Controler

Base-Load Storage System (Meine Grundlast-Batterie)

The GLB (Grundlast-Batterie) is a smart battery system concept that is connected to your home grid and charges on cheap energy from home PV and feeds the home grid later. The concept is ideated some time ago when PV materials and solutions were very rare and expensive and less functional. Meanwhile commercial solutions for PV-Systems and stand-alone Base-Load storage batteries are available of the shelf for low cost and in case you need one a purchase is best option. This concept here is informational and educational purposes and does not generate a safe system you want to run live or un-supervised, please read the disclaimer and take it serious.

The repo contains: (10_System-Concept) System Notes and Drawings, Electrical Concepts, Datasheets (20_Battery) Just photos from my batteries, my notes are all on paper, but you find several good guides on homemade LeFePo4 Systems including BMS (30_EE-Design) place to collect EE design decisions, mostly also on paper and not digitalized (40_Controller-PCB) KiCad files for schematic and PCB (50_Controller-SW) Full software for the ESP8266-ESP12 using the Arduino Framework (60_Logging-Visualization) A setup to use a 24/7 home PC to store logs and visualize them with InfluxDB

The concept presented here covers the full system, means hardware and software. The central piece is the ESP8266 controller with power peripherals to drive to drive 2 chargers (AC-DC power supply units, PSUs) and 3 feeders (PV Inverters). The software switches the charging PSUs and grid-feed inverters, reads power levels from a Shelly3EM monitor, estimates and counts battery state of charge, and exposes a built-in web dashboard for status, configuration, and manual or timer-based control.

Disclaimer

This repository is a hobbyist project shared for informational and educational purposes only. It is not an official guide, does not constitute professional, electrical, or safety advice, and has not been certified or approved by any regulatory body.

Working with mains voltage, high-current batteries (e.g. LiFePO4 packs), chargers, and inverters is inherently dangerous and can result in electric shock, fire, injury, or death, as well as damage to property and equipment. By using, building, or adapting anything described in this repository, you do so entirely at your own risk.

• The author(s) and contributors provide this project "as is", without warranty of any kind, express or implied, including but not limited to fitness for a particular purpose, safety, or compliance with any code, standard, or regulation.
• The author(s) and contributors accept no liability or responsibility for any damage, injury, loss, or other consequence arising directly or indirectly from the use, misuse, or inability to use this project, its hardware designs, or its software.
• It is your responsibility to ensure that any build complies with the electrical codes, safety standards, and legal requirements applicable in your country/region, and to have any high-voltage or battery work reviewed/performed by a qualified professional where required.
• If you are not confident working with high voltage or high-energy battery systems, do not attempt to build or operate this system or similar derived systems.
• Any industrial and save product require much more design effort like functional safety assessments, failure analysis, deep testing, validation and much more. All this is neither done nor present in this repository material.

Features

• Relay control for 2 charger PSUs to provide different charging levels
• FET control of 3 feeding PV inverters to provide 3 power levels
• Battery state-of-charge estimation (voltage-based and coulomb-counting)
• Operation-mode state machine: deactivated, battery check, standby, charging (3 levels), feeding (3 levels)
• Web dashboard (served from flash, no external assets):
  • Header: uptime, date/time, heap usage, CPU load, operation mode, battery status, voltage, SoC, reboot button
  • Tabs: WLAN, Boot-Log, Error-Log, Running-Log, Clock, Manual Status, Timer Events, Rule Events
• WiFiManager captive portal for first-time WiFi setup — no WiFi credentials hardcoded in firmware
• OTA firmware updates via ArduinoOTA
• UDP syslog streaming for remote/centralized logging, in addition to the on-device log buffers
• Optional Shelly 3EM energy-meter polling for grid / inverter / charger power readings
• Timer-based operation events (up to 16 daily triggers)
• Config persisted to flash (LittleFS); exportable/importable as plain text via the web UI

Hardware / GPIO pinout

Target board: ESP12E (ESP8266). Pin assignments (see controller.cpp):

Getting started

Prerequisites

• PlatformIO (VS Code extension or CLI)

Build & flash

# First flash, over USB
pio run -e esp12e -t upload

# Subsequent updates, over WiFi (OTA)
pio run -e esp12e_ota -t upload

Before using the esp12e_ota environment, edit platformio.ini and set upload_port to your device's actual IP address, and change the --auth password to match the OTA password you configure in firmware (see Security notes below).

First boot / WiFi setup

On first boot (or after a WiFi reset), the device starts an access point named GLBattery. Connect to it with a phone or laptop, and a captive-portal page will let you pick your home WiFi network and enter its password. Credentials are saved by the ESP8266 SDK and reused automatically on subsequent boots.

To force the portal to reappear (e.g. to switch networks), use the reset button in the web UI's WLAN tab, which clears saved credentials and reboots.

Using the web UI

Once connected, find the device's IP from your router's DHCP client list (hostname defaults to GLB-2026, configurable), and open it in a browser. The dashboard header shows live status; the tabs give access to:

• WLAN — connection status, SSID, reset/reconfigure
• Boot-Log / Error-Log / Running-Log — on-device log buffers, refreshable
• Clock — NTP mode, server, and timezone offset
• Manual Status — direct operation-mode/level control
• Timer Events — up to 16 scheduled daily mode changes
• Rule Events — condition-based automation (see documentation)

Logging

Every log line is sent to Serial and, once WiFi is up, broadcast as UDP syslog (255.255.255.255:514) so it can be collected centrally (e.g. with rsyslog). See reqs_loging.md for details.

Security notes

• The web UI and its /api/... endpoints have no authentication. This project is intended for use on a trusted local network only — do not port-forward its port to the internet.
• Change the default OTA password and WiFiManager portal password in the firmware (main.cpp, wifi.cpp) before deploying, and avoid committing your real passwords if you fork/publish your own copy.

Secrets and IP setting

You need to set a few values before deployment (a few might be added later to the flash-config)

file | line | info platform.ini | 28 | upload_port = 192.168.x.x >>> set here the IP-addr of your ESP device platform.ini | 29 | upload_flags = --auth=CHANGE_ME_OTA_PASSWORD <<< set the OTA password similar to main.cpp main.cpp | 31 | ArduinoOTA.setPassword("CHANGE_ME_OTA_PASSWORD"); <<< set the OTA password similar to platform.ini read_energy_meter.cpp | 24 | SHELLY_IP = "192.168.x.x"; <<< set here the IP-addr of your Shelly-3EM device wifi.cpp | 17 | wm.autoConnect("GLBattery", "CHANGE_ME_PORTAL_PASSWORD") <<< see or change the wifi landing portal password

Project structure

Further design notes and requirements live in documentation/.

License

MIT — see LICENSE.txt.

Acknowledgments

• WiFiManager by tzapu
• ESPAsyncTCP by me-no-dev