# 7 Simple Inverter Circuits you can Build at Home. 12v 7ah battery inverter

## Battery Charge Time Calculator

Use our battery charge time calculator to easily estimate how long it’ll take to fully charge your battery.

## Battery Charge Time Calculator

Tip: If you’re solar charging your battery, you can estimate its charge time much more accurately with our solar battery charge time calculator.

### How to Use This Calculator

Enter your battery capacity and select its units from the list. The unit options are milliamp hours (mAh), amp hours (Ah), watt hours (Wh), and kilowatt hours (kWh).

Enter your battery charger’s charge current and select its units from the list. The unit options are milliamps (mA), amps (A), and watts (W).

If the calculator asks for it, enter your battery voltage or charge voltage. Depending on the combination of units you selected for your battery capacity and charge current, the calculator may ask you to input a voltage.

Select your battery type from the list.

Optional: Enter your battery state of charge as a percentage. For instance, if your battery is 20% charged, you’d enter the number 20. If your battery is dead, you’d enter 0.

Click Calculate Charge Time to get your results.

## Battery Charging Time Calculation Formulas

For those interested in the underlying math, here are 3 formulas to for calculating battery charging time. I start with the simplest and least accurate formula and end with the most complex but most accurate.

### Formula 1

Formula: charge time = battery capacity ÷ charge current

Accuracy: Lowest

Complexity: Lowest

The easiest but least accurate way to estimate charge time is to divide battery capacity by charge current.

Most often, your battery’s capacity will be given in amp hours (Ah), and your charger’s charge current will be given in amps (A). So you’ll often see this formula written with these units:

charge time = battery capacity (Ah) ÷ charge current (A)

However, battery capacity can also be expressed in milliamp hours (mAh), watt hours (Wh) and kilowatt hours (kWh). And your battery charger may tell you its power output in milliamps (mA) or watts (W) rather than amps. So you may also see the formula written with different unit combinations.

charge time = battery capacity (mAh) ÷ charge current (mA) charge time = battery capacity (Wh) ÷ charge rate (W)

And sometimes, your units are mismatched. Your battery capacity may be given in watt hours and your charge rate in amps. Or they may be given in milliamp hours and watts.

In these cases, you need to convert the units until you have a ‘matching’ pair.- such as amp hours and amps, watt hours and watts, or milliamp hours and milliamps.

For reference, here are the formulas you need to convert between the most common units for battery capacity and charge rate. Most of them link to our relevant conversion calculator.

Battery capacity unit conversions:

• watt hours = amp hours × volts
• amp hours = watt hours ÷ volts
• milliamp hours = amp hours × 1000
• amp hours = milliamp hours ÷ 1000
• watt hours = milliamp hours × volts ÷ 1000
• milliamp hours = watt hours ÷ volts × 1000
• kilowatt hours = amp hours × volts ÷ 1000
• amp hours = kilowatt hours ÷ volts × 1000
• watt hours = kilowatt hours × 1000
• kilowatt hours = watt hours ÷ 1000

Charge rate unit conversions:

The formula itself is simple, but taking into account all the possible conversions can get a little overwhelming. So let’s run through a few examples.

### Example 1: Battery Capacity in Amp Hours, Charging Current in Amps

Let’s say you have the following setup:

• Battery capacity: 100 amp hours
• Charging current: 10 amps

To calculate charging time using this formula, you simply divide battery capacity by charging current.

In this scenario, your estimated charge time is 10 hours.

### Example 2: Battery Capacity in Watt Hours, Charging Rate in Watts

Let’s now consider this scenario:

Because your units are again ‘matching’, to calculate charging time you again simply divide battery capacity by charging rate.

In this scenario, your estimated charge time is 8 hours.

### Example 3: Battery Capacity in Milliamp Hours, Charging Rate in Watts

Let’s consider the following scenario where the units are mismatched.

First, you need to decide which set of matching units you want to convert to. You consider watt hours for battery capacity and watts for charge rate. But you’re unable to find the battery’s voltage, which you need to convert milliamp hours to watt hours.

You know the charger’s output voltage is 5 volts, so you settle on amp hours for battery capacity and amps for charge rate.

With that decided, you first divide watts by volts to get your charging current in amps.

Next, you convert battery capacity from milliamp hours to amp hours by dividing milliamp hours by 1000.

Now you have your battery capacity and charging current in ‘matching’ units. Finally, you divide battery capacity by charging current to get charge time.

In this example, your estimated battery charging time is 1.5 hours.

### Formula 2

Formula: charge time = battery capacity ÷ (charge current × charge efficiency)

Accuracy: Medium

Complexity: Medium

No battery charges and discharges with 100% efficiency. Some of the energy will be lost due to inefficiencies during the charging process.

