About the MS2012 Inverter Charger

The MS2012 inverter charger by Magnum Energy is a “pure” sine wave inverter, making it compatible with all A/C devices. These units were built to meet the most demanding environments. Whether it be in a mobile application, off grid, or a power back up installation, the Magnum inverter charger can handle the job. This unit is arguably the most popular inverter charger used in RVs, so we decided to test it out with our Battle Born LiFePO4 batteries.

The Magnum MS2012 inverter charger will constantly monitor your battery banks voltage to ensure you are never without power. When first connected to a battery bank, the unit will go straight into a bulk charge which will rapidly bring the banks voltage up to 14.4 V. If using the optional Magnum remote, the user will be able to adjust to the desired voltage. Once the programmed voltage is reached, the charging will switch to an absorption stage to finish the charging cycle.

A main benefit of this charger is the remote, because it gives you complete control over the unit. As a user, you are able to set float voltage, low voltage cut offs, and many more parameters to ensure your battery is maintained in the best way possible.

The inverter side of the Magnum 2012 is as straight forward as it gets: connect your A/C line to the main distribution panel of the unit, and you are ready to go! Being a pure sine inverter, you have nothing to worry about when it comes to your electrical devices.

Testing with Battle Born Batteries

At Battle Born Batteries, we ran the unit numerous ways to fully understand how the inverter charger would work with our batteries. Our initial test was to simply turn the inverter on and see how low it would drain the batteries in its default settings.

In this test, we saw the voltage drop to 9.1 V before our BMS kicked off and interrupted the circuit. When using the charger side of this unit, we learned that if your battery bank falls below 5 v, the unit will detect a fault and not charge because a battery is not detected. To fix this issue, we recommend setting the low voltage cut off on the inverter to 11.5 volts or higher to ensure the inverter cuts off before the BMS activates in the battery.

If by chance your battery bank cuts off at low voltage and the inverter charger won’t recharge, there are 2 simple fixes.

  1. If in a motorized RV or are connected inline with an alternator, start the engine and the BMS will click back on automatically.
  2. If you are not in line with an alternator, you can use any 12 volt source, including a li-ion jump start pack to “wake” the battery up so the inverter charger will start delivering current to the batteries.

This issue does not exist in a system when a converter is used for charging. Keep in mind that when you set the low voltage cut off of the inverter charger to 11.5 volts (the point when your LiFePO4 batteries are empty), you will prevent this issue.

In our test, we saw the charger bring our batteries voltage up to 14.56 V, delivering roughly 38 A of current. Once it reached this point it dropped into a float mode slowly delivering less and less current.

Overall, this inverter charger works well with our batteries! However, we do highly recommend that the remote is purchased with the unit so the charging rates and battery status can be easily monitored and adjusted. Without the remote there is no other way to adjust the charging values or low voltage cut off.

Suggested adjustments

  • Bulk charge: 14.4 V
  • Float: >13.6 V
  • Low voltage cut off: 11.5 V
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