How Long To Charge 100Ah Battery? + Calculator & Charts

Use our battery charge time calculator to find out “How Long Does It Take To Charge A 100Ah Battery with solar panels?”

100Ah Battery Charge Time Calculator With Solar Panels

Solar Panel Size
Watts
Battery Capacity (Ah)
Ah
Battery Volts (V)
Volts
Battery Type
Battery Depth of Discharge (DoD)
%
Charge Controller Type


Tip: Use this solar panel size calculator to find out what size solar panel you need to charge your battery in desired peak sun hours.

Note: The estimated charge time is not the total number of sunlight hours but the number of peak sun hours (keep reading I’ll explain in a bit).

Calculator Assumptions

  1. Lead-acid, AGM, & Gel Battery charge efficiency: 85% 
  2. Lithium (LiFePO4) charge efficiency: 98%
  3. MPPT Charge Controller: 98% efficient
  4. PWM Charge Controller: 80% efficient
  5. Solar Panel Efficiency: 80% (which is the most common figure)

What Are Solar Peak Sun Hours?

Before explaining peak sun hours and why to use them, first let’s see, how solar panels are rated.

“Solar panels are designed to produce their rated wattage output under standard test conditions – STC”.

STC includes: 

  • 1000 watts per meter square (1kw/m2) of sunlight intensity hitting the solar panels directly.
  • 25oC temperature. 

So to calculate the sunlight intensity we use peak sun hour as a reference. 

  • 1 peak sun hour = Average of 1kw/meter2 of sunlight intensity for one hour.

This number will depend on the location to location. To calculate how many peak sun hours your city receives use this PVwatt solar calculator.

Step 1: Enter your full address of just a city name & Click GO

Step 2: Click on results

How many peak sun hours in florida?

Now you’d be able to see the total amount of solar radiation your location receives per day (from month to month)

Note! it would have to place my solar panels all day long under sunlight to get those total solar radiations per day. 

Read the below mentioned post to find out how much power output you can expect from your solar panels during peak sun hours. and also some tips to increase the solar panel’s output.

Must Read: Solar Panel Output Calculator – Average Solar Panel Output?

How Long To Charge 100ah Battery With 200 Watt Solar Panel?

Here’s a charge about how long a 200-watt solar panel will take to charge a 12v 100ah lead-acid and lithium battery using an MPPT or PWM charge controller

Solar Panel Size12v 100ah Battery TypeCharge Controller TypeEst. Charge Time
200 wattlead-acidPWM5.1 peak sun hours
200 wattLithium (LiFePO4)PWM9.1 peak sun hours
200 wattlead-acidMPPT4.2 peak sun hours
200 wattLithium (LiFePO4)MPPT7.5 peak sun hours

Summary

  • 12v 100ah lead-acid battery will take about 4.2 peak sun hours to get fully charged from 50% depth of discharge with 200-watt solar panel using an MPPT charge controller
  • 12v 100ah lithium (LiFePO4) battery will take about 7.5 peak sun hours to get fully charged from 100% depth of discharge with 200 watt solar panel using an MPPT charge controller

How Long To Charge 100ah Battery With 100 Watt Solar Panel?

Here’s a charge about how long a 100-watt solar panel will take to charge a 12v 100ah lead-acid and lithium battery using an MPPT or PWM charge controller

Solar Panel Size12v 100ah Battery TypeCharge Controller TypeEst. Charge Time
100 wattlead-acidPWM10 peak sun hours
100 wattLithium (LiFePO4)PWM18 peak sun hours
100 wattlead-acidMPPT8.5 peak sun hours
100 wattLithium (LiFePO4)MPPT14 peak sun hours

Summary

  • 12v 100ah lead-acid battery will take about 8.5 peak sun hours to get fully charged from 50% depth of discharge with 100-watt solar panel using an MPPT charge controller
  • 12v 100ah lithium (LiFePO4) battery will take about 14 peak sun hours to get fully charged from 100% depth of discharge with 100 watt solar panel using an MPPT charge controller

How Long To Charge 100ah Battery With 400 Watt Solar Panel?

Here’s a charge about how long a 400-watt solar panel will take to charge a 12v 100ah lead-acid and lithium battery using an MPPT or PWM charge controller

Solar Panel Size12v 100ah Battery TypeCharge Controller TypeEst. Charge Time
400 wattlead-acidPWM2.5 peak sun hours
400 wattLithium (LiFePO4)PWM4.5 peak sun hours
400 wattlead-acidMPPT2.1 peak sun hours
400 wattLithium (LiFePO4)MPPT3.7 peak sun hours

Summary

  • 12v 100ah lead-acid battery will take about 2.1 peak sun hours to get fully charged from 50% depth of discharge with 400-watt solar panel using an MPPT charge controller
  • 12v 100ah lithium (LiFePO4) battery will take about 3.7 peak sun hours to get fully charged from 100% depth of discharge with 400-watt solar panel using an MPPT charge controller

How Long To Charge 100ah Battery With 300 Watt Solar Panel?

