Misleading fault indications [RE-wrenches]

[Blair May]

OK BOYS back into yer corners!

Sent via BlackBerry by AT&T



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

From: Mark Edmunds <mark.edmunds at xantrex.com>



Date: Fri, 29 Feb 2008 16:59:48 

To:RE-wrenches at topica.com

Subject: RE: Misleading fault indications [RE-wrenches]







Wrenches,



I just saw this post, and it is truly flattering when a competitor tries

to call out your products with nebulous and unsubstantiated FUD (fear,

uncertainty, and doubt). So a few responses to the points raised: 



<<Using a fuse type GF protection system in a battery-less grid-tie 

inverter is reasonable to me >>

 

On this we can agree.  Xantrex alone has over 45,000 GT's fielded

worldwide and yes...the fused approach works for us, is code and UL

compliant, and also works for other volume players like SMA. We are

really happy that Outback views this as reasonable.  The whole grid tie

inverter industry is breathing a collective sigh of relief.  



 

<<If you want to talk about a real significant design problem - take a 

look at the fuse based GFP used on the Xantrex charge controller - if 

you have a low resistance ground fault from the DC negative to the 

grounding system it will not detect it - even though the GF fuse 

blows... which is not detected by the controller since the DC negative 

and ground are still connected. The PV array will still continue to 

produce power and the controller does not indicate a fault has occurred.



This does not meet the requirements of the UL1741 standard or the NEC in



my opinion.>>

 



Obviously this should be taken with a grain of salt.  Like we all

know...this is from a competitor serving their own objectives.  



Our fused GF detection approach is absolutely UL1741 compliant and,

similar to battery-less GT's, it does meet the spirit and intent of the

NEC.



Also, despite what Outback might want you to believe...virtually any

kind of fault with the XW charge controller will flag a fault indication

on the controller display AND on the system control panel.  In Xantrex's

opinion, you are far more likely to notice a message on your main system

display than noticing the position of a circuit breaker handle. Any

controller fault or even complete failure would cause it to disconnect

from the system and stop charging, along with the fuse clearing any

actual ground fault that might exist.  



Here are some additional thoughts that may lead you to question why

Outback is resorting to FUD to retain market share.

 



XW Charge Controller benefits:



-      Dynamic maximum power point tracking with no mini or full sweeps,

provides better energy harvest, especially in highly transient

conditions (sunny days with big fluffy clouds). Grid tie inverters

require a dynamic and accurate MPPT routine, why would anyone accept

less with a battery based system?



-      Convection cooled without sacrificing thermal performance.  Our

tests show that our thermal performance is better (full output current

to 45 C/ 113 F) while eliminating the possibility of fans failing.



-      Standard 5 year warranty with an option to upgrade to 10 years.

Outback only offers their optional 10 year warranty for California

Grid-Tie customers, since as Outback stated in a previous post,

"typically do not get the abuse that we see in the off-grid

applications". Xantrex optional XW Series Extended Warranty, which adds

5 years to provide 10 years total of warranty coverage is not specific

to California grid-tie customers. All installations within Canada or the

United States qualify, regardless whether they are off-grid or grid-tie.



-      Xanbus(tm) Network Enabled out-of-the-box. This means you don't

need to buy an Outback Hub ($195 MSRP ) or Mate ($295 MSRP) to get

charge controllers to share information, synchronize charging and

provide aggregated user level information. Again, saving installation

complexity and costs. 



-      Bundled battery temperature sensor; saves $29 (MSRP) as you don't

have to buy it separately as you do from Outback.



-      Built in PVGFP. This saves having to install the Outback breaker

approach saving $129 MSRP .  Since Outback has told you this is

wrong...is good for us.  I am guessing we will continue to have this

advantage since they can't go back now and rethink a safe and lower cost

fused approach.



 



Thanks for listening,



Mark





Mark Edmunds

Director Engineering

Residential Renewable Energy Group

Xantrex Technology Inc.





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

From: Christopher Freitas --- OutBack Power

[mailto:cfreitas at outbackpower.com] 

Sent: Friday, February 29, 2008 9:21 AM

To: RE-wrenches at topica.com

Subject: RE: Misleading fault indications [RE-wrenches]







-------------



If you want to talk about a real significant design ...





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