I have just successfully rebuilt a Duo Type III battery, and I thought I would share
some of the experience/challenges with the list.
The executive summary is as follows:
Be careful when separating the two halves of the battery on the side with the
contacts. There are parts just under the seam which can be damaged.
Some of the components are easily damaged by heat. Use a light touch and heat sinks
when soldering.
You might want to use a rigid glue when re-assembling the enclosure.
It appears that some posts on this list notwithstanding, there are no 2700
mAh replacement cells, and that the highest capacity available is 2150 mAh.
Total cost for cells, including shipping, was $42.
Now, for the full story:
The Creation and Bringing to Life of Frankenbattery!
It was a dark and stormy night in Seattle. I had a Duo type III battery which was
unable to hold a charge even though I had run Battery recondition, and tried this
several times. It had enough juice to start the
boot up, but then would die before even getting to the startup screen. When
I looked at the battery information in Battery Recondition, it gave the serial number,
but stated that the last recondition date was unknown, even though it had been that
day.
By trusty servant was no longer in the realm of the quick, but had passed to the realm
of the dead. I had read of others who had successfully performed a transplant, putting
new NiMH cells and life in their batteries,
and this gave me hope.
By reading the ancient emails, I realized that I needed a 4/5 A cells, and had heard
that there were cells of this type with a capacity of 2700 mAh. I
searched the web high and low for the mythical 2700 mAh cells, but to no avail.
Ultimately, the highest capacity I could find was 2150 mAh, and someone stated that
the reference to 2700 mAh was a mistake which had been perpetuated.
I found a source for 4/5A NiMH cells from Sanyo, with the designation HR-4/5AUX, with
tabs, for $3.50 each, with $7 for shipping. I awaited their
arrival with much anticipation, but nothing happened. After many calls and emails,
they finally arrived, about 6 weeks later.
I then proceeded to dismember my old assistant. After removing the sliding door, I ran
the sharpest blade repeatedly around the joint between the two halves, until it
started to separate, then carefully pried the case apart. To my chagrin, I discovered
that just under the contacts, there was a film with circuitry in it that I had almost
cut through with the knife. A vital
electrical connection had been severed!
Planning to fix this later, I proceeded to make a diagram of the numerous parts I
found inside, and how they were connected. I then started to solder
the new cells together in the same pattern, inserting the non-battery components in
the appropriate places. I tried to place all the components back in the case, and two
of the tabs broke off from the batteries from the
twisting stress!
I realized that I would not be able to use the same solder I used normally to solder
to the batteries, since they would become too hot. I found a solution at Radio Shack,
called Solder Weld (Catalog# 64-029). It is a paste that turns into a solder at a low
temperature. By putting some of this on the tabs, heating to melting, and lightly
touching to the batteries, I had a connection.
I repaired the connection I had severed during disassembly. I tested all of
my solder connections for continuity, and then squeezed the enclosure together,
putting it in the Duo and holding it there without the door, with
some tape. Starting up from the power supply was successful, and I charged the battery
overnight. It read full charge in the morning, so I tried removing the power adapter.
Instant shutdown. I tried starting from the battery. No response.
I disassembled the battery, and tested all of the connections for continuity. All were
fine. I then tested all of the non-cell parts for continuity, and found that one had
failed. I despaired. How was I to find a
replacement part?
Examining the part, I saw that there was some faint writing, of a cryptic nature. It
said:
Microtemp
KEDATX
G4A51
250V @ 10A
Tf 91C
Going to my assistant, Sherlock, I typed ?Microtemp?, hoping against hope for some
succor or guidance. Lo, my assistant informed me that the part was
a thermal fuse, from which I surmised that the last line of the inscription
referred to the fuse temperature, which I had surely exceeded with my clumsy soldering.
I searched for a replacement. The most convenient was through Radio Shack online,
where the closest match was Radio Shack Catalog # 90-8396, RSUX 11308475 Thermal Fuse
93C. I ordered two, not trusting my soldering skills to avoid causing another demise.
By use of the Solder Weld and a heat sink, I was able to replace the expired fuse, and
placed the battery back in the Duo for testing.
This time all was well, with a full charge and normal operation. All that remained was
to permanently re-assemble the battery.
Because of my timid nature, I did not want to use a rigid epoxy for reassembly, and
chose to use silicone adhesive. I placed a bead of adhesive
around the edge, clamped the halves together, and removed the excess adhesive. After
more than a day, I removed the clamps and tried to put the sliding door on. I got it
on, but it wouldn?t slide! After much anguish and testing, I discovered that when I
removed the clamps, the case became a little wider, which was enough to bind the door.
I hesitated disassembling the unit to re-glue it with epoxy or some similar adhesive.
I tried using WD-40 on the door, but it did not work. In desperation, I tried some
bicycle grease, and to my joy, it worked!
I placed the battery in the Duo, and performed a battery recondition. After
that, I had a full charge, and Battery recondition reported the correct date for the
last recondition! My clumsy creation made from old parts, new parts and replacements
worked. Frankenbattery lived! HA HA HA HA HA!
I have used it since (a few days), with great success. The battery life is long enough
that I have not yet found out what it is ( at least more than 1
1/2 hours).
I hope that this missive may act as a cautionary and instructive tale for those who
may be tempted to create new life out of old parts.
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