[RE-wrenches] Tigo and SMA AFCI

Wed Jun 12 13:58:43 PDT 2013

Steve,

I might contact you off-line as it would be great to know what to expect before we do this install. 

My reason for posting on wrenches is so that this issue can come to light, so that other installers can get a "head's up", and/or so that other installers can provide their own feedback based on their experience.

My personal experience is that I have contacted SMA and Tigo, back and forth now for the past three days trying to get absolute confirmation. So far, I have yet to be able to get any resolute answers from either company.

In fact, one tech at SMA told me that Tigo is currently field-testing an SB4000TL inverter with Tigo optimizers and has experienced no problems so far. This was great news as my design-in-question is using two SB4000TL inverters with Tigos. When I spoke to a head tech at Tigo he said they indeed are field testing one SMA inverter but it is not an SB4000TL and it has only been in testing for a few months.

I was told that there was an AFCI issue, then that there wasn't. Some techs told me I would need to disable the AFCI. Others told me I wouldn't have to. I asked about MPPT struggling between the two tracking systems and couldn't get a firm answer. The last tech I spoke to at SMA, who was audibly conversing with others in the background, said that his engineers were telling him that they did not have definitive answers; that they haven't done enough testing to know for sure but that so far everything seems OK.

I always say a broken compass is worse than no compass at all. Techs giving out wrong information is bad for everyone involved. It would be better to be honest and say "we don't know for sure but we'll make our support and resources available to you while you test this configuration in the field"; kind of like Enphase did for us Beta testing installers back in 2008.

If what you say is true and there are no issues then that is great news but that's news that this installer will be taking with a grain of salt...and a shot of tequila.

Eric Stikes
SunHarvest
001.530.798.3738 (Cell)

  ----- Original Message ----- 
  From: Steve Jefferson 
  To: RE-wrenches 
  Sent: Wednesday, June 12, 2013 12:30 PM
  Subject: Re: [RE-wrenches] Tigo and SMA AFCI - Was: AC coupled, grid-tied Sunny Island - contactor & bypass

  Afternoon Wrenches,

  Sorry been out of the office for a week or so.

  Not sure where/who/how anyone commenting on this is getting their information but, there is no compatibility issue with SMA inverters and Tigo equipment.

  There is a FW patch that some of the Tigo need (older units) to be compatible with the AFCI function.

  Past that no issues.

  No inverters blowing up or anything dramatic like that, just a FW update, that's all.

  Please contact me offline if you have further questions.

  SMA America, LLC

  Steve Jefferson

  Supervisor, Service Line

  6020 West Oaks Blvd, Suite 300

  Rocklin, CA 95765 - 3714

  U.S.A.

  Tel:  +1 916 625 0870

  Fax: +1 916 624-2445

  Service Line +1 877 697 6283 (Toll Free)

  Email: steve.jefferson at sma-america.com

  www.SMA-America.com

  This email and any attachments thereto may contain SMA America, LLC confidential, privileged and private material for the sole use of the intended recipient. Any review, copying, or distribution of this email (or any attachments thereto) by others is strictly prohibited. If you are not the intended recipient, please contact the sender immediately and permanently delete the original and any copies of this email and any attachments thereto. Thank you.

  From: re-wrenches-bounces at lists.re-wrenches.org [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Ryan
  Sent: Wednesday, June 05, 2013 5:36 PM
  To: re-wrenches at lists.re-wrenches.org
  Subject: Re: [RE-wrenches] Tigo and SMA AFCI - Was: AC coupled, grid-tied Sunny Island - contactor & bypass

  From Robin

  It has been pointed out that the Tigo modules can and do blow up some charge controllers and inverters. When a charge controller or inverter has fairly fast tracking, the two units fight each other. We have found Classics using the fast tracking mode will blow up with Tigo's in the system. We also found that putting the Classic in the slower tracking mode, Legacy, solves the issue. We are aware that at least one major inverter model must defeat the tracking in order not to blow up. We have not yet tested our arc fault detectors with Tigo modules, but plan on doing this in the near future. It might be possible that the Tigo modules present a signature that looks like an arc. That must be what is happening with the SMA inverter. 

  Robin

  On 6/5/2013 3:33 PM, SunHarvest wrote:

    Just an FYI for anyone wanting to use Tigo optimizers with SMA inverters incorporating AFCI -

    According to SMA the Tigo optimizers will not operate with the SMA inverters. They didn't go into detail. They just said the AFCI feature of the Sunny Boy is not compatible with Tigo. After further discussion they acknowledged that disabling the AFCI feature in the Sunny Boy would allow compatibility with the Tigo optimizer. Awesome.

    After talking this over with Tigo they came to the same conclusion but neither company seemed too happy or confident in the marriage. Awesome.

    Eric Stikes
    SunHarvest

      ----- Original Message ----- 

Wrenches,Here's an update on this configuration (20kW Enphase, AC coupled to  Sunny Islands) you should know about: Enphase will not support and warranty the use of their micro inverters  in an AC-coupled installation with battery-based inverters. Enphase  approved this verbally with us in design, but balked when we asked  them to back it up in writing. Their issue/point is that AC-coupling   violates the UL1741 listing. Thus, we're revising the design to use Sunny Boy string inverters. Our  customer would still like the module-level monitoring and optimization  offered by the micro-inverters (there is some shading issue), so we're  considering using string optimizers. We have not used string- optimization, yet. It looks like the leading options are Solar Magic  and Tigo. Any preferences, cautions, or advice with choosing and using  optimizers would be appreciated. Thanks, -Kelly Kelly Keilwitz, P.E.PrincipalWhidbey Sun & WindRenewable Energy SystemsNABCEP Certified PV InstallerWA Electrical Administrator987 Wanamaker Rd.Coupeville, WA 98239kelly at whidbeysunwind.comPH & FAX: 360.678.7131

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