High Settlement Bill with Solar PV System and Battery Back Up

[Hedges]

Makes sense your PV production is middle of the day. Actually peaks earlier than noon, is it SSE oriented?
Since you've got a battery, what you may want to do is recharge while PV is producing, discharge into the grid while rates are high.

Should be able to do that even in excess of loads, so you get credit at higher rate.
I haven't figured out the settings yet. Which vary with firmware revision. I have to stop at 1.50 in SBS, to support Resu-10H. Yours would work with newer firmware.

How about reports from SBS? Mine has a graph showing SoC during any given day.

 

[hwy17]

I don't think the charts are incongruent, the difference between them is in the main panel loads.

Some cost optimization is available as Hedges is getting at, if you can get the battery to export discharge during 4-9pm and still only charge from solar. Currently the battery is discharging to serve the CLP load pretty much 24/7.

 

[macanchan]

Yes, it is South East facing... they actually couldn't fit all 16 panels on the SE side, so they split them 12 facing SE, and 4 facing East.

Here's a graph of the SBS SoC on the same day i posted earlier 11/17

 

[macanchan]

I run a pentair intelliflo 3 variable speed pool pump from 7am-4pm.

 

[Hedges]

Battery SoC is gently draining from 100% 4:00 PM to 60% at 7:00 AM when it starts to recharge.

Is discharge limited to feeding loads, or can it backfeed grid?
You want to discharge only 4:00 PM to 9:00 PM or whatever is peak. And discharge as much as possible, whether 40% to save power in case grid goes down, or 90%+ to maximize credits.

Discharge off-peak does nothing at all for you. Unless you don't have net metering, in which case SBS trying to zero both exports and imports works; that seems to be the default that mine came with.

Since you have a bill due at true-up, discharging more at peak rates should earn credits.

 

[reader2580]

My take away is that $1000 for a years worth of utility service isn’t bad at all.

My electric bill before solar was under $70 a month, and I don’t really skimp on using electricity. I currently have a credit of $400 after 11 months. I’ll get the utility to send me a check in March, and start over on the credits adding up.

I did solar more to use less fossil fuels than to save money. My ROI is probably 12+ years starting in 2018. It was mostly DIY.

 

[macanchan]

Battery SoC is gently draining from 100% 4:00 PM to 60% at 7:00 AM when it starts to recharge.

Is discharge limited to feeding loads, or can it backfeed grid?
You want to discharge only 4:00 PM to 9:00 PM or whatever is peak. And discharge as much as possible, whether 40% to save power in case grid goes down, or 90%+ to maximize credits.

Discharge off-peak does nothing at all for you. Unless you don't have net metering, in which case SBS trying to zero both exports and imports works; that seems to be the default that mine came with.

Since you have a bill due at true-up, discharging more at peak rates should earn credits.

I'm not sure about the battery backfeed to grid. Ill look into the SMA settings but I was never able to connect through the LG app and make and changes to the battery. LG customer service hasn't been helpful with this either.

I will look into limiting battery discharge at 9PM. Right now I think its set to be used until it hits 35%.

The first battery I had was a faulty Resu 10h that was drained to 0%. I had it replaced with the 16h due to supply issues with the 10h. it took about 6 months to get. The delivery driver told me they had a ton in their warehouse, not sure why I had to wait so long.

 

[Hedges]

It is SMA SBS not LG which implements rules for self consumption, peak shaving, or time shifting.

Did warranty replacement of 10h give you a 16h? Or did you have to pay something?
I picked up two 10h, listed on eBay by an e-waste recycler (so they made out like a bandit.) At least on S/N is recalled, so I look forward to a free replacement. These were new in the box.

An icon near top right of SBS screen (you can connect by WiFi or Ethernet) lets you set power profiles. I don't know exactly how yet, not doing what I want.

There is little documentation on programming and use. One document gives an example, although shows GUI different from mine.

 

[time2roll]

Here is the same day from SCE usage view



View attachment 197384

Yes shown here illustrates how TOU has changed to where you are selling into the super-off-peak rate and buying at the higher on-peak and off-peak rates. So you can produce more than you consume but still owe the electric company.

To really gain advantage the battery needs to come into the 8am hour fairly low and absorb all the solar it can through the 3pm hour.
4p to 9p you want to use all the battery you can and also export as much as possible from the battery.
Then overnight hold tight during minimal usage to save some power for the 6a to 7am power demand.

Basically need to figure out to pull in power at low cost and use or export during high cost time frame. Your system is doing the opposite.

I would guess the A/C is a non critical load so Aug-Sep the system would be using a ton of grid power during on-peak 4p to 9p time slot and really cranked up the expenses.

Sorry I don't know how to reconfigure your system to load shift the energy usage. May need 2x or 4x more battery to power the whole house including the A/C during on-peak time zone.

 

[Hedges]

16 kWh x $0.30/kWh spread x 30 days x 6 months = $864 possible bill savings by charging low, discharging high.
Almost enough to zero the true-up charge.

At least it isn't charging high. It is charging and discharging low, zero benefit.

 

[macanchan]

So I checked my SMA app today, nothing powered by the main panel is showing as consumption by solar PV.

My home on the subpanel/clp is getting 0.4kWh, battery is getting around 3.5kWh at 67% charge. Total Solar PV was providing 4kWh.

