Product Advisory – Battle Born Batteries

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Issues with charging and failures

These are updated charging parameters for Battle Born LFP (LiFePO4) batteries and tips for restoring and maintaining Battle Born batteries. Improper charging of Battle Born batteries can result in greatly reduced useful lifespan and other issues. It is recommended to read this product advisory carefully and verify that your charging parameters are set correctly. Pay special attention to the yellow highlighted sections.

Battle Born has updated their charge parameter settings a few times since OGT started recommending them. If you are using LFP batteries, you should take time to evaluate your battery charger settings and solar electric system as a whole. (If you are using a different brand of LFP battery you should consult your battery manual as different models of LFP battery management systems require different charge parameters.) Currently these are the recommended settings for Battle Born 12V batteries:

Bulk/Absorption: 14.2V – 14.6V (OGT recommends 14.4V)

Absorption Time: 15 minutes per battery in parallel (E.g. 4 batteries in parallel is 1 hour)

Float: 13.4V – 13.8V (OGT recommends 13.6V)

Equalization: 14.4V / Disabled

OGT recommends you check your charger settings and confirm these values, immediately. Note these settings differ from SimpliPhi batteries. Instructions for setting the Outback FM80 and FXR inverters are further down in this document.

It is essential that Battle Born batteries are charged to a minimum of 14.25V at least three times a week. It is only when the battery voltage exceeds 14.2V that the internal cell voltage balancing will occur. Under normal operation the LFP cell voltages will become unbalanced, the Battle Born BMS (battery management system) will attempt to balance these differences in voltage, but it needs sufficient time above 14.2V to accomplish the internal cell voltage balancing. There are many things that can cause the voltage at the batteries to be different from the voltage set or displayed on your charger. It is for this reason that OGT recommends you use a voltmeter and measure the DC voltage on the top of each battery when your charger is in Absorb mode, at least once a month. Using a voltmeter set to DC voltage measure the voltage on the terminals of each of your LFP batteries when your charger is in Absorb, this voltage should be above 14.25V and below 14.5V. The voltage of each battery should differ by less than 0.05V compared to the others wired in parallel. Please contact OGT if the voltage is not in this range.

  • It is possible that a bad fuse or breaker on your battery combiner box has disconnected one or more batteries from your solar electric system without your knowledge. When a fuse or breaker disconnects a battery, it is no longer receiving a charge or contributing to the energy storage of your solar electric system. The easiest way to determine if a battery is connected to the solar electric system is to measure the voltage on the terminals of the top of each battery when the charger is in Absorb mode. Each battery should be within 0.05V of each other. This is another reason it is recommended that this voltage measurement be done once a month.
  • Do not over rely on the SOC (state of charge) display on your MATE3s, Victron SOC meter, or other SOC meters. These are not overly accurate. There are a lot of assumptions and math that go in to calculating the SOC of an LFP battery, over time these assumptions may not be accurate. Use the SOC as a guide to how much energy you have in your battery bank, but also use a SOC to Voltage chart to double check that the SOC makes sense.
Battle Born
SimpliPhi
  • Do not use temperature compensation with LFP batteries. In the past many charge controllers and battery chargers included a remote temperature sensor (RTS or BTS) that was placed on the side of lead acid batteries. This RTS allowed the charger to decrease the charge voltage (Absorb and Float) when the battery temperature was above 25 degrees C. This was important for lead acid batteries but the temperature compensation for lead acid battery is not correct for LFP batteries. For this reason, it is recommended to disconnect any RTS from your charge controllers, inverters and battery chargers.
  • Offgrid Tech does NOT recommend wiring LFP batteries in series. When wiring in series batteries are connected with the negative of one battery connected to the positive of the next battery, like the stacking of AA batteries in a flashlight. This allows two 12V batteries to be wired in series to produce 24V DC, or four 12V batteries wired in series to produce 48V. While some LFP battery manufacturers (including Battle Born) allow for wiring in series, OGT does not recommend this. Battle Born recommends that any batteries wired in series be disconnected and charged at their rated voltage (14.4V) every few months, to correctly balance the batteries. This would require both a separate 12V battery charger and a reminder to do this every few months. While it is posibile to add an external battery balancer to balance the 12V batteries wired in series, this adds another layer of complexity. LFP batteries are available in 12V, 24V and 48V in many countries of differing quality.
  • It has only been about 8 years since Offgrid Tech started recommending LFP batteries and there has been a lot to learn, and many changes since then. There are many different LFP battery brands to consider. Some are good brands with quality products and other brands fail new out of the box. OGT is open to helping missionaries consider purchasing locally available LFP batteries but be very cautions with the often low quality batteries available. Some missionaries have purchased what appeared to be a high quality LFP battery only for all of them to fail as soon as they were installed. Please contact Offgird Tech with questions or advice.
  • Offgrid Tech does NOT recommend buying LFP cells and building your own battery. There is a lot of complexity in building LFP batteries including selecting the correct BMS, cell temperature measurement, cell voltage balancing requirements, fire safety, over current protection, voltage isolation. Please reconsider, and do not building your own LFP batteries. Remember time is a non-renewable resource and remember what your purpose is on the mission field.
  • Offgird Tech has worked with a number of missionaries who have had failed or weak Battle Born LFP batteries. We have had mixed results restoring some of the storage capacity of these batteries. It is recommended that you ensure that the weak battery is connected to a charge system that will allow it to reach a minimum Absorb voltage of 14.25V for a minimum of 15 minutes each day. Ensure with a voltmeter that the battery terminals are actually at a minimum of 14.25V. Allow the battery to charge and reach this Absorb voltage for several weeks. It is ok to charge and discharge the battery while it is being restored. While being restored, a weak batteries BMS may disconnect itself from the other batteries wired in parallel with it, this is normal and may resolve in time.
  • Some missionaries have noticed very erratic DC battery voltage on their solar electric systems. This can be caused by LFP batteries BMS disconnecting the battery from the solar electric system. When all the batteries BMS disconnects them from a solar electric system, the charge controller tries to maintain the Absorb or Float voltage using just the solar panels, however it is not designed to do this, and the voltage can swing erratically. This erratic voltage can damage equipment. The batteries BMS will disconnect the battery to protect itself from damage for a number of reasons including: battery overvoltage, cell overvoltage, battery undervoltage, cell undervoltage, over temperature, under temperature, and over current. If you notice erratic DC voltages it is HIGHLY recommended that you immediately evaluate your solar electric system and resolve any issues that are found. Please consult with Offgird Tech as needed.
  • The Outback FM80’s, FXR Inverter’s and FlexNet DC’s built in battery voltage meter is not always accurate. Do not fully trust the voltage displayed on the screen of the FM80 or MATE3s. Outback tries to make these voltages accurate but for various reasons they are not always a true indication of the actual voltage. If you notice that the displayed voltage differs greatly from a high-quality voltmeter measuring DC voltage on the terminals of the equipment in question, please contact Offgrid Tech for assistance.

