Grid Sell Update?

[aaapilot]

Any updates as to when Grid Sell capability will be released?  As the weather improves into spring, my Rosie array is producing more power than needed to supply loads and charge batteries.  I hate to waste Kilowatts that won't get produced because there's no place to send/use them

[boB]

I don't know when but it is, of course, just SMOP (Simple Matter Of Programming)

Actually it isn't quite that simple...  Add many 10s of thousands of dollars and time for mafia, I mean, NRTL testing and certification.

boB

[Wizbandit]

Yesterday I successfully tested the new SELL Code, it worked great but not until I found a big problem...

I have 600Ah of EG4 Lithium batteries on a stack of Rosies, when I tried the first test.app release Rosie would not stay connected to AC IN & sell, kept ramping up and bam, drop AC in.  Like most inverters I have setup to sell I want it to sell to the float setting which is 54V which is what the EG4 sheet says to use for float.  I blamed Rosie and reverted back to beta.app code to run in grid-support mode for now.

Move up to yesterday, chatting with Ryan and testing it was the Lithium battery's BMS's causing the problem or just the way Lithium batteries work in general.  Even though we have to use lead battery settings and terms (yes, Absorb is a lead term) you can make any charge controller charge a lithium battery.

My Barcelona and Hawkes Bay on this dual Rosie system would ramp up to the 56.4v absorb setting and BAM, when it hit the amps/watts would drop to Zero and the charge controllers would ramp back up and repeat.  This drop in power also caused the SUnny Island I was using to sell to drop off.

I watched the battery voltage during charging from 70% SOC and once the voltage got to 54v it stopped and no matter how much current was going in it would not move.  I had 160A going in and steady at 54v until the SOC got to like 98% then the voltage went up really fast to 56.x and that's when the Charge Controllers would stop pushing current and cause selling issues.

The fix was to set the Absorb time (another lead battery setting) to max which is 6 hrs with battery type Lithium and use ENDAMPS to go to FLOAT. The new MPPT's make good power in FLOAT and don't need to be in BULK to sell like the Classic does (engineering is working on new Classic Lithium code that will fix that).  The issue was it seems the BMS's would open to stop charge current at 56v and above and this was the problem.

SO I set ABSORB = 54.5 and FLOAT = 54.1 and Rosie SELL to 54v, ENDAMPS to 10A  It seems the EG4 will charge with absorb set to 54.5 and when the current drops to <10 it must be like 90% full which is fine for on grid.  Yesterday was a perfect day selling power to the Grid.  My RV on L1 of the stack would show only like -500w selling on that leg but -2Kw plus on L2 with Rosie-2 only selling when needed.  When not selling Rosie-2 would be in standby.  I think I peaked out at like 5Kw to 6Kw selling around 1PM.  After a week or so testing with no issues we will move this code to BETA.APP

[Wizbandit]

Lotsa nice GREEN on this...

[aaapilot]

Great news, Wizbandit!  Thanks to you all for working thru the many details to bring this important function to Rosie.  I have LOTS of kilowatts just waiting for their chance to flow backwards to my neighbors!!!

Dave