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EV Basics – What’s a kilowatt hour?

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Tesla Model S dash display

So what’s a kilowatt hour or shall we ask Watts a Kilowatt hour?

As more car buyers take the plunge into owning an electric vehicle (EV), it’s important to educate on the EV specific units of measure which differ greatly than your traditional gas burning vehicle. What is a kilowatt hour? How does it differ from a kilowatt? And why does this even matter?

Background

First, let me preface everything by saying that much of what I’m about to write is based on US specific units of measure since that’s what I’m familiar with. For instance, miles vs km and US dollars versus Euros. I’m also over simplifying and breaking things down to basic laymen terms so please cut me some slack if you already know all this!

If you receive a utility bill for your residence then you should probably be somewhat familiar with, or have heard of, a kilowatt (kW) and kilowatt hours (kWh) since that’s what electricity bills are measured on. Your EV is no different and uses these same units of measure although it’s probably something you haven’t paid much attention to in the past.

kW and kWh Units

Depending on the EV display you may see watt hours (Wh) or kilowatt hours (kWh) in some places and watts (W) and kilowatts (kW) in others. The kilo or k is a standard prefix meaning a thousand. So 1 kWh is 1,000 Wh. If you own your EV long enough you may just get to the next level, megawatt hour (MWh) which would be one million Wh!

Now for the fundamental definitions:

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kW is a measurement of power and kWh is a measurement of energy.

Energy is the amount of work that can be performed. kWh, calories, joules are all units of energy. A slice of pizza has 285 calories which is 0.33 Wh of energy that can be derived from that substance. Energy can be converted and change in form. For instance we can convert that slice of pizza to heat by setting it on fire. The fuel is the pizza, but don’t try converting it in your EV!

Tesla-Model-S-Dash-Energy

Power is the rate at which energy is generated or used. kW is a unit of power. When you accelerate in your EV you’re using power and when you decelerate with regenerative braking you’re generating power. The Model S dedicates half the speedometer display to the unit of power on the right side. There you can see how many kW you are using (indicator is orange) or generating (indicator is green) at any instance in time. It’s great to be able to see this however you can’t easily convert this into a cost. In order to do that, you’ll need to measure it over time and convert it into a unit of energy.

Power is similar to your speed. 50mph is your speed, but you have to maintain that for an hour to travel 50 miles. Similarly, 40kW is how much power you’re using and you’ll have to maintain that consumption for one hour to use 40kWh. If you spend half that hour at 40kW and the other half at 20kW you’ll end up consuming 30kWh. Power usage is constantly changing and will depend on driving habit as well as usage of onboard amenities such as your seat heaters or A/C unit.

A 100W incandescent light bulb used over 1 hour will consume 100Wh of energy. If you use that 100W bulb for 8 hours every day, it will consume 800W or 0.8 kWh per day. After 30 days, it will have consumed 0.8kWh x 30 = 24 kWh. After 365 days it will have consumed 292 kWh. Measuring your EV is done in a similar fashion but keep in mind that an EV can both use and generate power (regenerative braking) over periods of time. The difference or net power used (used – generated) is what you see reported on your EV display.

Units for Charging

Charging RateCharging your EV you transfers energy back into your battery so you’re effectively storing kWh for later use. EVs report charging in different ways but the most common is to report by kW and kWh added. So a charge rate of 6 kW is storing 6kWh for every hour of charge. If you’re charging at 6kWh and charge for 2 hours you’ll have an extra 12kWh added at the end of your charge.

When it comes to driving, we’re trained to think in terms of miles, but not all miles travelled are the same when it comes to energy usage since there are variations in terrain and elevations. Weather also plays a factor for each mile travelled. A kWh stored, on the other hand, is always the same. The main difference is how you use that kWh.

The Model S offers the option to display charge rate by kW and kWh or by miles. Not surprisingly most Tesla owners choose to display charge rate in terms of miles. However it’s important to note that there’s a huge assumption being made about how many miles you can drive on a Wh and that assumption needs to account for charging efficiency. Tesla uses their proprietary algorithm to compute this value.