This formula builds on the previous one by factoring in charge/discharge efficiency, which differs based on battery type.

Here are efficiency ranges of the main types of rechargeable batteries (source):

Note: Real-world charge efficiency is not fixed and varies throughout the charging process based on a number of factors, including charge rate and battery state of charge. The faster the charge, typically the less efficient it is.

### Example 1: Lead Acid Battery

Let’s assume you have the following setup:

To calculate charging time using Formula 2, first you must pick a charge efficiency value for your battery. Lead acid batteries typically have energy efficiencies of around 80-85%. You’re charging your battery at 0.1C rate, which isn’t that fast, so you assume the efficiency will be around 85%.

With an efficiency percentage picked, you just need to plug the values in to the formula.

100Ah ÷ (10A × 85%) = 100Ah ÷ 8.5A = 11.76 hrs

In this example, your estimated charge time is 11.76 hours.

Recall, that, using Formula 1, we estimated the charge time for this setup to be 10 hours. Just by taking into account charge efficiency our time estimate increased by nearly 2 hours.

### Example 2: LiFePO4 Battery

Let’s assume you again have the following setup:

Based on your battery being a lithium battery and the charge rate being relatively slow, you assume a charge efficiency of 95%. With that, you can plug your values into Formula 2.

1200Wh ÷ (150W × 95%) = 1200Wh ÷ 142.5W = 8.42 hrs

In this example, your estimated charge time is 8.42 hours.

Using Formula 1, we estimated this same setup to have a charge time of 8 hours. Because lithium batteries are more efficient, factoring in charge efficiency doesn’t affect our estimate as much as it did with a lead acid battery.

### Example 3: Lithium Ion Battery

Again, let’s revisit the same setup as before:

First, you need to assume a charge efficiency. Based on the battery being a lithium battery and the charge rate being relatively fast, you assume the charge efficiency is 90%.

As before, you need to ‘match’ units, so you first convert the charging current to amps.

Then you convert the battery’s capacity from milliamp hours to amp hours.

With similar units, you can now plug everything into the formula to calculate charge time.

3Ah ÷ (2A × 90%) = 3Ah ÷ 1.8A = 1.67 hours

In this example, your estimated charge time is 1.67 hours.

### Formula 3

Formula: charge time = (battery capacity × depth of discharge) ÷ (charge current × charge efficiency)

Accuracy: Highest

Complexity: Highest

The 2 formulas above assume that your battery is completely dead. In technical terms, this is expressed by saying the battery is at 100% depth of discharge (DoD). You can also describe it as 0% state of charge (SoC).

Formula 3 incorporates DoD to let you estimate charging time regardless of how charged your battery is.

### Example 1: 50% DoD

Let’s revisit this setup, but this time assume our lead acid battery has a 50% DoD. (Most lead acid batteries should only be discharged to 50% at most to preserve battery life.)

As before, let’s assume a charging efficiency of 85%.

We have all the info we need, so we just plug the numbers into Formula 3.

(100Ah × 50%) ÷ (10A × 85%) = 50Ah ÷ 8.5A = 5.88 hrs

In this example, your battery’s estimated charge time is 5.88 hours.

### Example 2: 80% DoD

For this example, imagine you have the following setup:

As before, we’ll assume that the charging efficiency is 95%.

With that in mind, here’s the calculation you’d do to calculate charge time.

(1200Wh × 80%) ÷ (150W × 95%) = 960Wh ÷ 142.5W = 6.74 hrs

In this example, it will take about 6.7 hours to fully charge your battery from 80% DoD.

### Example 3: 95% DoD

Let’s say your phone battery is at 5%, meaning it’s at a 95% depth of discharge. And your phone battery and charger have the following specs:

As before, we need to convert capacity and charge rate to similar units. Let’s first convert battery capacity to amp hours.

Next, let’s convert charge current to amps.

Because the charge C-rate is relatively high, we’ll again assume a charging efficiency of 90% and then plug everything into Formula 3.

(3Ah × 95%) ÷ (2A × 90%) = 2.85Ah ÷ 1.8A = 1.58 hrs

Your phone battery will take about 1.6 hours to charge from 5% to full.

