Crotwell)<br> 2. Re: ANSS-netops Digest, Vol 59, Issue 6 (Greg Steiner)<br><br><br>----------------------------------------------------------------------<br><br>Message: 1<br>Date: Wed, 7 Jan 2015 12:32:48 -0500<br>From: Philip Crotwell <crotwell@seis.sc.edu><br>To: Patrick Bastien <bastienp@ldeo.columbia.edu><br>Cc: "anss-netops@geohazards.usgs.gov"<br><span class="Apple-tab-span" style="white-space:pre"> </span><anss-netops@geohazards.usgs.gov><br>Subject: Re: [ANSS-netops] solar power problems<br>Message-ID:<br><span class="Apple-tab-span" style="white-space:pre"> </span><CAGFrVcWYkYVwpZeZeamvSc_+vL91zN0gW3qoqGZntLXf+kgrWQ@mail.gmail.com><br>Content-Type: text/plain; charset="UTF-8"<br><br>We use the same batteries. But get the PVX-1040HT if you can as they<br>have a (H)andle. Very useful! :)<br><br>Philip<br><br>On Wed, Jan 7, 2015 at 12:18 PM, Patrick Bastien<br><bastienp@ldeo.columbia.edu> wrote:<br><blockquote type="cite">The Concorde Sun Extender PVX-1040T has a nominal capacity of 104AH, so<br>312AH for the northern TA stations and 208AH for the southern TA stations.<br><br>Beginning late last summer, the LCSN has begun to switch from older<br>PWM-style charge controllers to MPPT charge controllers. Although it is too<br>soon to say something definite, this is seeming to have a larger effect on<br>station up-time than just adding more panels or batteries. Something I am<br>doing that might be considered non-standard is wiring each solar panel<br>individually to its own small MPPT change controller. This allows each solar<br>panel to generate the maximum amount of power regardless of the lighting<br>condition of the other solar panels. The several MPPT charge controllers<br>then feed a common battery bank. I then regulate the voltage powering the<br>sensor by using a small low-noise DCDC converter imbedded inside a cable.<br>The MPPT benefits might be magnified for the LCSN because of the location of<br>many of our solar powered stations are in forests or forest-adjacent.<br><br><br>Patrick Bastien<br>LDEO-LCSN<br><br><br>On 1/7/2015 11:06 AM, Meremonte, Mark wrote:<br><br>Bob, May I ask the AH size of AGM batteries for an average TA station?<br>Thank you, Mark<br><br>On Wed, Jan 7, 2015 at 8:29 AM, Robert Busby <busby@iris.edu> wrote:<br><blockquote type="cite"><br>Hi Mitch et al.<br>This is a good discussion of Power for seismic stations, thanks.<br><br>In the Transportable Array deployment, all 1717 stations operate(d) off<br>solar power for at east two years. The average current draw for a station<br>is 0.5Amps on a 12V system, but can vary from 0.4 to 0.6A depending on the<br>telemetry system. High current telemetry systems such as VSAT are powered<br>separately. We avoided AC power because of the proximity of noise due to<br>pumps, motors, etc.<br><br>In general we use (2) 90W PV panels and (2) AGM Lead Acid batteries for<br>stations south of the Kentucky/Tennessee line (row U in TA station codes)<br>and (3) 90W PV panels and (3) AGM Lead Acid batteris north of there. Shady<br>or snowy sites occasionally got more panels and batteries. For permanent<br>stations I'd go with the (3) PV and 3 or 4 batteries. We prefer good<br>quality batteries designed for solar applications, such as the Concorde Sun<br>Extender PVX-1040T. We use PWM regulators with Low voltage disconnect at<br>10.8V. A few more sophisticated options are discussed below.<br><br>I would concur with the notion that the most effective way to improve a<br>marginal station power situation is to add 1 or 2 batteries, and often this<br>can be done without much infrastructure alteration. And the next option is<br>to add a panel. There is little concern about over driving the charge<br>controller with too much current from too many panels. In Alaska, the "more<br>batteries" approach is taken to extremes in which stations have 24 batteries<br>to float through the winter. I would also concur that, to date, neither wind<br>nor fuel cells have proved reliable enough to warrant their use, especially<br>in permanent stations of the Lower48.