Lithium

You are here: Home / Battery Chargers / How to Charge Li-Ion Battery Correctly How to Charge Li-Ion Battery Correctly LAST UPDATED ON DECEMBER 10, 2021 BY ADMIN 2 COMMENTS In this post we comprehensively discuss a few specialized circuits that can be used for charging any Li-Ion battrey correctly, and safely without any risk of damage to the battery. Introduction We're still a long way from the ultimate rechargeable battery. The proven Nicad (Nickel Cadmium or NiCd) cell has traditionally been recommended for high current applications. The so-called memory effect isn't any longer a factor with this sort of cell, according to extensive research. Nicads cells are inexpensive in terms of price, however these have an ecological impact. Because these include the heavy metal cadmium, these must not be dumped in landfills at the end of their useful lives. As a result, Europe had pledged to end Nicad manufacturing until 1998. Nickel metal hydride (NiMH) cells are rapidly being viewed as a superior option. These have the benefit of being free of toxic heavy metals and having a higher energy density (cell dimension to stored charge ratio). The Lithium-Ion (Li-Ion) cell is now the obvious victor in terms of energy density. These are somewhat costly and susceptible to abuse, yet they happen to be the first option for applications like computers, video recorders, cell phones, and mobile gadgets wherein weight (lithium is the lightest existing element) and backup and battery size are crucial. New advances have resulted in high-current cells that can operate automobiles and, in one example, a comprehensive aircraft with motorized assistance! Lange, a German aircraft maker, has used Li-Ion batteries to power their 'Antares' electric motor glider due to its light weight. The prototype was designed for Ni-MH batteries, however switching to Li-Ion would provide the 500-pound plane an 885-foot-per-minute ascend rate, propelling the pilot to a height of almost 10,000 feet with its 57-horsepower (42-kilowatt) brushless electric engine. Characteristics and Structure of Cells We shall now investigate the cell's internal workings. The terminal voltage of Li-Ion is 3.6 or 3.7 V, which is a substantial benefit. This indicates that every single Li-Ion battery may be equivalent to 2 to 3 Ni-MH or Nicad cells (that have a cell voltage of 1.2 V). A graphite anode and a lithium cobalt oxide or lithium manganese oxide cathode are immersed in an organically flowing electrolyte which includes absorbed lithium salt, which generates the lithium ions. The cell potential of manganese oxide cathodes is 3.7 V, while that of cobalt oxide is 3.6 V . However, you may find Li-Ion cells maybe susceptible to inappropriate usage in this scenario. The recharging voltage is 4.20 V for manganese oxide cathodes and 4.10 V for cobalt oxide cathodes in cells having manganese oxide cathodes. Considering, the cell is not to be irreversibly destroyed, this voltage level should be kept under 50 mV. It's also crucial to keep the cell voltage above 2.4 or 2.5 V during discharge; else, the cell's life would be severely harmed. The word 'Ion' existing with the battery's name merely means that Lithium must never be encountered in its metallic form in the battery. The electrolyte collects lithium ions (Li+) on the graphite anode throughout the charging process. The dangers of incorrect usage Li-Ion batteries are readily damaged by charging at too high a voltage. Internal gassing, overheating, and finally exploding might occur if the charging voltage is pushed over its optimal value of 4.1 V or 4.2 V. Even a 1% rise in voltage over this ideal level could induce the lithium ions in the cell to start converting to metallic lithium. This, then, interacts strongly with water in the electrolyte, and consequently we should all retreat to a safe distance at this time rather than risk a direct confrontation with the cell explosion and its constituents. On the other hand, if the charging voltage is rather below the ideal level, the cell will be considerably undercharged. A cell voltage level of about 100 mV below the optimal limit (4.2V) reduces the stored capacity by 7%. As if that weren't terrible enough, Li-Ion is also affected by how low the cell voltage is permitted to drop while discharging. Deep discharging a cell causes a fast and permanent loss of cell capacity. Li-Ion batteries, as you may know, aren't the most fault-tolerant on the industry. Li-Ion cells are commonly used in specialized battery packs for specialized tools, such as laptops, mobile phones, and camcorders, when the hardware has been specifically developed to take a Li-Ion battery and proper charging devices has been ensured. Battery Packs To avoid wrong usage, Li-Ion battery packs are frequently equipped with some type of electrical protection. Figure 1 depicts various common designs. One of the easiest systems (Figure 1a) communicates cell temperature with the linked electronics through an in-built NTC sensor. Figure 1b shows a rather more complex circuit that protects against overcharging and undercharging. In this design, the threshold voltage is detected by a protector IC, and the charge or discharge current could be prevented by shutting off MOSFET T2 or T1. To enable current to pass via the unswitched MOSFET, the intrinsic MOSFET body diode is employed in each scenario. When both MOSFETs are turned off, the battery pack is completely disconnected. While charging and deep discharge, the Protector IC inhibits over-voltage. In idle state, the protector IC uses only about 1A. A battery pack with a built-in battery management IC and a System Management Bus (SMB) interface is shown in Figure 1c. The IC uses Rsense, a low-resistance sense resistor (just few tens of milliohms), to monitor individual cell's voltage as well as the current drain. This enables the control IC to assess how much charge is left in the