Back to Winter Mode for my DIY ESS - Energy Storage System at Home making the best out of TOU rate

We are slowly entering winter here with pretty low temperatures in Paris, also the sun is lower and lower, allowing less and less solar production during the day, especially with grey clouds covering it sometimes all day long ....



So since last night, my DIY ESS goes back to its "Winter Mode", meaning it charges the battery pack at night, using half priced grid electricity - TOU plan -, and re-uses it through out the day



On the Power graph above, you can see that after the water heater has stopped at 00:30AM, the chargers continue to use 350W (limited to 4 chargers on purpose) until the electricity goes back to day rateat 6:24AM - and it started at 10:24PM the day before -

Follow my Live Power Usage and Generation with Solar and the DIY ESS



This is possible thanks to the Forced Charge Mode implemented in the Arduino program running my Home Energy Storage System




More on Forced Charge Mode on the DIY ESS Kit Website

DIY ESS Kit - General Presentation

After a year of successful Energy Storage at home, here is my very first Presentation of the system I designed from ground up ...



Here are the slide I made and commented for this video:















Visit my dedicated website here: http://www.diyesskit.com

Winter: Charging during the night, using the Stored Energy from the ESSand Solar during the day

Winter: Charging during the night - off peak rate TOU -, and using the Stored Energy from the ESS and Solar during the day to shave peaks and compensate home usage as much as possible 

DIY ESS - First Full Night of Forced Charge Mode and the next day

After moving the ESS, now in the living room, we were ready to use the Forced Charge Mode all night long for the first time

Right after a good movie with the kids



Nikita: Always good to watch a good Luc Besson movie

At 10:30PM, when the low rate period starts, I just pushed the Control Board pushbutton for 4 seconds and the ESS went into Forced Charge Mode, switching all the Chargers on 

As you can see on the graph, after the water heater is done, only the ESS is on and using around 500W and was shut down at 6:30AM, end of the low rate period, using a regular AC timer, as the battery pack was almost full, its voltage showing 26.7V

Sunday morning, with a full pack the ESS helped a lot with the heating (Daikin heat pump),  breakfast, etc all along the morning and some lunch

This is the overview at the end of the day: We covered quite a bit of our Usage with the ESS and the Solar (sunny day for once)

And tonight, I will switch the ESS to Forced Charge Mode again ... in one hour exactly, before going to bed 

DIY ESS - We're moving !

Like I was writing few days ago, we are going deeper into fall and the temperature is decreasing rapidly here in Paris; It is the perfect time to go ahead and move the ESS upstairs, from our bedroom to the living/dining room, to be able to use the Forced Charge Mode at night, when electricity from the grid is cheaper thanks to our TOU (Time Of Use) plan. 

I had planned this move several weeks before, and yesterday was the right time to do this because we started using the heating again (Daikin heat pump) after several months of no use at all: The only very heaving stuff is the battery pack, and it is easy to break it into several pieces

First thing: Switch everything off: the Main Control Board Switch, then the AC breakers and the Battery Pack DC Breaker 

So here I started unscrewing the battery pack terminals and removing the cells two by two

The modified Wattson is also unplugged from the Control Board and removed from the top of the metal cabinet 

All the CALB CA180FI cells have been removed from the cabinet and moved two by two upstairs

Then, the biggest part: the cabinet is moved with all the rest in it: Chargers, Control Board, Grid Tie Inverters and Cables; the ESS is installed in the living/dining room here on top of the stairs

I left the cells in the exact same configuration and asked the kids to stay away from them (!!)

During the moving some items moved a bit and I had to rearrange them 

Now I am putting the batteries back where they were ...

Et voila !

The modified Wattson has been plugged back into the Control Board, and the second one is still displaying the Generated Power

After switching back to on the Battery Pack DC Breaker, the Control Board is now energized again, and I switch on its Main switch: The Arduino board is powered and goes through its initializing sequence, the ESS is now fully on and in Charge Mode

Everything works as usual, and the first charger is switched on by the first AC relay, controlled by the Arduino board 

A little view from the back, and the modified Wattson displays a blue Color Code, meaning the NEt Usage is Low ... perfect ! 

Keep it blue :-)

All the AC lines have been plugged back: GTI side going the Solar junction box like before, and Charger side going to any outlet of the house 

Working well: Solar + ESS = 777W  /  Net Usage = 115W

Another shot to see the kitchen in the background

Solar + ESS = 895W  /  Net Usage = 34W

Solar + ESS = 907W  /  Net Usage = 5W

Graphs for the day:
Power


Energy

DIY ESS - Solar & Energy Storage under Grey Sky ...

We always see pictures and videos of Solar panels under a great sunshine, but to tell the truth, it is not always like this ...

Here are Energy Monitors, Graphs, Pictures and Video of the bare reality of what happens when the sun is hiding

Sometimes the solar generation is rather low - with my 1000W solar install - but still something is coming out of it steadily during the day; Now fall is here, sun starts producing around 9AM instead of 7AM, but around 200-250W all day long when the sky is grey

Fo rnow, no heating is required yet, and the ESS I built is doing the job: Capturing any excess/surplus of power into the Battery pack for later use and always keep the Net Usage (= Usage - Generation) as close to 0W as possible

Whenever a washing machine water heating cycle comes on, the ESS stops charging the Battery pack and uses the Energy saved in it to push it back into our home grid, reducing the usage from the utility company. It is really a Peak Shaving device  

As you can see, the ESS keeps the Net Usage around 0W; That's the yellow line on these graphs

Here we can see that the early morning consumption is not covered by the ESS anymore like it used to be during summer : The Battery pack voltage is too low and no Power will be drawn from it until it reaches a certain level with Solar; Also, at night, the sun setting earlier, I often see the SMA inverter quit around 6PM now especially when grey, and the ESS quicks in right away to supply all the household Power for lights, TV, computer, etc ... until the Battery is back to low and the ESS then quits too - If sunny the whole evening usage can usually be covered - 

When Power is required, the ESS switches from Charge Mode to Grid Tie Inverter Mode to help supply this additional Watts to our home

This video shows an example of power pushed by the ESS into our home while cooking lunch

As we go deeper into fall and heating will soon be on during the day, I think I will use the Forced Charge Mode on the ESS to start charging during off peak hours (TOU), at night, and start the day with a Fully charged Battery pack, ready to crush it !  :-)