Victron BMV-702 Black Battery Monitor with Fuel Gauge

The Victron BMV-702 Battery Monitor in black measures current into and out of the bank, with a programmable auxiliary input.

Black is the alternative bezel to the gray version, and it should be chosen to match the surrounding instruments. A battery monitor mounts alongside engine gauges and switch panels, so the bezel is a visible decision rather than an internal one.

The auxiliary input measures second-battery voltage, battery temperature or midpoint voltage in a series bank. Midpoint monitoring is the one worth understanding: it identifies imbalance before a weak battery drags a series string down, which nothing measured at the terminals will reveal.

State of charge comes from measured current combined with voltage and programmed battery capacity. That is more reliable than voltage alone, though it depends on the programmed capacity being close to what the bank actually still holds. Explore more battery monitoring.

• Black or gray bezel, matched to the instruments
• Auxiliary input: second battery, temperature or midpoint
• It finds imbalance in a series string
• Nothing at the terminals will reveal it