Choose a battery monitor by current range, low-current measurement, display access and system compatibility, then install it so all intended current passes through it.
A battery monitor is one of the most important components in a van electrical system — it's how you know whether you can run that extra appliance or need to charge. Here are the best options.
Top picks
Victron SmartShunt 500A (~$65) — Best overall
The default recommendation for van builds:
- True shunt-based coulomb counting — accurate regardless of LiFePO4's flat voltage curve
- VictronConnect app (iOS/Android): clean UI, historical graphs, configurable alarms
- Integrates with Victron ecosystem (MPPT, MultiPlus, Cerbo GX)
- Bluetooth range: ~30 feet
- Installation: 2 wires (shunt on negative, power wire to positive)
The SmartShunt is the minimum recommended monitor for any build with LiFePO4.
Victron BMV-712 Smart (~$100) — Best with display
Identical accuracy to SmartShunt plus a dedicated 52mm display panel:
- Shows SoC%, voltage, amps at a glance without a phone
- Temperature monitoring with optional sensor ($15)
- Bluetooth + display — two ways to read data
- Best for builds with a purpose-built electrical panel
Renogy 500A Battery Monitor (~$60) — Best for Renogy systems
Similar shunt-based accuracy to the SmartShunt:
- Integrates with Renogy DC Home app alongside solar controllers and DC-DC chargers
- Dedicated display included
- Good choice if your system is all Renogy
Not as widely used or supported as Victron, but solid for Renogy-centric builds.
Bayite Battery Monitor (~$25) — Budget with display
A basic shunt monitor with a small wired display:
- 100A shunt (limited to smaller systems)
- Shows voltage, current, amp-hours, power
- No Bluetooth — wired display only
- Accuracy adequate but less configurable than Victron
Works fine for simple builds on a tight budget. The $40 savings vs SmartShunt is real if you don't need Bluetooth or ecosystem integration.
US equipment options
Compare the SmartShunt options
Choose from display needs, installation environment and measured-current range. A battery monitor helps explain energy use; it does not protect a circuit from overcurrent.
Battery monitoring
Victron SmartShunt 500A/50mV Bluetooth Battery Monitor
Compare a shunt-based monitor if voltage alone is not enough to understand your battery use.
Check before choosing: The current range, enclosure location and app-based display; the shunt is not a circuit-protection device.
Battery monitoring
Victron SmartShunt 500A/50mV IP65 Bluetooth Battery Monitor
An enclosure option to compare where the monitor needs additional environmental protection.
Check before choosing: The exact IP rating and mounting instructions; protection ratings do not make every installation waterproof.
These links open our US shop. Check the exact configuration, current price and availability there; affiliate products are purchased from the named supplier. We may earn a commission from qualifying purchases.
What to avoid
Voltage gauges sold as "battery monitors": LED bar gauges or simple voltmeters show voltage but can't tell SoC for LiFePO4. These are not battery monitors in any meaningful sense.
100A max shunt monitors for larger systems: A 2,000W inverter at 12V draws ~175A. A 100A shunt can't measure this correctly — it'll saturate and give wrong readings. Use a 500A shunt for any build with an inverter over 1,000W.
Installation checklist
- Install shunt on battery negative cable (between battery − and negative bus bar)
- Run all loads and charging sources to the bus bar — nothing directly to battery negative (bypasses the shunt)
- Connect monitor power wire to battery positive
- Configure in app: set battery capacity, chemistry, charged voltage
Worked planning check
A small 0.2A continuous parasitic load uses 4.8Ah per day. Over ten days that is 48Ah, so low-current behaviour matters for storage monitoring even if the inverter's maximum current dominates the headline shunt rating.
The figures or dimensions in this example are explicit planning assumptions, not a product test or an installation specification. Replace them with your equipment data and actual measurements.
Planning questions
Is a Bluetooth battery app the same as a shunt?
Not necessarily. An app can expose internal BMS information, while an external shunt measures current through a defined whole-bank path. Check what the particular device actually measures.
Why does the battery monitor percentage drift?
Missed current paths, incorrect capacity or synchronisation settings, small-current measurement limitations and changing battery condition can all affect its estimate.
Where should the negative returns connect?
For a typical negative shunt arrangement, loads and chargers connect on the system side so their current is measured. Follow the exact monitor manual and the complete grounding design.
Related
Use the free electrical planner to organise your daily loads and charging assumptions.
Continue planning
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Compare the exact equipment.
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Jack Kennedy is a self-builder who has built two vans. He created Roam Wired to simplify conversion planning and share free tools, supported by affiliate links.
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