<br><br>More complexity described below:<br>Our system has, in addition to the main battery bank, a small reserve<br>battery. When the system switches to the reserve, certain loads such as the<br>telemetry radio and local data storage are duty cycled at four hour<br>intervals. This reduces the power of the station to about 3W, yet still<br>provides complete telemetry (though with episodic latency) and complete<br>local storage. For us, this reserve power serves to identify the source of<br>the outage is clearly power as opposed to a host of other possibilities. In<br>the original design this reserve battery was Alkaline Lattern 30AH batteries<br>[(3) x 6Volts] (a primary battery, disposed of after use). More recently,<br>We have also used 100-300AH rechargeable batteries that are then connected<br>to the main batteries using a battery isolator circuit-which connects the<br>reserve batteries to the charger only when the main battery has recharged to<br>13.2V. We add a 10A current limit to the battery interconnection. The<br>reserve power load shedding can be thought of as doubling the capacity of<br>the reserve batteries, reducing the cost of overall power system for this<br>reserve capability. Without that sophisitication of load shedding, adding<br>more batteries is effective but there is a cost in terms of station uptime.<br>When a very large, undifferentiated battery bank is depleted, it will take a<br>longer time for the batteries to reach the reconnect voltage. In this time,<br>the station itself could be operating on the minimal power produced. We keep<br>the main battery bank fairly modest so it recovers voltage quickly, and<br>defer recharging the reserve pack until there is ample power-sometimes<br>weeks, or in Alaska, months later. Its meant to get you through an<br>ocasional bad spell. One issue in this reserve battery switching is the dc<br>currents can introduce magnetic pulses seen on the seismometer-particularly<br>Trilliums within a few meters of the switches.<br><br>If you are plannning a Net-ops meeting in the future, I'd be happly to<br>elaborate on the power system for Alaska, which uses a Genasun MPPT charge<br>controller and LiFePO4 (Lithium Ion) batteries and the same duty cycle<br>loads, reserve battery concepts. These significantly reduce the weight of a<br>1440AH system to 420 lbs and do not require derating the capacity for cold<br>temperatures. They are very expensive, but not as much as a helicopter<br>trip.<br><br>Bob Busby<br>TA Manager<br><br>On 1/6/2015 7:36 AM, Kyle Persefield wrote:<br><blockquote type="cite"><br>Mitch,<br><br>My 2 cents worth<br><br>Because of cost, we have found throwing on more solar panels to be the<br>cheapest and least maintenance intensive solution. Fuel cells and<br>thermoelectric generators are expensive and then there is the recurring<br>cost for fuel, getting fuel to the site, then monitoring of the fuel<br>supply level to consider, and the added required maintenance. We have<br>not<br>found a solution to use these devices as demand requires their use. Or<br>turning them on and off as needed. So long as there is fuel they are on.<br><br>We have been very disappointed with wind turbines. The smaller ones,<br>which are designed for the consumer market, the bearings always fail.<br>Expect no more than 2 or3 years out of these "cheap" units. Then of<br>course there is the need for wind. No wind for extended periods is just<br>as bad as your overcast scenario.<br><br>Kyle<br><br>-----Original Message-----<br>From: ANSS-netops [mailto:anss-netops-bounces@geohazards.usgs.gov] On<br>Behalf Of Mitchell M Withers (mwithers)<br>Sent: Monday, January 05, 2015 7:12 AM<br>To: Philip Crotwell<br>Cc: anss-netops@geohazards.usgs.gov<br>Subject: Re: [ANSS-netops] solar power problems<br><br><br>Here is a snippet from a recent report from a visit to an example station<br>with a reftek, three S-13's, and an episensor. Stations vary of course<br>and we do use low voltage cutouts at every station (fancy ones that cut<br>out the transmitter first, then the DAS and everything else if the<br>voltage<br>continues to get lower).