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Tesla-Model-S-Limousine-Watts-on-Wheels

On Tesla’s online calculator they assume 300Wh/mile average use and a 90% charging efficiency. My own measurements show the average Wh/mile usage to be a bit higher (306 lifetime average) and the charging efficiency to be slightly less (81% last month).

What about Volts vs Amps?

Now you may be wondering how all this relates to volts and amps. This gets us back to the basics. One can calculate watts by multiplying volts with amps. W = V x A. So if you’re at a public charger and it’s charging at 199V and 30A (reference picture above), you’re essentially charging at 199V x 30A = 5,970W or about 6kW. This equates to 6kWh added after an hour of charging, but as we all know this is based on an ideal world where it charges at 100% efficiency with no loss. At 199V and 30A, the Model S is reporting this as a rate of 16 mi/hr.

Lets check that math:

5,970W/300Wh/mile standard assumption = theoretical 20 miles/hr charge rate. But that doesn’t account for charging efficiency. The Model S is reporting 16 mi/hr so its assuming an 80% charging efficiency (16/20) under these conditions.

Cost

Electric Costs

Utility bills price per kWh. Your electric company may break it down by distribution vs generation, time of use, etc. and then associate a different cost per kWh on each pricing tier. It seems complex but you can simplify this.

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To figure out your total cost per kWh just take your total amount of the bill and divide it by your total energy usage for the same period. That may include the various service fees, taxes, etc. but in the end you’re paying the electric company that total amount for those kWh regardless of what it’s derived from. Knowing this will help you calculate the costs for your road trips based on the kWh used.

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Tesla Semi futuristic sci-fi acceleration sound will never get old

Videos that capture the Semi moving at speed are most notable due to their sheer cool factor.

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Credit: Tesla Owners Silicon Valley/X

The Tesla Semi is not yet in mass production, but the company has accumulated over 7.9 million miles across its test fleet. With Tesla using the Semi for its operations, it is no surprise that sightings of the Class 8 all-electric truck have been abounding. 

These sightings from Tesla enthusiasts vary, but those that capture the the Class 8 all-electric truck moving at speed are most notable, possibly due to their sheer cool factor.

Tesla Semi’s Roar

There is something that just stands out with the Semi, particularly on the road. While the Semi does not have the Cybertruck’s brutalist, angular design, it is still very striking because it’s such a massive machine that moves far too quietly for its size. This is, of course, one of the reasons why the vehicle also becomes extra noteworthy when it fires up its electric motors and accelerates.

Take this video from Tesla Owners Silicon Valley, for example, which shows the all-electric hauler accelerating while pulling what appears to be a full load. In these situations, the Tesla Semi actually becomes audible, but unlike traditional diesel-powered truck, the Class 8 all-electric truck “roars” with its own, unique futuristic, sci-fi sound. In such situations, one could feel the Semi’s raw power, which comes from its three independent motors on its rear axles.

Tesla Semi Ramp

Tesla has been promoting the Semi quite a bit as of late, and recent reports have suggested that the company is putting in a lot of effort to prepare the vehicle for its production in Nevada. Tesla’s Careers website has gone live with over 80 Semi-related job openings recently as well, and a recent report has suggested that Tesla has ramped the Semi’s factory workers in Nevada to over 1,000 employees.

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The company has even shared an update video of the Semi factory’s progress near Giga Nevada, as well as the design of the vehicle’s new logo. The Semi’s updated logo is quite interesting as it features elements from the Tesla Model 3’s first logo, which was unveiled way back in 2016.

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Elon Musk jokes he will join Mr Beast’s “100 Men vs 1 Gorilla” challenge

It’s a good sign, if any, that the overworked Musk is becoming a bit more lighthearted again.

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Credit: Elon Musk/X

Following the first quarter Tesla earnings call, CEO Elon Musk seems to have become a bit more relaxed—relaxed enough to joke about fighting a gorilla with 99 other people, at least.

It’s a good sign, if any, that the overworked Musk is becoming a bit more lighthearted again and not too busy picking fights with politicians on social media.

