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 results.

Solar Panel Size Calculator

Battery Capacity (Amp-hours)
Ah
Battery Voltage
V
Battery Type
Battery Depth of Discharge (DoD)
%
Charge Controller Type
Desired Charge Time (Peak sun hours)
hours

Note: If you already have a solar panel and want to know how long it will take to charge your battery, use our solar battery charge time calculator.

Calculator Assumptions

  1. Battery charge efficiency rate: Lead-acid - 85%, AGM - 85%, Lithium (LiFePO4) - 99%
  2. Charge controller efficiency: PWM - 80%; MPPT - 98% [1]
  3. Solar Panels Efficiency during peak sun hours: 80%, this means that a 100 watt solar panel will produce 80 watts during peak sun hours. Click here to read more.
  4. There are no devices drawing power from the battery during the charging process.

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? (click here to read more about peak sun hours, and how many peak sun hours your area receives).

Click “Calculate” button to get the result.

Note: Scroll to the bottom of this page (or click here) to find out how you can calculate the size of solar panels in the future without any need for an online calculator.

for Example

Let's suppose, you have:

  • Battery capacity: 50ah
  • Battery voltage: 12v
  • Battery type: Lithium (LiFePO4)
  • Battery depth of discharge: Fully discharged (100%)
  • Charge controller: MPPT
  • Desired charge time: 6 peak sun hours
What size solar panel to charge 50ah battery

Result: You need about 120 watt solar panel to fully charge a 12v 50ah lithium (LiFePO4) battery from 100% depth of discharge in 6 peak sun hours.

Read the below post to find out how fast you can charge your battery.

Related Post: Guide: Maximum Charging Current & Voltage For 12v Battery

6 steps to calculate the Perfect solar panel size For battery

Solar panel size calculator, how to calculate solar panel size, what size solar panel to charge battery, solar panel to recharge battery

Follow these 6 steps to calculate the estimated required solar panel size to recharge your battery in 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.

Battery capacity in Wh = 50 × 12 = 600wh

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.

Discharged Battery capacity in Wh = 600 × 0.5 = 300wh

3- Divide the battery capacity after DoD by the battery's charge efficiency rate (lithium: 99%; Lead-acid: 85%).

Power required to charge the battery = 300 ÷ 85% or 300 × 1.15 = 345wh

4- 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.

Solar power required in peak sun hour = 345 ÷ 5 = 69 watts

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.

Solar power required after charge controller = 69 ÷ 80% = 86.25 watts

6- Add 20% to the solar power required after the controller to cover up the solar panel inefficiency.

Solar panel Required = 86.2 + 20% = 103 watts

That's it! easy right?

Must Read: Battery Charge And Discharge Rate Calculator: C-Rating To Amps

Now I’ll show you tables and charts showing recommended solar panel sizes to charge different capacity batteries in different peak sun hours.

What Size Solar Panel To Charge 12v Battery?

Here's a chart about what size solar panel you need to charge different capacity 12v lead-acid and Lithium (LiFePO4) batteries in 6 peak sun hours using an MPPT charge controller.

12v Battery Size (Ah)Battery TypeRequired Solar Panel Size
20AhLead-acid30 watts
50AhLead-acid70 watts
60AhLead-acid80 watts
80AhLead-acid110 watts
100AhLead-acid140 watts
120AhLead-acid165 watts
140AhLead-acid190 watts
150AhLead-acid210 watts
170AhLead-acid235 watts
200AhLead-acid280 watts
220AhLead-acid300 watts
250AhLead-acid345 watts
300AhLead-acid415 watts
350AhLead-acid480 watts
400AhLead-acid550 watts
20AhLithium (LiFePO4)50 watts
50AhLithium (LiFePO4)120 watts
60AhLithium (LiFePO4)145 watts
80AhLithium (LiFePO4)190 watts
100AhLithium (LiFePO4)240 watts
120AhLithium (LiFePO4)290 watts
150AhLithium (LiFePO4)360 watts
170AhLithium (LiFePO4)410 watts
200AhLithium (LiFePO4)485 watts
220AhLithium (LiFePO4)530 watts
250AhLithium (LiFePO4)600 watts
300AhLithium (LiFePO4)730 watts
350AhLithium (LiFePO4)850 watts
400AhLithium (LiFePO4)970 watts

Summary

  • You need around 200-300 watts of solar panels to charge most of the 12V lead-acid batteries from 50% depth of discharge in 6 peak sun hours with an MPPT charge controller.
  • You need around 400-550 watts of solar panels to charge most of the 12V lithium (LiFePO4) batteries from 100% depth of discharge in 6 peak sun hours with an MPPT charge controller.

