[RE-wrenches] Enphase voltage out of range errors

William Miller william at millersolar.com
Tue Nov 27 12:05:11 PST 2012


Bill:

Good question.  I called Enphase back and they say it is definitely a 
hardware problem.  There are at least two registers that indicate AC line 
voltage and in this case they disagree, with VRMS indicating zero.  Enphase 
has advanced diagnostics they can call up on-line, apparently.

William



At 09:49 AM 11/27/2012, you wrote:
>William
>
>Double check your voltage drop on the AC branch circuits, and make sure 
>that you consider your wiring between inverters.  Remember that voltage 
>drop is additive and each inverter will see a slightly lower voltage drop 
>which could account for the voltage over error, especially if you are 
>seeing it at the end of the string.  Enphase does have a white paper on 
>that and they are now recommending splitting long strings int he middle to 
>make to branch circuits out of one now to alleviate this problem.  The 
>White Paper explains this in more detail.  There was also a Solar Pro 
>article describing how voltage drop can result in voltage rise at the 
>inverter, and I have seen and measured this with a meter.  Maybe the 
>inverters are correctly reporting the voltage rise?
>
>Bill




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