By 10:30AM the battery was 100% charged. 0.4kWh going to home, and 4kWH going to SCE's grid now.

My pool pump is running 1kWh is not showing up on SMA app as consumption.

Am I missing a sensor or connect for the main panel? Or is this an SMA parameter setup issue?

 

[Hedges]

I don't know yet.
I think it expects WattNode or similar with CT by utility meter. I dummied that up in my lab and it shaved import/export up to its discharge/charge limits.

It should be able to charge from PV exports (maybe PV production) and export into grid to earn credits.
The Profile options in my firmware version only seem to supply loads, not more to export.

Have you looked at the power profile settings on SBS GUI?
Here's what one of mine looks like. I intend it to discharge enough to support loads between 4:00 and 9:00 PM.
But somehow disabled at the moment.

 

[macanchan]

I'm using the plant setup assistant so it looks different from yours. I can select peak load shaving but have to change parameters on the control plan. Ill try connecting to the IP address when I get home

 

[macanchan]

Just spoke with SMA. They said the CT's cannot be on the main panel so the battery can only feed my subpanel/CLP. My only option is to move more breakers into the CLP (depending on the load)

They said everything looks good on their end and that the battery should never feed into utilities grid, if you want to go that route, you need to sign a waiver, etc.

SMA didn't want to go into peak load shaving, they said they'll send my installer a start-up guide.

 

[Hedges]

If that is the quick-start guide, it just says see performance profile document.

SMA - Customer Community

I'm not finding "Sunny Boy Storage US performance profile configuration" at the moment. I have it at home, and it just has 3 example pages for force charge from grid, charge from PV, shave peak consumption. Maybe those will work for you, but I'm not having success yet.

You do want to charge from PV off-peak and at the very least supply loads on-peak, preferably discharge into grid on-peak if utility allows. That's the whole point of Calif NEM 3.0 tariff offering high credits for backfeed during a couple evening hours.

 

[Hedges]

I've got mine doing most of what we want.

I set profiles for forced charging from grid Midnight to 3:00 PM



Discharging to support loads (any draw of 0W) but no charging (allow up to 500kW export) 4:00 PM to 9:00 PM


It wasn't working when Active Power Reduction at higher frequency was disabled,
now works with "Linear gradient".



For some reason, PC WiFi connection closed, and when reconnected it wasn't discharging into load any more.
Active power reduction for frequency still showed Linear. Kicking it (tried to turn it off) left it still enabled as Linear, and discharge again worked.
Maybe this thing resets itself sometimes.

Here charging from grid:



Here discharging to support load:



What the available options don't do is discharge to backfeed grid.
You will want that, to earn extra credits, unless you can fully discharge battery just supporting loads at peak times (of course you should try not to have loads then.)

 

[Hedges]

Told to discharge as needed to support loads only from 4:00 PM to 9:00 PM, it happily continued until 10:13 PM when I turned off the load.
Bug? Or do I have to enumerate all hours of the day because otherwise it has a default mode?

 

[Hedges]

I've got all the charge and discharge options working.

Problem I'm having now is "Active Power Limitation" keeps being shown as disabled (in that box of GUI with power transmission tower.)
In the Device Parameters tab, things related to that seem to be activated. If I edit and turn them off, then "Active Power Limitation" shows as enabled and it starts the feed-in or charge cycle it was supposed to. Just seems to turn itself off daily, until kicked.

[Edit, another problem. I told it to stop charging at 95%, stop discharging at 10%. It reached 4%, so I manually edited profile to stop.]

All hours of the day need to have a profile, or it returns to default peak shave, charge whenever export > 0W, discharge whenever import > 0W.

The Profile settings I use are:
Time of use, force charge from grid (700W, to gently recharge over many hours.)
Peak shaving, 500000W threshold before charge, 500000W before discharge, prevents either from occurring for some range of hours.
Peak shaving, 500000W threshold before charge, 0W threshold before discharge, feeds loads from battery during high rates.
Peak shaving, 500000W threshold before charge, -2000W before discharge, backfeeds grid with 2000W.

The trick is, GUI says 0W to 500000W. Parameter field goes red when negative number entered. But it works.

Try altering your profiles to not discharge during off-peak rates, and then either just support loads or export for higher credit during peak rates (and don't charge during peak, of course.)

 

[Hedges]

@macanchan - were you able to set performance profiles, so your battery can now shave your peak rate consumption rather than spinning its wheels without financial benefit?

I'm using the plant setup assistant so it looks different from yours. I can select peak load shaving but have to change parameters on the control plan. Ill try connecting to the IP address when I get home

Should be just a matter of setting parameters. Make enough profiles to cover all 24 hours in the day, preventing export during low rates and import during high rates.

 

[Hedges]

For about a week, my system charged each morning and discharged each evening as intended, not quite to 0% SoC.
Since then it has toggled every other day for the past two weeks. One days charges and discharges as intended. Next day it doesn't charge (except briefly just before time to discharge), and proceeds to discharge to zero. Following day it works correctly. Then incorrectly.

I'll update my support inquiry to SMA one of these days, focusing on this one issue.

One at a time. They denied it has Island Mode 60, say that's a Sunny Boy GT PV inverter mode. But I have a screen shot from their HECO documentation showing SBS with Island Mode 60.