Welcome to the experimental aircraft page of the most used and trusted lithium battery on the market! If you know what you want, scroll to the bottom of the page for products. For a great flowchart to help you determine the compatibility and which battery to use, click here:

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.  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, included:

1- 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.

2- 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.

3- short circuit protection- up to 1000 amps

4- 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.

5- cell balancing technology built in

6- 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?

1. You will instantly remove 11+ pounds compared to the lead acid battery in your experimental aircraft! Now that is a huge weight savings.
2. 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!
3. 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.
4. 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.
1. Can it turn the engine over (CCA)?
2. Does it have enough capacity to run your needed instruments if the alternator fails (true amp hours) ?
3. Is it designed for the application you are using it in (alternator amperage output)?

As Odyssey batteries are widely used in the experimental market so we have a chart of the Odyssey’s batteries and the EarthX batteries to assist you in a comparison.
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).




(1 hr 1C rate)

Crank Amps (PCA/CCA)


Case Size                (L x W x H)

Aircraft Guidelines

ETX680C*$37913.212.4680/3203.9 lb (1.8Kg)5.9” x 3.4” x 4.5”

150mm x 86mm x 115mm

400ci engine size or less;

60 amp alternator or less

ETX680*$37913.212.4680/3204.1 lb (1.86Kg)6.5” x 3.1” x 6.6”

166mm x 79mm x 168mm

400ci engine size or less;

60 amp alternator or less

ETX900*$44913.216840/4004.9 lb (2.2Kg)6.5” x 3.1” x 6.6”

166mm x 79mm x 168mm

540ci engine size or less;

80 amp alternator or less

ETX1200*$72513.224.81200/6007.7 lb. (3.5Kg)6.5” x 3.1” x 6.6”

166mm x 79mm x 168mm

550ci engine size or larger;

120 amp alternator or less

* ETX680C, 680, 900, and 1200 has redundant electronics and battery cell / hardware fault monitoring.                                                                                                                                                                                               Operating temperature – 30°C to 60°C or -22°F to 140°F

For Comparison Purposes Only…

VoltageWeightAh     (1 hour 1C rate)Case Size inches                         (L x  W x H)Cranking Amp (PCA/CCA)Overcharge Protection?Overdischarge Protection?Max Alternator Charging Amp’s
Odyssey PC1200*1238.2lb (17.3kg)32.17.87 x 6.66 x 7.601200/540NoNonot specified
Odyssey PC 925*1226lb (11.8kg)24.36.64 x 7.05 x 5.83900/300NoNonot specified
Odyssey PC680*1215.4lb (7kg)12.37.27 x 3.11 x 6.65520/170NoNonot specified
Odyssey PC625*1213.2lb (6.2kg)13.66.7 x 3.9 x 6.95530/200NoNonot specified
Odyssey PC545*1211.2lb (5kg)9.67 x 3.38 5.17460/150NoNonot specified
*information used from www.odysseybattery.com
**without metal jacket for the Odyssey                                                                                                                                                                                                   Operating temperature -40 C to 45 C or -40°F to 113°F
The all new ETX900-TSO designed for certified aircraft!

Introductory price is $1153.35 and you can place your order now! We do not have any STC’s yet so you will have to attain your own field approval to install it.

This battery is only 5.4 pounds and can be used in an aircraft that has an alternator/generator with 80 amps output or less. This battery has electronic protections (BMS) and built in thermal runaway containment and venting with 2 venting tubes that are 3 feet in length each. The ETX900-TSO meets all of the DO-311a and DO-160 requirements for a lithium battery in aircraft.

This battery also has an LED battery fault light indicator on the battery itself plus it can be programed into your EFIS or wired to an LED on your panel. The fault indicator alerts you to the state of charge and state of health of the battery. (Please see manual for details)

The battery management system (BMS) protects the cells from:

over discharge
over charge
short circuit
excessive cranking
cell balancing technology
PLUS these protections are redundant for another layer of protection.
EarthX is proud to be one of the most trusted brands in the experimental aircraft market and soon certified aircraft market!

FAA Required Statement:
“The conditions and test required for TSO approval of this article are minimum performance standards. Those installing this article either on or within a specific type or class of aircraft must determine that the article installation conditions are within the TSO standards. The article may be installed only according to 14 CFR part 43 or the applicable airworthiness requirements.”