What Size Solar Panel To Charge 24v Battery?

Here's a chart about what size solar panel you need to charge different capacity 24v lead-acid & Lithium (LiFePO4) batteries in 6 peak sun hours using an MPPT charge controller.

24v Battery capacity (Ah)Battery TypeRequired Solar Panel Size
50AhLead-acid140 watts
100AhLead-acid280 watts
120AhLead-acid330 watts
150AhLead-acid415 watts
200AhLead-acid550 watts
300AhLead-acid930 watts
400AhLead-acid1100 watts
50AhLithium (LiFePO4)240 watts
100AhLithium (LiFePO4)480 watts
120AhLithium (LiFePO4)580 watts
150AhLithium (LiFePO4)730 watts
200AhLithium (LiFePO4)930 watts
300AhLithium (LiFePO4)1450 watts
400AhLithium (LiFePO4)1940 watts

Summary

  • You need around 300-500 watts of solar panels to charge most of the 24V lead-acid batteries from 50% depth of discharge in 6 peak sun hours with an MPPT charge controller.
  • You need around 600-900 watts of solar panels to charge most of the 24V lithium (LiFePO4) batteries from 100% depth of discharge in 6 peak sun hours with an MPPT charge controller.

Full article: What Size Solar Panel To Charge 24v Battery?

What Size Solar Panel To Charge 48V Battery?

Here's a chart about what size solar panel you need to charge different capacity 48v lead-acid & Lithium (LiFePO4) batteries in 6 peak sun hours using an MPPT charge controller.

24v Battery capacity (Ah)Battery TypeRequired Solar Panel Size
50AhLead-acid280 watts
100AhLead-acid550 watts
120AhLead-acid660 watts
150AhLead-acid830 watts
200AhLead-acid1100 watts
300AhLead-acid1660 watts
400AhLead-acid2200 watts
50AhLithium (LiFePO4)490 watts
100AhLithium (LiFePO4)970 watts
120AhLithium (LiFePO4)1160 watts
150AhLithium (LiFePO4)1460 watts
200AhLithium (LiFePO4)1940 watts
300AhLithium (LiFePO4)2900 watts
400AhLithium (LiFePO4)3880 watts

Summary

  • You need around 800-1000 watts of solar panels to charge most of the 48V lead-acid batteries from 50% depth of discharge in 6 peak sun hours with an MPPT charge controller.
  • You need around 1600-2000 watts of solar panels to charge most of the 48V lithium batteries from 100% depth of discharge in 6 peak sun hours with an MPPT charge controller.

What Size Solar Panel To Charge 120Ah Battery?

Here's a chart about what size solar panel you need to charge your 12v 120ah lead-acid (50% depth of discharge) and lithium battery (100% depth of discharge) with different peak sun hours and using an MPPT charge controller.

Charge TimeBattery TypeRequired Solar Panel
4 peak sun hoursLead-acid250 watts
5 peak sun hoursLead-acid200 watts
10 peak sun hoursLead-acid100 watts
15 peak sun hoursLead-acid65 watts
20 peak sun hoursLead-acid50 watts
25 peak sun hoursLead-acid40 watts
4 peak sun hoursLithium (LiFePO4)440 watts
5 peak sun hoursLithium (LiFePO4)350 watts
10 peak sun hoursLithium (LiFePO4)175 watts
15 peak sun hoursLithium (LiFePO4)115 watts
20 peak sun hoursLithium (LiFePO4)90 watts
25 peak sun hoursLithium (LiFePO4)70watts

Summary

  • You need around 200 watts of solar panels to charge a 12V 120ah lead-acid battery from 50% depth of discharge in 5 peak sun hours with an MPPT charge controller.
  • You need around 350 watts of solar panels to charge a 12V 120ah lithium battery from 100% depth of discharge in 5 peak sun hours with an MPPT charge controller.

Full article: Charging 120Ah Battery Guide

What Size Solar Panel To Charge 100Ah Battery?

Here's a chart about what size solar panel you need to charge a 12v 100ah lead-acid & lithium battery using an MPPT charge controller with different peak sun hours of sunlight.