battery pack and communicate that information to the device's charging circuit through the SMB two-wire interface's clock (SCL) and data (SDA) lines. Each cell in Li-Ion batteries also includes an over-pressure valve installed for safety purposes. This permits pressure in the cell to be expelled to the air as a result of a high ambient temperature (– for example, a fire). The cell also has a low-resistance Positive Temperature Coefficient (PTC) circuit. When large currents are used, this component heats up, and its resistance rises, lowering the short circuit current. How to Charge Lithium-ion battery Correctly Recharging Li-Ion cells with a constant voltage and a current controlled source necessitates careful monitoring of the cell voltage. Improper charging might result in the complete loss of battery capacity or even death. The charging device will measure the no-load cell potential at the start of a normal recharging cycle. If this value is less than 2.5 V, the cell is in a deep discharge state and will require a 'prequalification' charging period. This is accomplished by charging the cell at 5 mA until the voltage hits 2.5 V. The charger will begin the rapid charging stage at around this voltage level. Until the cell voltage hits 4.1 V (for cobalt oxide) or 4.2 V (for manganese oxide), the current is restricted to 1C to 2C (where C denotes the Ah rating of the cell) . The charger now enters the constant voltage phase, where it keeps the voltage (+/– 5 mV) and continuously checks the current until it decreases below a pre-determined threshold. Once the charging current drops below 5% of the current supplied during the constant current phase, i.e. 0.05 C to 0.1 C, the top-off phase terminates. Now, the battery has been completely charged. Pulsed charging with a voltage more than 4.2 V is allowed, provided the cell is not completely charged. It is required to utilize a couple of timers to restrict the charging times for safety concerns. A rapid charging phase is restricted by one timer, while the overall charging time is limited by the other. The charging operation is interrupted and an error message suggesting a defective cell is delivered if the rapid charge timer runs out before the voltage hits 4.2 V. If the 'total time' timer is not shut off during the normal schedule, the top-off phase will be terminated. Because Li-Ion cells exhibit an extremely reduced self-discharge, these do not demand a float charge; in fact, doing so would cause the cell to overcharge. To keep the cell temperature within its operational range of +2°C to +45°C, an NTC sensor device is employed. When a cell overheats, the controller would stop the charging until the temperature settles down. ICs for charging Lithium-Ion batteries Figure 2 below depicts a straightforward charger for recharging single Li-Ion batteries. The MAX 1679 (IC1) from MAXIM is at the core of the circuit. IC1 uses a pulsed waveform with a configurable markspace ratio to monitor the cell voltage at its BATT input and toggles MOSFET T1 such that the charging current from the constant current source supplied by IC2 and R1 may be regulated as required by the IC1. T1 is always on during the rapid charge phase, and it is pulsed during the top-up phase. This IC's charging mechanism is quite similar to the charging method mentioned previously. The IC MAX 1679 has a precision of lower than 1% for measuring cell voltage level. The charger's activity is shown via an LED (see Table 1). Once the charging process is completed, the Schottky diode D1 guarantees that the Li-Ion cell doesn't really discharge via the body diode of MOSFET T1. To monitor the temperature of the cell, an NTC thermistor R3 is attached to the THERM input of IC1 and need to be in direct physical contact with the cell. The ADJ input toggles an internal voltage reference, allowing you to choose between 4.2 V and 4.1 V for the terminal charging voltage, with regards to the battery type. R2 determines this voltage level selection. Table 1 LED state Function Flashing Qualifying (Vbatt < 2.5V) On Charging (fast charging or top-off charging) Flashing Fast charging finished Flashes every 3.5 s Charging finished The maximum charging time is selected via the jumper at input TSEL (this time could be between 2.8 and 6.25 hours). The MAX 1679 would transition to low power mode at the finish of a charging process, using less than 1 amp from the battery. A main power module adapter could be used to make a cheaper Li-Ion charger. Figure 3b depicts the output characteristic of a standard unregulated mains AC to DC adapter. An ideal voltage source should actually have a flat load line, which means it should provide the same voltage regardless of load. Nevertheless, when the load current climbs, the output voltage of a standard unregulated mains AC to DC adapter drops due to the transformer winding resistance. This feature is brought to excellent advantage in the circuit depicted in Figure 3a. The transformer must deliver +4.5 V at a current of 0.5 to 1.0 times the cell's capacity in A/hr. This output current is 0.4 A in figure 3b. While the constant current charging phase is in progress, the battery is connected directly to the transformer's output. Transformer impedance limits the charge current, and the cell voltage steadily increases. As soon as the cell voltage reaches 4.2 V, the MC79050 shifts to constant voltage charging and monitors the cell current until the cell is completely charged. Using IC LM3622 Figure 4 depicts a Li-Ion charger circuit in accordance with the National Semiconductor IC LM 3622. To regulate the voltage on the cell at 4.1 or 4.2 V, this design employs a PNP transistor as a linear regulator. The charging current is proportional to the value of Rsense and may be calculated using the following equation: Charge current = 0.1 V / Rsense To disperse the heat in transistor T1, a heatsink should be employed.

