Lecture 02 Overview Of Voltage Regulators

What is a positive electrode for a lithium ion battery?

Positive electrodes for Li-ion and lithium batteries (also termed “cathodes”) have been under intense scrutiny since the advent of the Li-ion cell in 1991. This is especially true in the past decade.

What are the recent trends in electrode materials for Li-ion batteries?

This mini-review discusses the recent trends in electrode materials for Li-ion batteries. Elemental doping and coatings have modified many of the commonly used electrode materials, which are used either as anode or cathode materials. This has led to the high diffusivity of Li ions, ionic mobility and conductivity apart from specific capacity.

Can lithium insertion materials be used as positive or negative electrodes?

It is not clear how one can provide the opportunity for new unique lithium insertion materials to work as positive or negative electrode in rechargeable batteries. Amatucci et al. proposed an asymmetric non-aqueous energy storage cell consisting of active carbon and Li [Li 1/3 Ti 5/3]O 4.

What are commercial electrode materials in Li-ion batteries?

This review critically discusses various aspects of commercial electrode materials in Li-ion batteries. The modern day commercial Li-ion battery was first envisioned by Prof. Goodenough in the form of the LCO chemistry. The LiB was first commercialized by Sony in 1991. It had a LCO cathode and a soft carbon anode.

Can lithium metal be used as a negative electrode?

Lithium metal was used as a negative electrode in LiClO 4, LiBF 4, LiBr, LiI, or LiAlCl 4 dissolved in organic solvents. Positive-electrode materials were found by trial-and-error investigations of organic and inorganic materials in the 1960s.

What is a lithium ion battery?

Lithium-ion batteries consist of two lithium insertion materials, one for the negative electrode and a different one for the positive electrode in an electrochemical cell. Fig. 1 depicts the concept of cell operation in a simple manner . This combination of two lithium insertion materials gives the basic function of lithium-ion batteries.

What is the voltage of a lead acid battery?

The 24V lead-acid battery state of charge voltage ranges from 25.46V (100% capacity) to 22.72V (0% capacity). 48V Lead-Acid Battery Voltage Chart (4th Chart). The 48V lead-acid battery state of charge voltage ranges from 50.92 (100% capacity) to 45.44V (0% capacity). Lead acid battery is comprised of lead oxide (PbO2) cathode and lead (Pb) anode.

What is the difference between lithium and lead-acid batteries?

Most common example of lead-acid batteries are car batteries. When compared to the lithium battery voltage charts here, we can quickly see that the lead-acid state of charge and corresponding voltage has a narrower range (12.73V to 11.36V for 12V lead-acid batteries vs. 14.4V to 10.0V for LiFePO4 batteries).

What is a lithium battery voltage chart?

A lithium battery voltage chart is an essential tool for understanding the relationship between a battery's charge level and its voltage. The chart displays the potential difference between the two poles of the battery, helping users determine the state of charge (SoC).

What is the highest voltage a lead-acid battery can achieve?

The highest voltage 48V lead battery can achieve is 50.92V at 100% charge. The lowest voltage for a 48V lead battery is 45.44V at 0% charge; this is more than a 5V difference between a full and empty lead-acid battery. With these 4 voltage charts, you should now have full insight into the lead-acid battery state of charge at different voltages.

What is the voltage of a 24V lead-acid battery?

We see the same lead-acid discharge curve for 24V lead-acid batteries as well; it has an actual voltage of 24V at 43% capacity. The 24V lead-acid battery voltage ranges from 25.46V at 100% charge to 22.72V at 0% charge; this is a 3.74V difference between a full and empty 24V battery.

What is a 12V flooded lead acid battery?

12V flooded lead acid batteries reach full charge at around 12.64 volts and reach complete discharge at about 12.07 volts. Below is a table showing a flooded lead-acid 12V battery chart and it has a lower maximum: Lithium iron phosphate batteries are the most common batteries used in solar systems.

What are capacitors made of?

At a fundamental level, capacitors are made of two electrodes (conductors, often metal) separated by a dielectric (insulator). When an electrical signal is applied to one of the electrodes, energy is stored in the electrical field between the two separated electrodes.

What is a low voltage capacitor?

