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Exploring Solar Power Systems: On-Grid vs. Off-Grid vs. Hybrid

In today’s world, harnessing the power of the sun has become an increasingly popular choice for homeowners and businesses alike. Solar power systems offer a clean, sustainable, and cost-effective way to generate electricity. However, choosing the right solar power system can be a daunting task. In this blog, we will compare three popular options: On-Grid, Off-Grid, and Hybrid solar power systems, to help you make an informed decision for your energy needs.

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Exploring the Solar System in Ludhiana: A Bright Future with Roop Solar

In the ever-evolving world of energy, the solar system in Ludhiana has emerged as a beacon of sustainable power generation. Roop Solar, a key player in the Ludhiana solar industry, has been at the forefront of this transformative journey. Let’s embark on a solar-powered adventure, shedding light on the potential and promise of Ludhiana’s solar system. Harnessing Solar Energy: A Green Revolution The solar energy landscape in Ludhiana has witnessed a remarkable transformation in recent years. As the world grapples with climate change and the need for cleaner energy sources, solar power has emerged as a green revolution. Roop Solar has played a pivotal role in this transformation, offering innovative solutions that harness the power of the sun. Ludhiana’s Solar Potential Ludhiana, with its abundant sunlight, is perfectly poised to capitalize on solar energy. The region’s geographical location and climate make it an ideal candidate for solar power generation. Roop Solar recognizes this untapped potential and has been instrumental in bringing solar solutions to the heart of Ludhiana. Roop Solar: Pioneering Sustainable Solutions Roop Solar, a name synonymous with excellence in the solar industry, has been a driving force behind Ludhiana’s sustainable energy adoption. With a commitment to innovation and quality, Roop Solar has been instrumental in the installation of solar panels and systems across Ludhiana. Their dedication to harnessing clean energy sources has made them a trusted partner for both residential and commercial projects. The Advantages of Going Solar 1. Sustainable Energy Source Solar power is a sustainable and renewable energy source. By harnessing the sun’s energy, we reduce our reliance on fossil fuels, contributing to a cleaner environment and a greener future. 2. Cost Savings Investing in solar panels can lead to significant cost savings in the long run. As energy bills continue to rise, solar power allows homeowners and businesses in Ludhiana to generate their electricity and reduce expenses. 3. Environmentally Friendly Solar energy is a clean and eco-friendly alternative to traditional power sources. It produces no harmful emissions and reduces the carbon footprint, making it a responsible choice for Ludhiana’s residents. 4. Energy Independence By adopting solar power, Ludhiana residents gain energy independence. They are less susceptible to power outages and fluctuations, ensuring a consistent and reliable energy source. 5. Government Incentives The government of Punjab, in collaboration with organizations like Roop Solar, offers incentives and subsidies for solar installations. This further encourages Ludhiana’s residents to embrace solar energy. Conclusion: Ludhiana’s Solar Future Shines Bright As we conclude our exploration of Ludhiana’s solar system with Roop Solar, it’s clear that the future is indeed bright. The city’s solar potential, coupled with the expertise of Roop Solar, paves the way for a sustainable and eco-conscious future. By embracing solar power, Ludhiana takes a significant step towards reducing its carbon footprint and ensuring a cleaner environment for generations to come. Roop Solar’s commitment to excellence and innovation continues to drive Ludhiana’s solar revolution forward. With solar energy, we not only illuminate our homes but also light the path to a greener and more sustainable future.

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Lithium (LiFePO4) Battery Charge Time Calculator & Formula

