[ANSS-netops] ANSS-netops Digest, Vol 59, Issue 7
Robert Busby
busby at iris.edu
Thu Jan 8 14:44:32 UTC 2015
A brief summary of our experience with EFOY methanol fuel cells was that
in four separate deployments the system ended up running from 1-6 weeks
before shutting down with a blinking fault indicator.
It generally took 1-4 months to return to the site to assess the
issues-back pressure on outlet tube, dehydration of fuel core, unknown
(just pushed button to resume) , etc.
Regarding the plastic fuel cartridges. We had one develop a small split
at a seam in the plastic-presumably due to cold and/or shipping. This
resulted in a puddle of methanol, which in field conditions is not easy
to distinguish from water puddles. Methanol has a clear flame and its
quite hard to see if the puddle is alight. So there is a threat of of
burning yourself or worse, the plastic tank melting, leaking, whoosh...
Roy Stehle of SRI has successfully run one for 3 winters on the north
slope, powering a VSAT. Which is very impressive.
For us, the prospect of routinely visiting to fill up methanol, was less
economical than larger batteries that can recharge without a visit.
We also have very high cost to visit. The economics are much more
favorable if the site is a few hours drive that you can schedule in the
coming week or so.
And you have data coming in telling you what its doing. So it certain
circumstances they might work well.
We'll probably try ours again in Southeast AK where its dim solar always
and there are people around.
Integrated packages for methanol fuel cells and propane fuel cells
available at:
**
Sirius Integrator
**
**
www.siriusintegrator.com
<http://r20.rs6.net/tn.jsp?f=001ROlgzaXon3fijUnDQqcjUVj0V6ZL4fGAQg8iqNTwdX1qFVcF58Giq-N0pLrwaT-P1Z2KR7MnRA2mSoWCagyddHFPQgvuysZxp0p1MJj2hgxh8m9c6jye2SJYPOZ27l9JxVHrGCTOavxGG6q9gv33loX6m-D5onlIvC3eDVdTUw_ErVAT3N7e4v40AZsspYYi7PkXBkwgFuVe8JG58Hahn2UGsIMw_tQlNpIp-7-5GaP94DueX6JL3rOYVcxxhZi2CYYlCxIB4S_a1vt_2HX7JhRIvOMWrSA5Aoy-v4fJAq0ciD5rfB2wyZ4nsNlsm7b5dT_oKHHRBGifXzDq-QQm-Q==&c=ryW-j55Pie0tXYfCnXbFieca7qibtuko5k_L775MZ6AgCh9SaYjtNw==&ch=xqztRwPdzMjsdD0fYQiCdGTWE8jgUoTfRkdi3xaK4juNW3yQNPqO4w==>
John at siriusintegrator.com
855-747-4874
**
On 1/7/2015 2:20 PM, John R Evans wrote:
> Hi All,
>
> Agreed — excellent discussion.
>
> 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.
>
> 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.
>
> 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).
>
> Anyone have specific experience with reliability of the SFC cells? Bob?
>
> 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:
>
> SFC Energy AG
> Christian Böhm
> VP Defense and Security Business
> Eugen-Saenger-Ring 7
> 85649 Brunnthal/München
> Germany
> +49 (89) 673.592.364
> +49 (160) 90.52.74.72<Cell
> +49 (89) 673.592.169<FAX
> Christian.Boehm at sfc.com <mailto:Christian.Boehm at sfc.com>
> www.sfc.com
> www.efoy-pro.com/page/efoy-proenergybox
>
> Björn Ledergerber(U.S. Rep.)
> Bjoern.Ledergerber at sfc.com
>
>
> 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.
>
> Cheers,
> John
>
> John R. Evans
>
> -------------------------
>
> 831-460-7593 direct
> 408-209-6219 mobile
> jrevans at usgs.gov <mailto:jrevans at usgs.gov>
>
> -------------------------
>
> Normally at (mail or shipping):
> U.S. Geological Survey
> 400 Natural Bridges Dr
> Santa Cruz CA 95060
>
> -------------------------
>
> Intermittently at:
>
> Mail ONLY
> USGS/ASL
> P.O. Box 82010
> Albuquerque NM 87198-2010
>
> Shipping ONLY
> USGS/ASL
> Target Rd 10002 Isleta SE
> Kirtland AFB NM 87117
>
> -------------------------
>
> We have found the ground.