### Why None of These Formulas Is Perfectly Accurate

None of these battery charge time formulas captures the real-life complexity of battery charging. Here are some more factors that affect charging time:

• Your battery may be powering something. If it is, some of the charge current will be siphoned off to continue powering that device. The more power the device is using, the longer it will take for your battery to charge fully.
• Battery chargers aren’t always outputting their max charge rate. Many battery chargers employ charging algorithms that adjust the charging current and voltage based on how charged the battery is. For example, some battery chargers slow the charge rate down drastically once the battery reaches around 70-80% charged. These charging algorithms vary based on charger and battery type.
• Batteries lose capacity as they age. An older battery will have less capacity than an identical new battery. Your 100Ah LiFePO4 battery may have only have around 85Ah capacity after 1000 cycles. And the rates at which batteries age depend on a number of factors.
• Lithium batteries have a Battery Management System (BMS). Besides consuming a modest amount of power, the BMS can adjust the charging current to protect the battery and optimize its lifespan. iPhones have a feature called Optimized Battery Charging that delays charging the phone’s battery past 80% until you need to use it.
• Lead acid battery chargers usually have a timed absorption stage. After being charged to around 70-80%, many lead acid battery chargers (and solar charge controllers) enter a timed absorption stage for the remainder of the charge cycle that is necessary for the health of the battery. It’s usually a fixed 2-3 hours, regardless of how big your battery is, or how fast your charger.

In short, batteries are wildly complex, and accurately calculating battery charge time is no easy task. It goes without saying that any charge time you calculate using the above formulas.- or our battery charge time calculator.- should be viewed as an estimate.

## Simple Inverter Circuits you can Build at Home

These 7 inverter circuits may look simple with their designs, but are able to produce a reasonably high power output and an efficiency of around 75%. Learn how to build this cheap mini inverter and power small 220V or 120V appliances such drill machines, LED lamps, CFL lamps, hair dryer, mobile chargers, etc through a 12V 7 Ah battery.

## What is a Simple Inverter

An inverter which uses minimum number of components for converting a 12 V DC to 230 V AC is called a simple inverter. A 12 V lead acid battery is the most standard form of battery which is used for operating such inverters.

Let’s begin with the most simplest in the list which utilizes a couple of 2N3055 transistors and some resistors.

## ) Simple Inverter Circuit using Cross Coupled Transistors

The article deals with the construction details of a mini inverter. Read to know regrading the construction procedure of a basic inverter which can provide reasonably good power output and yet is very affordable and sleek.

There may be a huge number of inverter circuits available over the internet and electronic magazines. But these circuits are often very complicated and hi-end type of inverters.

Thus we are left with no choice but just to wonder how to build power inverters that can be not only easy to build but also low cost and highly efficient in its working.

### 12v to 230v inverter circuit diagram

Well your search for such a circuit ends here. The circuit of an inverter described here is perhaps the smallest as far its component count goes yet is powerful enough to fulfill most of your requirements.

## Construction Procedure

To begin with, first make sure to have proper heatsinks for the two 2N3055 transistors. It can be fabricated in the following manner:

• Cut two sheets of aluminum of 6/4 inches each.
• Bend one end of the sheet as shown in the diagram. Drill appropriate sized holes on to the bends so that it can be clamped firmly to the metal cabinet.
• If you find it difficult to make this heatsink you can simply purchase from your local electronic shop shown below:
• Also drill holes for fitting of the power transistors. The holes are 3mm in diameter, TO-3 type of package size.
• Fix the transistors tightly on to the heatsinks with the help of nuts and bolts.
• Connect the resistors in a cross-coupled manner directly to the leads of the transistors as per the circuit diagram.
• Now join the heatsink, transistor, resistor assembly to the secondary winding of the transformer.
• Fix the whole circuit assembly along with the transformer inside a sturdy, well ventilated metal enclosure.
• Fit the output and input sockets, fuse holder etc. externally to the cabinet and connect them appropriately to the circuit assembly.

Once the above heatsink installation is over, you simply need to interconnect a few high watt resistors and the 2N3055 (on heatsink) with the selected transformer as given in the following diagram.

### Complete Wiring Layout

After the above wiring is completed, it’s time to hook it up with a 12V 7Ah battery, with a 60 watt lamp attached at the transformer secondary. When switched ON the result would be an instant illumination of the load with an astonishing brightness.

Here the key element is the transformer, make sure the transformer is genuinely rated at 5 amp, otherwise you may find the output power a lot lesser than the expectation.

I can tell this from my experience, I built this unit twice, once when I was in college, and the second time recently in the year 2015. Although I was more experienced during the recent venture I could not get the awesome power that I had acquired from my previous unit. The reason was simple, the previous transformer was a robust custom built 9-0-9V 5 amp transformer, compared to the new one in which I had used probably a falsely rated 5 amp, which was actually only 3 amp with its output.

