DG8FBV,
Homebrew
Each battery pack 11 cells, each
1,2V, 4.500 mAh
1. Part List
Part
# are from the German company CONRAD, www.conrad.de
- 22 pcs SANYO NiMH accu cells, Type HR-4/3FAU, 1,2V/
4500mAh,
with soldering pads. Each cell 67 mm length, diameter 18mm
- 2 pcs temperature switch (release temperature 72 deg.C) # 540459-55
- 1 plate 200mm x 400mm x 1mm
#
528064-59
- Soldering connectors for 1 mm pins (for the battery
connector)
- Insulation tape
- 2 fuse with fuse holder #
532983-55
- 2 pcs low voltage connector with switch # 733946-59
2.
First I build a battery compartment to insulate the cells
and to avoid possible cell leakages to penetrate into the transceiver.
The bottom plate and the side plates are sealed with ´hot glue´.
The thickness of the plate should not exceed 1 mm. Otherwise the available room
for the battery can be to small.
The battery compartment should firmly fit into the housing, otherwise you loose space for the accu cells.
3. Arranging Accu Cells
The most time I spent for arranging the 22 cells into
the battery room. Every millimetre counts….:-)
The rows (2 x 5 cells) are separated by 1 mm insulation plate. I took care that
the battery contacts are
well insulated.
4. Charging Connectors
For the charging connector I use one with a switching
contact.
With this type of connector, the battery pack is disconnected from the
transceiver during charging.
With a ´dummy plug´ you can disconnect both battery
packs from the radio during operation with external power supply.
The connectors are installed into the original plastic
covers at the rear side. Because there
is only limited space between the battery compartment and the cover, I have to
bend the connections 90 degree.
5. Fuses
A temperature switch is installed at each battery pack
directly at one of the cells. If the battery temperature
exceed 70 deg.C. the
´temperature fuse´ will disconnect the +
line.
A current fuse with holder in the + line protects
again over current.
Current fuses
temperature fuse
The temperature fuses are pressed again the battery
cell by a soft distance piece at the cover.
6. Result
It looks not as nice as the original battery packs. But the when the cover is
closed you can not see it :-)
Up to now I could not test the running time.
Warning:
The user is solely responsible for all his doings at the transceiver and all works
are on users own risk.
Liability of damages and consequential damages to any equipment and/or parts or
others is the sole responsibility of the user.
There is no guarantee that the described battery pack works without failures
and collateral damages at the transceiver or
other parts/equipment.
73 de Thomas, DG8FBV