Here’s a charge about how long a 300-watt solar panel will take to charge a 12v 100ah lead-acid and lithium battery using an MPPT or PWM charge controller

Solar Panel Size12v 100ah Battery TypeCharge Controller TypeEst. Charge Time
300 wattlead-acidPWM3.4 peak sun hours
300 wattLithium (LiFePO4)PWM6 peak sun hours
300 wattlead-acidMPPT2.8 peak sun hours
300 wattLithium (LiFePO4)MPPT5 peak sun hours

Summary

  • 12v 100ah lead-acid battery will take about 2.8 peak sun hours to get fully charged from 50% depth of discharge with 300-watt solar panel using an MPPT charge controller
  • 12v 100ah lithium (LiFePO4) battery will take about 5 peak sun hours to get fully charged from 100% depth of discharge with 300-watt solar panel using an MPPT charge controller

How Long To Charge 100ah Battery With 10 Amp Charger?

To Calculate how long to charge a 100ah battery 10 amp charger follow these steps.

1- Multiply the battery capacity (ah) with its depth of discharge (DoD). let’s say you have a lead-acid battery with a 50% depth of discharge

100 * 50% or 100 * 0.5 = 50 amp-hours (Ah)

2- Divide battery amp-hours after the depth of discharge by the charger amps

50 / 10 = 5 hours.

10 amp charger will take 5 hours to fully charge the lead-acid 100ah battery from 50% depth of discharge and 10 hours to fully charge the Lithium (LiFePO4) battery from 100% depth of discharge.

How Long To Charge 100ah Battery With Solar Panel?

Here’s a chart about how long will it take to charge a 12v lead-acid or lithium battery with different size solar panels using an MPPT charge controller

Solar Panel Size100ah Battery TypeEst. Charge Time
50 wattLead-acid17 peak sun hours
100 wattLead-acid8.5 peak sun hours
150 wattLead-acid5.6 peak sun hours
200 wattLead-acid4.2 peak sun hours
300 wattLead-acid2.8 peak sun hours
400 wattLead-acid2 peak sun hours
500 wattLead-acid1.7 peak sun hours
50 wattLithium (LiFePO4)30 peak sun hours
100 wattLithium (LiFePO4)15 peak sun hours
150 wattLithium (LiFePO4)10 peak sun hours
200 wattLithium (LiFePO4)7.5 peak sun hours
300 wattLithium (LiFePO4)5 peak sun hours
400 wattLithium (LiFePO4)3.7 peak sun hours
500 wattLithium (LiFePO4)3 peak sun hours

Summary

  • 12v 100ah lead-acid battery will take about 3 – 8 peak sun hours to get fully charged from 50% depth of discharge with solar panel.
  • 12v 100ah lithium (LiFePO4) battery will take about 5 – 10 peak sun hours to get fully charged from 100% depth of discharge with solar panel

How To Calculate How Long To Charge Battery With Solar Panels?

To calculate manually how long will it take to charge the battery with a solar panel follow these steps.

Steps

1- convert the battery capacity from amp-hours (Ah) to watt-hours (Wh) by multiplying the battery capacity (Ah) by battery volts. let’s say you have a 12v 100ah battery

Battery capacity in watt-hours = 100 * 12 = 1200wh or 1.2 kwh 

2- Multiply the battery capacity watt-hours by the battery depth of discharge %. let’s suppose you have a lead-acid battery with a 50% depth of discharge limit (DoD).

Discharged battery capacity in watt-hours =  1200 * 50% or 100 * 0.5 = 600wh

3- Multiply the discharged battery capacity (Wh) by 1.15 for lead-acid and 1.02 for lithium battery ( Battery charge efficiency rate, lead-acid; 85% efficient, lithium-ion; 98% efficient ).

Energy required to charge the battery = 600 * 1.15 = 690 watt-hours

4- Multiply the solar panel wattage by 80% to into account system losses. let’s suppose you have a 200 watt solar panel

Average solar panel output = 200 * 80% = 160 watts

5- Multiply the average solar panel output by the charge controller efficiency rate ( PWM; 80%, MPPT; 98% ). Let’s say you have an MPPT charge controller

Solar panel output after charge controller = 160 * 98% = 156.8 watts

6- Divide the Energy required to charge the battery by the solar panel output value after the charge controller.

Solar panel size required = 690 / 156.8 = 4.4 hours 

Note! Charge time (hours) will be the number of peak sun hours.

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I'm an experienced Sales Consultant with a demonstrated history of working in the renewables and environment industry. Skilled in Photography, Customer Service, and Sales.

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