### Parts List

You will require just the following few components for the construction:

• R1, R2= 100 OHMS./ 10 WATTS WIRE WOUND
• R3, R4= 15 OHMS/ 10 WATTS WIRE WOUND
• T1, T2 = 2N3055 POWER TRANSISTORS (MOTOROLA).
• TRANSFORMER= 9- 0- 9 VOLTS / 8 AMPS or 5 amps.
• AUTOMOBILE BATTERY= 12 VOLTS/ 10Ah
• ALUMINUM HEATSINK= CUT AS PER THE REQUIRED SIZE.
• VENTILATED METAL CABINET= AS PER THE SIZE OF THE WHOLE ASSEMBLY

### Video Test Proof

Output Waveform better than square wave (Reasonably suitable for all electronic appliances))

### Cross Coupled MOSFET Inverter

The next design is a cross coupled simple MOSFET inverter circuit will be able to supply 220V/120V AC mains voltage or DC volts (with a rectifier and filter). The circuit is an easy to build inverter that will boost 12 or 14 volts to any level depending on the transformer secondary rating.

In this circuit, the primary and secondary of transformer T1 is a 12.6 V to 220 V step down transformer, connected in the reverse format.

MOSFETs Q1 and Q2 can be any high power Nchannel FETs. Do not forget to apply heat sink to the MOSFETs Q1 and Q2. Capacitors C1 and C2 are positioned in order to suppress high voltage reverse spikes from the transformer. You can use any nearby value for the resistors R1-R4 having a tolerance of ± 20% to the shown values in the diagram.

The circuit is perfect to power a tube circuit, or it could be coupled with a step-up transformer to generate a spark gap, a Jacob’s Ladder, or, by adjusting the frequency, it could be accustomed to energize a Tesla coil.

## ) Using IC 4047

As shown above a simple yet useful little inverter can be built using just a single IC 4047. The IC 4047 is a versatile single IC oscillator, which will produce precise ON/OFF periods across its output pin#10 and pin#11. The frequency here could be determined by accurately calculating the resistor R1 and capacitor C1. These components determine the oscillation frequency at the output of the IC which in turn sets the output 220V AC frequency of this inverter circuit. It may set at 50Hz or 60Hz as per individual preference.

The battery, mosfet and the transformer can be modified or upgraded as per the required output power specification of the inverter.

For calculating the RC values, and the output frequency please refer to the datasheet of the IC

### Video Test Results

In this simple inverter circuit we use a single IC 4049 which includes 6 NOT gates or 6 inverters inside. In the diagram above N1N6 signify the 6 gates which are configured as oscillator and buffer stages. The NOT gates N1 and N2 are basically used for the oscillator stage, the C and R can be selected and fixed for determining the 50Hz or 60 Hz frequency as per country specs

The remaining gates N3 to N6 are adjusted and configured as buffers and inverters so that the ultimate output results in producing alternating switching pulses for the power transistors. The configuration also ensures that no gates are left unused and idle, which may otherwise require their inputs to be terminated separately across a supply line.

The transformer and battery may be selected as per the power requirement or the load wattage specifications.

The output will be purely a square wave output.

Formula for calculating frequency is given as:

where R will be in Ohms and F in Farads

## ) Using IC 4093

Quite similar to the previous NOT gate inveter, the NAND gate based simple inverter shown above can be built using a single 4093 IC. The gates N1 to N4 signify the 4 gates inside the IC 4093.

N1, is wired as an oscillator circuit, for generating the required 50 or 60Hz pulses. These are appropriately inverted and buffered using the remaining gates N2, N3, N4 in order to finally deliver the alternately switching frequency across the bases of the power BJTs, which in turn switch the power transformer at the supplied rate for generating the required 220V or 120V AC at the output.

Although any NAND gate IC would work here, using the IC 4093 is recommended since it features Schmidt trigger facility, which ensures a slight lag in switching and helps creating a kind of dead-time across the switching outputs, making sure that the power devices are never switched ON together even for a fraction of a second.

## ) Another Simple NAND gate Inverter using MOSFETs

Another simple yet powerful inverter circuit design is explained in the following paragraphs which can be built by any electronic enthusiast and used for powering most of the household electrical appliances (resistive and SMPS loads).

The use of a couple of mosfets influences a powerful response from the circuit involving very few components, however the square wave configuration does limit the unit from quite a few useful applications.

### Introduction

Calculating MOSFET parameters may seem to involve a few difficult steps, however by following the standard design enforcing these wonderful devices into action is definitely easy.

When we talk about inverter circuits involving power outputs, MOSFETs imperatively become a part of the design and also the main component of the configuration, especially at the driving output ends of the circuit.

