Path: ...!Xl.tags.giganews.com!local-2.nntp.ord.giganews.com!nntp.supernews.com!news.supernews.com.POSTED!not-for-mail NNTP-Posting-Date: Fri, 31 May 2024 21:15:41 +0000 From: boB Newsgroups: sci.electronics.design Subject: Re: Solar panels Date: Fri, 31 May 2024 14:15:40 -0700 Message-ID: <17fk5jpefj1432ek1knnq165nj12gah43g@4ax.com> References: User-Agent: ForteAgent/8.00.32.1272 MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit Lines: 38 X-Trace: sv3-DxRfIQVZJEhOTHBg63lQhmCuZCrYftYl27z7hWvlZgj9M5ktbv2UF/OcLDrWO+32I6EpIy9UCSSKCTY!yFh+AjxqEW1kdziYJUid7NUYXZB9FrHrNkR+r18TlVIP9lLAr5VNFI/2dXb2vLULLHQrjMUQ1HFZ!TKOwyXNS X-Complaints-To: www.supernews.com/docs/abuse.html X-DMCA-Complaints-To: www.supernews.com/docs/dmca.html X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly X-Postfilter: 1.3.40 Bytes: 2419 On Fri, 31 May 2024 13:50:41 -0700, Don Y wrote: >On 5/31/2024 1:43 PM, Don Y wrote: >> On 5/31/2024 12:56 PM, KevinJ93 wrote: >>> On 5/30/24 10:00 PM, Don Y wrote: >>>> But, the individual wafers (on a panel) are probably wired in a >>>> series-parallel configuration with a nominal 48VDC output. >>> >>> Not usually true - I don't know of any panels where there is a >>> series-parallel configuration. As wafer sizes increase the panel current >>> increases. >> >> I count ~72 wafers on a panel I have here.  How does *it* get to a 48V >> nominal output? > >Ah! Each *wafer* is a *single* PV cell? The metalization layers led me >to think each was *three* cells (~2V output) series connected. > 72 cells is a common PV module (panel) configuration. So is 60 cells. An MPPT charger is usually a buck converter so that's how it gets there. A nominal 48V PV array will need to have a higher Vmp than the battery voltage to charge that battery bank. Sounds like Kevin knows his stuff regarding this and you aren't far off, if at all. Rapid Shutdown requires the array at the string (HV) inverter or charge controller input to be at or below 30V in 30 seconds after its clear to go signal is removed. At least those who are being inspected to NEC. boB