Electric VehiclesTransportation

How Long Does It Take To Charge A Chevy Bolt EV?

There is no single answer to the question of how long it takes to charge an electric vehicle. The answer depends on several things, but it is not random. With a little bit of basic math, you can work out the numbers.

The rhythm of life with an EV is not the same as with a gasoline powered vehicle. You don’t fill it up, drive until it’s almost empty, and then fill it back up again. Like many EV owners, I am able to charge at home. So, each night when I get home, I grab the charger plug that hangs a few feet from my car and plug it in. I unplug the car in the morning and the battery is completely topped up and ready for the day. On cold mornings I even remotely pre-heat the cabin while it’s still plugged in to get everything toasty warm without using up any battery power. The exact amount of time it takes for the battery to charge doesn’t really matter because I’m not standing next to it the whole time. I’m off doing other things while it charges – like sleeping. As long as the car is able to recharge over night, the exact charging speed is irrelevant.

Flying J/GM Energy chargers.

The time when charging speed matters is when I travel far enough from home that I have to recharge using a public charger. This only happens to me a few times each year on road trips. I fully understand that your driving habits may not match up with mine and charging speeds might be far more important to you than they are to me. So, I’ll break down the charging speeds for my Chevy Bolt EV and show you the math needed to work out real world charge speeds for any EV.

Working Out Charging Times with a Little Basic Math

All of the numbers that car companies publish about charging times are estimates because there are a lot of things that influence charging speeds. The estimates are usually in the ballpark. But, just because I don’t give much thought to charging times most days doesn’t mean I haven’t ever worked out the math. I’ll break down the numbers for you and give you a detailed look at the real-life charging speeds for my 2020 Chevy Bolt EV.

The first number you need to know is the capacity of the battery – expressed as kilowatt hours (kWh). The battery size of my 2020 Chevy Bolt EV is 66 kWh. For the health of your EV’s battery, you never want to run it all the way to empty and you usually want to avoid charging to 100% unless you really need the extra range. I charge my battery up to 80% on a daily basis and it’s rare for me to have less than 50% charge at the end of the day. On road trips I try not to drop below 10%. So, I am typically operating with the battery between 6.6 kWh and 52.8 kWh.

The next thing you need to know is how much electricity the charger can supply (expressed in kilowatts – kW) and whether your car is capable of using the full amount of energy the charger can supply.

Home chargers are either level 1 (which plugs into a regular household wall outlet) or level 2 (which uses 240v power similar to an electric clothes dryer or stove.) Level 1 chargers are the slowest and will provide between .96 kW and 1.92 kW of electricity. Level 2 chargers will provide between 3.84 kW and 11.52 kW of electricity. My 2020 Chevy Bolt EV’s onboard charger maxes out at 7.7 kW – most newer EVs will handle 11.52 kW.

Level 3 chargers are the DC Fast Chargers you see at public charging stations. Older systems might produce as little as 50 kW of electricity, but most DC chargers today provide between 150 kW and 350 kW of electricity. Not all cars can charge at these highest speeds. My 2020 Chevy Bolt has a maximum charging speed of just 55 kW – it’s slow. Even if I plug into a 350 kW fast charger, the electrical system of the car will only be able to use a maximum of 55 kW. The car tells the charger how much electricity to send and the charger adjusts its output.

I usually use about 10 kWh of electricity during my daily commute to work. My level 2 home charger provides 240v at 16 amps. Here is the basic math:

Volts x Amps = Watts | 240 x 16 = 3,840
Watts / 1000 = Kilowatts | 3,840 / 1000 = 3.84

This results in a charge speed of 3.84 kW for my level 2 charger (a bit on the low side for a home system, but enough for my needs.) So, 10 kWh divided by 3.84 kW equals 2 hours and 36 minutes to recharge at night since the car can easily use 100% of the available energy from my level 2 charger. The actual time will be slightly higher because the system is not 100% efficient, but this calculation is close enough. Efficiency losses during charging can range from 6% – 17% and I’ve never calculated them for my car. The charge time could be as much as 24 minutes longer if my car’s efficiency is on the low side. But, since it stays parked for at least 10 hours each night, I have plenty of time to recharge.

