🚀 go-pugleaf

>    My question: The battery was very low, and so I plugged the unit and
>the transmitter battery pack into the factory supplied recharger
>overnight. Ofter about 24 hours of recharging, the voltage on the
>transmitter pack read at about 5.6 V, according to my Tower Hobbies
>voltmeter (top of the "green" scale). However, the transmitter pack read
>at only 9.5 V, which is rather low (the low end of the "green" scale).
>Also, the voltmeter on the transmitter read only about 80%. When the
>unit was new, the voltmeter read above 11 V, and the scale on the
>transmitter read above 100%.
>    Is my batter dead? Can I fix it? Or should I just get a new battery.
>Is this the expected life?(two years)?

(Klaxons...!)  WARNING - BATTERY UNSTABLE, DO NOT FLY.  REPEAT... ....

:)

The battery may not be dead, but you might have to cycle it a few times
to restore it's working order.  Charge/discharge it 3-4 times, noting
how long it takes to discharge each time.  This is probably best done
with a cycler for best results, especially since leaving the transmitter
on for 2-3 hours at a time may heat up your RF deck more than you want.

But anyway, if you can determine that the pack comes up to normal standards,
then you should be safe to fly, but keep an eye on the pack over time,
it may not be stable.

Considering the price of another pack ($25?), you might be able to rescue
your current one; but considering the price of a replacement plane (???)
you might want to replace it. 

By the voltage numbers you stated, one cell is obviously not charging,
and may not come around, but it's worth the effort of trying.

  -swb-  (Steve Bixby, sbixby@cup.portal.com)

You have a dead cell in the transmitter pack.  There are eight cells, each
rated at 1.2 volts.  Determine the dead cell by exposing the batteries, and
using a volt meter to test each one.

It may be possible to restore the dead cell by building a custom circuit.
I don't have a copy of the circuit, but it was posted here a good while ago.
Did anyone build the circuit and restore a dead battery?


What size soldering irod does one need to remove and replace a dead cell in
a Futaba transmitter pack?

mm7q+@andrew.cmu.edu (Michael Oliver Muller) writes:

>    My question: The battery was very low, and so I plugged the unit and
>the transmitter battery pack into the factory supplied recharger
>overnight. Ofter about 24 hours of recharging, the voltage on the
>transmitter pack read at about 5.6 V, according to my Tower Hobbies
>voltmeter (top of the "green" scale). However, the transmitter pack read
>at only 9.5 V, which is rather low (the low end of the "green" scale).
>Also, the voltmeter on the transmitter read only about 80%. When the
>unit was new, the voltmeter read above 11 V, and the scale on the
>transmitter read above 100%.
>    Is my batter dead? Can I fix it? Or should I just get a new battery.
>Is this the expected life?(two years)?

Looks like your transmitter battery pack has a "dead" cell in it,
cause voltage should really be above 10V after recharging.
You should keep an eye on NiCad's during the winter or any time when
you're not using them. They need a frequent recharge to prevent a deep
discharge of one or more cell's. The best thing is to do a
discharge/recharge cycle every 4-8 weeks.

How to solve the problem: Open the battery pack so the contacts of the
cells are reachable and measure the voltage of each cell (at upper and
lower contact point). There should be one, which voltage is much below
1.2 volts. This is the defect cell ! Remove it and solder a new one
(try to get one of the exact type as the old one) in place. That's it.

You could use your airplane covering film to shrink around your
revived battery pack if you cannot get one of those shrinkable hoses.

Hope that helped !

Bye,
  Torsten.

-- 
  +-------------------------------------------------------------------------+
  |   Torsten Leibold, Konrad-Adenauer-Allee 105, 6806 Viernheim, Germany   |
  |  UUCP: torsten@rnivh.rni.sub.org    ..!unido!orfeo!rnihd!rnivh!torsten  |
  +-------------------------------------------------------------------------+