switching transistor

https://everycircuit.com/circuit/5748842502553600

Transistor

TeraHertz Transistors
Terahertz transistors are the new generation
semiconductor transistors developed by Intel
Corporation. The researchers in Intel had developed a
new transistor structure that maintains Moore’s law
and would lead them into the discovery of these high
speed new generation transistors. The terahertz
transistor basically has higher speed (in GHz), High
power efficiency, and high heat reduction capacity.
These transistors have a fast switching rate of more
than trillion times per sec. They also have the
capability to perform 50 to 100 times faster than
normal traditional transistors. The first terahertz
transistor was only capable for handling 3GHz. But the
latest…
Metal Oxide Varistor (MOV)

I was always a shy person, I’m an introvert. This thing haunted me many times. I start thinking that I won’t be able to talk in public or anything that includes socializing. Now, after a few years I’m going pretty well with talking in public so I want to share with you my “secrets”. So let’s start.

1. Being confident

It matters so much to have a good opinion about yourself, that’s where everything starts. If you aren’t sure on your abilities and you don’t see yourself in a good way, how can you wait from others to see you in a good way?

2. Don’t care too much about people’s opinion

People have different opinions and some of them won’t encourage you. Accept everything helps you but if some people laugh at you, just ignore them. They are just jealous. Talking in public means that you assume that others have other opinion than yours and still talk about it.

3. Start socializing even if that’s not in your comfort zone

As I said, I wasn’t a sociable person but now I am. How can you made it too? You have to get over your comfort zone because you can’t find success there and start socializing. It’s so simple to say, I know. But it will be simple in real life too with exercising.

4. Exercise in front of a mirror

Maybe this sounds really stupid but it helps. When you talk to yourself in the mirror you see all your good points and bad points as well. Exercising in front of a mirror also helps you to work at your non verbal talking and to your diction, which is also important.

