• A smart battery monitor kit that includes a blue LCD display with a digital screen, a black and gold shunt, and red and black wires for connection.
  • Smart battery monitor BM02 LCD Front View | Sapphire Energy
  • Backside view of the BM02 Sapphire Energy Battery Monitor LCD
  • 3 views of the sensing shunt monitor part of the BM02 Energy Monitor system
  • BM02 Energy Monitor Basic Wiring Diagram with Features list
  • Surface Mounting Adapter Ring for the BM02 Energy Monitor on a white background
  • Digital display with Sapphire Energy branding on a wooden surface
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Sapphire Energy

BM02 Bluetooth Battery Monitor w/LCD

BM02 Bluetooth Battery Monitor w/LCD

$75.95 CAD
$139.95 CAD $75.95 CAD
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BM02 Bluetooth Battery Monitor w/ LCD

Meet the easiest way to truly understand your battery bank. The BM02 pairs a precision shunt with a bright LCD and Bluetooth, so you can see live amps in/out, voltage, state of charge, and time remaining at a glance. No more guessing—just clear numbers that help you run your system with confidence.

Perfect for van builds, RVs, off-grid cabins, marine house banks, golf carts/UTVs, and solar troubleshooting. If you’ve ever wondered “how long can I run this?” or “did my panels really recharge me today?”, BM02 gives you the answer. You’ll get accurate coulomb-counted SOC, auto-dimming backlight for night use, optional data logging in the app, and Bluetooth that broadcasts from the LCD—so your phone connects reliably from where you actually sit.

See also

Why you’ll love it

LCD + App — read it on-screen or check history/logs in the Bluetooth app.
Accurate shunt — true state of charge and time-to-empty (not just voltage guessing).
Auto-dimming backlight — bright in daylight, soft at night.
Bluetooth from the LCD — great range even when the shunt lives in a battery bay.
Simple wiring — connect battery negative (B-) and system negative (P-), done.
Low standby draw — ~0.8 mA in sleep so it won’t drain your bank.

Specifications

Voltage Range 8–80 V DC
Current Range 150 A max (BM02-100) / 500 A max (BM02-350)
Capacity Range 0.1–9999 Ah
Accuracy ±0.1%
Backlight Yes, auto-dimming
Data Cable 3 m included (longer available)
Bluetooth BLE 5.0 (broadcasts from LCD)
Working Consumption 4–40 mA (backlight low → high)
Standby Consumption ≤ 0.8 mA (sleep)

Applications

  • RVs, vans, campers — know remaining capacity and real run-time for fridges, fans, lights, inverters.
  • Off-grid cabins — track solar charging and overnight usage to right-size panels and storage.
  • Marine & boating — confidence for trolling motors, anchor winches, and house loads.
  • Golf carts & UTVs — accurate SOC helps prevent deep discharges and extend battery life.
  • Solar diagnostics — instantly see charge/discharge currents and system balance.

Frequently Asked Questions

Short answer: pick the shunt for your peak current, which depends on voltage. Current (amps) = power (watts) ÷ voltage (volts).

Example: a 3000 W inverter draws ~250 A on a 12 V system → you need the 500 A shunt. The same inverter on 48 V only draws ~62 A → the 150 A shunt is fine.

Rule of thumb: If your loads can exceed ~120 A (big inverter at 12/24 V, high-thrust trolling motors, anchor winches), go with the 500 A. For modest RV/cabin systems, fridges/fans/lights, or inverters at 24–48 V, the 150 A is ideal.

Yes — BM02 supports 8–80 V DC. That covers all common setups: 12 V vans, 24 V cabins, 36 V golf carts, and 48 V solar/marine banks.

No. The LCD shows volts, amps, SOC, and time remaining. The app is optional but adds history graphs, logging, and remote checks from inside your RV or cabin.

From the LCD module. That means you can mount the shunt deep in a battery bay but still have great signal since the display (in your living space) is the Bluetooth broadcaster.

Yes. The BM02 comes with a 3 m data cable. For longer runs (5 m or 10 m), please contact us so we can supply the correct extension cable for your installation.

The BM02 uses coulomb counting, measuring every amp in and out. During normal cycles it will re-calibrate to 100% when the bank reaches full voltage. You can also set the current capacity manually in the app.

Yes — works with any battery type (LiFePO₄, AGM, GEL, Flooded) as long as it’s in the 8–80 V range. Just enter your bank’s capacity and you’re good to go.

No. Each BM02 tracks one bank through one shunt. If you have a starter and house bank (or port and starboard banks), you’ll want one monitor per bank.

It’s very low: about 4–40 mA when active (depending on backlight brightness) and ~0.8 mA when sleeping. That’s negligible, safe to leave connected long-term.

Mount the shunt close to your battery’s negative post. Connect the battery to the B- terminal, and all system loads/chargers to the P- terminal. Keep connections tight with proper lugs. Protect the LCD cable from abrasion when routing.

Yes. Use the optional surface-mount ring to avoid making a rectangular cutout. It gives a clean look on walls or cabinets and makes installation easier.

The BM02 uses coulomb counting—measuring every amp flowing in and out through the shunt. During normal use, it will automatically re-calibrate to 100% when the bank reaches full voltage. You can also manually set the current capacity via the mobile app if needed.

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Customer Reviews

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C
Christine
Stress free battery monitoring!

As usual with Sapphire I am thrilled with my purchase! This monitor installed easily and has given me the peace of mind of always knowing exactly how my solar panels are charging and what sort of draw I am having on the batteries. This has allowed me to track easily how much various items in my cabin affect the solar consumption and to modify what I use depending on the conditions. I might also add that the batteries I purchased have hugely extended battery life when we don't have sunny conditions so there is really not much modifying going on. Next purchases - upgrading our RV!

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