String sizing Question [RE-wrenches]

[Bruce Roush]

Allan-
The figures used by BP are from 1/2 to 1% per year degradation. Of this 
power loss, 1/2 is voltage and 1/2 current.
Bruce Roush

Allan Sindelar wrote:
> 
> Referring to original post:
> > > Wrenches,
> > > Originally an off-grid system, then brought in grid, now new owner with
> > > different needs: Is there a batteryless grid-tied inverter that will
> work
> > > with ten BP275 75W 12V modules?
> > >
> 
> Michael, thank you. I was wrong, and you gave me reason to look at the 
> SB700
> more closely. I also spoke with Paul Mync at SMA tech support about 
> this,
> and it brings up a closely related question, which I am posting to this 
> list
> in hopes of a good answer.
> 
> The SB 700 in the 250V configuration is the better choice, as it has a 
> full
> 700W output and the same string sizing parameters. Using the online 
> string
> sizing, ten BP275 modules bumps up against the low-temperature max VOC 
> of
> 250 VDC at -4 degrees F. This is unlikely but possible at our 7,000'
> elevation in New Mexico.
> 
> What we both discussed is that the ten modules are 8 years in service. 
> We
> both understood that output degradation may be the factor that lets us 
> get
> away with this right-on-the-edge array low-temperature voltage. We also
> think we recall that output degradation happens as loss of voltage, more
> than as loss of current. If this is true, we should be OK. Can anyone 
> verify
> this, please?
> 
> Thanks again,
> Allan at Positive Energy
> 
> ----- Original Message ----- 
> From: "Michael Cook" <mike at powerupco.com>
> >
> > A SB700 in a 200V configuration seems to work.
> > >
> 


- - - -
To send a message: RE-wrenches at topica.com

Archive of previous messages: http://lists.topica.com/lists/RE-wrenches/read

List rules & how to change your email address: www.mrsharkey.com/wrenches/etiquette.php

Check out participant bios: www.mrsharkey.com/wrenches/

Hosted by Home Power magazine

Moderator: michael.welch at homepower.com
--^----------------------------------------------------------------
This email was sent to: michael.welch at homepower.com

EASY UNSUBSCRIBE click here: http://topica.com/u/?bz8Qcs.bz9JC9.bWljaGFl
Or send an email to: RE-wrenches-unsubscribe at topica.com

For Topica's complete suite of email marketing solutions visit:
http://www.topica.com/?p=TEXFOOTER
--^----------------------------------------------------------------