Yaesu Battery charger flashing read
Dan Wells
A question for the radio experts…
I left my FT-250 radio on and drained the battery completely. Put it on the charger and in a short time I got a green light. Later I turned on and saw the frequency displayed so thought all was good. Later when I turned it on the radio was dead. When I put the FNB-64 Ni-Cd battery back in the charger it flashed red and now definitely will not take a charge.
Time to order a new battery? Or is there a way to bring the old battery back to life?
Dan Wells
vince price
If you drain a lithium ion or nickel metal hydride battery completely to zero, it cannot be recharged. Replace it.
V
Dan Wells
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gabe
ma...@mgforbes.com
series-connected packs, as is typical in radios. The reason
is that as they discharge, one of the cells is eventually
going to run out of charge first. Once it does, the other
still-somewhat-charged cells will continue to drive current
through the cell in the reverse direction.
The reverse-current causes the formation of nickel "whiskers"
which grow through the fibrous plate separator inside
the battery. Internally the battery is made up of two rolled
foil layers separated by a thin tissue-like fiber material.
It's like a cinnamon roll with cinnamon-sugar insulation.
If a whisker grows across and shorts the plates, there is
no way (using normal charging) to get it to go away...the
current just runs through the whisker instead of making
the battery chemicals return to their charged state.
This is why you never want to discharge a pack below 1.0
volt/cell. For a six-cell pack, nominally 7.2V when
charged, that means 6.0V is your lower limit. NiCd
cells have a very flat discharge characteristic, so
their output remains almost constant until they use up
the last of their reactants. After that the voltage
drops off very quickly.
It is possible to burn away the whiskers if they're not
too numerous, and if the battery hasn't been too badly
abused in the past. The technique I've used has been to
charge a large capacitor (40,000uf or so) to whatever
maximum voltage it can sustain, and discharge it into
the battery using heavy-gauge braided copper conductors.
The idea is to deliver an enormous current pulse, on the
order of 1000 amperes or so, for a brief time. It makes
quite a bang, and you should wear glasses because it can
throw off sparks and molten metal. The pulse burns away
the whisker, hopefully without doing extensive damage
to the insulator.
The best way is to clamp the copper conductors onto the
battery pack first, perhaps with a non-conductive spring
clamp, then make contact with the charged capacitor
using a solid contact...this is not a time to flinch.
Expect a bang as it makes contact.
Don't make the mistake of applying a large continuous
current; that just heats up the batteries until they
boil and vent, or in extreme cases boil and explode.
Either way, they're not salvageable after that.
When all of this fun fails to work, the next best step
is either to replace the pack, or get a set of cells
and re-battery it. If it were me though, I'd bypass the
entire problem by buying a 6-cell battery case (FBA-25A)
and loading it with your choice of cells. NiMH, NiCd
or Alkaline...whatever you like. Charge them externally,
and keep a set of spare alkalines in your harness for
emergencies.
MGF
Kevin Lee/ Thermal Tracker Paragliding
Cheers,
Kevin
Instruction Sales Tours
6370 Hwy. 66
Ashland, Oregon 97520
541-890-7142
email: in...@thermaltracker.com
Website: www.thermaltracker.com