Low voltage types with highly roughened anodes display capacitance at 100 kHz approximately 10 to 20% of the value measured at 100 Hz. Capacitance may also change with applied voltage. This effect is more prevalent in class 2 ceramic capacitors. The permittivity of ferroelectric class 2 material depends on the applied voltage.

What do capacitors have in common?

From the smallest capacitor beads to large power factor correction ones, they all have one thing in common: the capability to store energy in the form of an electrical charge producing a potential difference. The capacitor market is complex, with many product geometries, designs, properties and applications.

What materials can be used to protect a capacitor?

ELANTAS Europe offers a full portfolio of materials for protecting capacitors in different applications and environments, including one and two component epoxy resins, two component polyurethane resins, soft gels and polyimide varnishes.

How many conductors does a capacitor have?

Most capacitors contain at least two electrical conductors, often in the form of metallic plates or surfaces separated by a dielectric medium. A conductor may be a foil, thin film, sintered bead of metal, or an electrolyte. The nonconducting dielectric acts to increase the capacitor's charge capacity.

What materials are used for film capacitors?

The plastic films used as the dielectric for film capacitors are polypropylene (PP), polyester (PET), polyphenylene sulfide (PPS), polyethylene naphthalate (PEN), and polytetrafluoroethylene (PTFE). Polypropylene has a market share of about 50% and polyester with about 40% are the most used film materials.

How to fix solar panel low voltage problem?

The steps below explain how to fix solar panel low voltage problem: 1. Solving Environmental Issues a) Shading Solutions To prevent shading issues, ensure that you position your solar panel so that trees or buildings won't block sunlight. The key is to have sunlight hit the panel directly. b) Battling Dirt Buildup

Why is my solar panel low voltage?

You might be facing a low voltage problem. Low Voltage in Solar panels often happens due to the panel not getting sufficient light. Shading, Dirt Buildup, and Environment often cause this. Other things that cause low voltage are faulty wiring, degraded panel, and low-quality equipment.

What are some common problems with zero voltage solar panels?

Common problems with zero voltage include a faulty inverter or charge controller, a solar panel that has failed, shading, increased temperature, hotspots in a solar panel, poor connection or faulty wiring, and delamination caused by water entering one of the solar panels. We will look at the most common scenarios where PV systems fail:

Should I troubleshoot or repair my PV system?

Before calling a repair company, consider troubleshooting common issues with your PV system. This may save you money. Common problems that can be identified include low voltage, faulty inverters, and electrical issues. Solar panel installation guarantees a long-term supply of clean, renewable energy.

How do I troubleshoot a faulty solar inverter?

To troubleshoot this issue, you will need to test the inverter, the charge controller, and the solar panels to determine where the fault lies. To do this, you will need a multimeter that can confirm whether there is voltage output.

Do solar panels have no voltage?

No Voltage From Solar Panel (Solutions) - Solar Panel Installation, Mounting, Settings, and Repair. It can be frustrating to find you don't have voltage from your solar panels, but the potential problems are relatively straightforward to diagnose as there can only be a few issues that cause the lack of power.

Why is voltage chart important for lithium ion phosphate (LiFePO4) batteries?

Voltage chart is critical in determining the performance, energy density, capacity, and durability of Lithium-ion phosphate (LiFePo4) batteries. Remember to factor in SOC for accurate reading and interpretation of voltage. However, please abide by all safety precautions when dealing with all kinds of batteries and electrical connections.

What is the voltage of a lithium phosphate battery?

Every lithium iron phosphate battery has a nominal voltage of 3.2V, with a charging voltage of 3.65V. The discharge cut-down voltage of LiFePO4 cells is 2.0V. Here is a 3.2V battery voltage chart. Thanks to its enhanced safety features, the 12V is the ideal voltage for home solar systems.

What is a lithium iron phosphate battery?

Lithium Iron Phosphate batteries also called LiFePO4 are known for high safety standards, high-temperature resistance, high discharge rate, and longevity. High-capacity LiFePO4 batteries store power and run various appliances and devices across various settings.

What voltage is a LiFePO4 battery?

Explore the LiFePO4 voltage chart to understand the state of charge for 1 cell, 12V, 24V, and 48V batteries, as well as 3.2V LiFePO4 cells.

What is the difference between a lithium ion and a discharged battery?

The chart displays the potential difference between the two poles of the battery, helping users determine the state of charge (SoC). For example, a fully charged lithium-ion cell typically has a voltage of 4.2V, while a discharged cell may have a voltage of 3.0V or lower.