>
> -- JPL, Curiosity control room
>
> -------------------------
>
>
>
>
>
> --------------------------------------------------
>
>
>
>
> On 2015-Jan-07, at 10:40 , anss-netops-request at geohazards.usgs.gov
> <mailto:anss-netops-request at geohazards.usgs.gov> wrote:
>
>> Send ANSS-netops mailing list submissions to
>> anss-netops at geohazards.usgs.gov <mailto:anss-netops at geohazards.usgs.gov>
>>
>> To subscribe or unsubscribe via the World Wide Web, visit
>> https://geohazards.usgs.gov/mailman/listinfo/anss-netops
>> or, via email, send a message with subject or body 'help' to
>> anss-netops-request at geohazards.usgs.gov
>>
>> You can reach the person managing the list at
>> anss-netops-owner at geohazards.usgs.gov
>>
>> When replying, please edit your Subject line so it is more specific
>> than "Re: Contents of ANSS-netops digest..."
>>
>>
>> Today's Topics:
>>
>> 1. Re: solar power problems (Philip Crotwell)
>> 2. Re: ANSS-netops Digest, Vol 59, Issue 6 (Greg Steiner)
>>
>>
>> ----------------------------------------------------------------------
>>
>> Message: 1
>> Date: Wed, 7 Jan 2015 12:32:48 -0500
>> From: Philip Crotwell <crotwell at seis.sc.edu>
>> To: Patrick Bastien <bastienp at ldeo.columbia.edu>
>> Cc: "anss-netops at geohazards.usgs.gov"
>> <anss-netops at geohazards.usgs.gov>
>> Subject: Re: [ANSS-netops] solar power problems
>> Message-ID:
>> <CAGFrVcWYkYVwpZeZeamvSc_+vL91zN0gW3qoqGZntLXf+kgrWQ at mail.gmail.com>
>> Content-Type: text/plain; charset="UTF-8"
>>
>> We use the same batteries. But get the PVX-1040HT if you can as they
>> have a (H)andle. Very useful! :)
>>
>> Philip
>>
>> On Wed, Jan 7, 2015 at 12:18 PM, Patrick Bastien
>> <bastienp at ldeo.columbia.edu> wrote:
>>> The Concorde Sun Extender PVX-1040T has a nominal capacity of 104AH, so
>>> 312AH for the northern TA stations and 208AH for the southern TA
>>> stations.
>>>
>>> Beginning late last summer, the LCSN has begun to switch from older
>>> PWM-style charge controllers to MPPT charge controllers. Although it
>>> is too
>>> soon to say something definite, this is seeming to have a larger
>>> effect on
>>> station up-time than just adding more panels or batteries. Something
>>> I am
>>> doing that might be considered non-standard is wiring each solar panel
>>> individually to its own small MPPT change controller. This allows
>>> each solar
>>> panel to generate the maximum amount of power regardless of the lighting
>>> condition of the other solar panels. The several MPPT charge controllers
>>> then feed a common battery bank. I then regulate the voltage
>>> powering the
>>> sensor by using a small low-noise DCDC converter imbedded inside a
>>> cable.
>>> The MPPT benefits might be magnified for the LCSN because of the
>>> location of
>>> many of our solar powered stations are in forests or forest-adjacent.
>>>
>>>
>>> Patrick Bastien
>>> LDEO-LCSN
>>>
>>>
>>> On 1/7/2015 11:06 AM, Meremonte, Mark wrote:
>>>
>>> Bob, May I ask the AH size of AGM batteries for an average TA station?
>>> Thank you, Mark
>>>
>>> On Wed, Jan 7, 2015 at 8:29 AM, Robert Busby <busby at iris.edu> wrote:
>>>>
>>>> Hi Mitch et al.
>>>> This is a good discussion of Power for seismic stations, thanks.
>>>>
>>>> In the Transportable Array deployment, all 1717 stations operate(d) off
>>>> solar power for at east two years. The average current draw for a
>>>> station
>>>> is 0.5Amps on a 12V system, but can vary from 0.4 to 0.6A depending
>>>> on the
>>>> telemetry system. High current telemetry systems such as VSAT are
>>>> powered
>>>> separately. We avoided AC power because of the proximity of noise
>>>> due to
>>>> pumps, motors, etc.
>>>>
>>>> In general we use (2) 90W PV panels and (2) AGM Lead Acid batteries for
>>>> stations south of the Kentucky/Tennessee line (row U in TA station
>>>> codes)
>>>> and (3) 90W PV panels and (3) AGM Lead Acid batteris north of
>>>> there. Shady
>>>> or snowy sites occasionally got more panels and batteries. For
>>>> permanent
>>>> stations I'd go with the (3) PV and 3 or 4 batteries. We prefer good
>>>> quality batteries designed for solar applications, such as the
>>>> Concorde Sun
>>>> Extender PVX-1040T. We use PWM regulators with Low voltage
>>>> disconnect at
>>>> 10.8V. A few more sophisticated options are discussed below.
