Hi William, The 5200TL has two independent MPPT zones, each with two string inputs (essentially a two string combiner on each MPPT zone). The 'combiners' can't be bypassed at the moment, and the max fuse size that is allowed is 20A. Sorry, but fuses greater than 20A are not allowed; they would violate our compliance to our product listing.
Also, please be aware that the MPPT zones can't be configured to act as a single zone. Any one zone will input limit at 70% of the inverter's nameplate output, and the two zones together will limit when the inverter's AC output is reached. So, for the 5200TL, one zone is allowed to have a max input of 3640W, while the other zone will have the balance to achieve 5200W on the output side. In other words, in your example of only two strings, don't put both of your strings on one MPPT zone, because you will limit that MPPT zone and your output will only be around 3.6kW. I hope this is helpful. Let me know if I am not understanding your example correctly. Best, Mike From: RE-wrenches [mailto:[email protected]] On Behalf Of William Miller Sent: Monday, October 6, 2014 18:27 To: 'RE-wrenches' Subject: Re: [RE-wrenches] TL inverter with long DC Feeder Mike: If I have just two strings of Solarworld SW275 modules per inverter, can I use one input to the built-in combiner to feed in a combined string? My calculations indicate that I might be able to feed the two strings into one 25 amp KLKD fuse. The Isc is 8.94. times 1.25 = 11.715. Times 2 = 22.35. The manual says use of any fuse higher than 20 amps voids the warranty. Could an exception be made if only one set of 25 amp fuses were installed? William PS: I am not sure fuses are required in a combiner with just two strings. The SW275 module can withstand 16 amp external feed (from the max fuse rating). A parallel module will output 8.94 times 1.56 or 13.95. This is less than the 16 amps. This used to be allowed in earlier versions of the code, I will have to look and see if it still is. Wm [Gradient Cap_mini] Lic 773985 millersolar.com<http://www.millersolar.com/> 805-438-5600 From: RE-wrenches [mailto:[email protected]] On Behalf Of Michael Kelly Sent: Monday, October 06, 2014 3:10 PM To: RE-wrenches Subject: Re: [RE-wrenches] TL inverter with long DC Feeder Hi William, I wanted to let you know that currently, there is no bypass terminal to allow for combining at the array in this series of inverters. We have gotten a lot of feedback from customers that this is a required feature. Working toward that, in the next few months, we will phase into production an update that will include a bypass, but the existing stock does not have the feature. I wanted to let you know so you could plan appropriately. Best, Mike Michael Kelly [Solectria_Yaskawa_signature_logo]<http://www.solectria.com/> HQ: 360 Merrimack Street, Bldg 9, Fl 2, Entrance I, Lawrence, MA 01843 USA O: +1 978-683-9700 x167 | F: +1 978-683-9702 [email protected]<mailto:[email protected]> | www.solectria.com<http://www.solectria.com/> NOTICE: This e-mail may contain confidential and/or privileged information. If you are not the intended recipient, or an authorized representative of the recipient, please be advised that you may not use, copy or disclose its contents in part or in whole. If you have received this message in error, please advise the sender by replying to this e-mail, and delete the message. Thank you. From: RE-wrenches [mailto:[email protected]] On Behalf Of William Miller Sent: Monday, October 6, 2014 14:40 To: RE-wrenches Subject: [RE-wrenches] TL inverter with long DC Feeder Wrenches: We are getting up to speed on using transformer-less inverters. I have advocated long for the additional safety offered by these inverters but I am realizing the trade-offs with the new technology: The implementation gets more complicated with the requirement for PV wire, OCPD and disconnecting means for plus and minus and plus providing Arc Flash rated equipment. I am currently designing a system that will locate the PV about 400 feet from the residence. The system will utilize 2 Solectria 5200 watt inverters at the residence. I would like to provide disconnecting means for the 4 strings at the array, in case of any needed service or excavating. Preferably I'd like the disconnecting means to be deployable by a lay person (i.e. the gardener). Finding an 8 pole, arc flash, 600 VDC rated disconnect is not easy. I could install an Outback 8 circuit combiner with 8 touch-safe fuse holders. The new combiners have had dead-fronts for a while now. The gardener needs only to have a Philips screw driver to open this cover. Any better ideas out there? Thanks, William [Gradient Cap_mini] Lic 773985 millersolar.com<http://www.millersolar.com/> 805-438-5600
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