The Viral 100 Men vs 1 Gorilla Challenge

Over the weekend, a post on social media platform X went viral. The post itself was quite simple, with user @DreamChasnMike stating that he thinks 100 men could beat one gorilla. “Everybody just gotta be dedicated to the sh*t,” the X user joked. The post exploded on the platform, garnering 284 million impressions as of writing.

The silly question also triggered a massive debate about whether 100 men would really stand a chance against a literal gorilla. Some users even lamented that the premise was a sign of male hubris. Nevertheless, the question proved to be a fun topic on X, with some more dedicated users even posting simulated videos of what the “100 Men vs 1 Gorilla Challenge” could look like. 

Mr. Beast and Elon Musk Join In

The premise is quite similar to other viral videos from noted YouTube creator Mr. Beast, so it was no surprise that edited images of Mr. Beast YouTube thumbnails with “100 Men vs a Gorilla” also started spreading on the social media platform. Mr. Beast, who tends to be game to such silly ideas, actually reposted the edited image, joking “Need 100 men to test this, any volunteers?”

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In true Elon Musk fashion, the Tesla and SpaceX CEO noted that he would join the challenge. “Sure, what’s the worst that could happen” Musk wrote in his post on X. Musk’s reply triggered quite a few laughs on X, with some stating that the world probably still needs the CEO.

While silly, Musk’s comment and his recent, more frequent posts about his companies’ products like Starlink and Grok have been received well by his supporters. Over the past months, after all, Musk has been very political and quite confrontational on social media. With Musk soon taking a step back from the Department of Government Efficiency’s (DOGE) daily operations, however, it seems like X will soon get a more tempered and lighthearted Elon Musk once more.

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Possible first glimpse of Tesla “Model 2” affordable car in Fremont Factory

The models that Tesla will release in the coming months will resemble the company’s current lineup.

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Image Credit: @metgodinwilderness7130/YouTube

During the Q1 earnings call, Tesla VP of Vehicle Engineering Lars Moravy set expectations on the design of the affordable models that the company is expected to launch this 2025. As per the Tesla executive, the models that Tesla will release in the coming months will resemble the company’s current lineup.

Drone footage from the Fremont Factory earlier this month might have provided the EV community its first potential glimpse at Tesla’s affordable cars–fondly dubbed by EV fans and analysts as the “Model 2” or even “Model Q”–or at least their components and overall shape.

The Sighting

Tesla watcher and drone operator Met God in Wilderness, who has been posting aerial videos of the Fremont Factory for years now, recently shared some footage from his drone flyovers this month. While the Fremont Factory was abuzz with activity as usual, a couple of rather strange vehicles were quickly spotted by EV watchers on social media.

During the drone operator’s flyover on the 17th, for example, an unfinished vehicle could be seen parked next to what appeared to be fully-built Model S and Model Y units. What was especially interesting was the vehicle’s roof, which seemed to be slightly narrower than the Model Ys around it. Based on the video, at least, the vehicle seemed to be shaped like a crossover as well.

Footage from the 24th of April also proved quite interesting, with the drone operator capturing footage of another cryptic vehicle. Unlike the mysterious, unfinished, crossover-esque car spotted on the 17th, this particular unit seemed to have a more sloping rear, at least based on the shape of its covering.

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What Lars Moravy Said

In Tesla’s Q1 2025 Update Letter, Tesla noted that “plans for new vehicles, including more affordable models, remain on track for start of production in the first half of 2025.” Tesla also noted that the new vehicles will utilize aspects of its next generation and its current platforms. They will also be produced on the same manufacturing lines as its present vehicle lineup, likely the Model Y and Model 3. 

During the earnings call itself, Moravy specifically stated that the new models that would come out in the next months would resemble the company’s current vehicles. They will, however, be affordable. “Models that come out in next months will be built on our lines and will resemble, in form and shape, the cars we currently make. And the key is that they’ll be affordable, and you’ll be able to buy one,” Moravy stated.

Watch the drone operator’s footage from April 17 below.

The drone operator’s footage from April 24 can be viewed below.

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