How to Program a Victron BMV-712 for 12V Epoch Lithium Batteries

A Victron BMV-712 Smart must be configured correctly to display an accurate state of charge for an Epoch LiFePO₄ battery bank. Incorrect capacity, synchronization or charged-detection settings can cause the monitor to remain at 100%, lose accuracy over time or fail to recognize a complete charge.

This guide provides practical starting settings for 12V Epoch lithium batteries using the VictronConnect app.

Recommended BMV-712 settings for Epoch batteries

Setting	Recommended starting value
Battery capacity	Total bank capacity in amp-hours
Charged voltage	14.0V
Tail current	4%
Charged detection time	3 minutes
Peukert exponent	1.05
Charge efficiency factor	99%
Discharge floor	10–20%
Current threshold	0.10A
Battery SOC on reset	Keep SOC

These are starting values for a typical 12V Epoch LiFePO₄ installation. Always check the manual for your exact Epoch battery model and adjust the settings when its specifications differ.

1. Check the shunt wiring

Correct programming cannot compensate for incorrect shunt wiring.

The battery bank’s negative connection should connect directly to the battery side of the BMV shunt. Every charger, inverter and DC load must connect to the load and charger side of the shunt.

Nothing other than the shunt should connect directly to battery negative. Any device that bypasses the shunt will create an inaccurate state-of-charge calculation.

2. Connect with VictronConnect

Open the VictronConnect app and select the BMV-712 through Bluetooth. Press the gear icon to open the settings.

Check for available firmware updates before changing the battery settings. Current firmware provides the latest features and state-of-charge behavior.

3. Enter the Epoch battery-bank capacity

Set Battery capacity to the total amp-hour capacity of the bank.

For batteries connected in parallel, add the capacities together:

• One 300Ah Epoch battery: 300Ah

• Two 300Ah Epoch batteries in parallel: 600Ah

• Three 120Ah Epoch batteries in parallel: 360Ah

• Four 105Ah Epoch batteries in parallel: 420Ah

Batteries connected in series increase the system voltage, but the amp-hour capacity stays the same. This guide is intended for 12V banks.

4. Set the charged voltage

Set Charged voltage to 14.0V as a practical starting point.

Many 12V Epoch batteries specify a bulk and absorption range of approximately 14.2–14.6V. Setting the BMV slightly below the charger’s absorption voltage allows it to recognize a completed charge without resetting to 100% while the battery is simply resting.

If the monitor synchronizes too early, increase the charged-voltage setting slightly. If it never synchronizes after a confirmed full charge, check the actual voltage measured at the battery and review the charger settings.

5. Set the tail current

Set Tail current to 4%.

Tail current is calculated as a percentage of the battery-bank capacity. For example:

• 100Ah bank: 4A

• 300Ah bank: 12A

• 600Ah bank: 24A

The BMV considers the battery fully charged when voltage is above the charged-voltage setting and current has fallen below the tail-current setting for the charged detection time.

Loads that continue operating during charging can prevent current from falling below this threshold. The setting may need adjustment for boats with significant continuous DC loads.

6. Enter the lithium calculation settings

Set the following values:

• Peukert exponent: 1.05

• Charge efficiency factor: 99%

• Discharge floor: 10–20%

• Charged detection time: 3 minutes

• Current threshold: 0.10A

The discharge floor controls the BMV’s time-to-go calculation. It does not shut the battery off or replace the protection provided by the Epoch battery’s internal BMS.

7. Fully charge and synchronize the monitor

Before manually synchronizing the BMV:

1. Fully charge the Epoch battery bank using the correct LiFePO₄ charging profile.

2. Allow the charger to complete its normal absorption stage.

3. Confirm that the battery has reached a full charge.

4. Open VictronConnect.

5. Select the BMV-712.

6. Open Settings → Battery.

7. Press Synchronise to set the state of charge to 100%.

Do not synchronize a partially charged battery to 100%. That gives the monitor an incorrect starting point and causes future readings to be inaccurate.

Epoch charger settings versus BMV settings

The BMV-712 measures and calculates battery usage; it does not control the charging voltage.

Many 12V Epoch models use charger settings within these general ranges:

• Bulk/absorption: 14.2–14.6V

• Float: 13.4–13.8V

• Equalization: Disabled

• Temperature compensation: Disabled

Use the charging requirements from the manual for your exact battery model. Do not assume every Epoch battery has identical charging limits.

Why the BMV-712 may show the wrong percentage

Common causes include:

• Incorrect battery-bank capacity

• A load or charger bypassing the shunt

• Synchronizing before the batteries are fully charged

• Charged voltage set too low

• Tail current set too high

• Charger settings that do not match the Epoch battery

• The battery bank rarely reaching a complete charge

• Different negative connections installed on both sides of the shunt

If the state of charge slowly becomes inaccurate, begin by checking the shunt wiring and confirming that the BMV reaches its synchronization conditions during a complete charging cycle.

Need help with your Victron and Epoch system?

Onboard Marine Goods supplies Victron Energy equipment, Epoch lithium batteries and marine electrical components. Contact our Marathon, Florida store if you need help selecting compatible equipment or confirming the correct settings for your battery system.

Battery and charging requirements vary by model and installation. Always follow the current Epoch battery manual, Victron documentation and applicable marine electrical standards.