What does depth of discharge mean on a LiFePO4 battery?

This is what EVE, a major LiFePO4 cell manufacturer recommends: What is Depth of Discharge? Depth of Discharge (DoD) refers to the percentage of a battery's capacity that has been used up compared to its total capacity.

What causes lithium batteries to go in protection mode?

Connect with Darren on LinkedIn. The BMS causes lithium batteries to go in to protection mode when overheating, high currents, and high or low voltage. Learn more on how to prevent those and recharge your battery

How to protect a lithium battery?

Use special lithium battery protection chip, when the battery voltage reaches the upper limit or lower limit, the control switch device MOS tube cut off the charging circuit or discharging circuit, to achieve the purpose of protecting the battery pack. Characteristics: 1. Only over-charge and over-discharge protection can be realized.

What are the benefits of lithium battery protection boards?

In addition to basic overcharge, over-discharge, over-current, and over-temperature protection, future lithium battery protection boards will also integrate more functions, such as power estimation, balanced charging, etc. These features will help improve the efficiency and management of lithium batteries. 3. Intelligent

What is lithium battery overcharge protection?

Lithium battery overcharge protection allows the battery to shut off and the current goes away. The battery will cool down but if it goes back into protection mode after the battery turns back on you may have to reduce your load, reduce the charge rate, or improve the ventilation around the batteries. Next is current protection.

What should you know about lithium ion batteries?

The most important key parameter you should know in lithium-ion batteries is the nominal voltage. The standard operating voltage of the lithium-ion battery system is called the nominal voltage. For lithium-ion batteries, the nominal voltage is approximately 3.7-volt per cell which is the average voltage during the discharge cycle.

What is a safe voltage for a lithium ion battery?

Lithium-ion batteries function within a certain range at which their voltage operates optimally and safely. The highest range where the fully charged voltage of a lithium-ion battery is approximately 4.2V per cell. The lowest range which is the minimum safe voltage for lithium-ion batteries is approximately 3.0V per cell.

What are the directives relating to power capacitors?

These directives will be considered individually below in relation to power capacitors. According to Article 1 of the Low Voltage Directive itself, the directive governs the safety of “electrical equipment” where operated within a range from 50 to 1000 V AC or 75 to 1500 V DC.

How is rated voltage applied to a capacitor?

For this purpose, the rated voltage is applied to the capacitors via a series resistance of approxi-mately 100 for VR 100 V DC, or 1000 for VR >100 V DC, for a period of one hour. Subsequently, the capacitors are stored under no-voltage conditions for 12 to 48 hours at a tem-perature between 15 and 35 °C.

What is a low-voltage dry-type alternating current (AC) power capacitor?

This document provides standard requirements and general guidelines for the design, performance, testing and application of low-voltage dry-type alternating current (AC) power capacitors rated 1,000V or lower, and for connection to low-voltage distribution systems operating at a nominal frequency of 50Hz or 60Hz.

Why do electrolytic capacitors need to be set climatic limits?

Limits must be set for the climatic conditions to which electrolytic capacitors are subjected (in part for reasons of reliability and in part due to the variation of the electrical parameters with tempera-ture).

Do power capacitors have a declaration of conformity?

This is the case with some forms of power capacitor. The declaration of conformity applies in this case only to the safety aspects that can be assessed directly on the capacitor itself in conjunction with reference to manufacturer's specifications for its installation.

What is the maximum voltage difference between capacitors?

Thus their value should be quite high, and the resulting power losses are practically negligible. The capacitor voltages then remain within the range: 1⁄2 Vbank ± VT (where VT is the transistor threshold voltage), so that the maximum voltage dif-ference between capacitors can reach approximately 2·VT.

How a distributed energy storage system is connected to a photovoltaic system?

The distributed energy storage and photovoltaic are connected at the same node. The total load of the system and the active output of photovoltaic are shown in Figure 8. Figure 6. Schematic of distribution network structure and distribution of photovoltaic-storage system. Figure 7. Installed capacity of PV vs. peak load power. Figure 8.

Is distributed photovoltaic a fixed power source?

The above methods have mainly focused on consideration of distributed photovoltaic as a fixed power source, and the uncertainty has not been fully considered. In response to this, reference proposed a dynamic voltage control method for a distribution network based on distributed model predictive control.