Inverter circuits being the favorites with these devices, we would be discussing one such design incorporating MOSFETs for powering the output stage of the circuit.

Referring to the diagram, we see a very basic inverter design involving a square wave oscillator stage, a buffer stage and the power output stage.

The use of a single IC for generating the required square waves and for buffering the pulses particularly makes the design easy to make, especially for the new electronic enthusiast.

### Using IC 4093 NAND Gates for the Oscillator Circuit

The IC 4093 is a quad NAND gate Schmidt Trigger IC, a single NAND is wired up as an astable multivibrator for generating the base square pulses. The value of the resistor or the capacitor may be adjusted for acquiring either a 50 Hz or 60 Hz pulses. For 220 V applications 50 Hz option needs to be selected and a 60 Hz for the 120 V versions.

The output from the above oscillator stage is tied with a couple of more NAND gates used as buffers, whose outputs are ultimately terminated with the gate of the respective MOSFETs.

The two NAND gates are connected in series such that the two mosfets receive opposite logic levels alternately from the oscillator stage and switch the MOSFETs alternately for making the desired inductions in the input winding of the transformer.

### Mosfet Switching

The above switching of the MOSFETs stuffs the entire battery current inside the relevant windings of the transformer, inducing an instant stepping up of the power at the opposite winding of the transformer where the output to the load is ultimately derived.

The MOSFETs are capable of handling more than 25 Amps of current and the range is pretty huge and therefore becomes suitable driving transformers of different power specs.

It’s just a matter of modifying the transformer and the battery for making inverters of different ranges with different power outputs.

### Parts List for the above explained 150 watt inverter circuit diagram:

• R1 = 220K pot, needs to be set for acquiring the desired frequency output.
• R2, R3, R4, R5 = 1K,
• T1, T2 = IRF540
• N1—N4 = IC 4093
• C1 = 0.01uF,
• C3 = 0.1uF

TR1 = 0-12V input winding, current = 15 Amp, output voltage as per the required specs

Formula for calculating frequency will be identical to the one described above for IC 4049.

f = 1 /1.2RC. where R = R1 set value, and C = C1

## ) Using IC 4060

If you have a single 4060 IC in your electronic junk box, along with a transformer and a few power transistors, you are probably all set to create your simple power inverter circuit using these components. The basic design of the proposed IC 4060 based inverter circuit can be visualized in the above diagram. The concept is basically the same, we use the IC 4060 as an oscillator, and set its output to create alternately switching ON OFF pulses through an inverter BC547 transistors stage.

Just like IC 4047, the IC 4060 requires an external RC components for setting up its output frequency, however, the output from the IC 4060 are terminated into 10 individual pinouts in a specific order wherein the output generate frequency at a rate twice that of its preceding pinout.

Although you may find 10 separate outputs with a rate of 2X frequency rate across the IC output pinouts, we have selected the pin#7 since it delivers the fastest frequency rate among the rest and therefore may fulfil this using standard components for the RC network, which may be easily available to you no matter in which part of the globe you are situated in.

For calculating the RC values for R2 P1 and C1 and the frequency you can use the formula as described below:

Or another way is through the following formula:

f(osc) = 1 / 2.3 x Rt x Ct

Rt is in Ohms, Ct in Farads

Here’s yet another cool DIY inverter idea which is extremely reliable and uses ordinary parts for accomplishing a high power inverter design, and can be upgraded to any desired power level.

## ) Simplest 100 Watt Inverter for the Newcomers

The circuit of a simple 100 watt inverter discussed in this article can be considered as the most efficient, reliable, easy to build and powerful inverter design. It will convert any 12V to 220V effectively using minimum components

### Introduction

The idea was published many years back in one of the elecktor electronics magazines, I present it here so that you all can make and use this circuit for your personal applications. Let’s learn more.

The proposed simple 100 watt inverter circuit disign was published quite a long time ago in one of the elektor electronics magazines and according to me this circuit is one of the best inverter designs you can get.

I consider it to be the best because the design is well balanced, well calculated, utilizes ordinary parts and if done everything correctly would start working instantly.

The efficiency of this design is in the vicinity of 85% that’s good considering the simple format and low costs involved.

### Using an Transistor Astable as the 50Hz Oscillator

Basically the whole design is built around an astable multivibrator stage, consisting of two low power general purpose transistors BC547 along with the associated parts consisting of two electrolytic capacitors and some resistors.

This stage is responsible for generating the basic 50 Hz pulses required for initiating the inverter operations.

The above signals are at low current levels and therefore requires to be lifted to some higher orders. This is done by the driver transistors BD680, which are Darlington by nature.