>>>>
>>>> I would concur with the notion that the most effective way to improve a
>>>> marginal station power situation is to add 1 or 2 batteries, and
>>>> often this
>>>> can be done without much infrastructure alteration. And the next
>>>> option is
>>>> to add a panel. There is little concern about over driving the charge
>>>> controller with too much current from too many panels. In Alaska,
>>>> the "more
>>>> batteries" approach is taken to extremes in which stations have 24
>>>> batteries
>>>> to float through the winter. I would also concur that, to date,
>>>> neither wind
>>>> nor fuel cells have proved reliable enough to warrant their use,
>>>> especially
>>>> in permanent stations of the Lower48.
>>>>
>>>> More complexity described below:
>>>> Our system has, in addition to the main battery bank, a small reserve
>>>> battery. When the system switches to the reserve, certain loads
>>>> such as the
>>>> telemetry radio and local data storage are duty cycled at four hour
>>>> intervals. This reduces the power of the station to about 3W, yet
>>>> still
>>>> provides complete telemetry (though with episodic latency) and complete
>>>> local storage. For us, this reserve power serves to identify the
>>>> source of
>>>> the outage is clearly power as opposed to a host of other
>>>> possibilities. In
>>>> the original design this reserve battery was Alkaline Lattern 30AH
>>>> batteries
>>>> [(3) x 6Volts] (a primary battery, disposed of after use). More
>>>> recently,
>>>> We have also used 100-300AH rechargeable batteries that are then
>>>> connected
>>>> to the main batteries using a battery isolator circuit-which
>>>> connects the
>>>> reserve batteries to the charger only when the main battery has
>>>> recharged to
>>>> 13.2V. We add a 10A current limit to the battery interconnection. The
>>>> reserve power load shedding can be thought of as doubling the
>>>> capacity of
>>>> the reserve batteries, reducing the cost of overall power system
>>>> for this
>>>> reserve capability. Without that sophisitication of load shedding,
>>>> adding
>>>> more batteries is effective but there is a cost in terms of station
>>>> uptime.
>>>> When a very large, undifferentiated battery bank is depleted, it
>>>> will take a
>>>> longer time for the batteries to reach the reconnect voltage. In
>>>> this time,
>>>> the station itself could be operating on the minimal power
>>>> produced. We keep
>>>> the main battery bank fairly modest so it recovers voltage quickly, and
>>>> defer recharging the reserve pack until there is ample power-sometimes
>>>> weeks, or in Alaska, months later. Its meant to get you through an
>>>> ocasional bad spell. One issue in this reserve battery switching
>>>> is the dc
>>>> currents can introduce magnetic pulses seen on the
>>>> seismometer-particularly
>>>> Trilliums within a few meters of the switches.
>>>>
>>>> If you are plannning a Net-ops meeting in the future, I'd be happly to
>>>> elaborate on the power system for Alaska, which uses a Genasun MPPT
>>>> charge
>>>> controller and LiFePO4 (Lithium Ion) batteries and the same duty cycle
>>>> loads, reserve battery concepts. These significantly reduce the
>>>> weight of a
>>>> 1440AH system to 420 lbs and do not require derating the capacity
>>>> for cold
>>>> temperatures. They are very expensive, but not as much as a helicopter
>>>> trip.
>>>>
>>>> Bob Busby
>>>> TA Manager
>>>>
>>>> On 1/6/2015 7:36 AM, Kyle Persefield wrote:
>>>>>
>>>>> Mitch,
>>>>>
>>>>> My 2 cents worth
>>>>>
>>>>> Because of cost, we have found throwing on more solar panels to be the
>>>>> cheapest and least maintenance intensive solution. Fuel cells and
>>>>> thermoelectric generators are expensive and then there is the
>>>>> recurring
>>>>> cost for fuel, getting fuel to the site, then monitoring of the fuel
>>>>> supply level to consider, and the added required maintenance. We have
>>>>> not
>>>>> found a solution to use these devices as demand requires their
>>>>> use. Or
>>>>> turning them on and off as needed. So long as there is fuel they
>>>>> are on.
>>>>>
>>>>> We have been very disappointed with wind turbines. The smaller ones,
>>>>> which are designed for the consumer market, the bearings always fail.
>>>>> Expect no more than 2 or3 years out of these "cheap" units. Then of
>>>>> course there is the need for wind. No wind for extended periods
>>>>> is just
>>>>> as bad as your overcast scenario.
