HM‐1500, 4x 385W, 150 35 MPPT, 2x 25,6V (51,2V) LiFePo
This example configuration uses 4x JaSolar 385W panels connected to a Victron SmartSolar 150/35 MPPT. The MPPT feeds into 2x 25,6V Powerqueen LiFePo Batteries, configured as one as 51,2V 100Ah Battery (2 batteries in series). OpenDTU onBattery manages a Hoymiles HM-1500 Inverter connected to the two batteries. The inverter receives the information about the required power from a Shelly 3em. MPPT, Batteries, and inverter are connected by bus bars on plus and minus.
graph TD;
Panel1_and_Panel2-->GAK;
Panel_3_and_Panel4-->GAK;
GAK-->MPPT;
MPPT-->Busbars;
Busbars-->Battery;
Busbars-->Inverter;
Inverter-->Household;
| Component | Model | Connections | Details, Notes related to installation |
|---|---|---|---|
| Solar Panels | 4x JaSolar JAM60S20-385/MR | Peak power (Pmax) 385 W, Open circuit voltage (Voc) 41.78 V, Max.power voltage (Vmp) 35.04V, Short circuit current (Isc) 11.53 A, Max.power current(Imp) 10.99 A | |
| MPPT | Victron SmartSolar 150/35 | PV +/- to GAK, Battery +/- to Bus bar, cables = 16 mm². Connected to OpenDTU ESP via Ve.Direct cable. Connected to Victron SmartShunt 500A via Victron proprietary Bluetooth Ve.Smart | |
| GAK | Standard 2-in 1-out | 2 positive & 2 negative inputs, One fuse per input and surge protection for positive & negative each. Main switch to disconnect/connect the solar panels to MPPT. | |
| Busbars | standard 4 x M8 | Galvanized copper, 4x M8, 3x M4, 250A max. current | |
| Battery Fuse | Combined switch & fuse | Main switch to disconnect/connect the Battery. M6 screw connectors, 70A max. | |
| DTU | OpenDTU-onBattery | DIY ESP32 with OLED Display and Ve.Direct connection to MPPT. nRF24 antenna for Inverter communication and external WIFI antenna since the DTU is inside the outdoor cabinet. Powered by simple USB charger. | |
| Batteries | 2x 25,6V 100Ah | Manufacture: Power Queen. M8 battery terminals. Internal BMS with basic protective features (overvoltage, under voltage, over current). The BMS cannot be accessed. | |
| Temperature Monitoring | ESP32 Board + 6 DS18B20 sensors | 3 Sensors glued to the batteries (3 mtr. wires - bottom, middle, top). Additionally 1 sensor behind the MPPT, 1 outdoor sensor at the bottom of the cabinet, 1 internal cabinet sensor glued to a bus bar. The ESP is flashed with ESPhome and the temperatures are monitored in Homeassistant. | |
| Shunt | Victron SmartShunt 500A | M10 screw terminals. Used to measure all battery KPIs (details). Connected via Ve.Smart to the MPPT. Connected via Ve.Direct to a ESP8266 Board which is flashed with ESPhome to integrate the Battery data in homeassistant. | |
| Battery Sense | Victron Battery Sense | M10 screw lugs. Used to measure temperatures & battery voltage. Both values are transmitted via Ve.Smart Bluetooth to the MPPT. The MPPT uses the values to manage the battery charging. | |
| Main Switch | Shelly Plus 1pm | Main Switch to measure energy feed into household and to disconnect/connect the Inverter on the AC side from/to household. DIY Integrated in the Powerline from inverter to household. Mounted in a waterproof outdoor box and connected to an outdoor plug. |
The entire system is installed outdoors, including the LiFePo batteries (inside a isolated box). The outdoor environment is typical of Central European, with subzero temperatures in Winter and above 30°C during summer. Building a lasting solution to keep the batteries dry and in the range of 10 - 30°C was a crucial challenge in this setup.
2x 2 panels in pairs, each facing SSO & SSW. Each panels is mounted on a Renusol Console+ and a wooden substructure to angle the panels by 25°. In each of the Renusol consoles 3x 10Kg concrete plates are inserted for weighting.
2x 25,6V 100Ah Powerqueen LiFePo Batteries. The batteries have an internal BMS which is not accessible and takes care of under voltage/overvoltage etc. . The batteries are connected in series and form a 51,2V 100Ah Battery. The Battery is loaded up to a voltage of 56,8V (according to the manual) and the discharge is being stopped at 51,2V (approx. 20% capacity of the battery according to the manual). All cables to and from the batteries are 16mm2 copper battery cables with 8mm cable lugs. The battery voltage, state of charge and ampere hours going in and out are measured and reported by the Victron Smartshunt (glued to one of the batteries). Three temperature sensors are glued to the batteries on different positions. Temperatures and voltages are also measured by the battery sense which is also glued to one of the batteries. The battery sense data is used to manage the charging. The values of the 3 temperature sensors are used only to manage the heating of the battery box.
