[RE-wrenches] [!! SPAM] Re: SMA electrical noise?

[Dave Palumbo]

Christopher,

OCV calculation 37.0v + (37 x .0035 x 56) x 12 = 531 volts Maximum system
voltage

Schuco MPE 230 PS09 modules 29.81Vmp, 7.69 Imp, 37.0 Voc, 8.43 Isc

3 strings of 12 for 8,280 Watts into SB800US 240v inverter

SMA Sunny Design:
- nominal power ratio 104% good
- String MPP Voltage at 15C 370 V   good
- String MPP Voltage at 50C 326 V   good
- String MPP Voltage at 70C 301 V    OK conditionally

says OK "as long as grid voltage is not too high".

I have an almost identically designed system (modules are 225W not 230W) in
for one year with no problems. Admittedly, grid voltage would be a variable.

Note: Hot temperatures have not been an issue here since system was
installed. Dusk and dawn, when problem occurs, we've been seeing temps from
25 to 55 degrees F.

Dave



-----Original Message-----
From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Christopher
Warfel
Sent: Friday, October 28, 2011 9:32 AM
To: RE-wrenches
Subject: [!! SPAM] Re: [RE-wrenches] SMA electrical noise?

Check array open circuit voltage calculation?

On 10/28/2011 8:46 AM, Dave Palumbo wrote:
>
> Wrenches,
>
> This is a new one on me. Any ideas of what may be happening?
>
> In a follow up she said it happens every day. System was installed two 
> months ago. SB8000US inverter 8.28kW array.
>
> << Dave
>
> We are experiencing electrical noise at dawn and dusk. The power back 
> ups for our computers start beeping, going off and on, and finally 
> causing the computers to shut down. This is probably not good for the 
> computers. Is this something you are aware of in these systems?
>
> Can you give us some advice or perhaps come over to check into it?
>
> Like I said, at dawn and dusk, just when the sun is changing intensity. >>
>
> David Palumbo
>
> Independent Power LLC
>
> 462 Solar Way Drive
>
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>
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>
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>
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>
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>
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-- 

Christopher Warfel, P.E.
ENTECH Engineering, Inc.
Energy Utilization Experts
(401)466-8978

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