MADE IN THE USA!
Free Economy ShippingProduct Specifications for EarthX ETX680 Lithium Battery for Experimental Aircraft & Race Car with 60 Amp Alternator Or Less
| BM Part #: | LTX680 |
|---|---|
| Brand: | EarthX |
| Made In: | U.S.A. |
| Voltage: | 13.2 Volt |
| Cold Cranking Amps: | 320 CCA / 680 PCA |
| Capacity: | 12.4 Ah |
| Type: | LiFePO4 |
| Length: | 6.5" |
| Width: | 3" |
| Height: | 6.6" |
| Shipping Weight: | 4.10Lbs |
| Warranty: | 2 Year Factory Direct |
| Product Manual: | Download |
| Datasheet: | Download |
What's in the box:
- 1 x ETX680
- 2 x 6mm screws
- Foam for proper fitment
- Made in the USA. Why it matters:
- Superior craftsmanship; rigorously tested; high-quality parts.
- Dramatic Weight Savings: Weighs just 4.1 lbs, more than 11 lbs lighter than the Odyssey PC680 it replaces.
- Exceptional Cranking Power: Delivers 680 Peak Cranking Amps and 320 CCA for confident starts in cold weather down to -22°F.
- Integrated Battery Management System: Automatically guards against overcharge, over-discharge, short circuit, and cell imbalance.
- Fault Indicator Pigtail Included: Connect to an LED panel light or EFIS to monitor battery health from the cockpit.
- Rotax-Approved and Made in the USA: Meets Rotax engine lithium battery requirements, engineered and assembled in America.
- Long-Term Value: Rated for up to 4,000 charge cycles and an 8-year service life for years of reliable service.
Product Description
Every pound matters in an experimental aircraft. If you're still flying with a heavy lead-acid battery, you're leaving useful load on the table. The EarthX ETX680 is a lithium iron phosphate (LiFePO4) aircraft battery built for experimental aircraft and motorsport — delivering more cranking power than conventional batteries at a fraction of the weight.
Compared to the popular Odyssey PC680, the ETX680 weighs just 4.1 lbs versus 15.4 lbs. That's more than 11 pounds you can convert directly into payload, fuel, or comfort. Pilots who have made the switch report noticeable improvements in how quickly and confidently their engines turn over, even in cold weather.
Why the ETX680 Outperforms Lead-Acid
It's not just lighter. The ETX680 also hits harder at startup. With 680 Peak Cranking Amps (PCA) and 320 Cold Cranking Amps (CCA), it has a clear edge over the PC680's 520 PCA and 170 CCA. And unlike a lead-acid battery, the ETX680's integrated Battery Management System (BMS) keeps watch over cell voltage, state of charge, and resistance around the clock — automatically balancing cells and protecting against overcharge, over-discharge, and short circuits without any input from you.
The ETX680 is also Rotax-approved for use as a lithium battery with Rotax engines, and its IP66 environmental rating means it can handle a high-pressure washdown without issue.
Know What Your Battery Is Doing — From the Cockpit
The ETX680 comes with a black pigtail wire (fault indicator connector) that lets you monitor battery health in real time. Connect it to an LED indicator light on your instrument panel or to your EFIS, and you'll get an immediate visual alert if something moves outside the normal range. The EarthX 5MM12 12V LED Battery Fault Indicator Light is available separately and is a straightforward addition to your panel. Full wiring details are in the product manual.
Designed for 60-Amp Alternator Systems
The ETX680 is designed for aircraft and vehicles with a charging system producing 60 amps or less. Before installing, confirm your alternator output. If your system runs higher, the ETX900 or ETX1200 may be a better fit. For those within spec, installation is straightforward using the included 6mm screws and foam inserts for proper fitment.
Compatible Accessories
- EarthX 5MM12 12V LED Battery Fault Indicator Light
- BB-TH Thermal Battery Box — FAA PMA Approved
- BB-CU Custom Lightweight Battery Box
- BB-MU2 Lightweight Aluminum Battery Box
- Adapter-CDE Terminal Adapters
Engineered and assembled in the USA, the ETX680 is backed by a 2-year factory warranty and free standard shipping to all 48 contiguous states. Add it to your cart today and take back the weight.
Typical Charging Times
| Charging Amps | Charging Time |
|---|---|
| 1 amp | 12 hours |
| 5 amp | 2.5 hours |
| 15 amp | 45 min. |
Fault Conditions
This table shows the most common fault conditions and possible causes.
