High Power NiMH pack
Canon AE Motor drive FN
This is not a big design project as the other ones I have listed,
but more of a feasible and cheap way to repair and improve the Canon High
Power NiCad Pack. In my case the outcome is a High Power NiMH Pack with double
the power of the original for less than half the price compared to what a
new set of cells would have cost from Canon (work excluded).
Special Note: If You do something similar to what I have done I
am in no way taking any responsibility of the possible consequences if something
should go wrong. You may see this as a hint of what is possible to do if you
can and know what you are doing, but you are the one that takes all the responsibilities.
My pack did not take charge very well and when I checked it it had
around 10 V output compared to the 14.5 V it should have.
I took out the cells from the pack by:
Now you will find that the cell package actually consists of 12 ordinary
AA cells. This makes it easy to do a replacement, although it involves a
lot of hard work. The way forward is as follows:
- Open the pack at the "plug" that attaches to the motor drive.
- Unsoldering the two cables that corresponds to the pins (+ and -)
in the plug where the charger is connected.
- Removing all the gripping material from the pack, note that this is
possible to do on bottom and also on front and rear (the later two I thought
was just a pattern in the plastic the pack is made of, but it is removable
and must be taken away).
- Removing the cover on the left side by removing three screws, one
on each of the sides bottom, front and back (on my pack they are blank metal
- It is now possible to get the cell pack out of the housing.
Finally you attach the cables, put the cell package into the housing and
solder the cables back into position. protect the soldering with a layer of
coating and assemble the housing of the Pack.
- Get 12 cells of either NiCad or NiMH type in AA size with soldering
tags and heat shrinkable tubes that the cells can be put into.
- Solder the cells together two by two and secure them in a heat shrinkable
cover. Note that the soldering tags should be bent so that it is close to
the cells with the - end in the soldered connection (this in order to prevent
any cell from being damaged by a shortage, this happened to me and is not
a happy situation). Ensure during this process that the cell pairs are connected
and shrank into a straight package without any angel on the middle (there
will be very little room to get the final pack into the cover and a bent
cell pair will be beyond the acceptable).
- Make a good note on how the original cell package is structured and
disassemble it in order to get your hands on the "spacer".
- Build a new package by using the cell pairs and putting them together
according to the notes about the original package, glue with epoxy. It has
to be noted that the NiMH cells are a little bit larger than the NiCad cells
(0.1 mm in diameter) and that the heat shrinkable tubes available normally
are a little bit thicker than the ones used by Canon. These two things may
make it necessary to file the tubing around the cell pairs during the building
process in order to make it possible to load the ready cell package into
its housing. The final fit will probably be a little bit tight why it can
be useful to have a string attached around the "spacer in order to simplify
removal of the cell package during the work (and possibly even for future
removal when the project is finished).
- Cover all uncovered metal with a thin insulating coating, available
at stores that sell electronic components.
If you have chosen NiMH cells you have to be careful not to charge
them for more that 14 hours if using the standard Canon charger. NiMH cells
are easily damaged if overcharged and the project was not that fun that you
want to perform it too often.