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BT521 Battery Analyser

The FLUKE BT521 Battery Analyser reduces testing complexity resulting in a simplified workflow! Measures all key parameters: Battery resistance, dc & ac voltage, dc & ac current, ripple voltage, frequency & battery temperature.

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5823.60 incl. VAT)
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If you spend £150+ you will receive a great FLUKE tool absolutely FREE! Call us on 01782 563030 Ends: 31/08/2024



FLUKE BT521 Battery Analyser with Wireless Communication

Looking for an advanced battery analyser? The FLUKE BT521 battery analyser is designed to make battery monitoring more efficient and effective, and is the ideal test tool for your maintenance program of individual, stationary batteries and battery banks. Specifically designed for measurements on stationary batteries of all types, including gel AGM, lithium-ion and wet-cell lead-acid batteries.

Handy hardware features of the BT521

On the front you‘ll find control buttons and an easy-to-use rotary switch for making measurement mode selection. The side USB port is used to download data to your computer so you can compare measurement results and trends, and generate battery analysis reports.

The smart battery utilises built-in LEDS to indicate the batteries current state of charge so you can easily check its status. Hanging straps located on both top and bottom of the unit are used for the magnetic hangar, hanging harness, or carrying harness. The main measurement input for all parameters, to the instrument, is via the multi-pole connector on the top of the instrument. The BTL10 probe is a simple two prod probe with a kelvin connection. The insulated centre pin carries current, while the outer pin measures voltage. Voltage drop caused by the test current draw is zeroed out by the kelvin connection nullifying its effects.

▶ Video: Overview of The BT521 Battery Analyser

Video thumbnail for the FLUKE BT500 Battery Analysers

▶ Video: BT521 Battery Analyser Other Modes

Video thumbnail for the FLUKE 500 Series Battery Analysers - Other Modes

FLUKE BT521 Key Features:

  • Key measurements: Battery resistance, dc and ac voltage, dc and ac current, ripple voltage, frequency and battery temperature.
  • Sequence measurement mode: Automatic or manual sequence testing of battery strings with automatic measurement storage including voltage, resistance and temperature (with BTL21 intelligent test probe).
  • Comprehensive logging: All measured values are automatically captured during testing and can be reviewed on the instrument before downloading for on the-go analysis.
  • Optimised user interface: Quick, guided setup ensures you‘re capturing the right data every time, and the combined visual and audio feedback cues reduce the risk of measurement confusion.
  • Threshold comparison: Configure multiple reference values and thresholds for resistance and voltage. Comparison result feedback after each measurement via visual and verbal cues.
  • Ergonomic test leads: Rugged coaxial two pole kelvin test pins with remote SAVE button reduce test time and increase efficiency.
  • Test probe extenders: Long reach probes for double stacked cells.
  • Intelligent test probe set (BT520 and BT521): Integrated LCD display, infrared temperature measurement (BT521 only), flashlight, verbal audio feedback and captures voltage readings and temperature logging automatically or via integrated save button.
  • Enhanced data analysis: Quickly compare trends, analyse results and create reports with included battery management software.
  • Easy reporting: Generate PDF report on the PC software with analysis graphics and data table or quick email format report with csv file on the mobile app.
  • Wireless communication: For data download and remote display while measuring. Browse and email measurement data via iOS app.
  • Battery life: 7.4 V 3000 mAh lithium-ion battery for more than eight hours continuous operation.
  • USB port: For fast data download to supplied data analysis and report management application software.
  • Highest safety rating in the industry: CAT III 600 V, 1000 V dc max. rated for safe measurements all around the battery power supply equipment.

▶ Video: BT520 Battery Analyser‘s BTL-21 Intelligent Test Probes

Video thumbnail for the FLUKE BTL-21 Intelligent Test Probes

What comes with the FLUKE BT521?

  • FLUKE BT521 Battery Analyser
  • 4-Wire Test Pin (Set)
  • BTL10 Basic Test lead (Set)
  • TL175 TwistGuard Test Leads with Adapter
  • 2x L300 Attachable LED Torches
  • BTL21 Intelligent Test Probe Set with Extender and Temperature Sensor
  • i410 AC/DC Current Clamp
  • Lithium Ion Battery
  • AC Charger
  • Mini USB Cable
  • Shoulder Strap
  • Belt Strap
  • Magnetic Hanging Strap
  • FlukeView Battery Management Software
  • Soft Carrying Case
  • 2 x Spare Fuses
  • 100 x Paper Battery Tags


Comparison Chart for: Fluke BT521 Battery Analyser

Battery Resistance / Strap Resistance (1)3 mΩ0.001 mΩ1% + 8
30 mΩ0.01 mΩ0.8% + 6
300 mΩ0.1 mΩ0.8% + 6
3000 mΩ1 mΩ0.8% + 6
VDC6 V0.001 V0.09% + 5
60 V0.01 V0.09% + 5
600 V0.1 V0.09% + 5
1000 V1 V0.09% + 5
VAC (45 Hz to 500 Hz with 800 Hz filter)600 V0.1 V2% + 10
Frequency (displayed with VAC and AAC) (2)500 Hz0.1 Hz0.5% + 8
AC voltage ripple (20 KHz  Max)600 mV0.1 mV3% + 20
6000 mV1 mV3% + 10
ADC/AAC (with accessory Fluke i410)400 A1 A3.5% + 2
Temperature0°C to 60°C1°C2°C (4°F)
Measurement Modes
Resistance (mΩ)
Battery voltage
Voltage DC
Voltage AC and frequency  (Hz)
Ripple volt
Temperature of negative battery post (using BTL21 straight probes)
DC and AC current (and frequency)
DMM mode
Sequence mode
Discharge measurement mode
Automatic measurement save
Wireless communication
Memory view
(1) & (2) - see data sheet


Accessory Code Description Price (Ex VAT)
BTL-A BTL-A Voltage/Current Probe Adapter £54.00 ADD
BC500 BC500 AC Power Charger £155.00 ADD
BP500 BP500 Lithium-ion battery 7.4V 3000 mAh £134.00 ADD
BT500-PROBE-TIP BT500 Probe Tip Set £160.00 ADD