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Charge Controllers & Smart Energy Monitoring Systems

• Charge Controller Features , Types and Applications

• Smart Energy metering

Reddyprasad, AP, SVCE,Bengaluru.

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How solar works ? ( Grid Connected system )

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Charge Controllers ( Off-Grid System )

Manage Energy Flow between : Solar Panel - > Battery

Battery - > Load

Battery charging Methods

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• Constant Voltage Cheap battery chargers

• Constant Current Switches off at voltage set-point

• Taper Current Unregulated constant voltage

• Pulsed charge Voltage PWM, on/rest/on

• Negative Pulse Charge Short discharge pulse

• IUI Charging Constant I, constant V, equalize

• IUO Charging Constant I, constant V, float

• Trickle charge Compensate for self discharge

• Float charge Constant voltage below gassing V

• Random charging Direct Solar Panel

Factors that decide Life of a Battery

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• Incorrect charge voltage.

• Too low a voltage >> Less % of charging >> sulphating >> loss of Capacity

• Excessive voltage >> causes excessive gas >> to water loss and drying out.

• Excessive discharging >> Early failure / Shorter Life

• Too many cycles >> Shorter Life

• Charging without 3 step regulation and very high electrolyte

temperatures.

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Battery Charging - Graphically

Single-stage battery charging is simpler to manage, but

multistage battery charging brings battery to a higher state

of charge.

Multistage battery charging needs intelligent controllers.

Why Charge Controllers ?

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• Prevents battery overcharge

• Blocks reverse current

• Prevent over-discharge from batteries (some models)

• Prevent electrical overload (some models)

• Displays battery status

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Overcharge Protection

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Overdischarge Protection

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Charge Controller Status

Some charge controllers include displays or LEDs to

indicate battery voltage, state of charge, and/or

presenting operating mode.

Types of Charge Controllers

• Shunt type charge controller

• Series type charge controllers

• PWM type

• MPPT type

• Diversionary

&

• Hybrid charge controller

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Shunt Charge Controllers

Shunt charge controllers control charging current by short-circuiting the array.

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Series Charge Controllers

Series charge controllers control charging current by opening

the circuit from the array.

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Pulse-Width Modulation

Pulse-width modulation (PWM) simulates a lower current level by pulsing a higher current level ON and OFF for short intervals.

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Maximum Power Point Tracking

Maximum power point

tracking manipulates

the load or output

voltage of an array in

order to maintain

operation at or near the

maximum power point

under changing

temperature and

irradiance conditions.

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MPPT – How it works ?

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Diversionary Charge Controller

A diversionary charge controller regulates charging current by diverting excess power to an auxiliary load when the battery is fully charged.

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Hybrid Charge Controller

Charge controllers

designed for hybrid

PV systems must

manage multiple

current source

simultaneously.

Importance of Various Set Points

• Charge regulation set points

• Voltage regulation set points

• Load control set points

Temperature compensation ??

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Charge Regulation Setpoints

Charge regulation setpoints are the voltage levels at which the charge controller interrupts or limits the charging current from the array to the battery bank.

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Voltage Regulation Setpoints

The optimal voltage regulation setpoints depends

on the type of battery and charge controller.

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Load Control Setpoints

Load control setpoints

are the voltage levels

at which the charge

controller interrupts or

limits the discharging

current from the battery

bank to the loads.

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Setpoint Adjustments

Setpoints are adjusted

with controls inside the

charge controller.

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Battery Temperature Sensors

Temperature probes are

placed between batteries

and connect to a charge

controller to compensate

for the charge regulation

setpoint.

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Charge Controller Selection Criteria

Many criteria should be considered when selecting charge controllers for PV systems.

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Multiple Arrays

Larger PV system often

use independent charge

controllers for each

array source circuit.

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Battery Banks With Charge Controllers

Separate charge

controllers are usually

recommended for

charging independent

battery banks.

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Battery Banks With One Charge Controller

In some cases, a single charge controller may

be used to charge independent battery banks.

Do I need Charge controller for

every Solar Application ?

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Self-Regulating PV Systems

To balance a charge to

and from the battery in a

self-regulating PV system,

the load must be well

defined, the battery must

be oversized, and the

array current must be self-

limiting.

Smart Energy Metering

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Net metering

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Smart APPs – Cloud powered

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Q & A

Thank you

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