These transistors receive the low power 50 Hz signals from the BC547 transistor stages and lift them at higher current levels so that it can be fed to the output transistors.

The output transistors are a pair of 2N3055 which receive an amplified current drive at their bases from the above driver stage.

### 2N3055 Transistors as the Power Stage

The 2N3055 transistors thus are also driven at high saturation and high current levels which gets pumped into the relevant transformer windings alternately, and converted into the required 220V AC volts at the secondary of the transformer.

### Parts List for the above explained simple 100 watt inverter circuit

• R1,R2 = 27K, 1/4 watt 5%
• R3,R4,R5,R6 = 330 OHMS, 1/4 watt 5%
• R7,R8 = 22 OHMS, 5 WATT WIRE WOUND TYPE
• C1,C2 = 470nF
• T1,T2 = BC547,
• T3,T4 = BD680, OR TIP127
• T5,T6 = 2N3055,
• D1,D2 = 1N5402
• TRANSFORMER = 9-0-9V, 5 AMP
• BATTERY = 12V,26AH,

### Heatsink for the T3/T4, and T5/T6

Specifications:

• Power Output: 100 watts if single 2n3055 transistors are used on each channels.
• Frequency: 50 Hz, Square Wave,
• Input Voltage: 12V @ 5 Amps for 100 Watts,
• Output Volts: 220V or 120V(with some adjustments)

From the above discussion you might be feeling thoroughly enlightened regarding how to build these 7 simple inverter circuits, by configuring a given basic oscillator circuit with a BJT stage and a transformer, and by incorporating very ordinary parts which may be already existing with you or accessible by salvaging an old assembled PC board.

### How to Calculate the Resistors and Capacitors for 50 Hz or 60 Hz Frequencies

In this transistor based inverter circuit, the oscillator design is built using a transistorized astable circuit.

Basically the resistors and capacitors associated with the bases of the transistors determine the frequency of the output. Although these are correctly calculated to produce approximately 50 Hz frequency, if you are further interested to tweak the output frequency as per own preference you can easily do so by calculating them through this Transistor Astable Multivibrator Calculator.

### Another Simple Transistorized DC to AC Inverter Circuit

Q1 and Q2 can be any small signal PNP transistor such as BC557.

### Universal Push-Pull Module

If you are interested to achieve a more compact an efficient design using a simple a 2 wire transformer push pull configuration, then you can try the following couple of concepts

The first one below uses the IC 4047, along with a couple of p channel and n channel MOSFETs:

If you wish to employ some other oscillator stage as per your preference, in that case you can apply the following universal design.

This will allow you to integrate any desired oscillator stage and get the required 220 V push pull output.

over it also has an integrated auto-changeover battery charger stage.

### Advantages of Simple Push-Pull Inverter

The main advantages of this universal push-pull inverter design are:

• It uses a 2 wire transformer, which makes the design highly efficient, in terms of size and power output.
• It incorporates a changeover with battery charger, which charges the battery when the mains is present, and during a mains failure changes over to inverter mode using the same battery to produce the intended 220 V from the battery.
• It uses ordinary p-channel and N-channel MOSFETs without any complex circuitry.
• It is cheaper to build and more efficient than the center tap counterpart.

### SCR Inverter

The following inverter circuit uses SCRs instead of transistors and thus allows even higher power output with a simple configuration.

The oscillation is triggered by a pair of UJTs, which ensure accurate frequency control. and also facilitates the adjustment of the frequency across the two SCRs

The transformer can be be any ordinary iron core 9-0-9 V to 220 V or 120 V step down transformer, connected in the reverse order.

The above explained were a few straightforward inverter circuit designs, however if you think these are pretty ordinary for you, you can always explore more advanced designs which are included in this website. Here are a few more links for your reference:

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## Yuasa NPW45-12 lead battery 12V 45W

Special ups

General characteristicsExcellent recovery after deep discharge.Immobilization of electrolyte system.Recombination of gas.Versatile: application of floating and cycling.Usable in all positions (except upside down).Superior energy density.Plates lead calcium high yield for a prolonged life.Manufactured worldwide.Designs tailored to applications.