Charge TimeBattery TypeRequired Solar Panel
4 peak sun hoursLead-acid210 watts
5 peak sun hoursLead-acid165 watts
6 peak sun hoursLead-acid140 watts
10 peak sun hoursLead-acid80 watts
15 peak sun hoursLead-acid55 watts
20 peak sun hoursLead-acid40 watts
4 peak sun hoursLithium (LiFePO4)360 watts
5 peak sun hoursLithium (LiFePO4)290 watts
6 peak sun hoursLithium (LiFePO4)240 watts
10 peak sun hoursLithium (LiFePO4)150 watts
15 peak sun hoursLithium (LiFePO4)100 watts
20 peak sun hoursLithium (LiFePO4)70 watts

Summary

  • You need around 210 watts of solar panels to charge a 12V 100ah lead-acid battery from 50% depth of discharge in 4 peak sun hours with an MPPT charge controller.
  • You need around 360 watts of solar panels to charge a 12V 100ah Lithium (LiFePO4) battery from 100% depth of discharge in 4 peak sun hours with an MPPT charge controller.

What Size Solar Panel To Charge 50Ah Battery?

Here's a chart about what size solar panel you need to charge a 12v 50ah lead-acid & lithium battery using an MPPT charge controller with different peak sun hours of sunlight.

Charge TimeBattery TypeRequired Solar Panel
4 peak sun hoursLead-acid100 watts
5 peak sun hoursLead-acid80 watts
6 peak sun hoursLead-acid70 watts
10 peak sun hoursLead-acid40 watts
15 peak sun hoursLead-acid30 watts
20 peak sun hoursLead-acid20 watts
4 peak sun hoursLithium (LiFePO4)180 watts
5 peak sun hoursLithium (LiFePO4)145 watts
6 peak sun hoursLithium (LiFePO4)121 watts
10 peak sun hoursLithium (LiFePO4)70 watts
15 peak sun hoursLithium (LiFePO4)50 watts
20 peak sun hoursLithium (LiFePO4)35 watts

Summary

  • You need around 100 watts of solar panels to charge a 12V 50ah lead-acid battery from 50% depth of discharge in 4 peak sun hours with an MPPT charge controller.
  • You need around 180 watts of solar panels to charge a 12V 50ah Lithium (LiFePO4) battery from 100% depth of discharge in 4 peak sun hours with an MPPT charge controller.

Related Post: How Long Will A 50Ah Battery Last?

What Size Solar Panel To Charge 20Ah Battery?

Here's a chart about what size solar panel you need to charge a 12v 20ah lead-acid & lithium battery using an MPPT charge controller with different peak sun hours of sunlight.

Charge TimeBattery TypeRequired Solar Panel
4 peak sun hoursLead-acid40 watts
5 peak sun hoursLead-acid33 watts
6 peak sun hoursLead-acid27 watts
10 peak sun hoursLead-acid16 watts
4 peak sun hoursLithium (LiFePO4)70 watts
5 peak sun hoursLithium (LiFePO4)60 watts
6 peak sun hoursLithium (LiFePO4)50 watts
10 peak sun hoursLithium (LiFePO4)30 watts

Summary

  • You need around 40 watts of solar panels to charge a 12V 20ah lead-acid battery from 50% depth of discharge in 4 peak sun hours with an MPPT charge controller.
  • You need around 70 watts of solar panels to charge a 12V 20ah Lithium (LiFePO4) battery from 100% depth of discharge in 4 peak sun hours with an MPPT charge controller.

What Size Solar Panel To Charge 150Ah Battery?

Here's a chart about what size solar panel you need to charge a 12v 150ah lead-acid & lithium battery using an MPPT charge controller with different peak sun hours of sunlight.

Charge TimeBattery TypeRequired Solar Panel
4 peak sun hoursLead-acid310 watts
5 peak sun hoursLead-acid250 watts
6 peak sun hoursLead-acid210 watts
10 peak sun hoursLead-acid125 watts
20 peak sun hoursLead-acid60 watts
4 peak sun hoursLithium (LiFePO4)550 watts
5 peak sun hoursLithium (LiFePO4)440 watts
6 peak sun hoursLithium (LiFePO4)360 watts
10 peak sun hoursLithium (LiFePO4)220 watts
20 peak sun hoursLithium (LiFePO4)110 watts

Summary

  • You need around 310 watts of solar panels to charge a 12V 150ah lead-acid battery from 50% depth of discharge in 4 peak sun hours with an MPPT charge controller.
  • You need around 550 watts of solar panels to charge a 12V 150ah Lithium (LiFePO4) battery from 100% depth of discharge in 4 peak sun hours with an MPPT charge controller.

Full article: What Size Solar Panel To Charge 150ah Battery?

What Size Solar Panel To Charge 200Ah Battery?

Here's a chart about what size solar panel you need to charge a 12v 200ah lead-acid & lithium battery using an MPPT charge controller with different peak sun hours of sunlight.