Does PV access affect distribution network voltage?

First, the impact mechanism of PV access on the distribution network voltage needs to be further investigated; second, the regulation costs of photovoltaic and energy storage are different, and the effects of the control by different node powers on node voltage are also different.

What is the voltage control strategy of a distribution network containing PV?

Therefore, it is of great significance to study the voltage control strategy of a distribution network containing PV. The most traditional reactive power voltage control in distribution networks is to use reactive power resources such as transformer taps and capacitor banks [6, 7] for regulation.

Where is the feeder current distribution when the photovoltaic-storage system discharges?

where is the feeder current distribution when the photovoltaic-storage system discharges during peak period, and x1 is the ratio of the distance between photovoltaic-storage system location and the start of the feeder line to the total length of the feeder line. Figure 4. Current distribution during discharge of photovoltaic-storage system.

How much voltage does a solar farm need?

If the nearest transmission line to your property has a voltage of, say, 115 kV (115,000 volts), the output voltage from the solar farm needs to “step up” to 115 kV to feed power into it. Likewise, the power that line carries to a neighborhood 50 miles away eventually needs to “step down” in voltage so that homes can use it.

What is a mobile energy storage system?

Abstract: A mobile energy storage system (MESS) is a localizable transportable storage system that provides various utility services. These services include load leveling, load shifting, losses minimization, and energy arbitrage. A MESS is also controlled for voltage regulation in weak grids.

What is the optimal scheduling model of mobile energy storage systems?

The optimal scheduling model of mobile energy storage systems is established. Mobile energy storage systems work coordination with other resources. Regulation and control methods of resources generate a bilevel optimization model. Resilience of distribution network is enhanced through bilevel optimization.

Do mobile energy storage systems have a bilevel optimization model?

Therefore, mobile energy storage systems with adequate spatial–temporal flexibility are added, and work in coordination with resources in an active distribution network and repair teams to establish a bilevel optimization model.

How do different resource types affect mobile energy storage systems?

When different resource types are applied, the routing and scheduling of mobile energy storage systems change. (2) The scheduling strategies of various flexible resources and repair teams can reduce the voltage offset of power supply buses under to minimize load curtailment of the power distribution system.

What is a mobile energy storage system (mess)?

During emergencies via a shift in the produced energy, mobile energy storage systems (MESSs) can store excess energy on an island, and then use it in another location without sufficient energy supply and at another time, which provides high flexibility for distribution system operators to make disaster recovery decisions .

Can mobile energy storage systems improve resilience of distribution systems?

According to the motivation in Section 1.1, the mobile energy storage system as an important flexible resource, cooperates with distributed generations, interconnection lines, reactive compensation equipment and repair teams to optimize dispatching to improve the resilience of distribution systems in this paper.

What are the performance requirements of lithium iron phosphate batteries?

Lithium iron phosphate batteries, which use LiFePO4 as the positive electrode, meet the following performance requirements, especially during high discharge rates (5-10C discharge): stable discharge voltage, safety (non-burning, non-explosive), and long life (cycle times).

What is the nominal voltage of lithium iron phosphate battery?

The nominal voltage of the single lithium iron phosphate battery is 3.2V, the charging voltage is 3.6V, and the discharge cut-off voltage is 2.0V. Lithium iron phosphate battery packs reach the required voltage by the equipment through battery cell series connection. The battery voltage is equal to N* series connection number.

What is the difference between lithium ion and lithium iron phosphate batteries?

Both battery charging methods are constant current and constant voltage (CCCV), but the constant voltage point is different. The nominal voltage of lithium iron phosphate battery is 3.2V and the charging cut-off voltage is 3.6V. Conventional lithium ion batteries have a nominal voltage of 3.6V and a cut-off voltage of 4.2V.

How to test a LiFePO4 battery?

Multimeter: This tool will allow you to measure the voltage of your LiFePO4 cells. Battery Capacity Tester: This device will allow you to test the capacity of your LiFePO4 cells. Safety Equipment: When working with batteries, it's important to take safety precautions. Wear gloves, eye protection, and a respirator if necessary.

What equipment do I need for a LiFePO4 battery test?