Outback FM80 Settings for Battle Born:

  • Using the buttons and screen on the FM80, from the Main Display Screen
  • Set the Absorb and Float Voltage.
    • Press the Left most button.
    • Move the arrow to the “Charger” menu.
    • Select “Go” by pressing the Right most button.
    • Use the button with the down arrow to select “Absorbing” voltage.
    • If a password is requested enter “141”.
    • Press the “+” or “-” button as needed to adjust the Absorb voltage to 14.4V.
    • Use the button with the down arrow to select “Float” voltage.
    • Press the “+” or “-” button as needed to adjust the Absorb voltage to 13.6V.
    • Press the EXIT button.
  • Set the Absorb Time.
    • Press the Left most button.
    • Move the arrow to the “Advanced” menu.
    • Select “Go”.
    • Repeatedly Press the “NEXT” button until the “Absorb Time” menu is reached.
    • Press the “+” or “-” button as needed to adjust the Absorb time is set to 15 minutes for each parallel battery on the solar electric system. (As an example, if you have 4 Battle Born batteries in parallel, set to 1 hour.)
    • Press the EXIT button.
  • Set the Equalization settings. (Equalization not desired, by setting these values low it will not overcharge if an equalization is started by accident.)
    • Press the Left most button.
    • Move the arrow to the “EQ” menu.
    • Select “Go”.
    • Press the “+” or “-” button as needed to adjust the Battery Equalize Voltage to 14.4V.
    • Press the “NEXT” button.
    • Press the “-HRS” button as needed to adjust the Battery Equalize Time to 1 hour.
    • Press the “NEXT” button.
    • Press the “Stop” button.

Outback FXR Inverter MATE3s Settings for Battle Born.

  • Using the MATE3s, from the Main Display Screen.
  • Set the Absorb Voltage, Time and Float Voltage.
    • Press the “Lock” button.
    • Use the wheel to adjust the User Password to “141”. Press the “Center” button to enter.
    • Use the wheel to select “Settings” and press the “Center” button.
    • Select “Inverter” and press the “Center” button.
    • Select “Battery Charger” and press the “Center” button.
    • Select each value with the wheel, then press the “Center” button to adjust.
    • Use the wheel to adjust the setting values.
    • Absorb Voltage: 14.4V.
    • Absorb Time: 15 min per battery in parallel.
    • Float Voltage: 13.4V.
    • Re-Float Voltage: 13.0V.
    • Re-Bulk Voltage: 12.8V
    • When done press the “Up” button.
    • Select “Battery Equalize” and press the “Center” button.
    • Use the wheel to adjust the setting values.
    • Equalize Voltage: 14.4V.
    • Equalize Time: 0.0 Hour.
    • Press the “Lock” button to exit.

Additional MATE3s settings for Battle Born

  • Using the MATE3s, from the Main Display Screen.
  • Set addition parameters for Battle Born Batteries
    • Press the “Lock” button.
    • Use the wheel to adjust the User Password to “141”. Press the “Center” button to enter.
    • Use the wheel to select “MATE3s” and press the “Center” button.
    • Select “Global Charger Output Control” and press the “Center” button.
    • Enabled: N
    • Press the “Up” button.
    • Select “Global Charger Output Control” and press the “Center” button.
    • Enable Chage Termination Control: N
    • Low SOC Warning: 30%
    • Critical SOC Warning Level: 20%
    • When done press the “Lock” button.

Outback FlexNet DC MATE3s Settings for Battle Born.

  • Using the MATE3s, from the Main Display Screen.
  • Adjust the settings for the FNDC to calculate the battery bank SOC. (These settings, especially the Battery Ah, may need to be adjusted as the batteries age.)
    • Press the “Lock” button.
    • Use the wheel to adjust the User Password to “141”. Press the “Center” button to enter.
    • Use the wheel to select “Settings” and press the “Center” button.
    • Select “Battery Monitor” and press the “Center” button.
    • Select “Battery Setup” and press the “Center” button.
    • Select each value with the wheel, then press the “Center” button to adjust.
    • Use the wheel to adjust the setting values.
    • Battery Ah: 100Ah for each Battle Born battery in parallel. (As an example, if you have 3 Battle Born batteries in parallel, set to 300 Ah.) (This can be adjusted down for ageing batteries.)
    • Charged Voltage: 14.2V
    • Time: 15 Minutes
    • Charged Return Amps: 2 A for each battery in parallel.
    • Charged Factor: 98% (This can be adjusted down for ageing batteries.)
    • When done press the “Lock” button.