Use our lithium battery charge time calculator to find out how long it will take to charge a lithium battery with solar panels or with a battery charger. Calculator Assumptions How To Use This Calculator? (Example) How Do You Calculate Lithium-Ion Battery Charging Time? Here are the methods to calculate lithium (LiFePO4) battery charge time with solar and battery chargers. 1: Lithium Battery Charging Time With Solar PanelsAdvertisements Formula: charge time = (battery capacity Wh × depth of discharge) ÷ (solar panel size × Charge controller efficiency × charge efficiency × 80%) Battery depth of discharge (DoD): Battery Depth of discharge refers to the percentage of a battery that has been discharged relative to the overall capacity of the battery. Lithium battery charge efficiency: 90 – 95% (Source) Note: In the real world, the battery charge efficiency rate will not be fixed and will depend on a number of factors. Like the battery charge rate (the faster the charge rate is the less efficient it is) and the battery depth state of charge (SOC). Charge controller efficiency – PWM: 80%, MPPT: 98% Battery capacity in watt-hours (Wh) = Battery Ah × Battery volts Example Let’s suppose 2: Lithium Battery Charge Time Using Battery Charger Formula: charge time = (battery capacity × depth of discharge) ÷ (charge current × charge efficiency) Note: Enter the battery capacity in Ah or mAh if the charger current output is mentioned in amps (A) or milliamps (mA). However, if the output value of the charger is mentioned in watts (W) or watt-hours (Wh), enter the battery capacity in watt-hours (Wh). Example Let’s suppose 100Ah lithium battery will take about 10.5 hours to get fully charged from 100% depth of discharge (0% SoC) using a 10A charger. How Long To Charge A Lithium (LiFePO4) Battery? Calculating the battery’s exact charge time is not an easy task. However, you can use our above lithium battery charge time calculators or formulas to get an estimated battery charge time.

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Lithium (LiFePO4) Battery Runtime Calculator

Use our lithium battery runtime (life) calculator to find out how long your lithium (LiFePO4, Lipo, Lithium Iron Phosphate) battery will last running a load. Calculator Assumption How To Use Lithium Battery Runtime Calculator? 1- Enter the battery capacity and select its unit. The unit types are amp-hours (Ah), and Miliamps-hours (mAh). Choose according to your battery capacity label. 2- Enter the battery voltage. It’ll be mentioned on the specs sheet of your battery. For example, 6v, 12v, 24, 48v etc. 3- Optional: Enter battery state of charge SoC: (If left empty the calculator will assume a 100% charged battery). Battery state of charge is the level of charge of an electric battery relative to its capacity. For example, enter 80 for an 80% charged battery. 4- Is your output load connected through an inverter? If you’re using a solar battery and running an AC load, it should be connected through an inverter. 5- Enter the total output load and select its unit. The units are, watts (W), and kilowatts (kW = 1000 watts). How To Calculate Lithium Battery Runtime? AdvertisementsI’ve seen many ways to calculate the battery runtime online. Which are easy but least accurate. So I’m gonna share the most accurate and difficult method. Formula #1 (Best For Large Capacity Batteries): Battery runtime = (Battery capacity Wh × battery discharge efficiency × inverter efficiency, if running AC load) ÷ (Output load in watts). Formula #2 (Best For Small mAh Batteries): Battery runtime = (Battery capacity Ah/mAh × battery discharge efficiency) ÷ (Output load in amps/milliamps). Formula 1: Example Let’s suppose, Formula 2: Example Let’s take the iPhone 14 pro max as an example, Lithium Battery Maximum Discharge Rate? Rechargeable batteries are designed to be charged/discharged at a limited current rate to increase the battery lifespan or life cycles. Lithium batteries can be discharged at 1C (for example, 100 amps for a 100Ah battery). Discharging your battery at a higher rate than what is recommended will increase the heat in battery cells. As a result, your battery will drain quickly. For instance, if you’re running a 100A load on a 100Ah battery, it will last 35-40 minutes instead of 1 hour. How Many Hours Does A Lithium Battery Last? Calculating how many hours your battery will last while running a load is not an easy task. There are so many factors to consider for an accurate value.