Here's a list of what you'll need: Multimeter: This tool will allow you to measure the voltage of your LiFePO4 cells. Battery Capacity Tester: This device will allow you to test the capacity of your LiFePO4 cells. Safety Equipment: When working with batteries, it's important to take safety precautions.

What is the capacity of lithium iron phosphate power lithium-ion batteries?

The capacity of a lithium iron phosphate power lithium-ion battery can be divided into three categories: small-scale, which is a few to a few milliamperes; medium-scale, tens of milliamp-hours; and large-scale, hundreds of milliamp-hours. The capacity of individual batteries can vary greatly.

How to diagnose a battery overvoltage & undervoltage fault?

Threshold-based fault diagnosis methods The battery overvoltage or undervoltage fault can be diagnosed using the threshold-based method. The voltage information collected by the voltage sensor is compared with the preset threshold. When the battery voltage exceeds the threshold, the fault occurrence state and fault occurrence time are defined .

How effective is battery management & fault detection in electric vehicles?

The robustness of the proposed method across varying conditions highlights its potential for effective battery management and fault detection in electric vehicles, ensuring better health monitoring and predictive maintenance. This contributes to extending battery lifespan and enhancing overall vehicle performance.

Can a Bayesian optimized neural network detect voltage faults in energy storage batteries?

Accurately detecting voltage faults is essential for ensuring the safe and stable operation of energy storage power station systems. To swiftly identify operational faults in energy storage batteries, this study introduces a voltage anomaly prediction method based on a Bayesian optimized (BO)-Informer neural network.

Why do EV batteries have voltage deviations?

Voltage deviations are a primary indicator of battery faults and can arise from various causes, including internal short circuits, external short circuits, and capacity degradation 8. These deviations are critical for timely fault detection and prevention, thus ensuring the reliability and safety of EV batteries.

Can segmented regression be used to detect battery faults?

This paper proposes segmented regression to better capture these distinct characteristics for accurate fault detection. The focus is on detecting voltage deviations caused by internal short circuits, external short circuits, and capacity degradation, which are primary indicators of battery faults.

Can a battery model be used to detect voltage anomalies?

Future studies can investigate extensions of the model to diagnose specific types of voltage anomalies, enhancing fault detection capabilities. Additionally, exploring the model's adaptability for voltage prediction in other battery systems can also be considered.

How to calculate solar panel output voltage?

If you know the number of PV cells in a solar panel, you can, by using 0.58V per PV cell voltage, calculate the total solar panel output voltage for a 36-cell panel, for example. You only need to sum up all the voltages of the individual photovoltaic cells (since they are wired in series, instead of wires in parallel). Here is this calculation:

How do you test a solar panel?

Test the solar panel voltage A voltmeter or multimeter can help you measure the solar panel output voltage. Simply connect the multimeter with the solar panel output terminals to measure current and voltage. The PV modules with high voltage are likely to generate more power than low-voltage panels.

How do you measure a solar cell voltmeter?

Measure the open circuit voltage (Voc) across the solar cell. This is the voltage when no current is flowing through the cell. Since no current flows through a perfect voltmeter, a voltmeter measures the open circuit's voltage. Tilt the solar cell in sunlight or lamplight and notice how the Voc changes.

What is a solar panel voltage?

Voltage is the push behind the electricity that flows through your solar panels. Speaking of panels, every solar panel has a certain voltage output. Keep in mind that this output might vary based on factors like sunlight, temperature, and the number of solar cells in the panel.

How does a solar cell work?

The maximum voltage, on the other hand, is fixed by the material the solar cell is made of. Solar cells also have an internal resistance, which reduces the voltage available at the terminals when current flows. Electric power is the product of the voltage across a device and the current through that device.

How does a solar panel charge a battery?

With solar panels, we can charge batteries, and batteries usually have 12V, 24V, or 48V input and output voltage. It is the job of the charge controller to produce a 12V DC current that charges the battery. Open circuit 20.88V voltage is the voltage that comes directly from the 36-cell solar panel.

How many volts does a solar cell produce?

Most common solar panels include 32 cells, 36 cells, 48 cells, 60 cells, 72 cells, or 96 cells. Each PV cell produces anywhere between 0.5V and 0.6V, according to Wikipedia; this is known as Open-Circuit Voltage or V OC for short. To be more accurate, a typical open circuit voltage of a solar cell is 0.58 volts (at 77°F or 25°C).

