Watching the LiFePO4 DIY ESS Charge all day at home, from work, and back home

When my LiFePO4 DIY ESS battery pack is depleted, at 24V, the programmable voltmeter's low limit relay opens, the contactor opens, and the Grid Tie Inverter mode is shut off (low red led ON); This is what happended here

Immediately, the pack voltage goes back up and settles down around 25.4V

Now in the morning, for testing purposes, I siwthed the ESS to Forced Charge Mode, and all the chargers then are charging the battery pack

Since I can not stay all day next to it, I usually leave Karotz watch it for me and take a look remotely from time to time while away from home

08:20

At work 

10:07

11:31

16:34

it then continues and goes up pretty quickly after 27.5V to 28V where the upper limit voltage is reached and the programmable voltmeter opens its other relay, opening the charger side contactor, and terminating the charge completely

and the total Enegry used to charge fully the pack is 5kWh

DIY ESS - Watching the End of Charge Remotely with Karotz

After charging last night for several hours during off-peak hours, this morning I turned on the ESS and it went to GTI Mode during shower and breakfast

When I left home for work, and switched it to Forced Charge Mode and placed Karotz - rabbit webcam - in front of the voltmeter

The battery pack voltage climbed nicely all morning ...



until it reached the programmed charge voltage limit of 28V (3.5V per cell times 8 cells), as you can see the upper left red is ON, meaning the voltmeter relay opened and the Charge Contactor opened as well, and all the chargers stop

As a result, the pack voltage drops slowly to 26.6V (3.32V per cell times 8 cells), which is normal ...

After and hour or so, I still have the same pack voltage of 26.6V and it does not seem to move anymore at this point

Tonight, full discharge of the ESS battery pack in GTI Mode - Normal Automatic Mode -

LiFePO4 ESS Update - Daytime Charging OK for a week now

Starting last saturday, I now have been charging and discharging my LiFePO4 ESS for almost a full week

Saturday = Charging all day



Sunday = Discharging all day (with some pauses)

On Monday, I set up a timer to start and stop the charger automatically and leave it all day long while at work 

Starting on a timer at 07:30, the batteries are slowly charging (@ 10A) at home, during the day, until the charge is cut off at 17:40 to simulate the daytime charging it will do with the solar system in the future

Using Karotz as a webcam, I can watch my meters from work while or on my iPhone from anywhere

Arriving home, here is the situation: we are at the very end of the charge, the charger is pushing 1A only into the batteries and voltage showing 29V, the cut off is very near

Lowest capacity cells groups shwoing 3.93V and 3.91V are fine, and probably did not reach 4V

Total energy used to charge on monday = 3.3 kWh

Charger is pushing 1A only into the batteries and voltage showing 29V, the cut off is very near

and charger end of charge cut off has now happened: Ampmeter is reading 0A and voltage is slowly dropping from 29V

Charger LED2 is now green, meaning the charge is over (and it will not start again unless the AC side is cut off for 10 seconds, it is a security feature)

Wattson Pro graph for Monday: Charging 07:30-18:40 & Discharging 18:40-22:30 

The blue line represents the production from the BESPSS and is almost perfectly matching the usage (in red), unless too high (production maximum output is 1000W for now)



Tuesday: Charging 07:30-17:40 & Discharging 17:40-22:30



After that I moved Karotz to see the Ampmeter too

Reaching the end of the charge: Ampmeter showing 5A (half and going down) and voltage 28.6V


Timer cut off => Ampmeter is showing 0A and voltage is dropping

Wednesday: Charging 07:30-17:40 & Discharging 17:40-22:30








Thursday: Charging 07:30-17:40 & Discharging 17:40-auto cut off at 22:45

Overall I am very satisfied with this week of tests:

 - Charger work fine (long periods of charge and automatic cut off at the end of charge) and the batteries are now well balanced (no group of cells is going too high)

- Automated power output from the BESPSS is matching the home usage (as much as possible) and automatic cut off is working fine, protecting the battery bank from going to low in voltage

LiFePO4 ESS Update - No more computer needed

After several weeks of testing, I finally unplugged the computer from the Arduino board and my LiFePO4 ESS is now running in standalone



The laptop computer is gone ...

Arduino board and Relay activated outlets

Grid Tie Inverters stack and Generated Power (in Watts)

Karotz is watching Wattson :-)
I can see our home Net consumption it anytime through its webcam when I am not home or upstairs 

LiFePO4 Battery pack voltage and Wattson Energy Monitor showing Net consumption  

Cell level voltage watching & Arduino board unplugged (except for power from the micro USB connector)

And the Wattson Professional graph shows that it is working well, following the usage and trying to minimize it using battery stored energy whenever necessary (last long test was from 19:00 to 22:00)