The math is a little trickier when you use a DC Fast Charger. The car can only use 100% of it’s maximum charge speed for a portion of the charging process. Once the battery hits 30%–40% full, the charging speed will start to slow down. When the battery reaches 80%-90% full the rate of charge will slow dramatically. The car’s battery management system (BMS) controls the charge speed to protect the battery. The specific speed pattern over time is referred to as the car’s charge curve. So, you have to know what the average charge speed is for your vehicle and then you can use that to run the rest of the calculations.

Since people use DC Fast chargers for speed, and EV charging on a fast charger slows down after 80%, most people only charge to 80% when using one. My goal during road trips is to maintain the battery charge between 10% and 80%. So, I’m working with 70% of the battery’s overall capacity which works out to 46.2 kWh for my 2020 Chevy Bolt EV’s 66 kWh battery pack.

Charge curve graph for my 2020 Chevy Bolt EV from a recent Level 3 charging session.
Actual Charge Curve for My 2020 Chevy Bolt EV

I took a road trip in my Bolt and the average charging speed on a DC charger was 45 kw. So here’s the math on that:

46.2 kWh / 45 kW = 1.03 hours (62 minutes)

My 2020 Chevy Bolt EV with its pokey 55 kW DC charging system takes about one hour to charge from 10% up to 80% in the real world. This is not a car built for long haul driving. Most EVs can charge at 150 kW. If their average charge curve follows a similar pattern to mine, they would charge up the same amount in about 23 minutes. The new Hyundai IONIQ 6 charges at 350 kW and could charge the same amount in just 10-15 minutes that’s barely enough time to use the bathroom and get a drink.

But Wait, There’s One More Thing*

There’s a small catch to these charge time breakdowns – temperature. When the internal temperature of a battery pack drops below freezing, it must be warmed up before it will accept a charge at all. Many cars have a ‘battery preconditioning‘ function that you can select when you are heading to a DC Fast Charger in cold weather that will warm up the battery to prepare it for driving. My car doesn’t have that feature, so I try to do a couple rounds of rapid acceleration followed by heavy regen braking (traffic and road conditions permitting) which has the effect of warming up the battery. This is referred to as ‘Yo-Yo Driving.’ During a recent winter road trip, every time I did a few Yo-Yo cycles just before charging I had consistently excellent charging sessions!

When you leave your car plugged into the charging cable overnight, the battery management system will use a little grid power to keep the battery temperature above freezing. In the colder months I plug in every night whether the car needs a charge or not just to keep the pack warmer going.

Extreme heat can also impact charging speeds. Modern EVs have active thermal management systems that heat and cool the battery pack to keep it within optimum temperature range. In extreme heat, the charge speed my be restricted to help control heat in the battery pack. Newer LFP (Lithium Iron Phosphate) batteries have a wider operating temperature range and are less sensitive to the ambient temperatures.

The TLDR; on Charging a Chevy Bolt EV

The short answer to how long does it take to charge a Chevy Bolt EV is about 60 minutes to go from 10%-80% at a DC Fast charger under average conditions and I don’t pay much attention at home because a level 2 home charger can top up the battery overnight while I am sleeping.

Do NOT use the charging speed of a Chevy Bolt EV as a benchmark for the experience of owning an EV.

The charging technology for the Chevy Bolt EV is old tech and very slow compared to nearly every other EV on the market today. Also, DO NOT BUY a Chevy Bolt EV if you plan to do lots of long road trips requiring frequent DC fast charging. It is a fantastic daily driver if you have home charging and only take occasional trips requiring public charging. But, regular road warriors will be better served by a different EV option.

Andrew Seltz

Andrew was born in Michigan, raised there and in Tennessee, and has since lived outside Orlando, in Chicago, New York City, and now Birmingham, Alabama. He produces videos and websites for a living and is married to a beautiful, generous, loving woman who also happens to be a talented actress and writer - www.ellenseltz.com. They have two daughters.

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