Charging an Electric Excavator on Site: Power Supply, Chargers and Charging Time

The same 2-tonne JCB 19C-1E electric mini excavator takes 10 hours 30 minutes to charge on a 110 volt lead, 5 hours on 230 volts and 2 hours 30 minutes on 415 volts. So electric excavator charging is decided mostly by the power supply at your site, and only partly by the machine.

That one fact shapes everything else on this page. Before you compare electric excavators on digging depth or bucket size, find out what power you can bring to the place where the machine will sleep. Some electric machines do not charge at all. They run on a cable from the grid, all shift long. Others carry a battery that has to be filled every day. Each kind asks something different of your site.

How does an electric machine get its power on site?

In one of three ways, and the spec sheet tells you which.

A battery machine carries its energy in a traction pack (the big battery that drives the motors; it is separate from the small 24 volt starting batteries every machine has). It works anywhere until the pack runs low, then it has to go back to a charger. A cable machine has no traction pack. It plugs into the grid through a heavy trailing cable and never stops to charge, but it can only work as far as the cable reaches. A mains-powered unit, such as a stationary concrete pump with an electric motor, is the simplest case: it is wired to a three-phase supply and runs like any factory motor.

Here is how the electric machines listed in India split up. The figures are from each machine’s own specification table.

None of these listings publishes a battery size in kWh or a charging time. That is the first thing to ask the dealer for, in writing, along with which charger the quotation includes.

Concrete pumps are the other big group. The Schwing Stetter BP 250 HDE, BP 350 E, SP 1200 E and SP 1400 E and the Aquarius 1003 E each run on a 45 kW motor. The Aquarius 1406 E and Putzmeister BSA 1406 E eSmart are 75 kW, the Aquarius 1405 E 90 kW, the 1400 HRE 132 kW and the 1400 HPE 160 kW. At the top sits the Schwing Stetter SP 8800 Electric at 400 kW. None of them charges anything. They need a three-phase connection big enough for the motor, and the guide to concrete pump engine power explains what those kW figures buy you in output.

How long does it take to charge an electric excavator?

Divide the battery size by the charger power. A battery is measured in kilowatt-hours (kWh), which is the energy it holds. A charger is measured in kilowatts (kW), which is how fast it pushes energy in. Battery kWh divided by charger kW gives you the rough hours to fill it from empty.

Volvo’s figures for its L120 Electric wheel loader show the arithmetic working. Its pack is 282 kWh, of which 254 kWh is usable. Volvo’s Indian product page lists a 40 kW DC charger that fills it from 0 to 100 per cent in 7 hours, and 282 divided by 40 is just over 7. The same page lists a 180 kW DC charger that does 10 to 100 per cent in 1 hour 40 minutes. The brochure gives slightly different fast-charge figures, 10 to 95 per cent within 90 minutes on a CCS2 charger, so read whichever document your quotation refers to.

Two things stretch the real time beyond the simple sum. Charging slows down near the top of the battery, which is why makers quote 10 to 80 or 10 to 95 per cent. And a cold or very hot pack charges more slowly; the L120 Electric heats and cools its battery for that reason.

The JCB 19C-1E figures show the other half of the story. Same machine, same battery, three supplies:

In India the 110 volt option hardly matters; it is a British site-tool voltage. What matters is the gap between an ordinary 230 volt single-phase socket and a 415 volt three-phase supply. On three-phase, the machine is ready after a lunch break and a tea break. On single-phase, it is an overnight job. JCB lists the 19C-1E on its UK site, and JCB India’s own range lists no electric excavator, but the physics is the same for any battery machine.

What power connection does your site need?

Start from your electricity bill, not from the machine. The bill shows your sanctioned load, the maximum power your distribution company (DISCOM) has agreed to supply, in kW or kVA. Add the charger’s rating to everything else that runs at the same time. If the total crosses the sanctioned load, you need a load enhancement before the machine arrives.

A few rules of thumb hold everywhere:

• A single-phase 230 volt connection suits only the smallest machines, and only for overnight charging.
• A 415 volt three-phase connection is the normal minimum for a mini or midi excavator charger.
• A fast DC charger in the 150 to 200 kW range is a factory-sized load. Most small sites cannot feed it without a new connection.
• A cable machine such as the Volvo EC500 Electric draws its full 250 kW motor load from the grid all shift. That usually means a high-tension (HT) supply with your own transformer at the site. Where the line between LT and HT falls is set by your state’s supply code, so ask your DISCOM.

Check the voltage too. Indian three-phase supply is nominally 415 volts, while the Volvo EC500 Electric’s India product guide states AC 380 V. Ask the dealer to confirm in writing that the machine and charger accept your supply as it is, or what will sit between them.

The connection itself is building work. A transformer, a feeder cable, a meter, a plinth for the charger and an earthing pit all need approval and a licensed contractor. The guide to the electrical contractor licence explains who is allowed to do that work. Get the sanctioned-load figure and the installation quotation at the same time as the machine price.

Not sure which electric excavator your supply can carry? Compare the electric excavator models listed in India and send an enquiry with your sanctioned load, so the dealer can match the charger to it.