>>>>>
>>>>> Kyle
>>>>>
>>>>> -----Original Message-----
>>>>> From: ANSS-netops [mailto:anss-netops-bounces at geohazards.usgs.gov] On
>>>>> Behalf Of Mitchell M Withers (mwithers)
>>>>> Sent: Monday, January 05, 2015 7:12 AM
>>>>> To: Philip Crotwell
>>>>> Cc: anss-netops at geohazards.usgs.gov
>>>>> Subject: Re: [ANSS-netops] solar power problems
>>>>>
>>>>>
>>>>> Here is a snippet from a recent report from a visit to an example
>>>>> station
>>>>> with a reftek, three S-13's, and an episensor. Stations vary of
>>>>> course
>>>>> and we do use low voltage cutouts at every station (fancy ones
>>>>> that cut
>>>>> out the transmitter first, then the DAS and everything else if the
>>>>> voltage
>>>>> continues to get lower).
>>>>>
>>>>> "The new battery banks, when installed were at 12.95 and 12.98.
>>>>> The total
>>>>> station draw is exactly 600ma (checked continuously for about three
>>>>> minutes). I did a quick calculation of 4 batteries at 96AH each,
>>>>> 384/.6 =
>>>>> 640/24 =26.6 days. This calculation would assume no solar charge, but
>>>>> does
>>>>> not take into account reduced battery capacity due to cold
>>>>> temperatures."
>>>>>
>>>>> The panels at that particular station were supplying about 700ma
>>>>> together
>>>>> on an overcast day and are being replaced with bigger panels this
>>>>> week.
>>>>> Of course one solution is more battery and more solar at every station
>>>>> along with more frequent refreshing of batteries. But that gets
>>>>> expensive
>>>>> and time consuming so I was fishing to see if anyone is doing
>>>>> something
>>>>> creative. (e.g. wind or hamster wheels).
>>>>>
>>>>> Mitch
>>>>>
>>>>> Center for Earthquake Research and Information (CERI)
>>>>> University of Memphis Ph: 901-678-4940
>>>>> Memphis, TN 38152 Fax: 901-678-4734
>>>>>
>>>>>
>>>>> ________________________________________
>>>>> From: Philip Crotwell <crotwell at seis.sc.edu>
>>>>> Sent: Monday, January 5, 2015 7:50 AM
>>>>> To: Mitchell M Withers (mwithers)
>>>>> Cc: anss-netops at geohazards.usgs.gov
>>>>> Subject: Re: [ANSS-netops] solar power problems
>>>>>
>>>>> Hi
>>>>>
>>>>> How did you come up with your 25 day figure? Can you put some
>>>>> numbers on
>>>>> power input and output?
>>>>>
>>>>> We use two 105 amp-hour batteries per station, where the load is about
>>>>> 1/2 an amp. That gives me about 17.5 days theoretically, but my
>>>>> understanding is that you never want to discharge batteries
>>>>> anywhere near
>>>>> their rating as they can be damaged by high discharges. So maybe worry
>>>>> less about age and more about installed capacity, ie double the
>>>>> battery
>>>>> and replace them half as often.
>>>>>
>>>>> We also, because of the cell modems, can monitor the battery
>>>>> voltage over
>>>>> time, we have a cron job to ping the cell modem once an hour and
>>>>> ask it
>>>>> what the input voltage is. For example here is the last few days
>>>>> at one
>>>>> station. You can definitely tell the difference between sunny days and
>>>>> rain, and we get a heads up if the power is getting low and can do
>>>>> something before the station goes down.
>>>>> http://eeyore.seis.sc.edu/earthworm/status/HAW_last720.png
>>>>>
>>>>> Here is another station that we are becoming worried about, looks
>>>>> like I
>>>>> might get to go on a road trip soon!
>>>>> http://eeyore.seis.sc.edu/earthworm/status/CASEE_last720.png
>>>>>
>>>>> Philip
>>>>>
>>>>> On Sun, Jan 4, 2015 at 9:07 AM, Mitchell M Withers (mwithers)
>>>>> <mwithers at memphis.edu> wrote:
>>>>>>
>>>>>> Many of our stations run on battery and solar and that normally works
>>>>>
>>>>> well. We have a routine battery replacement cycle to make sure they
>>>>> don't
>>>>> get old. Theoretically, we should be able to run with zero solar for
>>>>> about 25 days. But this has been an unusually dreary winter in the
>>>>> southeast and we haven't had much sun for the past two months or more.
>>>>> I'm wondering what others do in areas with limited sunlight to power
>>>>> stations that don't have AC available?
