On Thu, 9 Jul 2015 15:51:49 -0700 (PDT), "Ron D."
wrote:
Electric meters are likely a Zigbee (peer to peer) network and eventually
communicate via a cell phone data stream.
Not quite. The power meters typically use 900 MHz spread spectrum to
communicated with each other using a store and forward mesh network
system. Eventually, the meter reading is delivered through a series
of hops by other meters to an access point radio that is connected to
the internet. From there, the data goes to the utility company
computah or service company.
Some smart meters have a built in Zigbee radio, designed to
communicate with subscriber owned energy monitors. However, there are
few approved devices and the local utility (PG&E) doesn't seem
interested in expanding the selection:
http://www.pge.com/en/myhome/saveenergymoney/rebates/han/validateddevice/index.page
http://www.aztechmeter.com
I'm underwhelmed.
The meters are TWO-WAY.
Correct. Note that they are also simplex radios, that can either
transmit or receive, but not at the same time.
The power company can disconnect power remotely.
Most can do this. Allegedly, it's to deal with turning the power
on/off when a customer relocates. It saves a truck roll for connects
and disconnects. There are numerous anecdotes of people having their
power disconnected for non-payment, but the few where details were
supplied, were by a truck roll to recover the meter, not by a remote
disconnect. However, this may change in the future.
Water meters have batteries. Supposedly they are "truck" activated
and only talk back when prompted. Yes, they have a battery.
Both the power and gas meters have batteries. 10 years is the nominal
expected life from lithium-thionyl chloride (LTC) batteries. However,
these batteries are non-rechargeable and will need to be replaced
eventually. Fortunately, newer batteries are rechargeable and can
allegedly last 20 years.
http://www.tadiranbat.com/index.php/tli-series-rechargeable
http://www.tadiranbatteries.de/pdf/applications/battery-concepts-for-smart-utility-meters.pdf
I don't know they plan to handle the battery replacement or recharge
problem.
The gas meters, I don;t know, but they may operate the same way as
the water meters. They contain batteries.
Yep and also not rechargeable. Locally, the gas meters run in the
commercial UHF frequency range (450-470 MHz) and do NOT use spread
spectrum. I know the frequencies, but I'm not talking.
Battery life is estimated to be about 7 to 10 years as I understand it.
The battery life depends on how close to the internet connected radio
the smart meter is located. If it's quite close, it will be doing the
store and forward repeater dance for a large number of other smart
meters located further away. That will burn more power running the
transmitter, and produce a shorter battery life. Smart meters that
are further away, and don't do much store and forward repeating, will
last much longer.
More details:
http://www.pge.com/en/safety/systemworks/rf/faq/index.page
http://www.pge.com/en/safety/systemworks/rf/facts/index.page
http://www.pge.com/en/safety/systemworks/rf/ccst/index.page
http://www.pge.com/includes/docs/pdfs/shared/edusafety/systemworks/rfsafety/rf_summary_discussion_rat2.pdf
http://www.pge.com/includes/docs/pdfs/shared/edusafety/systemworks/rfsafety/amr_rf_analysis_report_2005.pdf
http://www.pge.com/includes/docs/pdfs/shared/edusafety/systemworks/rfsafety/rf_fields_supplemental_report_2008.pdf
etc...
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060
http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558