• EAN : 3052350710501
• Voltage (V): 12
• Capacity (Ah): 8.5
• Weight (Kg): 2.592
• Length (mm): 150
• Width (mm): 63
• Height (mm): 95
• Type of terminals: Faston 6.35 mm
• Type: Battery
• Power 45W /cell
• Model: Original manufacturer
• NPW45-12

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Par Pascal L. (GEISPOLSHEIM, France) le 15 Dec. 2017 ( Lead Yuasa battery 12V 45W NPW45-12 special inverter ) :

correspond parfaitement a la commande

produit livré rapidement, prix bien placé, bien emballé, et fonctionne parfaitement pour mon onduleur, je recommanderais quand j’aurais besoin

Par Patrick P. (CHEMERE LE ROI, France) le 29 Nov. 2017 ( Lead Yuasa battery 12V 45W NPW45-12 special inverter ) :

Par Eric V. (MACON, France) le 28 Aug. 2017 ( Lead Yuasa battery 12V 45W NPW45-12 special inverter ) :

Par Rémi L. (SAINT-QUENTIN, France) le 02 June 2017 ( Lead Yuasa battery 12V 45W NPW45-12 special inverter ) :

Tout est OK !

Pour remplacement dans un UPS.

Par Daniel N. (Sourzac, France) le 28 Sept. 2016 ( Lead Yuasa battery 12V 45W NPW45-12 special inverter ) :

Batterie Plomb Yuasa 12V 45W NPW45-12 spéciale onduleur

conforme à mes attentes livraison rapide

Par Bastien S. (Loix, France) le 26 July 2016 ( Lead Yuasa battery 12V 45W NPW45-12 special inverter ) :

Batterie puissante utilisée avec un moteur electrique

Tient très bien la charge

Par Bruno S. (CHAMPTEUSSE SUR BACONNE, France) le 08 Jan. 2016 ( Lead Yuasa battery 12V 45W NPW45-12 special inverter ) :

Batterie onduleur

Batterie conforme à l’originale. Bon fonctionnement. Rapidité de livraison et bon contact clientèle.

Par Ensch G. (L’Aiguillon-sur-Mer, France) le 22 Aug. 2015 ( Lead Yuasa battery 12V 45W NPW45-12 special inverter ) :

produit conforme. expédition trés rapide. tres bien.

Par Pierre A. (ASCHERES LE MARCHE, France) le 15 July 2015 ( Lead Yuasa battery 12V 45W NPW45-12 special inverter ) :

Produit conforme à mon cahier des charges.

Par Bernard L. (OUTINES, France) le 22 May 2015 ( Lead Yuasa battery 12V 45W NPW45-12 special inverter ) :

La fiabilité YUASA.

Monté 3 de ces accus sur un onduleur NITRAM Elite 2005 Pro 1500 RM, en remplacement de ceux d’origine. (YUASA- REW 45-12, que ce modèle remplace.) Si ces nouveaux accus ont la même fiabilité, je suis tranquille pour 5 ans, au moins.

## Introduction: Running a DSL Router From a 12v Battery (Anti-Loadshedding DSL)

Welcome to my first instructable.

Due to loadshedding in South Africa, which is nothing more than a fancy term provided for controlled rolling blackouts from the national electrical provider Eskom (loadshedding status page), we find ourselves for up to 4.5 hours being ‘loadshedded’ sometimes even more than once per day. This gets implemented by Eskom due to power constraints on the national electric grid in the country, after Eskom has neglected to build new power plants over the last decade for the increased demand for electricity and not performing regular maintenance on the older power plants.

So a lot of people are installing solar panels and generators at their homes, but what if you live in an apartment? 200 units in the apartment complex each running a generator? Better yet if you don’t have a balcony/garden were do you put the generator?

I have a UPS protecting my computer equipment and noticed that even during these blackouts my DSL provider actually stays on, but my UPS can only manage keeping the DSL router up for 40 minutes.

I did some research and decided to go the route of using an AC/DC Charger from the mains to charge a 12v battery which I will then use during the blackouts to power my DSL router which can provide me with some entertainment plus allow me to continue working (IT Engineer). The goal is to run the router on DC power straight from the 12v battery avoiding the DC. AC. DC conversion that would take place using an inverter in between and the losses that come with each conversion. These losses contribute to shorter run times.

Below I’ll be covering how to implement this simple setup using a standard ISP rebranded D-Link DSL-2750U router that has a 12v 1A power supply with a 3.5mm DC jack.

I won’t be covering any other power supply specifications and I’m not a professional electrician. I do not take any responsibility for damages or injuries occurred following this instructable.

For this instructable you’ll need the following:

• 12v Battery. at least 7 Ah to 10Ah depending on desired run time (I’m using a 26Ah)
• AC/DC Charger
• Multimeter
• Soldering Iron (I’m using a basic 45w model)
• Solder
• Wire cutter Wire stripper
• Utility knife
• RipCord (I’m using 3Amp 48v rated RipCord)
• DC Jack (I’m using a donor from another power supply due to 3.5mm being in short supply)
• Cigarette lighter plug
• Cigarette lighter socket with crocodile clips

This entire instructable was written and published from a laptop connected to my battery powered DSL router during loadshedding.