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Lead Acid Battery Life Calculator: (SLA, AGM, Gel)

Use our lead-acid battery life calculator to find out how long a Sealed Lead Acid (SLA), AGM, Gel, and Deep cycle lead-acid battery will last running a load. Calculator Assumptions How To Use This Calculator? Step 1: Enter the battery capacity and select the unit type. The unit types are amp-hours (Ah), and milliamp-hours (mAh). Step 2: Enter your battery voltage (V). Is this a 6v, 12v, 24, or 48v battery? Step 3: Optional: Enter the battery state of charge (SoC). SoC is defined as how much your battery is charged relative to its capacity. (The default value is 100%, meaning a fully charged battery). Step 4: Optional: Enter the battery depth of discharge limit (DoD). (The default value is 50% because most lead-acid batteries have a DoD limit of 50% in order to maintain their health). Check your battery specs sheet for a more accurate number. Step 5: Is your load connected through an inverter? Select accordingly. (The inverter is the device that converts the DC current into AC current so we can run our household appliances) Step 6: Enter the total output load and select the unit type. The unit types are Watts (W), and kilowatts (kW). Note: 1 kW = 1000 watts. Lead Acid Battery Life (Runtime) Formula Formula: Lead-acid Battery life = (Battery capacity Wh × (85%) × inverter efficiency (90%), if running AC load) ÷ (Output load in watts).\ ExampleAdvertisements AdvertisementsLet’s suppose, Why none of The Above Methods Are 100% Accurate? I won’t go in-depth about the discharging mechanism of a lead-acid battery. Instead, I’m going to share the key points to remember when discharging your lead-acid battery. 1. The Faster You Discharge A Lead Acid Battery The Less Energy You Get (C-Rating) The recommended discharge rate (C-rating) for lead acid batteries is between 0.2C (5h) to 0.05C (20h). Look at the manufacturer’s specs sheet to be sure. Formula to calculate the c-rating: C-rating (hour) = 1 ÷ C   Discharging your battery at a higher rate will increase the temperature in battery cells which as a result will cause power losses. e.g, a 100ah lead-acid battery with a C-rating of 0.05C (20 hours) will last about 20-25 minutes instead of 1 hour while running a 50 amp load (remember the 50% DoD limit). 2. Battery Age Count A lead-acid battery will lose its 20% storage capacity after 500-900 cycles (Look at the manufacturer’s specs sheet for an accurate value). So if you have an old battery it’ll store less power. As a result, it will deplete more quickly than the estimated time. 3. Batteries Don’t Discharge Evenly Your battery will be discharged at a different rate depending on how heavy the output load is connected. Which makes it really hard to guess the exact runtime of your battery.

Lead Acid Battery Life Calculator: (SLA, AGM, Gel) Read More »

Lithium Battery Watt Hour Calculator: (mAh / Ah ↔ Wh)

Use our lithium (LiFePO4) battery watt-hour calculator to convert the battery capacity from amp hours (Ah), or milliamp hours (mAh) to watt hours (Wh). How To Use This Calculator? 1 – Enter the battery capacity and select the unit type. The unit types are amp-hours (Ah), and milliamp-hours (mAh). For example, if you have a 100ah battery, enter 100 and select the unit type to Ah. 2 – Enter the battery voltage. Is this a 6v, 12v, 24v, or a 48v battery? It should be mentioned on the specs sheet of your battery or on the battery itself. 3 – Optional: Enter the number of batteries if you’re using multiple batteries. (Default value will be 1) How Do You Calculate Lithium Battery Watt-Hours? Multiply the battery capacity in amp-hours (Ah) by the battery voltage to calculate watt hours (Wh). Formula: Battery capacity Watt-hours = Battery capacity Ah × Battery voltage Example Let’s say you have a 12v 200ah lithium battery. Lithium Battery Amp-Hours To Watt Hour Calculation AdvertisementsHere’s a chart about different capacity (Ah) lithium batteries into watt hours @ 12v, 24, and 48v. Battery Ah watt-hours @ 12v watt-hours @ 24v watt-hours @ 48v 20Ah 240 Wh 480 Wh 960 Wh 50Ah 600 Wh 1200 Wh 2400 Wh 70Ah 840 Wh 1680 Wh 3360 Wh 100Ah 1200 Wh 2400 Wh 4800 Wh 120Ah 1440 Wh 2880 Wh 5760 Wh 150Ah 1800 Wh 3600 Wh 7200 Wh 200Ah 2400 Wh 4800 Wh 9600 Wh 300Ah 3600 Wh 7200 Wh 14,400 Wh 400Ah 4800 Wh 9600 Wh 19,200 Wh Why Calculate Battery Watt-Hours? Energy is equal to amp-hours multiplied by volts. Converting battery amp hours to watt-hours will give an idea of how much actual energy your battery can store or deliver. For example, A 36v 12.8ah battery can store or deliver more energy than a 12v 30ah battery. The benefit of converting battery amp hours to watt-hours:

