[RE-wrenches] kwh meters

[Matt Lafferty]

Hi Gary,
 
You did say you're using the neutral, so I'm assuming you've got the 5-jaw
socket and meter (Form 12S). You also need to make sure the meter itself is
non-detented. Once you reconfigure the socket to match the one shown in
David's reference you should be good to go.
 
Not sure which aspect(s) of "utility grade" you need. I'll assume you mean
"revenue grade" accuracy. The generally accepted threshold for this is +/-2%
overall. A lot of analog meters (most) are not certified as "revenue grade"
when running in the "backward" direction. Forget about "certified", they
simply are all over the map with accuracy tolerance in the backward
direction. For this reason, many were disqualified for use in Net Metering
applications. Since your use is technically measuring the Net Generation,
your accuracy may be off... Not as far off as some inverter manufacturers'
displays have been in the past, but still possibly quite a bit off,
relatively speaking. Think in terms of up to +/-5%. Don't know if this
matters for your purposes or not, but I thought I'd throw it out there so
you don't have to go all the way through the learning curve by yourself.
Lonely curve, that one...
 
If Net Generation accuracy is critical, you have three fine choices and many
that aren't so fine. 
 
1)  The obvious "easy" one is to get confirmation that your meter is
certified Bi-Directional &/or qualified/certified for Net Metering.
Occupants of Meter Meter Neverland are particularly paranoid person-objects.
Gaining a qualified confirmation of said information may take some
sleuthing. Don't bother trying to get information from GE. Start with the
vendor who sold it to you. If you have friends who work in the meter shop of
the local electric utility, you might want to talk with them. Hint: If you
get a blank stare from the meter guy when you say "Net Meter".... Just
smile, excuse yourself, and go get a donut.
 
2)  If #1 doesn't pan out, find a meter that does and use it.
 
3)  Use two meters and do some subtraction. 
 
Pray for Sun!
 
Matt Lafferty

  _____  

From: David Brearley

Is it a Form 12-S meter? If not, that's the reason its not working. Here's
an article you can refer to:

http://solarprofessional.com/article/?file=SP1_1_pg16_QandA_3
<http://solarprofessional.com/article/?file=SP1_1_pg16_QandA_3&search=>
&search=


On 1/28/10 2:57 PM, "gary at arp-solar.com" <gary at arp-solar.com> wrote:



I am using an analog GE kwh meter on an outback system with battery backup
to a protected loads panel.  The AC in to the inverter is attached to the
bottom of one leg of the meter and the AC out of the inverter is connected
to the top of the other leg. This should give me an accurate record of just
the production from the system. The idea is that the AC IN that will power
the protected loads panel at night will come in the bottom of one leg and
turn the meter backwards then exit through the top of the meter going
forward thus cancelling those kwh. out. I have a neutral hooked to the meter
because I am using it to record 120V but I am not getting accurate readings
with this configuration. Any suggestions on metering in this case? I need a
utility grade kwh meter.  
 


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