[RE-wrenches] Sunny Boy Time Bomb

[William Miller]

Friends:

There appears to be a generic problem cropping up with older Sunny Boy 
inverters.  Here is the scenario and what I have learned so far:

I have a commercial Sunny Boy based client (reportedly the first solar 
powered cinema in the US) that has reported a curious problem for the past 
few months:  The E-total all of a sudden went negative.  This is tallied 
with a SB Control Light with power line communications equipment.  We have 
experienced some communications problems and are preparing to upgrade to 
RS485 protocol.  Because of these communication problems, I disregarded the 
problem.

I received a call from an early adopter residential customer two days ago 
reporting the same problem.  I investigated further and the problem with 
the commercial installation is not related to the communications.  All 
inverters that are reporting exhibit the negative sign on E-total.  If you 
watch the E-total it is slowly decreasing at the rate of production.

SMA Tech support first claimed this as an anomaly that required a firmware 
upgrade to repair.  This upgrade necessitated ordering a replacement 
refurbished inverter at $360.00 each.

When pressed, SMA now tells me this is a problem endemic to Sunny Boy SWR 
series inverters.  Apparently, when the E-total reaches a certain value, 
the inverter can't count any higher.  It inserts a negative sign and counts 
backwards.

This problem does not appear to affect production.  This is not a problem 
if you don't have a display or if you don't look at your display.  This is 
a problem if you are relying on the e-total value for any reason.  This is 
a major problem if you have a lobby or web display and many people are 
viewing the results.

Have any of you experienced this problem?

Thanks in advance for sharing your information.


William Miller

If you have questions, I will answer next week, after vacation.

wm



William Miller
Miller Solar
Voice :805-438-5600
email: william at millersolar.com
http://millersolar.com
License No. C-10-773985
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