>>>>>>
>>>>>> Mitch
>>>>>>
>>>>>> Center for Earthquake Research and Information (CERI)
>>>>>> University of Memphis Ph: 901-678-4940
>>>>>> Memphis, TN 38152 Fax: 901-678-4734
>>>>>>
>>>>>> _______________________________________________
>>>>>> ANSS-netops mailing list
>>>>>> ANSS-netops at geohazards.usgs.gov
>>>>>> https://geohazards.usgs.gov/mailman/listinfo/anss-netops
>>>>>
>>>>> _______________________________________________
>>>>> ANSS-netops mailing list
>>>>> ANSS-netops at geohazards.usgs.gov
>>>>> https://geohazards.usgs.gov/mailman/listinfo/anss-netops
>>>>> _______________________________________________
>>>>> ANSS-netops mailing list
>>>>> ANSS-netops at geohazards.usgs.gov
>>>>> https://geohazards.usgs.gov/mailman/listinfo/anss-netops
>>>>>
>>>>
>>>> --
>>>>
>>>> ============================================================
>>>>
>>>> Robert W. Busby
>>>> Transportable Array Manager 508-801-7628
>>>> USArray / EarthScope 37 Haynes Avenue
>>>> www.earthscope.org/usarray Falmouth MA USA 02540-2312
>>>>
>>>> _______________________________________________
>>>> ANSS-netops mailing list
>>>> ANSS-netops at geohazards.usgs.gov
>>>> https://geohazards.usgs.gov/mailman/listinfo/anss-netops
>>>
>>>
>>>
>>>
>>> --
>>> *********************************************************
>>> Mark Meremonte Geophysicist
>>> U.S. Bureau of Reclamation: Seismotectonics & Geophysics Group
>>> Denver Federal Center Work: 303-445-3298 Cell: 303-808-3894
>>> POBox 25007, 85-833000 Email: mmeremonte at usbr.gov
>>> Denver, CO 80225 Web: http://www.usbr.gov
>>> Ship: U.S. Bureau of Reclamation, DFC, Bldg. 67-10th Floor, Denver, CO
>>> 80225
>>> **********************************************************
>>>
>>>
>>> _______________________________________________
>>> ANSS-netops mailing list
>>> ANSS-netops at geohazards.usgs.gov
>>> https://geohazards.usgs.gov/mailman/listinfo/anss-netops
>>>
>>>
>>>
>>> _______________________________________________
>>> ANSS-netops mailing list
>>> ANSS-netops at geohazards.usgs.gov
>>> https://geohazards.usgs.gov/mailman/listinfo/anss-netops
>>>
>>
>>
>> ------------------------------
>>
>> Message: 2
>> Date: Wed, 7 Jan 2015 12:40:18 -0600
>> From: Greg Steiner <vlf at cablerocket.com>
>> To: <anss-netops at geohazards.usgs.gov>
>> Subject: Re: [ANSS-netops] ANSS-netops Digest, Vol 59, Issue 6
>> Message-ID: <54AD7D92.6020804 at cablerocket.com>
>> Content-Type: text/plain; charset="windows-1252"; format=flowed
>>
>> Patrick, I'm curious as to how you get multiple MPPT controllers to
>> charge a single battery bank. Are they inherently designed for this form
>> of parallel operation?
>> Greg Steiner
>>
>> On 1/7/2015 11:16 AM, anss-netops-request at geohazards.usgs.gov wrote:
>>> Send ANSS-netops mailing list submissions to
>>> anss-netops at geohazards.usgs.gov
>>>
>>> To subscribe or unsubscribe via the World Wide Web, visit
>>> https://geohazards.usgs.gov/mailman/listinfo/anss-netops
>>> or, via email, send a message with subject or body 'help' to
>>> anss-netops-request at geohazards.usgs.gov
>>>
>>> You can reach the person managing the list at
>>> anss-netops-owner at geohazards.usgs.gov
>>>
>>> When replying, please edit your Subject line so it is more specific
>>> than "Re: Contents of ANSS-netops digest..."
>>>
>>>
>>> Today's Topics:
>>>
>>> 1. Re: solar power problems (Patrick Bastien)
>>>
>>>
>>> ----------------------------------------------------------------------
>>>
>>> Message: 1
>>> Date: Wed, 7 Jan 2015 12:18:20 -0500
>>> From: Patrick Bastien <bastienp at ldeo.columbia.edu>
>>> To: <anss-netops at geohazards.usgs.gov>
>>> Subject: Re: [ANSS-netops] solar power problems
>>> Message-ID: <54AD6A5C.6080608 at ldeo.columbia.edu>
>>> Content-Type: text/plain; charset="iso-8859-1"; Format="flowed"
>>>
>>> The Concorde Sun Extender PVX-1040T has a nominal capacity of 104AH, so
>>> 312AH for the northern TA stations and 208AH for the southern TA
>>> stations.