<br><br>"The new battery banks, when installed were at 12.95 and 12.98. The total<br>station draw is exactly 600ma (checked continuously for about three<br>minutes). I did a quick calculation of 4 batteries at 96AH each, 384/.6 =<br>640/24 =26.6 days. This calculation would assume no solar charge, but<br>does<br>not take into account reduced battery capacity due to cold temperatures."<br><br>The panels at that particular station were supplying about 700ma together<br>on an overcast day and are being replaced with bigger panels this week.<br>Of course one solution is more battery and more solar at every station<br>along with more frequent refreshing of batteries. But that gets<br>expensive<br>and time consuming so I was fishing to see if anyone is doing something<br>creative. (e.g. wind or hamster wheels).<br><br>Mitch<br><br>Center for Earthquake Research and Information (CERI)<br>University of Memphis Ph: 901-678-4940<br>Memphis, TN 38152 Fax: 901-678-4734<br><br><br>________________________________________<br>From: Philip Crotwell <crotwell@seis.sc.edu><br>Sent: Monday, January 5, 2015 7:50 AM<br>To: Mitchell M Withers (mwithers)<br>Cc: anss-netops@geohazards.usgs.gov<br>Subject: Re: [ANSS-netops] solar power problems<br><br>Hi<br><br>How did you come up with your 25 day figure? Can you put some numbers on<br>power input and output?<br><br>We use two 105 amp-hour batteries per station, where the load is about<br>1/2 an amp. That gives me about 17.5 days theoretically, but my<br>understanding is that you never want to discharge batteries anywhere near<br>their rating as they can be damaged by high discharges. So maybe worry<br>less about age and more about installed capacity, ie double the battery<br>and replace them half as often.<br><br>We also, because of the cell modems, can monitor the battery voltage over<br>time, we have a cron job to ping the cell modem once an hour and ask it<br>what the input voltage is. For example here is the last few days at one<br>station. You can definitely tell the difference between sunny days and<br>rain, and we get a heads up if the power is getting low and can do<br>something before the station goes down.<br>http://eeyore.seis.sc.edu/earthworm/status/HAW_last720.png<br><br>Here is another station that we are becoming worried about, looks like I<br>might get to go on a road trip soon!<br>http://eeyore.seis.sc.edu/earthworm/status/CASEE_last720.png<br><br>Philip<br><br>On Sun, Jan 4, 2015 at 9:07 AM, Mitchell M Withers (mwithers)<br><mwithers@memphis.edu> wrote:<br><blockquote type="cite"><br>Many of our stations run on battery and solar and that normally works<br></blockquote><br>well. We have a routine battery replacement cycle to make sure they<br>don't<br>get old. Theoretically, we should be able to run with zero solar for<br>about 25 days. But this has been an unusually dreary winter in the<br>southeast and we haven't had much sun for the past two months or more.<br>I'm wondering what others do in areas with limited sunlight to power<br>stations that don't have AC available?<br><blockquote type="cite"><br>Mitch<br><br>Center for Earthquake Research and Information (CERI)<br>University of Memphis Ph: 901-678-4940<br>Memphis, TN 38152 Fax: 901-678-4734<br><br>_______________________________________________<br>ANSS-netops mailing list<br>ANSS-netops@geohazards.usgs.gov<br>https://geohazards.usgs.gov/mailman/listinfo/anss-netops<br></blockquote><br>_______________________________________________<br>ANSS-netops mailing list<br>ANSS-netops@geohazards.usgs.gov<br>https://geohazards.usgs.gov/mailman/listinfo/anss-netops<br>_______________________________________________<br>ANSS-netops mailing list<br>ANSS-netops@geohazards.usgs.gov<br>https://geohazards.usgs.gov/mailman/listinfo/anss-netops<br><br></blockquote><br>--<br><br>============================================================<br><br>Robert W. Busby<br>Transportable Array Manager 508-801-7628<br>USArray / EarthScope 37 Haynes Avenue<br>www.earthscope.org/usarray Falmouth MA USA 02540-2312<br><br>_______________________________________________<br>ANSS-netops mailing list<br>ANSS-netops@geohazards.usgs.gov<br>https://geohazards.usgs.gov/mailman/listinfo/anss-netops<br></blockquote><br><br><br><br>--<br>*********************************************************<br>Mark