What is the voltage output of a solar panel?

The voltage output of a single solar cell under Standard Test Conditions (STC) is approximately 0.5 volts. To increase the overall voltage, these cells are connected in series within a solar panel. Solar panels generate Direct Current (DC) power, whereas most household appliances operate on Alternating Current (AC) power.

What is a typical open circuit voltage of a solar panel?

To be more accurate, a typical open circuit voltage of a solar cell is 0.58 volts (at 77°F or 25°C). All the PV cells in all solar panels have the same 0.58V voltage. Because we connect them in series, the total output voltage is the sum of the voltages of individual PV cells. Within the solar panel, the PV cells are wired in series.

How many volts does a solar panel have?

Generally, solar panels intended for residential or commercial installations typically have voltage outputs ranging from 12 volts to 48 volts. These panels are designed to meet the voltage requirements of common off-grid and grid-tied systems, ensuring compatibility with standard electrical components and appliances.

How many volts is a 36 cell solar panel?

36-Cell Solar Panel Output Voltage = 36 × 0.58V = 20.88V What is especially confusing, however, is that this 36-cell solar panel will usually have a nominal voltage rating of 12V. Despite the output voltage being 18.56 volts, we still consider this a 12-volt solar panel.

What is the maximum voltage of a solar panel?

: The maximum voltage of a solar panel is the panel's open circuit voltage (VOC) plus the voltage increase due to the temperature coefficient. What Are Some Solar Cells Examples?:

What voltage should a lithium battery be?

It is recommended to maintain the battery within the voltage range of 3.0V to 4.2V per cell to ensure optimal performance and avoid permanent damage to the cells. Lithium battery voltage is essential for understanding how these batteries operate.

What is the nominal voltage of a lithium ion battery?

The nominal voltage of lithium-ion cells is typically around 3.6V to 3.7V. This is the average voltage when the battery is in a stable state, neither charging nor discharging. State of Charge (SOC) is crucial for monitoring battery health. For best performance, lithium batteries should be within specific voltage ranges:

What is a lithium ion battery charge voltage?

Charging Voltage: This is the voltage applied to charge the battery, typically 4.2V per cell for most lithium-ion batteries. The relationship between voltage and charge is at the heart of lithium-ion battery operation. As the battery discharges, its voltage gradually decreases.

What should you know about lithium ion batteries?

The most important key parameter you should know in lithium-ion batteries is the nominal voltage. The standard operating voltage of the lithium-ion battery system is called the nominal voltage. For lithium-ion batteries, the nominal voltage is approximately 3.7-volt per cell which is the average voltage during the discharge cycle.

What is a lithium battery voltage chart?

A lithium battery voltage chart is an essential tool for understanding the relationship between a battery's charge level and its voltage. The chart displays the potential difference between the two poles of the battery, helping users determine the state of charge (SoC).

What is a cut-off voltage for a lithium ion battery?

Cut-off Voltage: This is the minimum voltage allowed during discharge, usually around 2.5V to 3.0V per cell. Going below this can damage the battery. Charging Voltage: This is the voltage applied to charge the battery, typically 4.2V per cell for most lithium-ion batteries.

How does energy storage work at high voltage?

considerably depending on specific system requirements. Energy storage at high voltage normally requires the use of electrolytic capacitors for which th ESR varies considerably, particularly over temperature. These variables need to be conside

What is high voltage energy storage (hves)?

high-voltage-energy storage (HVES) stores the energy ona capacitor at a higher voltage and then transfers that energy to the power b s during the dropout (see Fig. 3). This allows a smallercapacitor to be used because a arge percentage of the energy stor d choic 100 80 63 50 35 25 16 10 Cap Voltage Rating (V)Fig. 4. PCB energy density with V2

Which electrolytic capacitor is best for energy storage?

r losses with PHT4NQ10T (Q ),SUD15N15-95 (QD) and ES3C.operate at 50 V or higher. This leaves the aluminium electrolytic capacitor as the f rst choice for energy storage, based on volume and cost. On the bus side, depending on the operating voltage, additional selection includes tantalu

What is a L VBUS level with and without an energy-storage system?

l Vbus levels with and without an energy-storage system. For example, in telecommunications applications, the PICMG® AdvancedTCA® specification requires continuous operation in the presence of a 5-ms,0-V input-voltage transient (the total d rat