5. Know your abilities and defects

When you know your abilities you can work with them and use them. So you really must know which your best points are to use them when you’re talking in public. As of defects, you have just to correct them in time and try to control them.

6. Know that everyone is imperfect and can fail sometimes

When you know that you don’t have to be perfect to do well, you’ll be more relaxed when you talk in public.


I really hope that these things will help you talk in public. Good luck!

Learn How To Master The Law Of Attraction – Beginners

 In my opinion, Law Of Attraction exists in all of us even if we recognize it or not.

 

We can’t stop it and we can’t change it. But we can learn how to use it in our favour.
What is exactly The Law Of Attraction?
Law Of Attraction is a universal law that is governing in Universe.
It assumes that everything we think, want or do not want will happen sooner or later.
For example, if you want to make money fast and you keep thinking about in a certain way, you can achieve it.
Like Napoleon Hill said: “Whatever the mind can conceive and believe, it can achieve”
If you want Law Of Attraction to work you need to do it correctly.
You’re lucky because you are reading this right now.

1. Get Rid Of Negativity

You can’t achieve positive results if you’re thoughts are negative.
Firstly, you need to clean your brain and block those negative thoughts.
It’s okay if you have negative thoughts, we all have, but you need to control them.
Don’t let them take you down.
Your positive thoughts are stronger than the negative ones.
Remember that there are no problems but only solutions.

2. Create Good Habits

You can create your own good habits.
Develop your morning routine, propose to read at least 15 minutes daily, meditate etc.
Do more of what makes you happy.
Eat healthy and forget about drama movies and sad songs. Instead, watch comedy movies and listen to positive songs.
We have many bad habits. I had too. I loved junk food and I was very fat.
I started to eat healthy, run and go the gym.
Everything is better when you feel good in your own body and with your own mind.

3. Be Happy & Grateful

After you managed to clear your mind of negative thoughts and fulfil it with positive ones, you’re ready to go to the next step.
eing happy & grateful is the key to unleash and amplify Law Of Attraction in your life.
Ask yourself: “How do I feel right now? What do I actually feel?”
If you feel happy and good, that’s right. But if you don’t, then you can try this.
Think about something you love, focus your attention on something that makes you happy for at least 1 minute.
Be grateful and say Thank You for everything.
Thank You is a magic word that releases and amplifies your positive thoughts.

try it now or never

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Solar Calculations Math Tutorial

Solar Calculations Math Tutorial
for Solar Energy Power Systems

Electricity can be a mystery to folks who have never had any experience working with it, or for folks who took physics in high school (that's me) and can't remember much of anything other than that the battery made the light bulb glow.

Basic electric calculations for off grid solar applications are not that hard, but you have to know the terminology.  Here it is.  Don't quit now, it's really pretty easy, but you have to learn the vocabulary for it to make sense.

Amps

Amps is a measure of energy flow, measured in electrons moving per second.  The amount of Amps represents the amount of charge flowing past a point in a particular time period.

Volts

Volts is a measure of the force of the moving electrons.  It's the pressure which causes electrical current to flow. It is also used to describe the amount of energy stored, like a 12 volt battery.

Watts

Watts is a measure of power.  It describes the amount of energy converted by an electrical circuit.

Ohms

Ohms is a measure of electrical resistance.  It you have a wire with two conductors, like a lamp cord, and connect one conductor to the positive and the other to the negative pole of a 12 volt battery (like jump starting a car), the smaller the wire diameter and the longer length of the wire the greater the Ohms, which causes the Volts delivered to decrease.  An increased resistance measured in Ohms causes a reduction in current aka Volts.

The Good Old Garden Hose Example

Get your garden hose and turn on the water so that it is flowing at the rate of a couple of gallons a minute, so that you could fill up a 5 gallon bucket in 2-3 minutes.

The rate of flow of the water, which is pretty slow, is equivalent to Amps.  The lower the flow the lower the amps.

The force of the water coming out of the hose is the Volts.  The lower the force, the lower the volts.

The power (energy) of the water coming out of the hose is Watts.  Put your thumb over the end of the hose and see how far you can squirt.  The harder you squeeze the farther you can squirt?  The water flow is still a couple of gallons per minute.  In the same way, if you increase the Volts, a small amount of Amps can turn into a lot of Watts.