Meremonte Geophysicist<br>U.S. Bureau of Reclamation: Seismotectonics & Geophysics Group<br>Denver Federal Center Work: 303-445-3298 Cell: 303-808-3894<br>POBox 25007, 85-833000 Email: mmeremonte@usbr.gov<br>Denver, CO 80225 Web: http://www.usbr.gov<br>Ship: U.S. Bureau of Reclamation, DFC, Bldg. 67-10th Floor, Denver, CO<br>80225<br>**********************************************************<br><br><br>_______________________________________________<br>ANSS-netops mailing list<br>ANSS-netops@geohazards.usgs.gov<br>https://geohazards.usgs.gov/mailman/listinfo/anss-netops<br><br><br><br>_______________________________________________<br>ANSS-netops mailing list<br>ANSS-netops@geohazards.usgs.gov<br>https://geohazards.usgs.gov/mailman/listinfo/anss-netops<br><br></blockquote><br><br>------------------------------<br><br>Message: 2<br>Date: Wed, 7 Jan 2015 12:40:18 -0600<br>From: Greg Steiner <vlf@cablerocket.com><br>To: <anss-netops@geohazards.usgs.gov><br>Subject: Re: [ANSS-netops] ANSS-netops Digest, Vol 59, Issue 6<br>Message-ID: <54AD7D92.6020804@cablerocket.com><br>Content-Type: text/plain; charset="windows-1252"; format=flowed<br><br>Patrick, I'm curious as to how you get multiple MPPT controllers to <br>charge a single battery bank. Are they inherently designed for this form <br>of parallel operation?<br>Greg Steiner<br><br>On 1/7/2015 11:16 AM, anss-netops-request@geohazards.usgs.gov wrote:<br><blockquote type="cite">Send ANSS-netops mailing list submissions to<br><span class="Apple-tab-span" style="white-space:pre"> </span>anss-netops@geohazards.usgs.gov<br><br>To subscribe or unsubscribe via the World Wide Web, visit<br><span class="Apple-tab-span" style="white-space:pre"> </span>https://geohazards.usgs.gov/mailman/listinfo/anss-netops<br>or, via email, send a message with subject or body 'help' to<br><span class="Apple-tab-span" style="white-space:pre"> </span>anss-netops-request@geohazards.usgs.gov<br><br>You can reach the person managing the list at<br><span class="Apple-tab-span" style="white-space:pre"> </span>anss-netops-owner@geohazards.usgs.gov<br><br>When replying, please edit your Subject line so it is more specific<br>than "Re: Contents of ANSS-netops digest..."<br><br><br>Today's Topics:<br><br> 1. Re: solar power problems (Patrick Bastien)<br><br><br>----------------------------------------------------------------------<br><br>Message: 1<br>Date: Wed, 7 Jan 2015 12:18:20 -0500<br>From: Patrick Bastien <bastienp@ldeo.columbia.edu><br>To: <anss-netops@geohazards.usgs.gov><br>Subject: Re: [ANSS-netops] solar power problems<br>Message-ID: <54AD6A5C.6080608@ldeo.columbia.edu><br>Content-Type: text/plain; charset="iso-8859-1"; Format="flowed"<br><br>The Concorde Sun Extender PVX-1040T has a nominal capacity of 104AH, so<br>312AH for the northern TA stations and 208AH for the southern TA stations.<br><br>Beginning late last summer, the LCSN has begun to switch from older<br>PWM-style charge controllers to MPPT charge controllers. Although it is<br>too soon to say something definite, this is seeming to have a larger<br>effect on station up-time than just adding more panels or batteries.<br>Something I am doing that might be considered non-standard is wiring<br>each solar panel individually to its own small MPPT change controller.<br>This allows each solar panel to generate the maximum amount of power<br>regardless of the lighting condition of the other solar panels. The<br>several MPPT charge controllers then feed a common battery bank. I then<br>regulate the voltage powering the sensor by using a small low-noise DCDC<br>converter imbedded inside a cable. The MPPT benefits might be magnified<br>for the LCSN because of the location of many of our solar powered<br>stations are in forests or forest-adjacent.<br><br><br>Patrick Bastien<br>LDEO-LCSN<br><br>On 1/7/2015 11:06 AM, Meremonte, Mark wrote:<br><blockquote type="cite">Bob, May I ask the AH size of AGM batteries for an average TA<br>station? Thank you, Mark<br><br>On Wed, Jan 7, 2015 at 8:29 AM, Robert Busby <busby@iris.edu<br><mailto:busby@iris.edu>> wrote:<br><br> Hi Mitch et al.