Help me find the right battery charger

Discussion in 'Maintenance Bay' started by nickmatic, Apr 14, 2018.

  1. nickmatic

    nickmatic Pre-Flight

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    I've relocated to northern Spain and maintenance facilities here and nearby are pretty lacking, so I'm becoming a do-it-yourselfer by necessity. Lots of learning to do.

    My Mooney 252/Encore needed a new battery. The old one was a Gill G-242 (24V) that lasted 5 years, so I got a new one of the same. Great. Now I need to put the electrolyte in a do the initial charge.

    I'm asking around to see if anyone nearby has a charger, but it may be better for me to just get my own to do the initial charge and for future use and battery care.

    Can anyone recommend a decent but low cost battery charger for occasional use?

    The battery manual says the following:
    Charge the battery at 28.2-28.6V for a period of 24 hrs. Inrush current can be as high as 100 amps, provided the voltage does not exceed the value above.

    The inrush current noted is what concerns me... seems like not just any old 28V charger will be able to charge this battery initially. Thoughts?
     
  2. A1Topgun

    A1Topgun Pre-Flight

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    Last edited: Apr 14, 2018
  3. nickmatic

    nickmatic Pre-Flight

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  4. A1Topgun

    A1Topgun Pre-Flight

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    It is a micro processor controlled solid state charger. It will limit at 4Amps - when fully charged it will drop to a pulsed trickle charge.
     
  5. nickmatic

    nickmatic Pre-Flight

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    Ok thanks, I didn't know that. Now to find one that runs on 240V... :(
     
  6. Capt. Geoffrey Thorpe

    Capt. Geoffrey Thorpe Final Approach

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    Inrush current is a limitation not an expectation. 98.32% of the chargers won't supply that kind of current - the voltage will just sag for a while until it catches up. Snow big deal.
     
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  7. A1Topgun

    A1Topgun Pre-Flight

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    I was stationed at the Naval Station in Rota, mid 1960's. One weekend we flew the flying club T-34 to Barcelona.
     
  8. nickmatic

    nickmatic Pre-Flight

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    Thanks, I thought it was more complicated than that. So will basically any 24V charger do the job at least for the initial charge? I can probably find one locally if it doesn't have to be aviation specific.
     
  9. A1Topgun

    A1Topgun Pre-Flight

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    Correct, any 24v charger will charge the battery.
     
  10. nickmatic

    nickmatic Pre-Flight

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    Well that makes my life a little easier. Thanks!
     
  11. Bell206

    Bell206 Pre-takeoff checklist

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    FYI: batteries have specific charging rates that alter between current and voltage plus are based on time. There should be a document with a chart that shows you the charging cycle that came with the battery. A Battery Minder is not a charger only a maintainer.

    To get max performance and service life out of a battery it's best to use the recommended type of charger and maintenance schedule plus ensure your aircraft electrical is in good working order.
     
    Last edited: Apr 14, 2018
  12. denverpilot

    denverpilot Taxi to Parking

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    The battery will come with specific pre-charge instructions from the manufacturer. Follow those.
     
  13. Capt. Geoffrey Thorpe

    Capt. Geoffrey Thorpe Final Approach

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    "The battery manual says the following:
    Charge the battery at 28.2-28.6V for a period of 24 hrs."

    Seems pretty straight forward to me.
     
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  14. denverpilot

    denverpilot Taxi to Parking

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    Some have more detailed instructions either on their website or available via a phone call.

    I have the gear here to charge at 28.6V and limited to 100mA which would meet that stupid spec and the battery would still be dead. LOL.
     
  15. Bell206

    Bell206 Pre-takeoff checklist

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  16. denverpilot

    denverpilot Taxi to Parking

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    Yup. Lookie there.

    And notice how it has initial and final charge rates and all sorts of useful stuff.

    And I bet about 1% of shops do any of it. Selling new batteries every few years is cheaper and easier and nobody wants to pay for the labor hours.

    Think anyone is standing near the battery to notice when it starts outgassing or would ever hear the thing doing it in a typical hangar / noisy shop — to change the charging current?

    LOL. Sure they did. Followed those manufacturer initial charge instructions to a T, I bet.