Charge TimeBattery TypeRequired Solar Panel
4 peak sun hoursLead-acid420 watts
5 peak sun hoursLead-acid330 watts
10 peak sun hoursLead-acid165 watts
20 peak sun hoursLead-acid80 watts
4 peak sun hoursLithium (LiFePO4)730 watts
5 peak sun hoursLithium (LiFePO4)580 watts
10 peak sun hoursLithium (LiFePO4)290 watts
20 peak sun hoursLithium (LiFePO4)150 watts

Summary

  • You need around 420 watts of solar panels to charge a 12V 200ah lead-acid battery from 50% depth of discharge in 4 peak sun hours with an MPPT charge controller.
  • You need around 730 watts of solar panels to charge a 12V 200ah Lithium (LiFePO4) battery from 100% depth of discharge in 4 peak sun hours with an MPPT charge controller.

Full article: What Size Solar Panel To Charge 200Ah Battery?

What Size Solar Panel To Charge 60Ah Battery?

Here's a chart about what size solar panel you need to charge a 12v 60ah lead-acid & lithium battery using an MPPT charge controller with different peak sun hours of sunlight.

Charge TimeBattery TypeRequired Solar Panel
4 peak sun hoursLead-acid125 watts
5 peak sun hoursLead-acid100 watts
10 peak sun hoursLead-acid50 watts
20 peak sun hoursLead-acid25 watts
4 peak sun hoursLithium (LiFePO4)220 watts
5 peak sun hoursLithium (LiFePO4)175 watts
10 peak sun hoursLithium (LiFePO4)90 watts
20 peak sun hoursLithium (LiFePO4)40 watts

Summary

  • You need around 100 watts of solar panels to charge a 12V 60ah lead-acid battery from 50% depth of discharge in 5 peak sun hours with an MPPT charge controller.
  • You need around 175 watts of solar panels to charge a 12V 60ah Lithium (LiFePO4) battery from 100% depth in 5 peak sun hours with an MPPT charge controller.

Full article: What Size Solar Panel To Charge 60Ah Battery?

What Size Solar Panel To Charge 130Ah Battery?

Here's a chart about what size solar panel you need to charge a 12v 130ah lead-acid & lithium battery using an MPPT charge controller with different peak sun hours of sunlight.

Charge TimeBattery TypeRequired Solar Panel
4 peak sun hoursLead-acid270 watts
5 peak sun hoursLead-acid220 watts
10 peak sun hoursLead-acid110 watts
20 peak sun hoursLead-acid50 watts
4 peak sun hoursLithium (LiFePO4)470 watts
5 peak sun hoursLithium (LiFePO4)380 watts
10 peak sun hoursLithium (LiFePO4)190 watts
20 peak sun hoursLithium (LiFePO4)100 watts

Summary

  • You need around 220 watts of solar panels to charge a 12V 130ah lead-acid battery from 50% depth of discharge in 5 peak sun hours with an MPPT charge controller.
  • You need around 380 watts of solar panels to charge a 12V 130ah Lithium (LiFePO4) battery from 100% depth in 5 peak sun hours with an MPPT charge controller.

What Size Solar Panel To Charge 140Ah Battery?

Here's a chart about what size solar panel you need to charge a 12v 140ah lead-acid & lithium battery using an MPPT charge controller with different peak sun hours of sunlight.

Charge TimeBattery TypeRequired Solar Panel
4 peak sun hoursLead-acid290 watts
5 peak sun hoursLead-acid230 watts
10 peak sun hoursLead-acid115 watts
20 peak sun hoursLead-acid60 watts
4 peak sun hoursLithium (LiFePO4)510 watts
5 peak sun hoursLithium (LiFePO4)410 watts
10 peak sun hoursLithium (LiFePO4)200 watts
20 peak sun hoursLithium (LiFePO4)100 watts

Summary

  • You need around 290 watts of solar panels to charge a 12V 140ah lead-acid battery from 50% depth of discharge in 4 peak sun hours with an MPPT charge controller.
  • You need around 510 watts of solar panels to charge a 12V 140ah Lithium (LiFePO4) battery from 100% depth in 4 peak sun hours with an MPPT charge controller.

Full article: What Size Solar Panel To Charge 140ah Battery?

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Chris Tsitouris is a renewable energy professional with 10+ years of experience as Director of Engineering at Solar Spectrum, previously working as Project Manager at SunPower and Energy Analyst at the National Renewable Energy Laboratory. As a thought leader, Chris has authored numerous articles and research papers.

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