>>>
>>> Beginning late last summer, the LCSN has begun to switch from older
>>> PWM-style charge controllers to MPPT charge controllers. Although it is
>>> too soon to say something definite, this is seeming to have a larger
>>> effect on station up-time than just adding more panels or batteries.
>>> Something I am doing that might be considered non-standard is wiring
>>> each solar panel individually to its own small MPPT change controller.
>>> This allows each solar panel to generate the maximum amount of power
>>> regardless of the lighting condition of the other solar panels. The
>>> several MPPT charge controllers then feed a common battery bank. I then
>>> regulate the voltage powering the sensor by using a small low-noise DCDC
>>> converter imbedded inside a cable. The MPPT benefits might be magnified
>>> for the LCSN because of the location of many of our solar powered
>>> stations are in forests or forest-adjacent.
>>>
>>>
>>> Patrick Bastien
>>> LDEO-LCSN
>>>
>>> On 1/7/2015 11:06 AM, Meremonte, Mark wrote:
>>>> Bob, May I ask the AH size of AGM batteries for an average TA
>>>> station? Thank you, Mark
>>>>
>>>> On Wed, Jan 7, 2015 at 8:29 AM, Robert Busby <busby at iris.edu
>>>> <mailto:busby at iris.edu>> wrote:
>>>>
>>>> Hi Mitch et al.
>>>> This is a good discussion of Power for seismic stations, thanks.
>>>>
>>>> In the Transportable Array deployment, all 1717 stations
>>>> operate(d) off solar power for at east two years. The average
>>>> current draw for a station is 0.5Amps on a 12V system, but can
>>>> vary from 0.4 to 0.6A depending on the telemetry system. High
>>>> current telemetry systems such as VSAT are powered separately. We
>>>> avoided AC power because of the proximity of noise due to pumps,
>>>> motors, etc.
>>>>
>>>> In general we use (2) 90W PV panels and (2) AGM Lead Acid
>>>> batteries for stations south of the Kentucky/Tennessee line (row U
>>>> in TA station codes) and (3) 90W PV panels and (3) AGM Lead Acid
>>>> batteris north of there. Shady or snowy sites occasionally got
>>>> more panels and batteries. For permanent stations I'd go with the
>>>> (3) PV and 3 or 4 batteries. We prefer good quality batteries
>>>> designed for solar applications, such as the Concorde Sun Extender
>>>> PVX-1040T. We use PWM regulators with Low voltage disconnect at
>>>> 10.8V. A few more sophisticated options are discussed below.
>>>>
>>>> I would concur with the notion that the most effective way to
>>>> improve a marginal station power situation is to add 1 or 2
>>>> batteries, and often this can be done without much infrastructure
>>>> alteration. And the next option is to add a panel. There is
>>>> little concern about over driving the charge controller with too
>>>> much current from too many panels. In Alaska, the "more
>>>> batteries" approach is taken to extremes in which stations have 24
>>>> batteries to float through the winter. I would also concur that,
>>>> to date, neither wind nor fuel cells have proved reliable enough
>>>> to warrant their use, especially in permanent stations of the
>>>> Lower48.
>>>>
>>>> More complexity described below:
>>>> Our system has, in addition to the main battery bank, a small
>>>> reserve battery. When the system switches to the reserve, certain
>>>> loads such as the telemetry radio and local data storage are duty
>>>> cycled at four hour intervals. This reduces the power of the
>>>> station to about 3W, yet still provides complete telemetry (though
>>>> with episodic latency) and complete local storage. For us, this
>>>> reserve power serves to identify the source of the outage is
>>>> clearly power as opposed to a host of other possibilities. In the
>>>> original design this reserve battery was Alkaline Lattern 30AH
>>>> batteries [(3) x 6Volts] (a primary battery, disposed of after
>>>> use). More recently, We have also used 100-300AH rechargeable
>>>> batteries that are then connected to the main batteries using a
>>>> battery isolator circuit-which connects the reserve batteries to
>>>> the charger only when the main battery has recharged to 13.2V. We
>>>> add a 10A current limit to the battery interconnection. The
>>>> reserve power load shedding can be thought of as doubling the
>>>> capacity of the reserve batteries, reducing the cost of overall
>>>> power system for this reserve capability. Without that
>>>> sophisitication of load shedding, adding more batteries is
>>>> effective but there is a cost in terms of station uptime. When a
>>>> very large, undifferentiated battery bank is depleted, it will
>>>> take a longer time for the batteries to reach the reconnect
>>>> voltage. In this time, the station itself could be operating on
>>>> the minimal power produced. We keep the main battery bank fairly
>>>> modest so it recovers voltage quickly, and defer recharging the
>>>> reserve pack until there is ample power-sometimes weeks, or in
>>>> Alaska, months later. Its meant to get you through an ocasional
>>>> bad spell. One issue in this reserve battery switching is the dc
>>>> currents can introduce magnetic pulses seen on the
>>>> seismometer-particularly Trilliums within a few meters of the
>>>> switches.
