Battery Monitors
Battery monitors and meters so you always know your state of charge, voltage, and current draw.
Voltage alone is a terrible way to estimate battery state of charge — especially for lithium, where the voltage stays nearly flat across most of the discharge range. A proper shunt-based battery monitor solves this by counting every amp going in and out of your bank, giving you accurate state of charge, time remaining, voltage, current, and historical data. If you're investing in a serious battery bank, a monitor is the single most useful accessory you can add. It'll prevent over-discharge damage, help you size solar correctly, and take the guesswork out of every camping trip.
Top 5 Compared
| Product | Rating | Price | |
|---|---|---|---|
| Victron Smart Battery Shunt IP65 Bluetooth | ★★★★ ★ 4.8 | $155 | View |
| Victron Smart Battery Shunt Bluetooth Monitor | ★★★★ ★ 4.8 | $159 | View |
| Victron SmartShunt 500A Battery Monitor | ★★★★ ★ 4.8 | $159 | View |
| Victron SmartShunt IP65 300A Battery Monitor | ★★★★ ★ 4.7 | $149 | View |
| 500A Battery Monitor 3.5 inch Color Screen RV | ★★★★ ★ 4.4 | $65 | View |
All Battery Monitors
Battery Monitors Buyer's Guide
How shunt-based monitors work
A shunt is a precision resistor installed on your battery bank's negative cable. The monitor measures the voltage drop across the shunt to calculate exactly how much current is flowing in or out, then integrates that over time to track state of charge. Coulomb counting is far more accurate than voltage-based estimation.
Bluetooth vs LCD display
The Victron SmartShunt is the gold standard — Bluetooth-only, no display, you read everything from the VictronConnect app on your phone. Budget alternatives like Renogy's 500A monitor include a wired LCD display but skip Bluetooth. Both work well; the choice comes down to whether you'd rather pull out your phone or glance at a panel.
Installation tips
Install the shunt on the most-negative point of the system, then run every negative connection through it. Calibrate the monitor with your battery capacity, run it through one full charge cycle, and from that point forward you have accurate state-of-charge data.