## Step 1: Charge the Battery Using the AC/DC Charger

Since we are going to attempt to power our DSL router from a battery we should start by making sure that it’s charged.

I’m using 10A AC to DC Multi-step charger that has: Over load protection, Output over voltage protection and Output short circuit protection.

For the battery I went with a 26Ah model, since you should never discharge these batteries beyond 50% of the capacity or else you are shorting the life of the battery, thus it gives me roughly13Ah to work with.

Depending on the size of your battery and charger this could take a couple of hours.

## Step 2: Making Your New Power Cable for Your DSL Router

I’m using a cigarette lighter socket and plug for connectivity to make it easier to swap out or use other 12v devices already equipped with a cigarette plug directly from a battery. The crocodile clips also makes it easy to swap between the AC/DC charger and socket extension.

The cigarette lighter plug can be opened by unscrewing the the front tip and single screw on the body of the plug.

You should use a multimeter to measure your router’s power supply to determine the polarity of the DC jack. My model has a negative barrel (exterior) with a positive center(interior).-

So on one end of a piece of RipCord, about a 1 metre should do, solder on your DC Jack and on the opposite end solder on the cathode(-) and anode of the cigarette lighter plug.

Your cigarette lighter plug might come with a LED and resistor to serve as an indicator, it that case the long leg of the LED goes to the anode with the short to the resistor and from the resistor to the cathode.

## Step 3: Connecting the Cigarette Socket

Remove the charger from the battery.

Connect the crocodile clips to the battery, e.g. red to positive and black to negative.

These days everything is color coded in one form or another if the crocodile clips are not color coded look at the wires, positive usually gets marked with a white line and the terminals on the battery have indicators on the casing.

If there are no clear markings use your multimeter instead to determine which is the correct ones

## Step 4: Testing the New Cable Connect It to the Router

Once you’ve plugged in the cigarette lighter plug into the socket use your multimeter to confirm that the polarity is correct.

The voltage reading should be about 12.8v on a fully charged battery.

Plug the DC jack into the router and turn it on, and in about 2 minutes (depending on the boot and authentication times) you should be online using a 12v battery.

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## Комментарии и мнения владельцев

Very cool stuff! I use a little inverter to plug my Fibre in with the Wi-Fi router and run it off a cheap car battery. The problem with this is, that it converts the 12v to 240v and then the plug of the unit converters it back to 9v and 12v respectively. I can not imagine the energy inefficiency with the multiple voltage conversions.

From a cost perspective, purchasing a mini ups meant for routers costs over R1000 and they only last a couple of hours.

Keeping things simple will save you money and will last long. a 60ah battery will give you days of usage compared to hours. I’m now researching simple ways to just charge a cellphone and run home internet directly from a 12v source with various adaptors and step down plugs instead as it is so much cheaper and easier. Inverters should be used for higher voltage applications and 12v for the smaller electronics. Make sense. Use what you got instead of spending money on fancy stuff.

yea i’m using a 12v 7a sealed battery to power Wi-Fi the Wi-Fi needs 12v 2a but the battery only powers it for a few minutes any ideas

It’s everything still working ok? Tempted by this but car battery voltages can range from 9 to 13 volts, so slightly worried about frying the router. (But would rather avoid the overhead of an inverter if not.) I’m in Addis where we have similar.

Another way would be to use an DC 12v to AC 120 volts inverter. It would make things simpler.

Converting 12v DC to 120V AC is inefficient, especially since you are then reconverting it back to DC introducing more loss.

Any ideas what the max voltage for a router and modem are? I’m using a 12v agm battery and sometimes the charge gets to about 14.5v after a charge. I’m wondering if that will fry things.

What happends to the router when battery voltage dropped under 12 volts. Can it damage the router ? Thanks.

Can i run my DSL router 12v 1A on battery 175 Ah directly

Can I use 12V 10 watts led driver for DSL Router

what if you used a device like this one? http://www.maxoak.net/laptop-power-bank/show/11.html 50000mAh battery pack (K2).

Multi-use All in One ChargeOne 20V/3A, one 12V/2.5A, two 5V/2.1A and two 5V/1A output allow you charge several devices like laptop, tablet, cell phone simultaneously. Ultra High Capacity 50000mAh Once Fully Charged, Our MAXOAK K2 Portable Battery Pack Can Charge Your iPhone 6 Plus about 11 Times, iPhone 6 About 17 Times, Galaxy S6 Almost 11 Times. ? would this be suitable to run a Wi-Fi router?