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EarthX ETX-900 Aircraft Lithium Battery

Part# 11-13926
MFR Model# ETX900


Note: Not FAA Approved. Intended for use in experimental aircraft only.

The ETX900 is lightweight and crazy powerful!

This battery is intended for 540ci engine size or less; 80 amp alternator/generator or less.

The ETX battery series is fully protected by an integrated battery management system (BMS) that protects the cells from over discharge, overcharge, short circuit, temperature, plus cell balancing to ensure charge levels are equal. Additionally, our ETX Hundred series aircraft batteries have redundant electronic circuits and battery fault indication. The fault indicator can be connected into your EFIS or wired to a 12volt LED light on your control panel to alert you to the state of charge and state of health of the battery. (Please see manual for details)
California Prop 65 Warning Symbol

WARNING: Cancer and Reproductive Harm -


  • The ETX Hundred series is fully protected by an integrated Battery Management System that protects the cells from over discharge, over charge, short circuit, thermal protection and built in cell balancing to ensure charge levels are equal (balanced) 100% of the time for optimal performance
  • and life.
  • The most trusted and used lithium battery on the market. Multiple experimental aircraft manufacturers and experimental engine manufacturers such as Rotax Engines, Continental Motors, UL Power Engines and Viking Engines approve the EarthX brand.
  • LiFePO4 chemistry, the most abuse tolerant of all lithium battery chemistries.
  • Higher voltage while cranking mean faster starts.
  • Extremely light weight, 70-80% lighter than your lead acid battery.
  • 4,000 charge cycle life versus 350 charge cycle life of a lead acid battery. Can last up to 8 years.
  • Environmentally friendly, no hazardous lead or acid, will not corrode or sulfate.
  • Wider operational temperature range than a lead acid battery. (-22 F to 140 F, -30 C to 60 C) . A lead acids operational range is(-40 F to 113 F or -40 C to 45 C).
  • Vibration tested to DD-311 FAA standard.
  • Low self discharge rate and fast charging.


Voltage 13.2V
Capacity 15.6Ah @ I C Rate (See charts Below)
Capacity vs Temperature 25C= 100%
0C= 92%
-30C= 80%
Self-Discharge Rate <3% / month @ 25C
Pulse Crank Amps (PCA) 840A (3 sec @ 25C, voltage >9V
Cold Crank Amps (CCA) 400A (modified SAE test, 3 sec @ 0F, volts > 7.2V)
Continuous Discharge Amps 150A
Standard Charge Voltage 13.9 - 14.6V
Maximum Charge Voltage 15V
Recommended Charge Voltage 5 - 20A
Max Charge Amps 80A (from vehicle charging system)
Life (Charge cycles, 80% depth of discharge) 4000 cycles @ 1C discharge rate,
25C 2000 cycles @ 10C discharge rate, 25C
Life (Years) 8 Years
Weight 4.9 lb. (1.8kg)
Dimensions 6.5 in (L) x 3.1 in (W) x 6.6 in (H)
166mm (L) x 79mm (W) x 168mm (H)
Environmental Rating (resistance to water intrusion) IP 66 (wash down with a high pressure washer)
Operating Temperature -30C to +60C
Storage Temperature -40C to +70C

Why Choose EarthX

  • You will instantly remove 11+ pounds 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 CCAs from 170 to 320 and the PCAs from 520 to 680! Now thats 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!
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Incredible so far worth every pennny!

Steve B Verified Purchase


April 21, 2023

Awesome battery. Great cranking power.

Charles C Verified Purchase


April 1, 2023

Much lighter vs PC680 cranks better and less voltage drop. A pure aircraft battery!

Nick M Verified Purchase


March 2, 2023

This is a great battery. My last one was 6+ years old and still going strong. I replaced it because the manufacturer states that it will last up to 6 years,

Jeff. B Verified Purchase


February 28, 2023

I guess I waited long enough to see if its any good. My wife bought this battery over 7 years ago and installed it in her RV-7 with an ECI 370 CI engine. It is still going strong with no drop in typical voltage. It easily cranks the high compression 370 even when hot and flooded. I normally dont give 5-star reviews, but I cant help it here. When she bought it, I thought it was too expensive, but now I know it was well worth the money.

February 4, 2023

Received intact, undamaged.

Kenneth L Verified Purchase


July 12, 2022

Excellent battery replacement for the Odyssey in my RV-9. I got 6 years out of the first one,and only replaced it because an over voltage event damaged it. The only issue I had with the replacement is that EarthX relocated the status wire, requiring me to modify my hold down bracket.

Chris M Verified Purchase


April 13, 2022

Very lightweight battery. Cranks my IO 540 easily.

Gerald S Verified Purchase


February 10, 2022

Wild power, low weight. Nothing we have used compares

Decosse C Verified Purchase


June 25, 2021

Great battery. Very light weight. Lots of cranking power.

Kevin W
April 20, 2021


Please note, Aircraft Spruce's personnel are not certified aircraft mechanics and can only provide general support and ideas, which should not be relied upon or implemented in lieu of consulting an A&P or other qualified technician. Aircraft Spruce assumes no responsibility or liability for any issue or problem which may arise from any repair, modification or other work done from this knowledge base. Any product eligibility information provided here is based on general application guides and we recommend always referring to your specific aircraft parts manual, the parts manufacturer or consulting with a qualified mechanic.

Q: Does the EarthX ETX-900 come with terminal bolts?

The terminal screws are included.

Q: Are any of the EarthX batteries for certified aircraft?

Yes, the ETX900-TSO is FAA TSO approved. Please see our part # 11-18242.

Q: ETX lithium batteries adv. their redundant electronic. circuits: Q - What circuits EXACTLY have been duplicated on the BMS?

The discharge power control circuits.

Q: Does the Battery Status/Warning Light and wiring harness come with the purchase of a new ETX900 battery?

No. The customer can connect directly to their EFIS system and if they do this, no need for the LED light.

Q: What is the actual weight of this ETX-900 battery?

4.9 lbs approx

Q: Can the ETX-900 battery be airfreighted?

Yes, it can be shipped via air but it is considered hazardous and will incur hazardous fees.

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