Track Down Battery Drain Without Opening the Circuit
Clamp the BT270 around a conductor to read vehicle current draw, from milliamp parasitic loads to starter and charging current, with automatic AC/DC recognition and 99 stored readings. Runs on a 9 V battery, which is not included.
- 0 mA–60 A AC/DC
- 1 mA Resolution
- Auto AC/DC
- 99 Stored Readings
- One-Button DC Zero
Key Features
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Non-Contact Clamp Measurement
Reads AC or DC current through the clamp without disconnecting the circuit.
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Automatic AC/DC Recognition
Switches modes on its own for common checks; below 25 mA AC, long-press Power to switch manually.
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Leakage Diagnosis
DC and AC leakage current, ground-wire leakage and main-line current, plus motor starting and alternator charging current.
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One-Button Zero
The Zero/Backlight button zeroes the reading before a DC test; no adjustment knob is needed.
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Hold, Memory and Review
The Hold/Mem/Mr button holds and stores numbered readings; long-press it to review them.
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Backlit Display
A 4-digit backlit LCD stays readable in dark work areas.
More Specifications
| Over-range indication | LCD shows OL |
|---|---|
| Auto power-off warning | LCD flashes for 30 seconds before shutdown; press Power to keep the test status |
| Start-up mode | DC current |
What’s in the Box
- 1×BT270 leakage current clamp
- 1×Storage pouch
- 1×User manual
How to Use
- Power onInstall a 9 V battery if needed and press Power.
- Zero firstPress Zero/Backlight before clamping the wire for a DC test.
- Clamp the right wirePositive and negative together for DC leakage, live and neutral together for AC leakage, or the ground or main wire alone.
- Read and storeRead the LCD and press Hold/Mem/Mr to hold and store the value.
- Find the drainWith the vehicle asleep, pull fuses one at a time; a clear drop points to the circuit to check.
Measurement and safety details: BT270 user manual (PDF).
Good to Know
Caution
- The 9 V battery is not included.
- Do not exceed the measurement range, and take extra care on lines above 60 V DC or 30 V AC.
- The BT270 measures current only; it is not a power-probe tester for polarity, continuity or component activation.
- A low battery affects accuracy; replace it when the battery symbol appears.
Care
- Keep the jaw contact surfaces clean and protect the jaw joint from impact.
- Avoid long storage in heat, humidity, condensation or direct sun, and remove the battery for long storage.
- Leave disassembly and calibration to qualified service personnel.
FAQ
What quiescent current is normal?
Typically about 30–40 mA; some European vehicles are about 80–90 mA depending on class and equipment. Use the vehicle’s specified limit.
When does a reading suggest a drain?
100 mA or more after the vehicle reaches its specified sleep state may indicate electrical leakage.
Is CAT III 600V the measuring range?
No. CAT III 600V is a line safety rating; the current measurement range remains 0 mA–60 A.
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