<br> This is a good discussion of Power for seismic stations, thanks.<br><br> In the Transportable Array deployment, all 1717 stations<br> operate(d) off solar power for at east two years. The average<br> current draw for a station is 0.5Amps on a 12V system, but can<br> vary from 0.4 to 0.6A depending on the telemetry system. High<br> current telemetry systems such as VSAT are powered separately. We<br> avoided AC power because of the proximity of noise due to pumps,<br> motors, etc.<br><br> In general we use (2) 90W PV panels and (2) AGM Lead Acid<br> batteries for stations south of the Kentucky/Tennessee line (row U<br> in TA station codes) and (3) 90W PV panels and (3) AGM Lead Acid<br> batteris north of there. Shady or snowy sites occasionally got<br> more panels and batteries. For permanent stations I'd go with the<br> (3) PV and 3 or 4 batteries. We prefer good quality batteries<br> designed for solar applications, such as the Concorde Sun Extender<br> PVX-1040T. We use PWM regulators with Low voltage disconnect at<br> 10.8V. A few more sophisticated options are discussed below.<br><br> I would concur with the notion that the most effective way to<br> improve a marginal station power situation is to add 1 or 2<br> batteries, and often this can be done without much infrastructure<br> alteration. And the next option is to add a panel. There is<br> little concern about over driving the charge controller with too<br> much current from too many panels. In Alaska, the "more<br> batteries" approach is taken to extremes in which stations have 24<br> batteries to float through the winter. I would also concur that,<br> to date, neither wind nor fuel cells have proved reliable enough<br> to warrant their use, especially in permanent stations of the Lower48.<br><br> More complexity described below:<br> Our system has, in addition to the main battery bank, a small<br> reserve battery. When the system switches to the reserve, certain<br> loads such as the telemetry radio and local data storage are duty<br> cycled at four hour intervals. This reduces the power of the<br> station to about 3W, yet still provides complete telemetry (though<br> with episodic latency) and complete local storage. For us, this<br> reserve power serves to identify the source of the outage is<br> clearly power as opposed to a host of other possibilities. In the<br> original design this reserve battery was Alkaline Lattern 30AH<br> batteries [(3) x 6Volts] (a primary battery, disposed of after<br> use). More recently, We have also used 100-300AH rechargeable<br> batteries that are then connected to the main batteries using a<br> battery isolator circuit-which connects the reserve batteries to<br> the charger only when the main battery has recharged to 13.2V. We<br> add a 10A current limit to the battery interconnection. The<br> reserve power load shedding can be thought of as doubling the<br> capacity of the reserve batteries, reducing the cost of overall<br> power system for this reserve capability. Without that<br> sophisitication of load shedding, adding more batteries is<br> effective but there is a cost in terms of station uptime. When a<br> very large, undifferentiated battery bank is depleted, it will<br> take a longer time for the batteries to reach the reconnect<br> voltage. In this time, the station itself could be operating on<br> the minimal power produced. We keep the main battery bank fairly<br> modest so it recovers voltage quickly, and defer recharging the<br> reserve pack until there is ample power-sometimes weeks, or in<br> Alaska, months later. Its meant to get you through an ocasional<br> bad spell. One issue in this reserve battery switching is the dc<br> currents can introduce magnetic pulses seen on the<br> seismometer-particularly Trilliums within a few meters of the<br> switches.<br><br> If you are plannning a Net-ops meeting in the future, I'd be<br> happly to elaborate on the power system for Alaska, which uses a<br> Genasun MPPT charge controller and LiFePO4 (Lithium Ion) batteries<br> and the same duty cycle loads, reserve battery concepts. These<br> significantly reduce the weight of a 1440AH system to 420 lbs and<br> do not require derating the capacity for cold temperatures. They<br> are very expensive, but not as much as a helicopter trip.