Electric Construction Equipment: Your Charging Questions Answered

I get a lot of questions related to electric construction equipment, and the topic of machine charging seems to be the most prevalent.

Below I’ve provided answers to some of the more common questions I hear. And of course, if you have additional questions related to charging electric construction equipment, please send them to me in the comments section at the bottom of this post and I’ll get back to you. 

Written by Lars Arnold – Electromobility Product Manager for North America

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What type of charging infrastructure do I need for electric construction equipment?

To have an optimal charging time for electric machines, it’s strongly recommended to have a 240-volt, 32-amp Level 2 AC-charging setup utilizing an SAE J1772 charging adapter or J plug — the same as for electric vehicles. While you can charge the machines on a common household 120-volt network, it takes longer. Here are the approximate charging times for the two setups:

1. 240-Volt, Level 2 AC Setup Charging Times
ECR25 Electric Excavator: 6 hours, empty to full
L25 Electric Wheel Loader: 12 hours, empty to full

2. Common Household 120-Volt Outlet Charging Times
ECR25 Electric Excavator: 12 hours, empty to full
L25 Electric Wheel Loader: 24 hours, empty to full

The more power you can put into your electric machine, the faster it will charge. Think if it like filling your vehicle with a gas can versus a convenience store fuel pump.

And of course, we’ll continue to research, develop and provide a wider range of charging options in the coming months and years. As electric vehicles continue to rollout into the market more and more, improved charging infrastructure will follow suit — and that’s good news for the construction industry.

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Why does the Volvo L25 electric wheel loader take twice as long to charge as the ECR25 electric excavator?

The ECR25 has three battery packs. The L25 has the same battery packs, but it has six. Double the batteries is the reason it takes twice as long to charge battery-powered construction equipment.

Does Volvo offer a charger for working in remote locations where a power grid isn’t nearby?

Yes. We offer a Beam solar fast charger which is an off-grid, no connection, free-standing solar charger that has a battery pack similar to the size of the one inside the Volvo L25 wheel loader. A nice benefit is that the solar panels are always in the correct angle because they follow the movement of the sun.

Two North American Type 1 charging plugs — the same used for electric vehicles — are available for 240-volt charging. The charging time is same as on the 240-volt, Level 2 AC setup (six hours for the ECR25 and 12 hours for the L25), but keep in mind this is totally off-grid — you aren’t required to have any power cables running to it. You can simply charge your construction machines using the power of the sun.

What other future charging solutions is Volvo working on?

In addition to the Beam solar fast charger, we’re currently hard at work on a Benning DC rapid charger. The rapid charger charges the 48V batteries direct with 48V and up to 360 amps. As a result, the charging times are drastically reduced:
1. Benning DC Rapid Charger Charging Times
ECR25 Electric Excavator: 1 hour, empty to full
L25 Electric Wheel Loader: 2 hours, empty to full

Keep in mind the Benning unit isn’t off-grid, so it would need to be wired into a 480-volt, three-phase power grid at the location where you want to charge your electric equipment.

Which is the best charger for the battery life of electric construction machines?

The best for the battery life is AC Level 2 charging, which is slow charging, versus DC rapid charging — but again, it’s all about a customer’s needs. It’s not killing the battery, it’s just that you can extend the life of the battery with slower charging. We don’t yet know how long the batteries will last in electric construction equipment because the technology is so new, but we estimate the battery will likely last somewhere around 10 years.

Another thing to keep in mind is that the lithium-ion technology used in our batteries is far superior to the old lead-acid or nickel-cadmium technology we sometimes have in mind when thinking about electric vehicles. Volvo’s advanced batteries have no memory effect, they’re maintenance free, rapid charging is possible, and they experience less loss of power in cold temperatures. With a 12-volt, lead-acid car battery, as soon as it gets cold, the capacity is drastically reduced — that’s not the case with these batteries.

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What tips do you have for contractors to ensure charging is maximized throughout the day?

First, I always recommend that when you have any pause in your construction workday, charge the batteries (e.g. an hourlong lunch break). Because these are lithium-ion batteries, they have no memory effect. You can top them off during a break and continue working throughout the afternoon or evening.

It’s also best practice to charge the batteries of electric construction vehicles from mid-level to full, as opposed to draining the battery completely before recharging. When you charge from say 30 or 40% back up to 80 or 100%, it’s better for the overall lifetime of the battery. Remember, these aren’t the lead-acid or nickel-cadmium batteries like you’d see in early versions of electric power tools. Those were impacted by the memory effect — if you didn’t charge them properly, they became more or less useless after a short time. The lithium-ion batteries in Volvo electric machines are much more advanced and much more forgiving, so it’s perfectly fine to charge them back to full whenever a good opportunity arises.

A final tip is not to run the electric machine at full throttle all the time because oftentimes you don’t need the excessive power. Unless it’s needed, run in an appropriate rpm range to get the work done without slowing down, but there’s really no need to run full time at full electric motor rpm.

Do I need to train my operators to remember to turn off their electric construction machines throughout the day to save batter life?

No. Volvo compact electric machines come with Auto Electric Motor Shut Down. If an operator stops running the machine, the electric motor turns off after a defined period of time. The operator can select times anywhere between three and 20 seconds. And to get working again the electric motor turns on instantly and provide instant power. It’s not like a diesel engine where if you stopped working, it goes into idle and burns fuel. In the electric machines, the electric motors shut off according to the operator’s preference.

Another benefit is that all the lighting on these Volvo electric machines (rotating beacons, work lights, travel lights, etc.) are LED — so they’re very low power consumers. This helps extend battery life for your toughest construction projects.

How long do the electric vehicle batteries last in a typical day?

This is tough to answer because the machines can be used in so many ways, in a variety of applications. These differences in jobsite environments can significantly alter how long the batteries last.

That said, Volvo is currently working on a Net Operating Time Calculator that will be available to our dealer network later this year. This calculator will allow them to sit with customers and talk through specific applications to estimate daily charging needs. From fork handling and material handling to digging and trenching applications, it’ll be a tool that helps customers better understand where electric machines best fit into their fleets.

What’s the general outlook on U.S./Canada charging infrastructure development?

Currently, the charging infrastructure development is primarily driven by electric vehicles (EVs) — as more and more electric vehicles come out, more and better charging infrastructure will become available long term for electric construction equipment owners. Electric isn’t a fad — it’s here to stay. And we can expect charging infrastructure to remain a top priority for the EV industry, construction industry and more.

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Electric Construction Equipment and the Future

While charging is definitely an important consideration for those considering electric construction equipment, contractors need to also keep in mind all the new and different ways electric construction equipment can be used. The ability to work indoors thanks to zero emissions, the ability to work outside of normal business hours due to their quiet operation, the ability to have a fast-charging option to work longer hours — these benefits open the doors of possibility for those looking to expand their business down the road.