Power Banks: How to Charge Portable Electric Equipment with Battery Energy Storage Systems

Power Bank Pro Powr2

Infrastructure bills, regulations and incentives are encouraging companies to embrace green initiatives. Off-highway construction equipment like mini excavators, compact wheel loaders and dedicated dumpers are quickly moving towards electric. This transition is driving the need for effective onsite charging solutions.

Onsite Charging Challenges

Charging portable electric equipment on the jobsite presents logistical and operational challenges. Recharging options are limited and often complicated. Generally, there are two main options for onsite charging: diesel generators or power from the grid. In both cases, there is a finite amount of power available. This fixed amount can present a problem when the peak load spikes, caused by EV charging. Onsite power can be spotty.

When it comes to grid power, the first hurdle is having enough power to keep your standard equipment running, while handling the additional demand of charging electric equipment. The demand spike requires a much bigger supply from the utility which is not always possible. Overstretching the available power can require an upgrade to the standard supply. Upgrading can be a costly solution. A different set of challenges exist when relying on diesel generators to charge electric equipment. Peak power demand will dictate the size of the generator. Charging equipment on and off throughout the day will cause the load to fluctuate significantly. The generator will be oversized for much of the job. Generator oversizing causes unnecessary fuel burn, excess emissions and engine issues requiring greater maintenance requirements.

Remote locations create a particular challenge for portal equipment charging. Refueling a generator may be challenging and time-consuming. There is also concern about the negative appearance of charging electrical equipment with a diesel generator. The inference is that charging with diesel negates any positive environmental impact and makes a mockery of the sustainability push.

Solving Electric Equipment Charging Challenges

Companies are discovering that Battery Energy Storage Systems (BESS) ease many of the common pain points associated with charging electric equipment on jobsites. By design, diesel generators are at their optimal efficiency when they are running close to their maximum output. Extended periods of low load will impact engine health and reduce the overall lifespan of the gen set. When using BESS with a generator, excess power is used to charge the battery. When peak loads require more power, the BESS can handle the spike. For example, if the peak load is 400 amps, but the generator is only 125 amps, the battery kicks on to provide the additional power required. The BESS will handle the peak load. Selecting a smaller generator will reduce stress on the asset. A downsized generator also means reduced fuel waste and lower CO2 emissions.

Similarly, if there is a 200-amp supply from the grid and the load increases to 400 amps, the BESS can assist with the additional power required. This eliminates the need to increase the grid connection over the standard supply.

When it comes to green initiatives, charging portable electric equipment with BESS can accelerate the transition to sustainable power. BESS provide zero-emissions power, for a more sustainable charging choice. BESS can help companies further reduce their onsite carbon footprint. Storing renewable energy to charge equipment is also possible with energy storage solutions. BESS can integrate with green energy generators like wind and solar. During periods of high power production, BESS store the excess energy. Then, during periods of low irradiance or wind, the stored energy powers the required equipment. When sized correctly, this setup can provide endless hours of clean, emissions-free power. Other power solutions exist beyond the options mentioned. Solutions like hydrogen or propane can provide a greener alternative to diesel. However, these are not widely available or adopted in the market at this time.

BESS also reduce downtime associated with recharging electric equipment. Equipment can be plugged into the BESS overnight. This safe charging solution can be left unattended. Stored energy is discharged silently, eliminating the concern of overnight noise.

Battery Energy Storage System Sizing

Select the battery for the job by first determining the base load. Next, determine what equipment will be charged and how often. There will be a surge in required power when equipment is first turned on or set up to charge. Account for peak wattage at engine startup when calculating the cumulative load. The cumulative peak load provides the basis to calculate the total power demand and determine the size BESS system needed. Example:

battery energy storage system chart

In this example, a 30kW generator plus a 40kW battery efficiently powers the load.

The example assumes that the listed equipment will be charged at the same time. Battery Energy Storage systems are often capable of setting timers to indicate when equipment should be charged. Additional loads can be turned on and off automatically. These timers can also be based on maximum current at any given time, so they do not exceed the available power. This increases the efficient use of available power. Equipment charge times depend on the size of the BESS or other charging source.

Portable Charging, Standalone Onsite Setup

It’s possible that a diesel generator, grid power or other power generator may not be available onsite. Carting several pieces of equipment to and from home base for recharging is time-consuming and often a logistical nightmare. In these cases, we are seeing the trend of delivering a BESS with a 100 percent charge to the site. This provides a convenient charging option for electric equipment without the integration of an onsite power generator. It eliminates lugging electric construction equipment to and from the jobsite for recharging. When the battery has been depleted, this single piece of equipment can be changed out for another fully charged BESS. This setup is popular in remote areas or areas that are difficult to access by a fuel truck.

BESS Investment Costs

The upfront cost of investing in portable BESS may be higher than the cost of traditional equipment that clients are used to. The long-term savings far outweigh that initial investment. Integrating BESS to charge equipment reduces generator maintenance and lowers fuel and labor costs. It also increases the lifetime of the gen set by cutting engine runtime. A popular option is renting BESS for portable electric equipment charging. Rental rates will, of course, vary from provider to provider. Rental companies who are looking to stay ahead of industry trends have been offering portable industrial BESS for construction sites. The demand for greener power solutions has been driving that adoption into rental fleets. This is only the beginning of using portable, industrial energy storage solutions with compact equipment. The introduction of Battery Energy Storage Systems is transforming construction jobsites. The future of sustainable energy is here.

Anne Nelson is the director of marketing and Tim Doling is the director of innovation at POWR2.

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