Can you charge an electric excavator from a DG set?

Yes, if the generator is big enough, but you lose most of the reason for going electric.

DG sets are rated in kVA. Their kW output is roughly 0.8 times the kVA figure, because Indian DG sets are rated at a power factor of 0.8. So a 40 kW charger needs a set of at least 50 kVA before you add any margin, and a 180 kW fast charger needs well over 225 kVA. Ask the generator supplier to size it for the charger’s full input, since a charger running at its limit is a steady, heavy load.

The bigger problem is cost. The generator burns diesel to make electricity, and some energy is lost in the generator and again in the charger. You have paid extra for an electric machine and gone back to buying diesel, with more steps in between. The running-cost side of that trade-off is worked through in electric vs diesel excavator running cost.

A DG set still has honest uses. It can bridge the weeks before a grid connection is energised. It can top up a machine on a short job far from any line. Volvo also lists a PU500 Mobile Power Unit that it says can fully charge the L120 Electric in 1 hour 40 minutes; ask what powers a unit like that before you count on it. If a generator would be your main source of power every day, a diesel excavator is the more sensible buy.

Which sites suit each way of powering the machine?

A battery machine fits a site that it returns to every night, with a solid connection near the parking spot. Think of a factory yard, a city redevelopment plot, a metro depot, a basement dig or a material yard. Overnight charging on a modest charger is enough for one shift, and a fast charger lets it run two.

A cable machine fits a dig face that does not move much and a power line that already exists. That is a mine, a quarry, a crusher feed point or a port. Volvo describes the EC500 Electric as built for static applications, with a cable that comes up from the ground and joins the machine through a turning joint under the upper structure, so it can swing all the way round without twisting the cable.

Neither suits a highway stretch, a canal or a rural site that moves every few weeks. There is no connection to plug into, and building one for a short stay rarely pays. Electric tippers and dump trucks and electric wheel loaders hit the same limit.

How do you plan charging around a working shift?

Work backwards from the hours you need. Volvo says its L120 Electric delivers around 5 to 9 hours of work per charge, depending on the job. That spread is normal: heavy digging in hard ground drains a battery much faster than light loading. Ask the dealer for the runtime on your kind of work, not the best case.

Then fit charging into the gaps you already have. One shift a day with an overnight charge is the easy case. A second shift needs a fast charger, and the charge has to fit inside the change-over. Keep a small reserve too. Running the pack flat every day shortens its life, and a machine that comes back at 10 per cent cannot cover a surprise extra hour.

Three habits help on most sites. Park the machine at the charger at the same spot every night, so nobody forgets to plug it in. Give one person the job of checking the charge level at the end of each shift. And keep the charger under cover; in monsoon, rain and standing water are the main risk at an outdoor charging point.

What keeps charging and cable work safe?

High-voltage gear on a dusty, wet site needs more care than a diesel tank. The charger and its supply should be installed by a licensed electrical contractor, earthed to the Indian code of practice for earthing, IS 3043, and fitted with protection that trips on an earth fault. Volvo’s EC500 Electric lists overcurrent protection, leakage protection and a phase-sequence test among its standard equipment, which tells you what the maker expects the supply side to match.

For a cable machine, the cable is the weak point. Keep the tracks and the bucket off it, route it where trucks do not cross, and inspect it before each shift for cuts and crushed sections. For a battery machine, follow the maker’s rules for the charging area: no welding or open fire nearby, the plug fully locked before charging starts, and the charger switched off before anyone works on the machine.

What should you check before you buy an electric excavator?

Ask for each of these in writing:

• Battery size in kWh, both total and usable, and the battery type.
• Whether a charger is included, its power in kW, and the plug it uses. Volvo’s sheet, for example, lists both CCS2 and GB/T charging, two different fast-charge plug standards.
• Charging time on each charger offered, with the start and end percentage stated.
• The supply the charger needs: single-phase or three-phase, voltage, and kW or kVA.
• Runtime per charge on work like yours.
• For a cable machine, the cable length, the supply voltage and who provides the site-end connection.
• Who installs and services the charger in your district, and how long a fault takes to fix.
• Warranty terms on the battery and on the charger, which are often separate.

If the answers point to a supply you cannot get, a diesel machine of the same size is still the safer buy. Compare excavator models and prices across every class. If the numbers do work, the equipment finance options cover electric machines too. The wider picture, including forklifts and scissor lifts that charge from much smaller supplies, sits in the electric machines guide, and the electric JCB guide explains why there is still no electric backhoe loader.

The figures on this page come from each machine’s specification table and from the makers’ own documents, named where they are used: Volvo CE’s EC500 Electric India product page and India product guide, Volvo’s L120 Electric product page and brochure, and JCB’s 19C-1E product page.

Send an enquiry for an electric excavator or an electric concrete pump, and ask the dealer to quote the charger and the site connection along with the machine.

Prices, specifications and features are indicative, vary by variant, location and date, and should always be confirmed with the official OEM or authorised dealer before any purchase decision. DesiMachines is not liable for decisions taken on the basis of information that may have changed after publication.