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Frequently Asked Questions

Load Bank & EVSE Test Equipment — expert answers to real-world questions

Not sure where to start? Pick your application below.

I test generators / UPS / backup power → I test EV chargers (AC & DC) →

Load Bank FAQs 7 questions

Resistive vs. Reactive vs. Electronic — which one do I need?

Resistive: Most common. Simulates pure resistive loads like incandescent lighting and heaters. Tests steady-state power of generators.

Reactive (inductive/capacitive): Simulates motors, transformers, UPS — tests real-world performance under lagging/leading power factor.

Electronic: High precision, programmable, supports CC/CV/CP/CR modes. Ideal for R&D (batteries, chargers, power supplies).

Recommendation: Data centers & comms backup → resistive + reactive. Routine maintenance → resistive only (best value). R&D → electronic.

How do I calculate the right capacity (kW) for my generator/UPS?

Rule of thumb: Load bank capacity = rated power of the device under test × 1.25 (safety margin).

Example: For a 400 kW diesel generator → choose a 500 kW load bank. This ensures you can comfortably reach 100% load without running at the absolute limit.

For data center or marine systems, also factor in power factor (PF=0.8). Contact our engineers for a detailed sizing sheet.

Can I use a load bank outdoors in rain or high humidity?

Yes — if the IP rating is adequate.

Industrial containerised load banks typically meet IP55 (dust-protected and protected against water jets).
Before use in high humidity, always perform an insulation resistance test.
For long-term潮湿 environments, choose a model with built-in dehumidification/heating.

What clearance and safety distance do I need for installation?

Minimum clearances (industry standard):

Air intake (cold air): at least 2 m clearance.
Air outlet (hot air exhaust): at least 5 m from any wall or obstacle.

Never place objects above the outlet — hot air recirculation will cause overheating, derating, and potential damage to resistive elements.

Why does the load bank trip or unload immediately when I apply the load?

This is a safety protection being triggered. Check these three things first:

E-stop button: Is it locked? Rotate clockwise to release.
Over-temperature: Fan blocked or intake clogged? Clear the obstruction.
Ground fault: Leakage or insulation anomaly detected — inspect cables.

What routine maintenance does a load bank need for long-term use?

Monthly: Clean inlet filters, check fan operation, remove dust (dust = #1 killer of cooling).

Quarterly: Inspect all power cable terminations for looseness or oxidation.

Annually: Send to an accredited lab or the manufacturer for calibration of sensors and controllers.

What if the display shows garbled text or goes blank?

Before rushing to return the unit, try these steps:

Check the display cable connection (often loosened during shipping).
Verify the control mode selector matches your operation (e.g., "Local" vs "Remote").
If both are fine, the display module itself may need replacement.

View all load bank articles →

EVSE Tester FAQs 7 questions

Can AC and DC charger testers be used interchangeably?

No. They are completely different:

AC tester: Simulates the vehicle's onboard charger (OBC). Detects CP/CC signals and PWM duty cycle. Used for 7kW / 22kW AC chargers.
DC tester: Simulates the EV battery management system (BMS). Communicates via CAN bus (GB/T 27930 or ISO 15118). Used for 60kW – 480kW DC fast chargers.

Hardware and protocol stacks are entirely different — confirm your charger type before selecting.

What's the difference between a load bank and an EVSE tester?

Load bank = consumes electrical power to test the source (generator, UPS, battery). It's a "dummy load."
EVSE tester = communicates with the charger (the source) to verify voltage, current, protocols, and fault handling. It simulates a vehicle.

In short: load bank tests the power source; EVSE tester tests the charging station.

Why does the charger keep reporting "comm timeout" or "handshake failed"?

Top causes — most are configuration issues, not hardware defects:

CAN bus wiring: CAN_H / CAN_L reversed or poor contact.
Protocol mismatch: Ensure the tester's protocol version matches the charger (e.g., GB/T 27930 old vs new).
Handshake not triggered: Some testers require a manual "start handshake" command.
Insulation monitoring: Some DC chargers perform an insulation test first; if the tester doesn't respond correctly, communication stops.

Can the tester simulate a fully charged battery (SOC 100%)?

Yes. Professional DC EVSE testers support adjustable SOC (State of Charge) from 0% to 100%.

When set to SOC 100%, the tester sends a "battery full — stop charging" request to the charger. This validates the charger's auto-stop protection logic.

Can one tester test multiple chargers simultaneously?

Handheld / single-channel testers: One-to-one only.
Rack-mounted multi-channel systems: Support 4–16 parallel channels — ideal for charging station batch acceptance and aging tests.

If you need multi-station testing, contact us for a custom multi-channel configuration.

Are there special cable requirements for connecting the tester?

Yes — always use the dedicated test cables supplied.

DC fast-charge cables: Must support 1000V / 250A+ with forced air or liquid cooling.
Signal cables (CAN): Must be twisted-pair shielded to prevent EMI.
Keep cable length under 5 metres to avoid voltage drop and sampling errors.

How often does the tester need calibration?

Every 6 months — CNAS-accredited 3rd-party calibration (voltage, current, CAN timestamp accuracy).
Every 3 months — if used for metrology-certified factory test reports.
Some high-end testers support external standard source self-calibration, reducing downtime.

View all EVSE tester articles →

General Support & After-Sales (Applies to both product lines)

Common questions about warranty, customisation, lead time, and calibration.

What is the standard warranty period? Can I extend it?

Standard warranty: 12 months (parts & labour). Extended warranty up to 24 or 36 months is available upon request.

Do you support custom / non-standard specifications?

Yes. Both load banks and EVSE testers can be customised to non-standard voltage, current, and power ratings. Submit your technical specification sheet and our engineering team will provide a feasibility study and quotation.

What is the typical lead time?

Standard models: 7–15 working days.
Customised / non-standard: 4–6 weeks (depending on complexity).

Can you provide a third-party CNAS calibration certificate?

Yes. We offer an optional CNAS-accredited calibration certificate with each unit. The certificate can be issued either at the factory or by an accredited lab in your region.

Does the interface support English?

Yes. All units come with an English/Chinese bilingual interface as standard. Additional languages (Spanish, German, French) are available on request.