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EarthX Aircraft Batteries

EarthX is proudly used by a multitude of aircraft and helicopter manufacturers and endorsed by many engine companies such as Rotax, Continental, ULS Power and Viking. ​You can find a great flowchart to help you determine the compatibility and which battery to use down below.


The ETX Hundred series (ETX680C, ETX680, ETX900 and the ETX1200) are the only battery models recommended for your primary engine aircraft battery or backup battery. The battery management features, which have redundancy, include:

Over discharge protection - if you leave your master key on, the battery will disconnect internally prior to cell damage (approximately when about 95% of the energy has been drained). You will need to charge the battery before use in this scenario.

Over charge protection – if you have a voltage reading above 15.2V, your regulator has failed and you should take your alternator off line immediately to avoid damage to your electronics and possibly damage to the battery. See manual for details of this feature.

Short circuit protection - up to 1000 amps

Excessive cranking protection- if you are trying to start your engine continuously for a long period of time, the cells inside the battery will heat. The BMS will disconnect for approximately 90 seconds so the cells can cool off and not cause damage to the battery.

Cell balancing technology built in - LED battery fault light indicator to alert user to the state of charge and state of health of the battery. The LED light will illuminate to let you know when there is a problem. This is a very important safety feature; be sure to connect it to your EFIS or LED light on your control panel.

Why choose an EarthX lithium battery?

You will instantly remove 11+ pounds (over 5kg) compared to the lead acid battery in your experimental aircraft! Now that is a huge weight savings.

Significant increase in cranking power - if you have been using the PC680, you will increase your CCA’s from 170 to 320 and the PCA’s from 520 to 680! Now that’s power to crank your engine!​

Now you can easily have a backup battery and not worry about the additional weight. In fact, if you switch from a lead acid battery and add a backup battery, so you have a primary and a backup, you still have decreased your overall weight by 50%! Note that only the ETX680C/680/900/1200 have the aircraft specific BMS.

Innovative and sophisticated BMS designed and engineered with redundancy for safety, reliability, and performance. These are EXCLUSIVE features!

There are 3 main things you need to consider when choosing the right battery for your plane.

  • Can it turn the engine over (CCA)?

  • Does it have enough capacity to run your needed instruments if the alternator fails (true amp hours) ?

  • Is it designed for the application you are using it in (alternator amperage output)?

A common question is:

Can you wire the batteries in series or parallel with a lead acid battery?

NO, you cannot do this. The voltage of the lead acid is lower than the lithium so it will drain the lithium battery.

Do not use any lithium battery in a vintage engine that was not originally designed for a battery, such as a Rotax 503 pull start. (Provision 4, gear box with 4 bolts).

A lithium battery, having different properties than a lead acid battery, requires special consideration for its use to ensure longevity and safety. A lithium battery has a low resistance to charge current which is why a lithium battery can be recharged so quickly. But this low resistance also allows it to accept a charge current which may exceed its rating. A lithium battery is also more easily damaged due to over-voltage charging. As such, all EarthX batteries come with over-voltage (over-charging) protection. In addition to the battery’s over-voltage protection, EarthX strongly recommends having automatic over-voltage circuit protection (crowbar) for the aircraft charging system. This is an important backup safety feature to protect the aircraft electrical system from high voltage events. In the case of high output alternator charging systems, aircraft automatic over-voltage protection is required.

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