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Solar Panel Efficiency Calculator and Formula

Use our solar panel efficiency calculator to quickly calculate the efficiency of a solar panel. Also, let’s explain: Why you should care about solar panel efficiency — does it really matter? — Is it worth paying extra cash for highly efficient solar panels? How To Use Solar Efficiency Calculator? – Enter solar panel maximum power output (Pmax). For example, Enter 100 for a 100-watt solar panel. The value should be entered in watts (watts = kW × 1000). 2 – Enter solar panel dimensions (height and width and select the unit type). The unit types are millimeters (mm), and inches (inch). Usually, you’ll find the values on the backside of your solar panels or on the spec data sheet. Unit type for height and width should be the same. How To Calculate Solar Panel Efficiency? Solar panel efficiency formula: Solar panel efficiency = [ solar panel Max. output P(max) ÷ (solar panel area in m2 × 1000) ] × 100 Advertisementslet’s take the Renogy 100-watt solar panel as an example. Solar panel efficiency = [ 100 ÷ (0.54 × 1000) ] × 100 Solar panel efficiency = [ 100 ÷ (540) ] × 100 Solar panel efficiency = [ 0.18 ] × 100 Solar panel efficiency = 18.5 Solar Panel Efficiency: Explanation Solar panel efficiency is the measurement of a solar panel’s ability to convert the sunlight (irradiance) that falls on its surface area into electricity. For example, a 20% efficient solar panel with an area of 1 m2 (10.7 square feet) will produce about 200 watts and a 15% efficient solar panel with the same room will produce about 150 watts under standard test conditions — STC. Due to the advancement in photovoltaic technology in recent years, now most solar panels are about 20 — 22% efficient. As the efficiency of a solar panel increases, so will its cost. You may ask now, is it worth paying extra bucks for a highly efficient solar panel system? let’s find out. Solar Panel Efficiency — Does It Really Matter? You might think, a highly efficient solar panel will produce more power than a low-efficient solar panel. Well, that’s not exactly the case. The wattage rating of a solar panel is the single big factor that will determine the solar system’s power production, not efficiency.

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Battery Runtime Calculator: How Long Does Battery Last?

