Travis: This is the classic “repowering” dilemma. Low voltage string wiring versus new 1000 or 1500 VDC inverters.
We used CPS 60 K inverters and bypassed the on-board combiner. The CP60 will operate at lower string voltages. The inverters are operating somewhat outside the most efficient parameters but the system is working reliably. Here is a link to the case study: https://millersolar.com/MillerSolar/case_studies/30-Re-Powering/re-powering.html Good luck. William Miller Miller Solar.com 805-438-5600 www.millersolar.com On Mon, Feb 23, 2026 at 11:42 AM Travis Knipple via RE-wrenches < [email protected]> wrote: > Hi wrenches, > I've got a service call that needs a ~50kVA inverter, 3 phase (could be > 208 or 480) > I'm replacing an older system, and the existing stringing is set up with: > 3 strings, with each strings calculations ending up at: > ~359Vmp (Hottest Conditions) > -510Voc (Cold) > 40A Imp, 42.8A Isc > > So, I'm hitting 2 issues: > (A) Vmp too low for many newer inverters > (B) Newer inverters want to land each string individually, and this system > merged the strings in DC Cominers at the array, so I would prefer to give > the 40A input to 1 terminal if possible to avoid a 300' repull. (I have 3 > pairs of #4, and would have to repull 15 pairs of #10. It's possible, but > not preferred) > > If anyone has a brand of inverters I should investigate that may work, > please let me know. > Thanks, > Travis > > -- > Travis Knipple > Senior Engineer > Hudson Solar Solutions LLC > Rhinebeck, NY 12572 > 518-539-8040 x408 | [email protected] > > PVIP# PV-111821-013612 > > > _______________________________________________ > List sponsored by Redwood Alliance > > Pay optional member dues here: http://re-wrenches.org > > List Address: [email protected] > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > There are two list archives for searching. When one doesn't work, try the > other: > https://www.mail-archive.com/[email protected]/ > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org > > List rules & etiquette: > http://www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > http://www.members.re-wrenches.org > >
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