    That’s what the logbook entry will say though, no matter who did it or how.
     
  17. nickmatic

    nickmatic Pre-Flight

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    Yeah, I mean this is why I asked. I know corners are cut with this stuff and sometimes that's ok, sometimes it's not. I'm not looking to get a PhD in battery charging, just get this thing charged and my plane flying. If I cut 6 months off its life because I didn't do it 100% correctly with a world-class high end charger, that's ok. My last battery lasted over 5 years and it wasn't exactly treated well (not on purpose but plane sat longer than expected many times, fully discharged a couple times by accident, etc).

    So I ordered this charger from Amazon. It's the most suitable seeming thing I could find in Spain without it being obscenely expensive.

    https://www.amazon.es/gp/product/B01M0CPRKL/ref=oh_aui_detailpage_o00_s01?ie=UTF8&psc=1

    Seems like it should get the job done unless anyone sees any major issues. I'll follow the charging instructions as closely as I can.
     
  18. 3393RP

    3393RP Cleared for Takeoff

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    This is the correct answer. A discharged battery must be charged at the correct initial rate to break down sulfates and start the process of reversing the chemical reaction resulting from the discharge.

    As the electrolyte specific gravity recovers, the charge rate can be modified as mentioned below. Battery minders can't do this. They will maintain a fully charged battery, but don't have enough current output to properly charge a battery that has been discharged.

    As Bell206 mentioned above, get the correct specs for your battery and follow them. Charge rates and float voltages differ for lead acid, AGM, and gel cell types.




    [​IMG]

    Is there some sort of a standard maximum charge rate for flooded lead acid batteries? Someone mentioned not wanting to take them beyond a C/10. What’s the rationale for that? I’d rather hit them hard and fill them up quickly while my generator is running. Thanks,

    John Bartlett • Exeter, New Hampshire



    Hello, John. The maximum recommended rate is C/5 (a charge rate in amps of one-fifth the overall battery capacity in amp-hours), but only when the cells are between 10 and 85 percent state of charge (SOC). After the cells reach 85 percent SOC, then a C/10 is the maximum. After cells reach 95 percent SOC, between C/20 and C/15 is recommended. Having said this, I rarely charge faster than a C/10.

    The reason for the maximums is heat. Higher amperage means more heat, particularly when the cells are getting fully recharged. Thermal cycling wears the plates and sloughs off material.

    Finally, it’s always a good idea to get charging specifications from the manufacturer of the particular model of battery you’re running. Battery specific charge rates, and bulk, absorption, float and equalization set-points and times will all lead to better battery longevity.

    https://www.homepower.com/articles/...t-products/ask-experts-battery-charging-rates
     
  19. Gary Austin

    Gary Austin Filing Flight Plan

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    I just put two Concorde batteries in a Waco and they came already charged, just install and go, can't beat that
     
  20. 3393RP

    3393RP Cleared for Takeoff

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    The current will vary significantly when recharging a depleted battery using a target voltage.

    Using the C value method posted above allows maximum charge current without the possibility of thermal damage.
     
  21. Bell206

    Bell206 Pre-takeoff checklist

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    And what if the battery only lasts 6 months as some on this board have stated? It doesn't take a Phd to simply follow the manufacturer's recommendations. But it's your nickel.
     
  22. nickmatic

    nickmatic Pre-Flight

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    So I got the charger and everything this morning and have added the electrolyte and am charging the battery.

    Initial current was 10A, dropping to 5 within 15 minutes, and down to 1 in about an hour.

    Now at 3h 15m and voltage is 31.4V and falling slowly. Current holding at 1A.

    The manual says "Battery voltage may be used as an indicator. ON-CHARGE battery voltages will stabilize around 32 volts when charging at constant current for 24 volt batteries" and then "At the end of charge, all cells will be gassing freely and the battery voltage will stabilize and start to drop slightly"

    UPDATE: I spoke with Gill tech support and indeed the battery is fully charged when the current drops below 1A. Only took about 4 hours. Definitely not clear in the manual, but there it is.
     
    Last edited: Apr 19, 2018 at 12:52 PM
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  23. nickmatic

    nickmatic Pre-Flight

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    UPDATE 2: Installed the battery today and she started right up. Success.
     
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