KWH meter discrepancy [RE-wrenches]

[Jeff Clearwater]

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Hi Kelly & Bob-O,

Yes, Since I install systems in MA sometimes and for all those 
systems we need to install "utility grade" KWH meters for the rebate, 
I too find the inverter's meter running 15-20% higher than  the 
refurbished Austin Instruments meters like those bought through 
AEESolar or EO.

And come to think of it the ones that were the most off were the 120 
VAC units (SB1800) though the 240 VAC units are off too though by 
varying percentages - usually around 15-20%.

And that's a major drag as the MA rebate program depends on those KWH 
meters - not the inverters!  So if they are low instead of the 
inverters being high - the folks are not getting their full 
performance portion of the rebate back.

I recently installed two on some Windy Boys (120 VAC SB1800) and got 
21% more on the inverters than the meters.

For now I've stopped installing them - but need an alternative.  They 
are nice in that they are cheap

Anyone with a solution?

Best,

Jeff Clearwater
Village Power Design



>Hiya Kelly,
>It may be the 120V thing on the 240 meter, but in Oregon we are 
>required to put a revenue grade meter in almost every installation. 
>Most are 240V, but some are wired 120V like you have depending on 
>the inverter. I've NEVER seen the meter from the inverter and the 
>revenue grade meter agree regardless of the inverter manu. And 
>-here's the salient part- the inverter meter is always the high one. 
>Uh huh.....
>Bob-O
>On May 18, 2006, at 10:02 AM, Kelly Keilwitz wrote:
>
>>
>>Wrenches,
>>
>>We recently installed a small PV GT system with a SMA SB700, with display.
>>We also have a utility style "green tags" meter on the AC output. It's been
>>running for a couple of months and the SB display is recording 18% higher
>>energy production than the green tags meter. The green tag meter is a form
>>2S, 240-V meter, wired for the 120-V output of the SB700.
>>
>>We've wired 240-V meters for 120V operation before but never had a
>>(reliable) KWH meter to gauge against. Is the SB display meter reliable? Any
>>problems with wiring 240V meters for 120V output?
>>
>>Thanks,
>>-Kelly
>>
>>Kelly Keilwitz, P.E.
>>Whidbey Sun & Wind, LLC
>>Renewable Energy Systems
>>NABCEP Certified PV Installer
>>987 Wanamaker Rd,
>>Coupeville, WA 98239
>>PH & FAX 360-678-7131
>>sunwind at whidbeysunwind.com
>
>
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-- 
~~~~~~~~~~~~~
Jeff Clearwater
Village Power Design
Sustainable Energy & Water Solutions for Home & Village
http://www.villagepower.com
gosolar at villagepower.com
NABCEP (tm) Certified Solar PV Installer

530-470-9166
877-SOLARVillage
877-765-2784
72 Baker Rd.
Shutesbury, MA 01072
425 Nimrod St.
Nevada City, CA 95959
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