The Battery insulation is based on three layers - 1.) a outer metal enclosure box 2.) a wooden internal box inside the metal box 3.) an insulation bag inside the wooden box which contains the batteries. The box is covered with a truck plan to protect against rain/snow.
Details:
The Battery Box has been built with a metal garden tooling box (size approx. 110cm x 70cm x 70cm) insulated with two layers of 32mm Armaflex on all side and top walls and 2x 32mm + 1x 19mm Armaflex at the bottom.
Inside this metal box is a wooden box that contains the sealed battery bag. The wooden internal box has been sealed with silicone and internally isolated with 3mm reflective isolation foil and 9mm Armaflex.
Inside the wooden box is a sealed insulation bag that contains the 20W heating element underneath the batteries and the batteries. The bag is made of insulation bubble foil coated with a thin aluminum film. After connecting the wires to the batteries and fixing the three temperature sensors to the batteries and routing the 220V power cable for the heating, the bag was sealed with aluminum tape.
The room between the internal wooden battery box and the outer metal case has been filled with rock wool insulation.
All wires are routed through waterproof cable grommets into the metal box and 12mm holes into the internal battery box.
Heating:
The temperature inside the sealed battery bag is measured by a shelly uni with three sensors connected (each sensor on a 3m wire). The temperature values are transmitted to Homeassistant via WIFI. Underneath the two batteries, a 20W flat heating element has been installed and connected to the 220V Plug inside the connection cabinet. The heating will be switched on/off by a Shelly Plug integrated into Homeassistant. An automation inside homeassistant constantly compares the measured temperatures with target values and switches the Shelly Plug for the heating if needed. A message is sent to other devices like mobiles if the temperature drops or the heating is going on/off.
The connection cabinet is IP65 certified and has a size of 400x500x245mm. Weatherproof ventilations have been installed at the bottom and left wall, primarily to remove the warm air which the MPPT produces during operation.
ESP32 / ESPHome Temperature monitoring:
The ESP32 board has 6 Temperature sensors attached and is WIFI integrated into Homeassistant. The integration is done via ESPhome, which is flashed on the ESP32. The 6 sensors are connected to a terminal on which a 4,7K resistor is build in to allow a stable connection of the sensors to the ESP. The terminal is wired to GPIO32, 3,3V and GND. Homeassistant is used to record & report the battery box temperatures and to manage the heating (via automations) inside the box based on the measured temperatures. The ESP is plugged into a breakout board to ease wiring and it is powered by a USB charger.
Bus Bars:
Two 250A standard Bus Bars with 4x 8mm screw connectors.
Example, negative bus bar:
Shunt:
A Victron SmartShunt 500A. Connected to the negative pole of the battery. Measures the Battery voltage on the positive pole with the victron measurement cable connected to the screw connector of the 60A Battery fuse / switch. The shunt is connected to the MPPT (via Victron VE.Smart Bluetooth and the MPPT uses the shunt to read the battery voltage and in/out-going power). The Ve.Direct port is connected to a Wemos D1 Mini ESP32, wich uses ESPHome as "OS". ESPHome allows to integrate the ESP into Homeassistant and to read all data fields from the Shunt in Homeassistant and to build automations based on this data, e.g. disconnecting the Inverter on the AC-side by a Shelly Plug if the SOC or voltage drops.
Battery Fuse / Switch:
A 70A combined switch and fuse connected to the positive pole of the battery.
DTU:
OpenDTU-onBattery on a ESP32 with a OLED and Ve.Direct connection to the Victron charge controller.
Charge controller:
Victron MPPT 150|35 with 16mm2 cables incoming and outgoing. The Ve.Direct port is connected to the DTU.
4 port 220V extension:
Used to power the 20W heating for the batteries, the ESP32 connected to the Shunt and the DTU. Connected with an outdoor suitable cable to an outdoor household wall plug.
Cables:
16mm2 cables between Battery and Busbars, MPPT. 6mm2 cables from Busbars to Inverter. Simple Jumper cables soldered to a JST connector for the Ve.Direct cables from MPPT to DTU and Shunt to Shunt-ESP(Home). 8mm cable lugs for the Battery and Busbars. 10mm cable lugs for the shunt.
Hoymiles HM-1500. The four (2x positive, 2x negative) 6mm2 cables coming from the Busbars are splitted with a Y-connector to allow all 4 ports to be connected to the Busbars / Battery system. All 4 ports connected to the system allow approximately 1200W to be drawn from the battery.
A standard 2 in 1 generator connection box combines the incoming two positive and two negative phases into each positive and negative phase. Each incoming phase is secured with 15A. The combined phases are switched with a main DC switch.
HA is used to monitor the state of the system (on/off, state of charge, energy flow, temperatures, general conditions) and to run certain automation like the heating based on the temperature in the battery box. Ha is also used to automatically switch off the Inverter on the AC side if the SOC/battery voltage drops below 20% / 51,2V.
The HA dashboard is tailored towards mobile usage. There is a main view and a detailed, longer page.
