[RE-wrenches] Conext XW+ always feeding critical loads subpanel from battery bank

Maverick Brown maverick at mavericksolar.com
Mon Jul 18 17:27:11 PDT 2016


Dan

Barring some non-factory-default settings, they are not likely running on battery power at night. 

When the grid is up, the inverter will go silent at night (asleep) [with --- three dashes on its LED display]. That's good. 

During the day, the inverter will "prevent" the battery voltage from going above its sell voltage (unless some other mode is on like Grid Support or Standby, etc.) The charge controllers will attempt to Absorb & Float, but the inverter will offload the energy by keeping the voltage at the Sell setting. I generally set Sell to the recommended Float Voltage++. I set the charge controller float to 1.0v higher and Absorb as appropriate. 

There is a lot more to unpack here. 

Flooded batteries will consume a good amount of power just to maintain float. 

As a defense against sulphated plates forming, I program the inverter EQ button for a heavy Absorb / mild EQ and instruct the customer to press it (every other month opposite month from watering??)

Are you getting 20-25 kWh per day in production?

PS having the inverter always feed the critical loads panel is exactly it's intended use. 

Thank you,

Maverick


Maverick Brown

Maverick Solar Enterprises, Inc.
SunFlow Systems
Office:     512-919-4493
Cell:        512-460-9825

Sent from an iPhone. 

> On Jul 18, 2016, at 6:50 PM, Dan Fink <danbob88 at gmail.com> wrote:
> 
> Maverick; it's 6.0 kW of PV, 2 Midnite Classic 200s, Conext XW+ 5548, and 8 Crown Embassy VRSLA 6CEA390 for 390 amp-hours, 48v. Concerns me to be cycling those batteries every night when it's not supposed to happen as per the permit package.
> "Notes - Battery Backup: During an outage, an automatic transfer switch in the inverter opens the grid interconnect, isolating the inverter from the utility to prevent back-feeding the local power lines. The inverter then draws from the battery bank to provide AC power to the backup sub-panel. Battery power is only used to provide power to the backup sub-panel. The Battery inverter only sells energy to the grid from the solar array when available and not from the battery bank. The battery backup inverter is UL 1741 and IEEE 1547 compliant."
> 
> Dan Fink
> Adjunct Professor of Solar Energy Technology, Ecotech Institute
> IREC Certified Instructor™ for: 
> ~ PV Installation Professional
> ~ Small Wind Installer
> Executive Director, Buckville Energy
> NABCEP Registered Continuing Education Providers™
> 970.672.4342
> 
>  
> 
>> On Mon, Jul 18, 2016 at 5:23 PM, Maverick Brown <maverick at mavericksolar.com> wrote:
>> Dan
>> 
>> Does the inverter go silent at night? (---) on the inverter display?
>> 
>> There are lots of settings that can influence sell amount. 
>> 
>> What type and size is the battery bank? 
>> 
>> What is the solar size?
>> 
>> Thank you,
>> 
>> Maverick
>> Cell:        512-460-9825
>> 
>> Sent from an iPhone. 
>> 
>>> On Jul 18, 2016, at 5:56 PM, Dan Fink <danbob88 at gmail.com> wrote:
>>> 
>>> Installer went out of business, all I have to troubleshoot with is an as-built 3-line that "may or may not be right." The charge controllers are a pair Midnite Classic 200s. Customer complained that system selling only 2/3 of what was predicted back to the utility; that appears to be because everything out of his critical loads subpanel is running off the battery bank all night, every night, grid or no, so it takes 1/3 of the day to get the batteries charged up again every day and start selling to the grid.
>>> 
>>> I have very little experience with the XW+ thus my question for the folks here. My plan for next week is to show up, make my own as-built 3-line, and recommission the inverter. Anyone else seen this sort of thing before? Hard to believe that an electrician would mis-wire or not wire the bypass, I'm thinking software setting.
>>> 
>>> 
>>> Dan Fink
>>> Adjunct Professor of Solar Energy Technology, Ecotech Institute
>>> IREC Certified Instructor™ for: 
>>> ~ PV Installation Professional
>>> ~ Small Wind Installer
>>> Executive Director, Buckville Energy
>>> NABCEP Registered Continuing Education Providers™
>>> 970.672.4342
>>> 
>>>  
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