Subject: Batteries
From: rotaryeng
Date: 5/30/2012, 6:36 AM
To: AAAA Put this in the To box 



  I'm nearing the finish of my phase 1 testing, and am now looking
  for replacement  batteries. right now, I am using two of these:

  http://www.power-

 sonic.com/images/powersonic/sla_batteries/ps_psg_series/12volt/PS-12180_11_Feb_21.pdf
   .
   They are on separate contact-ors, so I can use either or both when
  flying. I use both
   when starting. They are two years old, and today when I went
  flying I noticed that  the voltage was getting down to 11.6 volts.
  after landing, the voltage was up around
   12.3 volts. Usually I show around 13~13.6 volts when running. I always
  use a float
   charger specifically designed for these batteries when the plane
  is put away. Usually  the float charger shows a slow charge, but
  when I cam back from flying today the  charger was showing a fast
  charge, meaning that the batteries were discharged a fair  amount.
  Any comments on the suitability of these batteries and suggestions
  on how to  test them out for holding a charge or otherwise
  determining  their suitability or not for my plane. I have a 40 amp Nippondenso
  alternator, and
   run an Xcom radio, a terra transponder, Dynon D10, Tracys EM2 and
  EC2, and one fuel  pump(at a time unless landing or taking off) that
  draws around 4 and no more than 6  amps.

   Thanks,
   Brian Trubee

   The 11.6 V is normal for sealed lead acid battery when not
  charging.  Other people are using the same type successfully.  They
  need to be charged from time to time when sitting around.  My guess
  is every 2 weeks.

   Paul Lamar

   I'm pretty sure that this is a charging issue that just cropped up
  on this last  flight- I usually run in the upper 13s voltwise but
  noticed the low voltage while out  flying yesterday. My float
  charger will automatically go to float charge unless the  batteries
  are discharged when I put the charger on when I put the plane away.
  I will  then turn on the master to see if the charger goes to fast
  charge, which it will do  if there is a drain on the battery. So,
  what I deduce is that the charging system has  been working up
  until the last flight. It should be easy to troubleshoot the
  problem.  I'll post what I find after I find it.

   Any comments on  the suitability of the Powersonic PS 12180 NB batteries?
  I use two
   of them, they are 18 AH, so I suppose with the relatively small
  load I use in flight,  I should have a fair amount of reserve if the
  alternator quits.

   Brian

   The battery voltage when charging should be 13.5 to 14.8. Do you
  have an ammeter in  the circuit.

   Paul Lamar

   No ammeter.

   Brian Trubee

    Hi  Paul,
                     Re charging voltage into a 12 volt lead acid
  battery, most car regulators charge at between 13.8 hot weather and
  14.4 cold weather, the regulators are temperature compensated, I
  have found that if they are charging at less than 13.8 v (at least
  in Australia), the batteries will not fully charge, and conversely
  if charged at over
  14.4 v they will boil the guts out of the battery! Of course our
  temperature range is not as extreme as you have in the States;-) .
  Brian, if your voltage is getting that low when the engine is
  running at a moderate speed, your alternator is at fault, probably a
  diode bank has gone to diode heaven!! If the alternator is rated at
  40 amps it should be able to charge enough to keep the voltage above
  13 volts at a current draw of 40 amps, it sounds like you have
  nowhere near that load. If your batteries will start the engine they
  are good enough, just need the alternator to keep them charged,
  sounds like your float charger is keeping them charged then when
  you fly they are going flat!! When flying you should have a minimum
  of 14 volts by the time you have warmed up the engine and taxied to
  takeoff you should have 14 volts.                  John Burey.

     I have run across some charging problems with all good
  components. The terminals and cables may appear clean on the outside
  but if I take  off the cables there has been a black oxide on the
  posts of the battery.  It seems that this causes a resistance at the
  connection and prevents the battery from reaching full charge. While
  baking soda cleans off the corosion it doesn't do anything to this
  black oxide and it must be removed with a wire brush or sandpaper
  from both the battery posts and cables.

         Since the problem in this case seems to have occurred
  suddenly it is likely the diode bridge rectifier or brushes in the
  alternator. Years ago we could disconnect the battery while a car
  was running and if it quit the alternator was dead, however the
  newer alternators are damaged by the loss of a reference voltage.
  The instructions that come in the box with a new alternator often
  require the alternator to be unplugged while the battery is
  connected and the battery to be at full charge so that the proper
  reference voltage is available when the plug is inserted.

  george grimes


  A quick check to see if the regulator/brushes (the field circuit) is working
 is to hold a screw driver close to the shaft at the pulley or at the rear
 bearing. If it is magnetic those components are good. If not magnet, it is one
 of them.

 Dale Davies


 Have you checked the terminals for oxide as George suggested, I had the
same issue with my diesel 2 weeks ago. the battery would charge but not
fully, resulting in low cranking power 5-6 cranks. replaced crappy factory
terminal clamp and now it is much better. There's a product on the market
that provides a quick reverse polarity pulse that is supposed to relieve
sulphation on battery plates, can't vouch for it's effectiveness but most
new chargers on the market now have a similar feature, so I'm guessing it
must have some merit but it could just be a gimmick. Think its called
megapulse, these units are fitted to the vehicle and are supposed to
increase battery life. From memory they were about $95 in Oz when they hit
the market around 5-6 years back so could be cheaper now, look similar to an
inverter, a good battery starts at around $100 for a 500-600cca. Our dollar
still doesn't have the buying power of the greenback reguardless of exchange
rate.


  Try this link
http://www.megapulse.net/products/first-aid-for-batteries-fab-mk5.html
 Graeme Riley

Graeme, What email program are you using? Your lines are hundred of characters long.
Turn on line wrap and HTML OFF!

Paul Lamar


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