How To Meadure Amp Hour Draw

September 29, 2021

Discussing electricity can become a charged topic in RV and gunkhole circles. But many campers and boaters are calculation solar solutions to and upgrading their electrical systems, so possessing a basic agreement of measuring currents, free energy, and storage can be helpful. Permit's run across if we tin break downwardly a few barriers and spark a conversation about turning watt-hours to amp-hours.

What is a Watt-Hour?
What is an Amp-60 minutes?
How Do Yous Convert Amp Hours to Watt Hours?
How Do You lot Catechumen Amp Hours from Watt Hours?
How Many Watt Hours in a 100 Ah Lithium Battery?
Where Tin can I Find an Ah to Wh Conversion Chart?
When Volition You Need to Make Watt- and Amp-Hour Calculations?
Knowledge Is Ability

What is a Watt-Hour?

A watt-hour (Wh) is a unit of free energy that measures the chapters of power (in watts) moving over fourth dimension (an 60 minutes). When talking most bombardment life, this would hateful the number of watts that an awarding uses per hour.

So, if an appliance is rated at 100W, it will utilise 100W of power in 1 hour and 200Wh in 2 hours. Conversely, if you accept five 100W devices running for ane hour, they would use 500Wh in total.

Here's the equation: (total number of watts) x (full number of hours) = watt-hours.

So, if you have a 60W bulb and you're trying to calculate how many watts your bulb uses in 24 hours, your equation would read sixty watts x 24 hours = 1440 watt-hours. Or, to use the abbreviated measurement, the answer would be 1440Wh.

What is an Amp-Hour?

An amp-hour is a measurement of current (in amps) flowing over a period (an hour). This measurement tells you the number of amps a device draws when you utilise it for an 60 minutes. Information technology's expressed with the abbreviation "Ah." Amp-hours is non a measurement of energy, simply rather a measurement of accuse. Because voltage is not included in an amp-60 minutes, you lot cannot calculate free energy from amp-hours alone.

If you have an 100Ah battery, this means it tin can expend 100 amps of energy in one hour. All the same, if you only utilize that 100Ah battery for half an hr, information technology can give 200A during that thirty-minute draw (if the battery operates at 100% efficiency).

How Do You lot Convert Amp Hours to Watt Hours?

When measuring your RV electrical system requirements, you'll need to catechumen watt-hours to amp hours. This will assist you in deciding on the voltage you will utilize, battery sizes, and even the thickness of wires for your solar system blueprint, etc.

The equation is watt-hours = amp-hours x volts.

In this example, if you don't know the number of watts, you'll multiply the total number of amp-hours times the voltage.

→ Need a quick refresher? Bank check out Amps, Volts, and Watts: Differences Explained

Equally an example, if you have a 12V battery for your RV, and your device is rated for 100Ah, you lot'll demand to multiply the amp hours by the volts: 100Ah x 12V = 1200Wh.

To showcase how amp-hours does not equal energy, yous could get the aforementioned 1200 watt-hours from a 24V battery. You'd multiply: 50Ah x 24V = 1200Wh.

watt hours and amp hours equations on chalkboard

How Do You Convert Amp Hours from Watt Hours?

On the flip side, if yous need to detect how many amp-hours (Ah) of current your electrical system can handle, use the following equation: amp-hours = watt-hours / voltage.

Permit's expect at an instance. If y'all're not certain your battery's amp hours, simply y'all know the watt-hours are 120, and the voltage is 12, you can summate the amp hours: 100Wh / 12V = 10Ah.

How Many Watt Hours in a 100 Ah Lithium Battery?

To answer this question, we demand to know the battery voltage. Let'southward assume it's a 12V lithium bombardment. Using the equation above, watt-hours = 100Ah x 12V. This means the bombardment'south capacity is one,200Wh.

Annotation that amp-hours volition vary slightly depending on nominal voltage. In a 12V Battle Born Battery, this is a little over 13V so nosotros meet around 1,300Wh of bachelor energy. This is partially why comparing battery amp-hours isn't apples to apples.

In the video below, Tom Morton of Mortons on the Motility compares "apples to apples" between atomic number 82-acid and lithium batteries with watt-hour capacities. He finds out but how hard it is to get the free energy ratings out of lead-acrid that they claim and just how much lithium batteries provide under diverse loads.

He likewise demonstrates that, over the life of ane of our Battle Built-in Batteries, the cost per watt-hour of energy is less than all of the tested atomic number 82-acid competitors! See the results hither: What is the Best Battery for the Money?

Where Can I Find an Ah to Wh Conversion Chart?

To assistance you with some quick and common amp-hour to watt-hr conversions, we've pulled together this handy chart for quick reference. Note that the watt-hours are with a 15-hour discharge at 70 degrees F, every bit energy capacities of batteries vary greatly with discharge and environmental conditions.

amp hour to watt hour conversion chart graphic

There are many conversion calculators and charts that you lot can find with a quick Google search.

But knowing the equations yourself volition help you add watts of several devices together to determine amperage needs for your RV. You lot never know when you'll demand to understand your battery'due south ability needs, and you don't take cell service to look it upwardly.

When Will Yous Demand to Make Watt- and Amp-Hr Calculations?

The biggest reason you lot'll demand to understand these calculations is to understand your bombardment's energy capacity. When trying to run a device on battery power, it'south important to sympathise how much bombardment capacity you'll need to run it.

You might too need to equate watt-hours to amp-hours when designing your solar setup. You'll make up one's mind how many watts you'll use in one twenty-four hours, adding each device'due south watts together. So you'll divide that full by the voltage in your rig to discover the amp-hours that will be created. This figure will determine the number and blazon of batteries you will demand, the size of solar panels required, and even the thickness of connecting wires.

Cognition Is Power

By understanding how amp-hours and watt-hours are related, you can effectively compare battery energy capacities. While multiple types of batteries are rated for "100 amp-hours," you now have the knowledge to figure out just how much energy those batteries will provide you and for how long. If yous ask united states of america, that'south some pretty crucial noesis when you lot need power off the grid.

Want To Learn More than About Electrical Systems and Lithium Batteries?

We know that building or upgrading an electrical organization can be overwhelming, and so we're here to help. Our Reno, Nevada-based sales and customer service squad is standing by at (855) 292-2831 to take your questions!

Also, join us on Facebook, Instagram, and YouTube to larn more about how lithium battery systems can power your lifestyle, see how others accept congenital their systems, and proceeds the conviction to become out there and stay out there.