How long will your battery last? find out with our easy-to-use battery runtime calculator. Calculator Assumptions Limitations Of This Calculator How To Use Our Battery Runtime Calculator? 1. Enter battery capacity in amp-hours (Ah): If the battery capacity is mentioned in watt-hours (Wh), Divide the watt-hours by battery voltage (V) to find out the battery capacity in Ah. 2. Enter your battery voltage (V): Do you have a 12v, 24, or 48v battery? For a 12v battery, ENTER 12. 3. Select your battery type: For lead acid, sealed, flooded, AGM, and Gel batteries select “Lead-acid” and for LiFePO4, LiPo, and Li-ion battery types select “Lithium”. 4. Enter your battery’s state of charge (SoC): SoC of a battery refers to the amount of charge it has relative to its total capacity. A fully charged battery will have 100% SoC. 5. Enter your battery’s recommended depth of discharge (DoD) limit: Battery depth of discharge (DoD) measures the used capacity of your battery from its total capacity. Lead-acid, AGM, sealed, flooded, and Gel batteries should not be discharged below 50%, while only lithium (LiFePO4, LiPo, and Li-ion) batteries can be safely depleted to 100%. Ask your manufacturer or have a look on at your battery’s specs sheet for a more accurate value. 6. Is your load connected through an inverter? Select yes, if you’re using an inverter to run the AC appliances. Or select no, if the appliance is directly connected to the battery without an inverter (usually not recommended). 7. Enter total output load in watts: If your appliance has an output load mentioned in amps, convert it into watts by multiplying the amps by the given volts of the appliance. 2 Ways To Calculate Battery Runtime Ready for calculation? Let’s dive in! I’ll share 2 methods to estimate battery life from basic (least accurate) to advanced (most accurate). Formula 1 Formula: Battery capacity in Ah ÷ Output amps (A) Or, Battery runtime = Battery capacity in watt-hours (Wh) ÷ Total Output in watts Accuracy: Lowest Dividing the battery capacity (in amp-hours – Ah, or milliamp-hours – mAh) by the output load (in amps – A, or milliamps – mAh) is the least accurate way to calculate the battery runtime. Because it doesn’t take into account for battery’s discharge efficiency rate, recommended depth of discharge, and state of charge. Mostly, the battery capacities are mentioned in amp-hours (Ah) but our appliances are in watts. Which makes it confusing in the first place. You can convert the battery capacity in watt-hours or the appliance input capacity into watt-hours to make it work. Battery capacity in watt-hours = Battery Ah × Battery voltage AdvertisementsOutput load in load in amps = Load in watts ÷ volts Example Let’s say you have: To calculate 50ah battery lifetime using this formula, divide 50ah by 10a.50ah ÷ 10a = 5 hrs According to this formula, a 50-ah battery will run a 10-amp load for 5 hours. Formula 2 Formula: Battery runtime = (Battery Ah × Battery volts × discharge efficiency × DoD limit × SoC × inverter efficiency) ÷ load Accuracy: Highest This formula takes into account for battery’s discharge efficiency rate, recommended depth of discharge, and state of charge. Based on data: Example Let’s continue with the previous example and find out the most accurate runtime estimate. Let’s say you have: Now let’s put this info into our 2nd formula. (50ah × 12v × 85% × 50% × 100% × 90%) ÷ 120 watt (229.5) ÷ 120 watt = 1.9 hours Turns out, in actuality a 50ah battery will run a 10A load for about 1.9 hours. Why None Of These Methods Guarantee 100% Accuracy? Battery runtime formulas aren’t fully accurate due to the complexity of battery discharge, as there are other factors that can impact discharge time. Which are… 1. Batteries Discharge Unevenly If you discharge a battery too quickly, it won’t provide as much energy as the label claims, known as Peukert’s law. This is because more energy turns into heat instead of powering devices when discharged quickly. The effect of Peukert’s law on Lead-acid vs. Lithium: Lead acid batteries lose energy faster when discharged quickly, while lithium batteries can be discharged at up to 50% of their capacity without losing power. Here’s an example of how discharge time affects the usable capacity of a 100ah lead acid battery. Usable 100ah lead acid battery capacity Hours of discharge 100ah 20 hours 90ah 10 hours 87ah 8 hours 82ah 6 hours 80ah 5 hours 70ah 3 hours 60ah 2 hours 50ah 1 hour 2. Battery Life Cycles Matter Batteries can only be charged and discharged for a limited number of times, which is called the life cycle. Lead-acid batteries last for a few hundred cycles if they are maintained properly. Lithium batteries can last for thousands of cycles. But as batteries are used and charged more, they hold less charge capacity. After about 500 cycles, a lead-acid battery will lose about 20% of its capacity, while a lithium battery will 20% of its capacity after about 2000 cycles. Check your battery’s data sheet for more accurate numbers. 3. Effect Of Temperature On Batteries Performance Temperature affects how well your battery works. Usually, batteries work best when it’s between 68°F and 77°F (20°C to 25°C). A higher or lower temperature (than what’s recommended) will affect the battery’s performance. A rule of thumb is “an increase or decrease in temperature to 77ºF or 25º C can reduce battery performance by 50%”. To get the most out of your battery, keep it at the right temperature by using a cooling system or putting it in a spot where it won’t get too hot or too cold. How Long Does A 12v Battery Last? Here’s a chart on how long 12v different amp-hour (Ah) batteries will last running a 10-watt load. Battery Size (Ah) Runtime (Lead-acid) Runtime (Lithium) 6ah 3 hrs 6 hrs 7ah 3 hrs 7 hrs 12ah 6 hrs 12 hrs 18ah 8 hrs 19 hrs 20ah 9 hrs 21 hrs 36ah 17 hrs 37 hrs 50ah 23 hrs 52 hrs 60ah 28 hrs 62 hrs 70ah 32 hrs 73 hrs 80ah 37 hrs