| LED Light | Voltage | Possible Cause | Recommended Action |
|---|---|---|---|
| Slow Flashing (5s on / 5s off) | Less than 12.8V | Battery over-discharged (due to faulty charging system) | Charge battery. Once charged, the light will stop flashing. |
| Slow Flashing (5s on / 5s off) | Less than 13.2V | Weak or failing cell | Charge battery. If voltage drops below 13.2V within a few days, discontinue use. |
| Slow Flashing (5s on / 5s off) (>1 hour time period) | 13.2V - 14.6V | Weak or failing cell | Discontinue use. If in flight, this is not an immediate issue unless it is in conjunction with a charging system failure. |
| Slow Flashing (5s on / 5s off) | Greater than 15.2V | Over-charging (due to faulty charging system) | If in flight, shutoff charging system immediately. Aircraft over-voltage protection is required if alternator charging system is greater than 20 amps (i.e. over voltage crowbar circuit) |
| Slow Flashing (5s on / 5s off) | 13.2V - 14.6V | Cell to cell charge levels are not balanced | May come on briefly during periods of high current charging until the cells are automatically balanced. Try charging with a plugin charger, like an Optimate Lithium charger. |
| Solid Light | Any voltage | BMS electronic issue | Discontinue use. If in flight, this is not an immediate issue unless it is in conjunction with a charging system failure. |
| Solid Light that turns off after 3 minutes | Any voltage | Short Circuit protection was activated | Nothing neds to be done. |
| Short Flashing (2s on / 2s off) | Any voltage | High battery temperature (> 65°C / 150°F) | Let battery cool down prior to cranking or charging. |
Frequently Asked Questions
Is the EarthX ETX680 compatible with my aircraft's charging system?
A: The ETX680 is designed for use with charging systems that produce 60 amps or less. It works with most vehicle charging systems and modern lead-acid battery chargers thanks to the built-in BMS. If your alternator exceeds 60 amps, the ETX900 or ETX1200 series would be a better match. Check your aircraft's electrical specs and refer to the product manual if you're unsure.
What is the black pigtail wire on the ETX680?
A: The black pigtail wire is a fault indicator connector included with all ETX Hundred Series batteries. It connects to a 12V LED indicator light (sold separately) on your instrument panel or to your EFIS. If the BMS detects something outside the normal range — such as a low-voltage condition, a weak cell, or an overcharge event — the LED will alert you. Wiring details and LED indicator meanings are covered in the product manual.
Can the ETX680 replace my Odyssey PC680?
A: Yes. The ETX680 is a direct replacement for the Odyssey PC680 and shares the same case dimensions. It also cross-references the following OEM part numbers: 12C16A-3B, 51814, 51913, CP18-12, YG51913, YS51913, and YT19BL-BS. At 4.1 lbs versus the PC680's 15.4 lbs, you'll also gain back more than 11 pounds of useful load.
What happens if the ETX680 fully discharges?
A: If the battery enters a deep discharge state, the BMS will shut it down to protect the cells. You'll need to recharge it with a compatible lithium or LiFePO4 charger before it will operate again. To prevent this during long storage periods, keep the battery connected to a maintenance charger. The fault indicator LED can warn you of low-voltage conditions before deep discharge becomes an issue.
Does the ETX680 require a special lithium battery charger?
A: Not necessarily — the ETX680 is compatible with most modern lead-acid battery chargers. That said, a charger designed specifically for LiFePO4 batteries will optimize charging performance and extend battery life. EarthX recommends charging at 0.8–15 amps. Avoid chargers with a desulfation or reconditioning mode, as these can damage lithium cells.
Cross Reference & Compatibility
Customer Reviews
I went from the Big Crank (agm) battery to the ext680. Lighter is better for my RV6A, the prop shins faster for sure. Only time will tell. I have been watching this technology advance for years now, and this is my time to dive in.
The weight saving while installing in a tight space and cranking power they have is well worth the expense.
I own a 2004 BMW R1100S. The battery is stuffed under the fuel tank & requires A LOT of effort to access & replace! As I don't ride year round, or in unfavorable weather here in the Northeast, the bike does sit around. So I was looking for a battery with good cranking power & the ability to not fully discharge, i.e. it would protect itself. The EarthX seemed to check all the boxes. Between the battery & the lithium battery charger I had around $500 invested. Cranking power was great. The big twin fired easily. However, if the battery discharged, it would lock to protect itself & that's where the "special" charger came in to "unlock" it. It wouldn't unlock the battery unless it was disconnected from the bike - so pull everything apart & remove the battery - I may as well have just put an AGM in there as I was effectively going through the effort of replacing a battery. Last year we moved & the bike wasn't on it's charger for awhile. After it locked this time, it wouldn't unlock & I had to replace it. For the $ invested I could have purchased 3-4 AGM batteries & the EarthX didn't save me any labor. So lesson learned, if you own an EarthX, keep the trickle charger on it all the time!
This battery is very light weight. I haven't tried to start my Harley with it yet,. Hoping it will shave some pounds off the bike.
Bought the battery and so far it’s everything that I read about ..I have a 2014 -110 Harley Davidson CVO Ultra ..
The standard batteries from Harley even when new ,would have some difficulty turning the high compression motor over .. and on top of that would only last 2 yrs tops ..either always on battery smart charge (1st one ) or charging ever two weeks or so ..
This new one .. Wow ! It cranks over so much better, you immediately hear the difference..
I have it 3 weeks now , so who knows the lasting effects..but it looks very promising 😁
One other thing ..the battery is less wide or thick ..and much lighter..I used styrofoam to fill in gap ..seems to be working great ! Might want to consider the battery holder they sell .
