Keeping the battery charged

ghendrghendr
in General Discussion
My battery has been at 12V or less lately, especially in colder weather. I know there are batter keepers, but I think they are expensive for what they are. So, I bought a digital timer at Walmart for $15 and now have the battery charging for 30 minutes per day at 2 amps. Can anyone suggest how effective this is vs. the battery keeper? BTW, I fly about every 10 days and the battery is less than a year old.

Comments

  • CaptPeteCaptPete
    The nice thing about the battery minder is that it adjusts the charge voltage to the ambient temperature which gives you the optimal charge per the battery manufacturer's recommendations.

    I got one and installed it in the front baggage area of my Lance (where the battery is) and just plug it in after every flight. It maintains an optimal charge on the battery at all times.

    I think getting an automotive charger would be better than nothing in moderately cool climes, but up here in Canada, where it can regularly dip to -20C overnight, you need all the help you can get.
  • Mike BMike B
    How are you attaching the battery tender/minder to the battery? On my Arrow the battery is inside a closed box and I assume the the same is true on other Pipers. Where did you attach the leads for the charger?
  • CaptPeteCaptPete
    "Battery chargers and battery maintainers are not the same."

    The Battery Minder is both a charger and a maintainer. It initially goes into charge mode if the voltage is down, and then switches to maintenance mode once the level comes up to within spec.

    I have the 2 leads connected directly to the 2 battery posts per the manufacturer's instructions. The temp sensor lead is connected to one of the posts as well, so it actually measures the temperature of the battery, not the ambient air, and thus properly sets the charge/float voltage. Again, per the manuf's instructions. I leave the unit connected to the battery at all times (ie. I fly with the unit in the plane attached to the battery) and just plug it in to the wall outlet when I shutdown. Dead simple. Battery is always fully charged and ready to go.

    Again, I would caution against using automotive chargers since the recommended float voltages on aviation batteries are different than automotive batteries. You should check the Gill and/or Concorde site or the Battery Minder website to see how the recommended levels vary with temperature. An automotive charger is preset to one voltage (I believe) and will not give you optimum charge on really cold days. Depends on what environment you are trying to tame I guess.

    YMMV
  • ghendrghendr
    Mike B wrote:
    How are you attaching the battery tender/minder to the battery? On my Arrow the battery is inside a closed box and I assume the the same is true on other Pipers. Where did you attach the leads for the charger?

    In my 140, the battery is under the rear seats. To get to it, I lift up the rear seats (they stay up), then I have to remove the lid of the battery box, then attach the leads to the battery. I've run an extension cord through the front left cabin vent and opened the pilot's window for ventilation (it's in a hangar). The battery was charged three days for 30 minutes each, and today I flew the airplane. At 52 DF (with no pre-heat), starting was iffy, but it finally started on the fourth try. I'm thinking the battery minder would be a better deal and will look for one.
    Thanks!
  • Piper TechPiper Tech
    Aircraft Spruce sells them. Some guys have used solar battery tenders with good results too, as they didnt have access to power, either the hangar didnt have power or they kept it tied down outside.
  • ghendrghendr
    Guest wrote:
    Have you ever checked what voltage your Alternator is charging at?

    Some Alternator Control Units ARE adjustable.

    There is a reason for that.

    During flight, I generally see 13.7 or 13.8 volts on the voltmeter. It never seems to go down much from that level. Last year, with a different battery, I had a big problem. We flew 28 hours in four days (14 hours each way separated by 4 days), and the battery boiled over. The battery vent was clogged by acid, and the bottom of the battery box was a mess. The battery, voltage regulator and alternator were changed out/overhauled and the mess cleaned up (lots of wire brushing, unclogging the vent, sanding, and primer paint. The battery box was cleaned up and repainted as well. I now consider the battery one of the weakest points of the airplane.
  • TMyersTMyers
    This was a great thread and there is lots to learn about taking care of your aircraft's battery. There are a few items that were however never answered.

    1. For those that used the permanent connection option with their battery minder. How did you route the cable? I have an Arrow III and in order to not disassemble the aircraft I would need to route the cable through the plastic bulkhead and then through the plastic battery box. Did anyone use this method and if so how did you seal the penetration points of the cable, and what type of sealant?

    2. I saw a post somewhere from the battery minder people that you can't use an automotive type battery minder ($20) but must purchase one specifically for an airplane ($195). Is there some truth to this or is someone just trying to sell $400 toilet seats here?

    3. Is the installation of a permanently attached cable legal by a non A&P.

    Thoughts?
  • PropFanPropFan
    Here's Aviation Consumer's assessment (the BatteryMinder "Wins in a Walk"): AV Con Review

    Check out BatteryMinder's Web Site for more info.
  • PropFanPropFan
    TM: I had my A&P install the quick connect just to be safe. I couldn't find unequivocal authority allowing me to do it. Plus, it involved drilling through the battery box and installing a grommet. Something I am only minimally qualified to do on a good day.
  • PropFanPropFan
    Apologies for the multiple posts. This free webinar by Mike Busch, the Savvy Mechanic, is excellent:

    All About Batteries
  • TMyersTMyers
    Excellent information. I will review the webinar tonight at home.

    I think I have one of the general purpose chargers on the plane right now. Just put it on yesterday afternoon and it was still charging when I left the hanger. Will stop by today to see if it has switched to maintenance mode yet and whether or not there is any moisture around the caps from the process.
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