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Solar Panel Size Calculator – Charge Your Battery In Desired Hours

Use our solar panel size calculator to find out what size solar panel you need to charge your battery in desired time. Simply enter the battery specifications, including Ah, volts, and battery type. Also the charge controller type and desired charge time in peak sun hours into our calculator to get your result Calculator Assumptions How To Use Our Solar Panel Size Calculator? 1. Enter battery Capacity in amp-hours (Ah): For a 100ah battery, enter 100. If the battery capacity is mentioned in watt-hours (Wh), divide Wh by the battery’s voltage (v). 2. Enter battery volts (V): Is this a 12, 24, or 48-volt battery? 3. Select battery type: Is this a lead-acid, AGM, or lithium-ion (LiFePO4) battery? 4. Enter battery depth of discharge (DoD): Battery DoD This is the percentage of the battery discharged relative to the total battery capacity. For half discharged battery you ENTER 50, and if the battery is fully discharged which you can achieve on a lithium battery, ENTER 100. 5. Select charge controller type: Are you using a PWM or MPPT charge controller to charge the battery?  6. Enter desired charge time (in peak sun hours): How fast would you like to charge your battery or how many peak sun hours your location receives? For Example Let’s suppose, you have: Result: You need about a 120-watt solar panel to fully charge a 12v 50ah lithium (LiFePO4) battery from 100% depth of discharge in 6 peak sun hours. 6 Steps To Calculate The Perfect Solar Panel Size For BatteryAdvertisements Follow these 6 steps to calculate the estimated required solar panel size to recharge your battery in the desired time frame. Steps Batteries are quite complex, making it nearly impossible to calculate the exact solar panel size needed to recharge them in a desired timeframe. However, I have covered the most impactful real-world factors in these steps. 1- Multiply the battery amp-hours (ah) by battery volts to convert the battery capacity into watt-hours (Wh). Let’s suppose you have a 12v 50ah battery. 2- Multiply the battery watt-hours by the battery depth of discharge limit. Lead-acid, AGM, and gel batteries come with a depth of discharge limit of 50%, and lithium batteries with 100% DoD. Let’s say you have a 12v 50ah lead-acid battery. 3- Divide the battery capacity after DoD by the battery’s charge efficiency rate (lithium: 99%; Lead-acid: 85%). Advertisements4- Divide the battery capacity value (after charge adding efficiency factor) by the desired number of charge peak sun hours. Let’s suppose you want to recharge your battery in 5 peak sun hours. 5- Divide the solar power required in peak sun hour by the charge controller efficiency (PWM: 80%; MPPT 98%). Let’s suppose you’re using a PWM charge controller. 6- Add 20% to the solar power required after the controller to cover up the solar panel inefficiency.

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Solar Battery Charge Time Calculator (12v, 24v, 48v)

