Schneider WX-6848 Grid support

shawnj72

Hello It has been a while since i have visited.. Due to unforeseen circumstances it has taken this long to get the PV array up due to chronic health. so here is the question XW-6848 two PV arrays 15x305w x 2 60-150 controllers. 805AH batteries. trying to dial it in i noticed it still pulls 200-300 watts from the grid at all times even though it produces enough energy.. Actually more than is needed. I sized it acordings to charging capacity  it trickels till there is enough sun and does a good job charging in a short time. then the controllers trickel down acording to usage and just curious why it still pulls from the grid. I cannot sell back as UPPCO caped it years ago @ 1 or 2 % so no more selling.. wonder if it is just the nature to still run 2 300 watts to keep the inverter qualifying or there is a setting.. Was thinking a transfer switch with a timmer or plc to disconnect after battery charging to cut down on grid usage.. just curious if i am doing something wrong.. or a setting.. Regards..

BB.

I will bump your post here...

I don't have any good answers (I don't have the experience)--But older systems don't seem to have the ability to give "true" zero backfeed to the utility grid. They just were not designed for that....

For XW systems... There are a ton of settings (not all on "one screen"?) that can affect the daytime load on the grid. But that "true zero" daytime draw (and zero backfeed) has been a request that many have asked for other the years (for exactly the same reasons--Utility pressure for zero "selling" of power to the grid).

Maybe somebody here can give you better answers than installing a utility cutoff switch (battery bank at ~100% charge, solar panels carry home load during sunny weather)--I think folks have done that over the years--But exactly what are you looking for?

Do you want zero battery cycling (i.e., solar supports home loads during the day, grid supports home loads at night)? The zero battery cycling can extend bank life (there can be issues--For example, standard deep cycle lead acid batteries do like "cycling" maybe to 75% of capacity at least once a month vs sitting at "float" most of the time--Lithium Ion batteries can sit at near full charge for years without issue).

Or do you want to cycle the batteries (discharge at night, charging during day) and just use the grid like a "backup Genset" (periods of bad weather for example)... For FLA batteries--The cycling of the batteries daily may make your total solar power costs higher than just running from utility power (i.e., change a FLA battery bank every ~7 years could lead to $1.00 to $2.00+ per kWH when all costs are rolled in; initial system cost, battery replacement, eventual electronics replacements after 10+ years, your time and energy to keep system running for 25+ years, etc.)... Vs just having a backup genset (say propane if you use for cooking/heating/hot water).... Only runs if you lose power (can be common in more remote areas).

Anyway... Some thoughts and questions.

-Bill

shawnj72

Bill Thanks a bunch for your Input.. All I really found was this..

"In grid support mode, the Conext XW+ supports the utility grid by limiting the

power drawn from the utility to close to zero. This mode is desirable for using
excess energy from auxiliary DC sources like PV, while still maintaining a

charged battery bank. No power is sold to the utility in this mode."

"Note: In grid support mode, the Conext XW+ should not draw a large amount
of current from the grid. If the Conext XW+ is drawing more than expected, it is
important to note that it cannot distinguish between real power and reactive
power. Large current draw will only affect reactive power and not real power,
and utility companies generally only charge by real power consumed."

While it didnt give a number it is always between 200-300 watts. but I'm sure that is required to keep the grid qualified. Its not a big deal but was hoping for zero but know in this mode it is what it is.. While on sunny days I can produce 4 times what i use I had to size it for battery charging.. I wanted to be able to charge in the 4 hours if i used battery capacity for the next day. Everything seems to work according to plan since the power company has a minimum anyway it isn't that big of an issue.. I didn't want to use the batteries overnight unless I absolutely had to just for the reason you mentioned.. the cost of replacing batteries is what deter from using it as the way mentioned. I do see times where it draws some from the battery and think it supplements. In the early morning. I have no grid charging from 6am to 12am or something like that so it wont charge from the grid but from the pv only.. unsure when or why the slight draw but see it early morning after 6 draw 200-300watts before the sun comes up and before the bulk charge starts.. it draws down roughly 2-5% hardly a real cycle. so it is fully charged less then an hr before throttling down as hard to get wife and kids to eat cook chores laundry ect while the power is free. might be installing timers on circuits and then maybe they will get the point.. haha.. :-) I know there is many settings just working on grasping eash one.. but so far things seem to work as good as i can expect..

Dave Angelini

Think of it as supporting the grid but not to the point of selling to the grid. The small load is there to make sure that you do not sell.
 The next generation of XW fixed this issue BTW.

shawnj72

Yes I saw that a year or so that My model was discontinued.. all and all knowing the annonyance everything seams to work as it should..