>>>>
>>>> If you are plannning a Net-ops meeting in the future, I'd be
>>>> happly to elaborate on the power system for Alaska, which uses a
>>>> Genasun MPPT charge controller and LiFePO4 (Lithium Ion) batteries
>>>> and the same duty cycle loads, reserve battery concepts. These
>>>> significantly reduce the weight of a 1440AH system to 420 lbs and
>>>> do not require derating the capacity for cold temperatures. They
>>>> are very expensive, but not as much as a helicopter trip.
>>>>
>>>> Bob Busby
>>>> TA Manager
>>>>
>>>> On 1/6/2015 7:36 AM, Kyle Persefield wrote:
>>>>
>>>> Mitch,
>>>>
>>>> My 2 cents worth
>>>>
>>>> Because of cost, we have found throwing on more solar panels
>>>> to be the
>>>> cheapest and least maintenance intensive solution. Fuel
>>>> cells and
>>>> thermoelectric generators are expensive and then there is the
>>>> recurring
>>>> cost for fuel, getting fuel to the site, then monitoring of
>>>> the fuel
>>>> supply level to consider, and the added required maintenance.
>>>> We have not
>>>> found a solution to use these devices as demand requires their
>>>> use. Or
>>>> turning them on and off as needed. So long as there is fuel
>>>> they are on.
>>>>
>>>> We have been very disappointed with wind turbines. The
>>>> smaller ones,
>>>> which are designed for the consumer market, the bearings
>>>> always fail.
>>>> Expect no more than 2 or3 years out of these "cheap" units.
>>>> Then of
>>>> course there is the need for wind. No wind for extended
>>>> periods is just
>>>> as bad as your overcast scenario.
>>>>
>>>> Kyle
>>>>
>>>> -----Original Message-----
>>>> From: ANSS-netops
>>>> [mailto:anss-netops-bounces at geohazards.usgs.gov
>>>> <mailto:anss-netops-bounces at geohazards.usgs.gov>] On
>>>> Behalf Of Mitchell M Withers (mwithers)
>>>> Sent: Monday, January 05, 2015 7:12 AM
>>>> To: Philip Crotwell
>>>> Cc: anss-netops at geohazards.usgs.gov
>>>> <mailto:anss-netops at geohazards.usgs.gov>
>>>> Subject: Re: [ANSS-netops] solar power problems
>>>>
>>>>
>>>> Here is a snippet from a recent report from a visit to an
>>>> example station
>>>> with a reftek, three S-13's, and an episensor. Stations vary
>>>> of course
>>>> and we do use low voltage cutouts at every station (fancy ones
>>>> that cut
>>>> out the transmitter first, then the DAS and everything else if
>>>> the voltage
>>>> continues to get lower).
>>>>
>>>> "The new battery banks, when installed were at 12.95 and
>>>> 12.98. The total
>>>> station draw is exactly 600ma (checked continuously for about
>>>> three
>>>> minutes). I did a quick calculation of 4 batteries at 96AH
>>>> each, 384/.6 =
>>>> 640/24 =26.6 days. This calculation would assume no solar
>>>> charge, but does
>>>> not take into account reduced battery capacity due to cold
>>>> temperatures."
>>>>
>>>> The panels at that particular station were supplying about
>>>> 700ma together
>>>> on an overcast day and are being replaced with bigger panels
>>>> this week.
>>>> Of course one solution is more battery and more solar at every
>>>> station
>>>> along with more frequent refreshing of batteries. But that
>>>> gets expensive
>>>> and time consuming so I was fishing to see if anyone is doing
>>>> something
>>>> creative. (e.g. wind or hamster wheels).