<br><br> Bob Busby<br> TA Manager<br><br> On 1/6/2015 7:36 AM, Kyle Persefield wrote:<br><br> Mitch,<br><br> My 2 cents worth<br><br> Because of cost, we have found throwing on more solar panels<br> to be the<br> cheapest and least maintenance intensive solution. Fuel cells and<br> thermoelectric generators are expensive and then there is the<br> recurring<br> cost for fuel, getting fuel to the site, then monitoring of<br> the fuel<br> supply level to consider, and the added required maintenance.<br> We have not<br> found a solution to use these devices as demand requires their<br> use. Or<br> turning them on and off as needed. So long as there is fuel<br> they are on.<br><br> We have been very disappointed with wind turbines. The<br> smaller ones,<br> which are designed for the consumer market, the bearings<br> always fail.<br> Expect no more than 2 or3 years out of these "cheap" units.<br> Then of<br> course there is the need for wind. No wind for extended<br> periods is just<br> as bad as your overcast scenario.<br><br> Kyle<br><br> -----Original Message-----<br> From: ANSS-netops<br> [mailto:anss-netops-bounces@geohazards.usgs.gov<br> <mailto:anss-netops-bounces@geohazards.usgs.gov>] On<br> Behalf Of Mitchell M Withers (mwithers)<br> Sent: Monday, January 05, 2015 7:12 AM<br> To: Philip Crotwell<br> Cc: anss-netops@geohazards.usgs.gov<br> <mailto:anss-netops@geohazards.usgs.gov><br> Subject: Re: [ANSS-netops] solar power problems<br><br><br> Here is a snippet from a recent report from a visit to an<br> example station<br> with a reftek, three S-13's, and an episensor. Stations vary<br> of course<br> and we do use low voltage cutouts at every station (fancy ones<br> that cut<br> out the transmitter first, then the DAS and everything else if<br> the voltage<br> continues to get lower).<br><br> "The new battery banks, when installed were at 12.95 and<br> 12.98. The total<br> station draw is exactly 600ma (checked continuously for about<br> three<br> minutes). I did a quick calculation of 4 batteries at 96AH<br> each, 384/.6 =<br> 640/24 =26.6 days. This calculation would assume no solar<br> charge, but does<br> not take into account reduced battery capacity due to cold<br> temperatures."<br><br> The panels at that particular station were supplying about<br> 700ma together<br> on an overcast day and are being replaced with bigger panels<br> this week.<br> Of course one solution is more battery and more solar at every<br> station<br> along with more frequent refreshing of batteries. But that<br> gets expensive<br> and time consuming so I was fishing to see if anyone is doing<br> something<br> creative. (e.g. wind or hamster wheels).<br><br> Mitch<br><br> Center for Earthquake Research and Information (CERI)<br> University of Memphis Ph: 901-678-4940<br> Memphis, TN 38152 Fax: 901-678-4734<br><br><br> ________________________________________<br> From: Philip Crotwell <crotwell@seis.sc.edu<br> <mailto:crotwell@seis.sc.edu>><br> Sent: Monday, January 5, 2015 7:50 AM<br> To: Mitchell M Withers (mwithers)<br> Cc: anss-netops@geohazards.usgs.gov<br> <mailto:anss-netops@geohazards.usgs.gov><br> Subject: Re: [ANSS-netops] solar power problems<br><br> Hi<br><br> How did you come up with your 25 day figure? Can you put some<br> numbers on<br> power input and output?<br><br> We use two 105 amp-hour batteries per station, where the load<br> is about<br> 1/2 an amp. That gives me about 17.5 days theoretically, but my<br> understanding is that you never want to discharge batteries<br> anywhere near<br> their rating as they can be damaged by high discharges. So<br> maybe worry<br> less about age and more about installed capacity, ie double<br> the battery<br> and replace them half as often.<br><br> We also, because of the cell modems, can monitor the battery<br> voltage over<br> time, we have a cron job to ping the cell modem once an hour<br> and ask it<br> what the input voltage is. For example here is the last few<br> days at one<br> station. You can definitely tell the difference between sunny<br> days and<br> rain, and we get a heads up if the power is getting low and can do<br> something before the station goes down.