How To Power the Level 2 EV Chargers with Solar Panels

This lecture contents include the study of solar cells i-v curves published by the solar panel manufacturer, comparison of all other types of lithium battery nominal voltage, and the reasons why lithium iron phosphate (LFP or LiFe4Po4) batteries shall be used for the SCMC system. Based on the nominal voltage studies of all three major components (solar panels, LFP battery & Solar Inverter), including the study of state of charge (SOC) of LFP batteries, we have come to a conclusion that the SCMC system will function well by proper voltage setting on the SCMC and the Solar Inverters.

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This lecture introduces the definition of Solar Charge Maximizing Controller System. This lecture also explores the construction of a LiFePo4 (LFP) battery with Battery Management System (BMS), for the students to understand why the LFP batteries used in the SCMC system must have a BMS included.

This lecture starts by reviewing the relationship between "Voltage" & "State of Charge (SOC)" of Lithium Iron Phosphate (LFP or LiFePo4) Batteries. This lectures further explains the voltage setting on the Solar Charge Maximizing Controller (SCMC), Automatic Transfer Switch (ATS), Inverters (Off-Grid Tricking and Grid-Tie) in case of grid-tie system, and PEM or AEM hydrogen Generator to maintain the optimum voltage range of LFP batteries.

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This lecture defines the Common Negative & Common Positive solar charge maximizing controller systems. With wiring diagrams, this lecture explains how the SCMC system shall be wired for the MPPT solar charge controller and SCMC to power the same DC load, and charge the same LFP battery bank. This lecture includes the information to help the students to determine and find out the types of existing MPPT solar charge controllers.

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This lecture explains what is a grounded solar array, and what is a floating solar array. The lecture suggests what parts of the SCMC system should be grounded, and which wires ("Pv+", "PV-", "PS", Batt+" & "Batt-") may be bonded and grounded to earth in the common positive or common negative SCMC systems.

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This lecture introduces the typical off-grid or hybrid system applications with regular hydro meter_the system without grid-tie approval. It includes applications in the 220vac/50hz/1ph, 120vac/240vac/60hz/split phase, 120/208vac/60hz/3ph power supply systems.

This lecture explains why it is beneficial to include class 1 and class 2 EV Chargers in the off-grid or hybrid PV system, so the PV power may be stored in the EV batteries during the day. Increasing AC or DC load during the day can have the advantage of a SCMC system fully utilized without a large LFP battery bank. The SCMC system with class 2 EV chargers stations may be set up in any remote area, to solve the current insufficient EV charging stations problems.

This lecture also introduces a method to produce green hydrogen in the off-grid systems, and explains how to benefit the high DC amperage of SCMC system to produce green hydrogen through the use of PEM Cells and metal hydride cylinders. The advantage of producing green hydrogen on site without power transmission loss in the grid system and hydrogen transportation cost is also introduced.

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This lecture introduces the typical grid-tie and off-grid hybrid system applications with net hydro meter_the system needs grid-tie approval. It includes applications in the 220vac/50hz/1ph, 120vac/240vac/60hz/split phase, 120/208vac/60hz/3ph power supply systems.

The grid-tie system may also include the EV chargers as AC load, and green hydrogen production to spend the energy from PV array SCMC system.

The grid-tie system generally has minimum LFP battery capacity requirement, as extra power can alway be exported to the grid. 

Compared to traditional grid-tie system, the Solar Charge Maximizing Controller grid-tie has its unique benefit that the SCMC system may still supply power to the emergency load in case of power outage in the grid.

This lecture explores the lead / acid battery application in a Solar Charge Maximizing Controller System. The lecture explains how the existing or new Lead / Acid based battery may be integrated into the SCMC system to expand the SCMC system energy storage capacity without significant cost for large capacity of LFP batteries. The lecture suggests how the second SCMC shall be connected to control the power supply from the MPPT charge controller and lead / acid battery. The benefit of including Lead/Acid battery in the SCMC system is also told.

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Through the study of the DC current distribution in all types of SCMC systems (Grid-tie hybrid, off-grid hybrid, and system with lead/acid battery), the students will understand how the solar array shall be arranged, and how to determine minimum charging current required for LFP batteries.

Based on the DC current distribution in a SCMC system, the students will be able to size the SCMC system components. It is also for the future cable sizing according to the maximum voltage drop allowed.

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This lecture introduce the SCMC system sizing guidelines based on following factors:

* The system is a grid-tie hybrid, or an off-grid hybrid system, and if the system has Lead / Acid battery bank with dedicated MPPT solar charge controller included.

* The maximum solar array capacity may be possibly installed at the site or property;

* The available solar inverter capacities;

* The budget available for the maximum storage capacity of LFP battery.

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This lecture explores many options to locate the major components of a Solar Charge Maximizing Controller System. Explains why temperature and humidity is clitical for the smooth operation of LFP battery, MPPT solar charge controller, solar charge maximizing controller, and solar inverter in the system.

This lecture also explains the possible system integration with a Lead / Acid based battery bank, and the benefit of such integration.

The students will learn how to perform the current calculation for the solar arrays with combination series and parallel connection in a solar charge maximizing controller system. This lecture introduces the minimum copper cable gauge required for a certain design amperage, including the comparison between imperial and metric cable sizes.

This lecture also introduces how high current capacity cables may be fabricated by using split-bolts to join many MC4 AWG#10 solar cables. And explains why the wire connecting SCMC is called split-bolt wire, and where a split-bolt shall be used.

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A sample SCMC system is used to explain how we shall plan for the solar charge maximizing controller system installation. This lecture explains why we should prepare a system wire diagram, based on the total number of solar panels used, and why a layout is required so the service clearance around the solar panels can be preserved, and the number of the solar cables going into each of the outdoor located PVC junction boxes can be determined.

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This lecture introduces the common electrical connection components used in the solar charge Maximizing Controller system, including the MC4 connectors and split-bolt connectors located inside the PVC junction boxes. The components also include solar cable gland fittings, PVC junction boxes, DC breakers, ANL fuses, & terminal blocks ....etc. components used in the SCMC systems.

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This lecture includes demonstration of forming solar cable MC4 connectors for low amperage solar cable connections. The SCMC system's unique split-bolt connection forming techniques are also introduced. For medium amperage near 45 amps connections, this lecture demonstrates the forming technique of the wire lugs and solar cable connection with an electrical soldering iron.

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Through the propane torch soldering demonstration, the students are expected to learn the torch soldering technique for high current wire lugs and solar cables. The students would be able to bundle up to 10 of AWG #10 solar cables for a single wire lug to form a reliable connection to handle over 200 amp electrical current.

Students will gain knowledge of DC breakers, fuses, terminal blocks, quick disconnects...etc. PV system accessories used in the electrical room or hydro vault. including what they are, what they look like, and where they are normally used in the Solar Charge Maximizing Controller system, and how they would be installed.

Students will have a further understanding of Lithium Iron Phosphate (LFP) battery, including its operating temperature and humidity range. LFP battery thermal runaway temperature range and thermal runaway behaviors are also introduced. Students will learn where LFP batteries shall be located, and how to ensure the fire safety of LFP battery applications.

This final lecture starts by summarizing the SCMC system installation, including the system planning, components locating, cables sizing, connectors forming, and explains how the SCMC system shall be powered up. The students will learn how the SCMC system shall be verified and commissioned to work.