>>>>
>>>> Mitch
>>>>
>>>> Center for Earthquake Research and Information (CERI)
>>>> University of Memphis Ph: 901-678-4940
>>>> Memphis, TN 38152 Fax: 901-678-4734
>>>>
>>>>
>>>> ________________________________________
>>>> From: Philip Crotwell <crotwell at seis.sc.edu
>>>> <mailto:crotwell at seis.sc.edu>>
>>>> Sent: Monday, January 5, 2015 7:50 AM
>>>> To: Mitchell M Withers (mwithers)
>>>> Cc: anss-netops at geohazards.usgs.gov
>>>> <mailto:anss-netops at geohazards.usgs.gov>
>>>> Subject: Re: [ANSS-netops] solar power problems
>>>>
>>>> Hi
>>>>
>>>> How did you come up with your 25 day figure? Can you put some
>>>> numbers on
>>>> power input and output?
>>>>
>>>> We use two 105 amp-hour batteries per station, where the load
>>>> is about
>>>> 1/2 an amp. That gives me about 17.5 days theoretically, but my
>>>> understanding is that you never want to discharge batteries
>>>> anywhere near
>>>> their rating as they can be damaged by high discharges. So
>>>> maybe worry
>>>> less about age and more about installed capacity, ie double
>>>> the battery
>>>> and replace them half as often.
>>>>
>>>> We also, because of the cell modems, can monitor the battery
>>>> voltage over
>>>> time, we have a cron job to ping the cell modem once an hour
>>>> and ask it
>>>> what the input voltage is. For example here is the last few
>>>> days at one
>>>> station. You can definitely tell the difference between sunny
>>>> days and
>>>> rain, and we get a heads up if the power is getting low and
>>>> can do
>>>> something before the station goes down.
>>>> http://eeyore.seis.sc.edu/earthworm/status/HAW_last720.png
>>>>
>>>> Here is another station that we are becoming worried about,
>>>> looks like I
>>>> might get to go on a road trip soon!
>>>> http://eeyore.seis.sc.edu/earthworm/status/CASEE_last720.png
>>>>
>>>> Philip
>>>>
>>>> On Sun, Jan 4, 2015 at 9:07 AM, Mitchell M Withers (mwithers)
>>>> <mwithers at memphis.edu <mailto:mwithers at memphis.edu>> wrote:
>>>>
>>>> Many of our stations run on battery and solar and that
>>>> normally works
>>>>
>>>> well. We have a routine battery replacement cycle to make
>>>> sure they don't
>>>> get old. Theoretically, we should be able to run with zero
>>>> solar for
>>>> about 25 days. But this has been an unusually dreary winter
>>>> in the
>>>> southeast and we haven't had much sun for the past two months
>>>> or more.
>>>> I'm wondering what others do in areas with limited sunlight to
>>>> power
>>>> stations that don't have AC available?
>>>>
>>>> Mitch
>>>>
>>>> Center for Earthquake Research and Information (CERI)
>>>> University of Memphis Ph: 901-678-4940
>>>> Memphis, TN 38152 Fax: 901-678-4734
>>>>
>>>> _______________________________________________
>>>> ANSS-netops mailing list
>>>> ANSS-netops at geohazards.usgs.gov
>>>> <mailto:ANSS-netops at geohazards.usgs.gov>
>>>> https://geohazards.usgs.gov/mailman/listinfo/anss-netops
>>>>
>>>> _______________________________________________
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>>>> _______________________________________________
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>>>>
>>>>
>>>> --
>>>>
>>>> ============================================================
>>>>
>>>> Robert W. Busby
>>>> Transportable Array Manager 508-801-7628
>>>> USArray / EarthScope 37 Haynes Avenue
>>>> www.earthscope.org/usarray <http://www.earthscope.org/usarray>
>>>> Falmouth MA USA 02540-2312
>>>>
>>>> _______________________________________________
>>>> ANSS-netops mailing list
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>>>> https://geohazards.usgs.gov/mailman/listinfo/anss-netops
>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> *********************************************************
>>>> Mark Meremonte Geophysicist
>>>> U.S. Bureau of Reclamation: Seismotectonics & Geophysics Group
>>>> Denver Federal Center Work: 303-445-3298 Cell: 303-808-3894
>>>> POBox 25007, 85-833000Email: mmeremonte at usbr.gov
>>>> <mailto:mmeremonte at usbr.gov>
>>>> Denver, CO 80225 Web: http://www.usbr.gov
>>>> Ship: U.S. Bureau of Reclamation, DFC, Bldg. 67-10th Floor, Denver, CO
>>>> 80225
>>>> **********************************************************
>>>>
>>>>
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============================================================
Robert W. Busby
Transportable Array Manager 508-801-7628
USArray / EarthScope 37 Haynes Avenue
www.earthscope.org/usarray Falmouth MA USA 02540-2312
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