<br> http://eeyore.seis.sc.edu/earthworm/status/HAW_last720.png<br><br> Here is another station that we are becoming worried about,<br> looks like I<br> might get to go on a road trip soon!<br> http://eeyore.seis.sc.edu/earthworm/status/CASEE_last720.png<br><br> Philip<br><br> On Sun, Jan 4, 2015 at 9:07 AM, Mitchell M Withers (mwithers)<br> <mwithers@memphis.edu <mailto:mwithers@memphis.edu>> wrote:<br><br> Many of our stations run on battery and solar and that<br> normally works<br><br> well. We have a routine battery replacement cycle to make<br> sure they don't<br> get old. Theoretically, we should be able to run with zero<br> solar for<br> about 25 days. But this has been an unusually dreary winter<br> in the<br> southeast and we haven't had much sun for the past two months<br> or more.<br> I'm wondering what others do in areas with limited sunlight to<br> power<br> stations that don't have AC available?<br><br> Mitch<br><br> Center for Earthquake Research and Information (CERI)<br> University of Memphis Ph: 901-678-4940<br> Memphis, TN 38152 Fax: 901-678-4734<br><br> _______________________________________________<br> ANSS-netops mailing list<br> ANSS-netops@geohazards.usgs.gov<br> <mailto:ANSS-netops@geohazards.usgs.gov><br> https://geohazards.usgs.gov/mailman/listinfo/anss-netops<br><br> _______________________________________________<br> ANSS-netops mailing list<br> ANSS-netops@geohazards.usgs.gov<br> <mailto:ANSS-netops@geohazards.usgs.gov><br> https://geohazards.usgs.gov/mailman/listinfo/anss-netops<br> _______________________________________________<br> ANSS-netops mailing list<br> ANSS-netops@geohazards.usgs.gov<br> <mailto:ANSS-netops@geohazards.usgs.gov><br> https://geohazards.usgs.gov/mailman/listinfo/anss-netops<br><br><br> --<br><br> ============================================================<br><br> Robert W. Busby<br> Transportable Array Manager 508-801-7628<br> USArray / EarthScope 37 Haynes Avenue<br> www.earthscope.org/usarray <http://www.earthscope.org/usarray><br> Falmouth MA USA 02540-2312<br><br> _______________________________________________<br> ANSS-netops mailing list<br> ANSS-netops@geohazards.usgs.gov<br> <mailto:ANSS-netops@geohazards.usgs.gov><br> https://geohazards.usgs.gov/mailman/listinfo/anss-netops<br><br><br><br><br>--<br>*********************************************************<br>Mark Meremonte Geophysicist<br>U.S. Bureau of Reclamation: Seismotectonics & Geophysics Group<br>Denver Federal Center Work: 303-445-3298 Cell: 303-808-3894<br>POBox 25007, 85-833000Email: mmeremonte@usbr.gov<br><mailto:mmeremonte@usbr.gov><br>Denver, CO 80225 Web: http://www.usbr.gov<br>Ship: U.S. Bureau of Reclamation, DFC, Bldg. 67-10th Floor, Denver, CO<br>80225<br>**********************************************************<br><br><br>_______________________________________________<br>ANSS-netops mailing list<br>ANSS-netops@geohazards.usgs.gov<br>https://geohazards.usgs.gov/mailman/listinfo/anss-netops<br></blockquote><br>-------------- next part --------------<br>An HTML attachment was scrubbed...<br>URL: <http://geohazards.usgs.gov/pipermail/anss-netops/attachments/20150107/ccb8aea5/attachment.html><br><br>------------------------------<br><br>Subject: Digest Footer<br><br>_______________________________________________<br>ANSS-netops mailing list<br>ANSS-netops@geohazards.usgs.gov<br>https://geohazards.usgs.gov/mailman/listinfo/anss-netops<br><br><br>------------------------------<br><br>End of ANSS-netops Digest, Vol 59, Issue 6<br>******************************************<br><br></blockquote><br><br>------------------------------<br><br>Subject: Digest Footer<br><br>_______________________________________________<br>ANSS-netops mailing list<br>ANSS-netops@geohazards.usgs.gov<br>https://geohazards.usgs.gov/mailman/listinfo/anss-netops<br><br><br>------------------------------<br><br>End of ANSS-netops Digest, Vol 59, Issue 7<br>******************************************<br></blockquote></div><br></body></html>