If you link together 2 or 3 or 4 garden hoses without changing the setting on the faucet, what you will see is that the rate of flow goes down because the resistance of the water passing though the hose reduces the flow.  This same effect is measured in Ohms in electrical circuits.

Solar Calculations Math

All of these electrical units of measure are used together to determine the Volts, Amps and Watts for any particular solar electric application.  I am not going to talk about Ohms or Ohms Law.  Ohms is not important for calculating solar component sizing.  Ohms IS important when you start looking at the available Volts and wire sizes and the distances between components like batteries, solar panels, charge controllers and inverters.  The lower the Volts and the greater the distance traveled, the bigger the wire that is needed.

Volts x Amps = Watts

This is the starting point for doing the math.

Convert Watts to Amps: Amps = Watts / Volts  (slash = divide)

12 Watts / 12 Volts = 1 Amp

Convert Amps to Watts:  Watts = Amps x Volts

1 Amp x 12 Volts = 12 Watts

Convert Watts to Volts:  Volts = Watts / Amps

120 Watts / 10 Amps = 12 Volts

Convert Volts to Watts:  Watts = Amps x Volts

12 Amps x 12 Volts = 144 Watts

Energy Measurements Over Time

When you are trying to figure out what size solar panels you need, and how much battery storage, and what size charge controller or inverter you need for any particular solar energy application, the time that the sun shines on your panels, the time between sunny days (cloudy weather), the time that you what to be able to operate whatever you are going to power with your solar energy - everything is about time. 

So, watts and amps are measured by time for any given voltage.  The voltage of your off grid system is a given based on what you decide - you are going to have a 12 volt system, or a 24 volt system, or a 48 volt system based on the batteries you decide to use.

Watt-HoursUsed to measure energy inflow from your solar panel
and outflow from the devices you are powering
Watt-Hours per day or other time period

Amp-HoursUsed to measure energy storage and outflow in batteries
and energy inflow from your solar panel.

A Simple Load Analysis

I have two 10 watt 12 volt LED lights I want to operate for 4 hours per night.  10 watts x 2 x 4 hours = 80 watt-hours.

80 watt-hours divided by 12 volts = 6.67 amp hours.  Because we can only use half the energy in a lead acid battery without harming the battery, the minimum battery size is 6.67 amps x 2 = 13.34 amp hours.

I want my system to be reliable if we have four consecutive days of cloudy weather, 4 days of autonomy x 13.34 = 53.36 amp hours for the battery.  Sun Xtender makes a 56 amp hour AGM battery, PXV-560T.

This installation is in a location that gets 5 hours of full sun (insolation) per day.  To recharge the battery for one day of use we need 13.34 amps in 5 hours = 2.67 amps from a 12 volt solar panel.  Most load calculations include a discount factor for the inefficiency of recharging the battery.  20 percent is typical.  2.67 / 0.8 = 3.34 amps.  We have a 60 watt solar panel that has an Imp (amps maximum power point) of 3.49.  Look at the 60 watt panel top of the page.

The 60 watt solar panel has a short circuit amp rating (Isc) of 3.86 amps.  3.86 x 1.25 = 4.83.  I can use a 5 amp or larger charge controller with this panel to charge the battery.  If I want to make sure I am getting the best efficiency available for charging the battery, I would use a small MPPT charge controller like the Genasun 5 amp for lead acid.

Summary

Solar energy math calculations for system sizing can be done with a simple calculator using the basic formulas shown here.

If you want to see an example already in the website, read my page about CPAP battery backup emergency solar power.

When you calculate your loads, you will quickly see the advantage of using the most energy efficient devices you can find, like our SunDanzer solar refrigerators and freezersfor example.  High efficiency refrigerators and other appliances like Vari-Cyclone super energy efficient ceiling fans, Pico portable LED lights and other electrical devices used around the house are less expensive than solar electric components.  If you can downsize your loads through efficiency, your solar system will be less costly and easier to justify from a return on investment perspective.