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Thread: Litium battery question

  1. #11
    Senior Member Eric Page's Avatar
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    Default Re: Litium battery question

    Note that the ETX680 and ETX900 share the same case size: "E". Either will fit in the same battery tray. If you have an electrically dependent engine and a single battery, you might consider using the 15.6Ah ETX900 instead of the 12.4Ah ETX680. Doing so will achieve longer alternator-out endurance, or the same endurance with less load shedding required. Weight difference is 0.8 lb.

    Even without an electrically dependent engine, there are advantages to using the ETX900. It can supply higher starting current and tolerate higher recharge current. Those things, combined with its higher initial capacity mean it will likely last longer in the same environment than an ETX680.

    Whether the longer lifespan will favorably amortize the $70 higher price is an open question...



    Edited to add:

    If you have a 912iS (and presumably a 915iS), neither of these batteries meet the minimum battery ampere-hour capacity listed in the Rotax installation manual, but the ETX900 is nearly big enough.

    Quote Originally Posted by Rotax 912iS Installation Manual
    ATTENTION
    The use of rechargeable batteries with lithium–ion technology should only be
    used in combination with a suitable battery management system. If such an battery
    is used, the responsibility is up to the aircraft manufacturer. The approval of
    the relevant aeronautical authority may be necessary. For installation of lithium ion
    batteries refer e.g. to FAA AC No: 20-184

    ATTENTION
    Observe the specifications of the battery.
    The size of the battery needs to be adequate for essential flight equipment and has to
    meet the airworthiness requirements of its place of operation.
    When sizing the battery ensure that during each operating state and also during the transition
    between two operation states a sufficient supply of the display is guaranteed (e. g.
    during engine start). Furthermore, it must be ensured that at least 30 minutes after failure
    of the primary power supply the display is supplied with sufficient energy, if it is necessary
    for a safe operation of the aircraft.

    Nominal voltage: 12 V
    Internal resistance: maximal 10mΩ at -18 °C (-0.4 °F)
    Cold Cranking Ampere (cca): At least 350 A at -18 °C (-0.4 °F) (SAE J537)
    Capacity: At least 16 Ah
    Last edited by Eric Page; 10-24-2021 at 09:27 AM. Reason: Add Rotax 912iS comment.
    Eric Page
    Building: Kitfox 5 Safari | Rotax 912iS | Dynon HDX
    Member: EAA Lifetime, AOPA, ALPA
    ATP: AMEL | Comm: ASEL, Glider | ATCS: CTO
    Map of Landings

  2. #12
    Administrator DesertFox4's Avatar
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    Default Re: Litium battery question

    Good info Eric. Battery choice IS dependent on engine installation and electrical load factors.

    ***My reply in post 10 is in response to Jerrytex’s question about what works for a Rotax 912uls installation specifically.
    The EarthX ETX-680 or ETX-680C should also work well with a 912ul or 914.


    For critical instrument battery backup, most go with TCW’s IBBS (Integrated Battery Backup System). Chose which battery backup system again depending on critical components needed for flight. https://www.tcwtech.com/product/inte...v=7516fd43adaa


    DesertFox4
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  3. #13
    Senior Member efwd's Avatar
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    Default Re: Litium battery question

    EarthX is just so good to do business with to start. To address Jump starting, EarthX sells the Jump Pack which is multipurpose. I have one. It has the ability to charge cell phones etc etc, it is a flashlight as well. I keep it in the airplane since I won't just be able to pull up in my car when Im 100miles from home. As for the Charger, EarthX has some pretty nice units that act as a power supply for long power on needs. They didn't have the option for that when I needed it so I had to poney up for the power supply unit as well.
    Eddie Forward
    Flying
    SS7, 912iS, Garmin G3X

  4. #14
    dginok's Avatar
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    Default Re: Litium battery question

    I'm using an Antigravity ATX20-RS, and loving it, especially combined with a John Deere-type regulator after the Ducati died. The plane starts better than ever, and I never keep it on a charger.
    Doug
    Super Sport
    912ULS
    Constant Speed IVOProp


  5. #15

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    Default Re: Litium battery question

    Quote Originally Posted by Shadowrider View Post
    Earth x also. They have their own internal board that controls the charging, discharging, balancing, voltage.
    At what voltage would it shut off the output to save the battery?...and would that voltage be the same for all the Earth X models?

  6. #16
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    Default Re: Litium battery question

    The BMS disconnects the battery from the load if it is drained to less than 5% remaining charge (an over-discharge condition). An over-discharged battery typically has a voltage less than 11.5V. If the BMS disconnects the battery, the voltage reading of the battery will be zero volts. Excessive cranking protection logic includes temperature monitoring to limit “high current use” (engine cranking) to 10 -30 seconds in any 60 second period. If the battery terminals are “shorted” (or a low impedance load is connected across terminals), which causes the battery volts to instantaneously drop to a very low level, the battery will disconnect from the load to protect the cells and BMS from damage (short circuit protection). If the BMS disconnects due to excessive cranking protection or short circuit protection, the BMS will automatically reconnect after a cooldown period (typically 1-3 minutes). The ETX series is designed for short circuit protection > 1000 Amps.
    ETX Hundred Series
    Dustin Dickerson

    Building 7ss STI x 2
    Oratex
    29" shock monster
    EP912STI 155hp
    Garmin
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    N53TF......FLYING!

  7. #17

    Default Re: Litium battery question

    Earth-X sun n fun discount is 10% off and free shipping if anyone is interested.

  8. #18
    Senior Member fastfred's Avatar
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    Default Re: Litium battery question

    I have run both types and mostly the Lithium for the past few years. areovoltz is the one kitfox put in mine I think. It works fine if you don't run it down too far . They do have their own charger that is complicated to use. I also use a lithium maintainer / charger than works fine also. the answer to your question is no you do not need to keep a charger on it when there is no load.

    On my Remos I recently traded the odyssey for An Antigravity lithium battery with more power and saved 12 lbs. They are much less than the earthx and it fit in my existing box. Google them.

  9. #19

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    Default Re: Litium battery question

    I’m still building but purchased a Earth X and it has sat in the shipping box for a year aprox and the other day I checked it and was 13.1 V. Then I charged it with a Lithium Optimate charger which took aprox 45 min and then was at 13.6 V right after charging.

  10. #20
    Senior Member Slyfox's Avatar
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    Default Re: Litium battery question

    I just went through changing to the earthX. I put in the 680C. I have the 912uls engine. I also put in the B and C regulator, very nice unit. I made sure it was charging like 14.3 volts. I also got the led light for the panel, something that earthX sells to tell you if you have a problem. I don't put it on a charger and it cranks very fast no matter what the temp outside is. plane starts right up. I like it.
    steve
    slyfox
    model IV 1200-flying
    912uls
    IVO medium in-flight
    RV7A-flying
    IO-360
    constant speed prop

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