[RE-wrenches] PV harvest in grid-tied systems

[Bill Loesch]

David,

What did you choose for revenue-grade monitoring?

Comments?

Bill Loesch
Solar 1 - Saint Louis Solar
314 631 1094


On 18-Apr-12 4:01 AM, David Katz wrote:
> William
> I have a grid tie system with a Outback Radian and Xantrex 600 volt charge controller with 4kw of modules and it sells back flawlessly.  I have revenue-grade monitoring on the system and I am very happy with the output.
> David Katz
>
> Sent from my iPhone
>
> On Apr 16, 2012, at 6:51 AM, "William Miller"<william at millersolar.com>  wrote:
>
>> Friends:
>>
>> There has been recent discussion on this forum about PV production in
>> grid-tied with battery systems.  I have been faced with this same problem
>> in a 3 XW system installed in 2009.
>>
>> The customer's power bill never went down.  PV harvest was abysmal.  The
>> system would create great short circuit current but would not harvest into
>> the batteries.
>>
>> It is starting to appear the XW firmware was at fault.  The inverters would
>> charge the batteries too high so the charge controllers would back
>> off.  Upgraded firmware seems to be helping, but the data set is still limited.
>>
>> Remember this:  just because a PV system can produce does not mean it
>> will.  The charge controller knows only one thing:  battery voltage.  If it
>> is high, production is curtailed.
>>
>> Off-grid production will also be reduced is consumption is curtailed.
>>
>> Charge controllers that can be set for grid-tied applications help, but
>> only if the inverter(s) do not keep the battery voltage too high.
>>
>> William Miller
>>
>>
>> Miller Solar
>> Voice :805-438-5600
>> email: william at millersolar.com
>> http://millersolar.com
>> License No. C-10-773985
>>
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