“Enter the battery specs and output load in watts into our battery runtime calculator“ to find out how long will a 24v battery last running a load
Also, I’ll explain some other factors as well which can affect the battery runtime.
24v Battery Runtime Calculator
Note! use my solar panel size calculator to find out what size solar panel you need to recharge your battery in desired hours with solar panels.
- Inverter Efficiency: 90%
- Lead-acid battery: 50% depth of discharge limit
- Lithium (LiFePO4): 100% depth of discharge limit
Battery Depth of discharge DoD: is the percentage of the battery that has been discharged relative to the total battery capacity. The recommended depth of discharge limit for lead-acid, AGM, and gel batteries is about 50%. Only lithium (LiFePO4) batteries can be fully discharged to 100%.
How To Use The Calculator
- Enter the battery capacity in amp-hours (Ah): Enter the battery capacity in amp-hours (ah), for 100ah battery you need to enter 100.
- Enter the battery voltage: is this a 12, 24, or 48-volt battery? in case it’ll be 24
- Select the battery type: Select “Lead-acid” if you’re using a flooded or sealed (AGM or gel) lead acid battery. Select “Lithium (LiFePO4)” if you use a lithium-iron phosphate battery.
- load Connected with inverter?: Are you using an inverter to run the load or is the load connected directly through the battery?
- Enter total load in watts: Enter the total load in watts (e.g 500 for 500 watts of output load)
After entering the information, click “Calculate” button to find out how long will a 24v battery last
if you’ve got some time keep reading… I’ll share a manual calculation method that you can use in the future to calculate any size battery runtime on any load and also some additional information about batteries that will affect the battery last time.
Example: how long will a 24v 200ah battery last?
24v 200ah lead-acid battery with 50% DoD limit will last between 4.3 hours (running a 500 watt AC load) to 1 hour (running a 2000 watt AC load)
Video – All about battery basics (Must watch!)
Steps to calculate 24v battery runtime
Follow these steps to calculate the battery life/runtime while running a load.
1- Converter battery ah into watt-hours (Wh). to calculate the battery capacity in watt-hours use this formula
Battery capacity in watt-hours = Battery amp-hours (Ah) * Battery Volts
let’s say you have a 24v 100ah battery
100ah battery in watts = 100 * 24 = 2400 watt-hours
2- Multiply the battery watt-hours by the battery depth of discharge limit. ( Default battery depth of discharge limit, Lead-acid battery: 50% DoD limit; Lithium: 100% DoD limit ). Let’s say you have a lead-acid type battery
Battery capacity in wh after DoD limit = 2400 * 50% = 1200wh
3- Multiply the battery capacity after the DoD limit with the inverter efficiency rate to calculate the AC watt-hours ( Most of the inverters are about 90% efficient)
Battery AC watts = 1200 * 90% = 1080 AC watt-hours
4- Divide the battery AC watt-hours by the total load connected. Let’s say 500-watt appliance is connected to your 24v 100ah battery
100ah battery runtime on 500w appliance = 1080 / 500 = 2.1 hours
Note: There are some shortcoming of these methods which i’ll discuss at the end of this post
how long does a 24 volt battery last?
Here’s a chart on how long will a 24v different capacity lead-acid & lithium (LiFePO4) battery will last running a 100 watts of AC load.
|24v Battery Capacity||Battery Type||Est. Runtime on 100-watt appliance|
|100ah||Lithium (LiFePO4)||22 hours|
|200ah||Lithium (LiFePO4)||43 hours|
|300ah||Lithium (LiFePO4)||65 hours|
|400ah||Lithium (LiFePO4)||87 hours|
- 24v lead-acid battery will last between 11 to 40 hours while running a 100-watt AC load.
- 24v Lithium (LiFePO4) battery will last between 22 to 80 hours while running a 100-watt AC load.
How long will a 24v 200Ah battery last – Chart
Here are some examples of how long will a 24v 200Ah battery will last while running appliances
|Home Appliance||Rated watts||Estimated run hours|
|Fridge||200 watts||28 Hours|
|TV||50 watts||76 hours|
|Toaster||1200 watts||3.2 hours|
|Computer||300 watts||12.8 hours|
|Ceiling Fan||60 watts||64 hours|
|Coffee machine||800 watts||4.8 hours|
|Air purifier||25 watts||153 hours|
|Space heater||1500 watts||2.5 hours|
|Oven||2000 watts||2 hours|
Note: after this, your battery will be fully drained so if you have an AGM or lead battery then the estimated hours will be half so make your calculations accordingly and also this estimated time is measured after subtracting the inverter efficiency from the total watts of 24v 200ah battery 4800 – 15% = 3840
Assumptions & Shortcomings of All These Methods
Here are some extra yet important points to keep in mind when figuring out how long will your 24v battery will last running a load
Battery life cycle count:
- The storage capacity of the battery will decrease with every cycle ( a cycle is when you charge and discharge the battery to its DoD limit ).
- if you have used your battery for a few hundred cycles then the result will be different. ( this factor isn’t included in my above-given methods )
Batteries are rated for 5 amps over 20 hours of time:
- Especially lead-acid type batteries are designed to be discharged at 20 hours. ( means 100ah lead-acid batteries are recommended to be discharged @ 5 amps in order to maintain the battery health and reduce the discharge efficiency ).
- on the other hand, AGM and lithium (LiFePO4) can be discharged at 50% of their capacity.
- Discharging your battery at a higher rate will increase heat in the battery’s internal cells which will cause power loss. (this factor isn’t included in my above-given methods).
- For example, if you discharge your lead-acid battery with 100 amps then it’s will not last 30 minutes ( keep in mind the 50% DoD limit ). but it may last about 10-15 minutes.
- Check the battery discharge rate on the specs sheet of your battery or it’ll be mentioned on the battery (1h → 1C, 2h → 0.5C, 5h → 0.2C, etc.)
Some Related FAQ’s
Yes, a 24v battery last longer than a 12v same-sized battery because a 24v battery can store more watts than a 12v battery (Watt = Ah x Volts)
24v 400Ah battery is equal to 9600 DC watts which will last 96 hours while running 100W DC appliance and 81 hours with an 85% efficient inverter (9600-15% = 8100)
using a charge controller will automatically block the power supply to the battery which as a result will not overcharge your 24v battery
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I hope this guide was helpful to you, if you have any queries Contact US thank you!