Portable vs Containerized Load Bank: A Complete Buying Guide

Short answer: Choose a portable load bank (wheeled or skid-mounted, up to ~500KW) when you test different generators or UPS systems at multiple sites and need to move the load between locations. Choose a containerized load bank (1MW and above) when you test large gensets, run rental fleets, or need a fixed or semi-permanent outdoor test asset with weatherproofing and easy forklift deployment.

What is a portable load bank?

A portable load bank is a self-contained unit on casters or a lifting base, typically rated from a few kilowatts up to around 500KW. It rolls through doorways, fits in elevators or vans, and connects directly to the generator or UPS output. Portable units are the workhorse of commissioning teams, maintenance providers and rental companies that test a different site every week. Most SmartPower portable units include a local touchscreen plus PC remote-control software, so an engineer can operate the load from the generator room or a safe distance.

What is a containerized load bank?

A containerized load bank packs 1MW to 3MW or more of load into a shipping-container-style enclosure. It is delivered by truck, positioned with a forklift or flatbed, and connected to the generator bus. The container format provides generous space for air intake and exhaust, which is essential for dissipating the heat of megawatt-scale testing, and it is naturally weatherproof for outdoor installation. Containerized units are the standard choice for utility-scale genset commissioning, rental fleets and permanent test facilities.

Comparison table

How do I decide between portable and containerized?

• You test generators up to ~500KW across different sites: portable is the right call - it moves with your team and sets up in minutes.
• You commission 1MW+ gensets or run a rental fleet: containerized units give you the capacity, weatherproofing and fast rigging you need.
• You need 1000KW of load but only occasionally, and sites are hard to reach: consider a single large portable/skid unit (SmartPower's 1000KW outdoor unit is weatherproofed for semi-permanent outdoor siting) or a containerized unit on wheels.
• You need permanent, year-round outdoor testing (remote power stations, telecom sites): choose an outdoor-rated unit designed for fixed installation near the genset.

Sizing your load bank correctly

A widely used rule of thumb: load bank capacity = rated power of the device under test x 1.25. For a 400KW generator, choose a 500KW load bank; for a 1000KW generator, plan for 1250KW or the nearest standard size. For data center or marine systems, also factor in power factor (typically PF 0.8) - and remember that reactive-capable (RLC/RCD) units cost more but reveal real-world behavior that resistive-only units cannot.

Frequently asked questions

Can a portable load bank test a 1MW generator?

Not in one unit at that class - you would either use a containerized 1MW+ load bank or parallel multiple portable units. SmartPower load banks support paralleling, but for a single 1MW test a containerized unit is simpler and safer.

What clearance do I need around a load bank?

Industry practice: keep at least 2m clearance at the cold-air intake and at least 5m at the hot-air exhaust, and never place objects above the outlet - recirculated hot air causes overheating and derating.

Can I use a load bank outdoors in rain?

Only if the enclosure is IP-rated for it (SmartPower outdoor units are). For indoor units used in humid environments, always perform an insulation resistance test before use.

Why does my load bank trip when I apply load?

Almost always a safety interlock: a locked emergency-stop, a blocked fan or intake (over-temperature), or a ground-fault alarm. Check these three before calling service.

What maintenance does a load bank need?

Monthly: clean inlet filters and remove dust. Quarterly: check power cable terminations. Annually: have sensors and controllers calibrated by the manufacturer or an accredited lab.

Need help choosing the right configuration?

SmartPower Electronics manufactures portable load banks from 6KW, outdoor units up to 1000KW, and containerized systems up to 3000KW - all with touchscreen control, PC remote software and full safety protection. Contact our engineers with your generator or UPS fleet details and we will recommend the right size and configuration.

Reference: NFPA 110 testing and maintenance requirements for emergency and standby power systems (NFPA codes and standards).