Use our solar battery charge time calculator to find out how long will it take to charge a battery with solar panels. How To Use Our Solar Battery Charge Time Calculator? To use the calculator, follow these steps: 1. Enter the total solar system size in watts: If you have multiple solar panels connected together, add their rated wattage and enter the total value in watts into the calculator. 2. Enter the battery capacity in amp-hours (Ah): If the battery capacity is given in watt-hours, divide the watt-hours by the battery voltage to find out the amp-hours. For example, enter 50 for a 50Ah battery. 3. Enter the battery voltage (V): Is this a 12, 24, or 48-volt battery? Enter 12 for a 12V battery. 4. Select your battery type from the options provided. 5. Enter the battery depth of discharge (DoD): Battery DoD indicates how much of the battery capacity is discharged relative to its total capacity. For example, enter 50 for a battery that is half discharged, and enter 100 for a battery that is fully discharged (which is achievable only with lithium batteries). 6. Select the charge controller type: Which type of charge controller are you using? PWM or MPPT? 7. find out the estimated battery charge time. Note: The calculator assumes the following efficiencies: 1. Battery charge efficiency – Lead-acid — 85%, lithium — 95% 2. Charge controller efficiency – PWM — 80%, MPPT — 95% 3. Solar panel output efficiency – 80% How To Calculate Solar Panel Charge Time? Dividing the battery amp-hours (Ah) by the solar panel’s output amps (Ah ÷ charging amps) is the most inaccurate way to calculate the battery charge time. Instead, use this formula: Formula Solar battery charge time = (Battery Ah × Battery volts × Battery DoD) ÷ (Solar panel size (W) × charge controller efficiency × battery charge efficiency × 0.8) This method takes into account most of the real-world factors that affect the battery’s charge time. Or follow these steps: Steps Let’s say you have a 12v 100ah lead acid battery with 50% Depth of discharge, a 100-watt solar panel, and an MPPT charge controller. 1. Multiply 12 by 100 to convert the battery capacity into watt-hours.12 × 100 = 1200 watt-hours 2. Multiple the battery capacity in watt-hours by its depth of discharge.1200 × 50% = 600 watt-hours 3. Multiply the solar panel-rated watts by the charge controller efficiency. PWM — 80%, MPPT — 95%.100 × 95% = 95 watts 4. Take into account for battery charge efficiency rate by multiplying the battery charge efficiency by the solar panel’s output (W) after the charge controller. AdvertisementsBased on data, on average: 95 × 85% = 80 watts 5. Take into account the solar panel’s output efficiency. Solar panels are designed to produce their rated wattage under ideal conditions, but in real-world conditions, on average, you’d receive about 80% rated output from your solar panel.80 × 80% = 65 watts 6. Now divide the battery capacity after DoD by the solar panel output (after taking into account the losses).600 ÷ 65 = 9.2 hours Turns out, a 100-watt solar panel will take about 9 peak sun hours to fully charge a 12v 100ah lead acid battery from 50% depth of discharge. How Fast Should You Charge Your Battery? Deep cycle or solar batteries are designed to charge and discharge at a specific rate, which is referred to as the c-rating. It’s important to note the recommended charge time for different types of batteries: Charging your battery at a higher rate than what’s recommended can increase the battery’s internal cell temperature, which will ultimately decrease the battery’s overall health and charging efficiency. Note: Refer to your battery’s data sheet to find its c-rating or maximum charge rate. Why none of The Above Methods Guarantee 100% Accuracy? Calculating the accurate charge time for a battery is a challenging task because there are numerous real-world factors that can impact it. Some of these factors include the state of charge of the battery, the absorption stage for lead acid and lithium batteries, solar panel output efficiency, and PWM charge controller efficiency. 1. Lead acid battery charge efficiency will depend on its state of charge (SoC). The below chart illustrates the lead acid battery charge efficiency based on its state of charge. lead acid battery charge efficiency will decrease drastically after 70-80% charge, that’s because of the absorption stage. 2. Absorption stage for lead acid and lithium battery: During the absorption stage, which is a phase in the battery charging process, a fixed amount of time is used to charge the battery, regardless of the amount of input power For lead acid batteries, this stage typically lasts between 2-3 hours and helps the battery reach its total capacity from 80% charge. The absorption stage is important for the health of the battery, as it helps to balance the battery cells and prevent damage. However, lithium batteries do not require an absorption stage, although charge controllers may perform a brief 20-30 minute absorption charge to balance the battery cells. 3. Solar panel output efficiency will depend on many factors, such as the tilt angle of the panel, weather conditions (e.g., sunny or cloudy), and ambient temperature. For example, if the panel is not tilted towards the sun, it may not receive optimal sunlight, resulting in lower efficiency. Similarly, if it’s cloudy or there is low light, the panel’s output will decrease. Moreover, solar panels become less efficient at higher temperatures, so if the ambient temperature is high, the panel’s output may be reduced. 4. The efficiency of a PWM charge controller can be affected by different factors, such as temperature and the voltage difference between the solar panels and the battery. A PWM charge controller can only lower the high voltage to match the battery voltage for safe charging but cannot increase the amps. As we know power (watts) = Amps × Volts. In contrast, an MPPT charge controller can reduce the voltage and boost the amps to compensate for any losses. High temperatures can cause the controller’s efficiency to decrease, while a greater voltage

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