The 35,000 rmp tool is just too fast for most of the bits I use and makes more noise than an angry mule in a tin barn. The Dremel Mini Mite, on the other hand, is fast, relatively quiet, lightweight, easy to handle and goes anywhere I want it to go.
It does have one major drawback though. It EATS batteries.
The factory supplied battery pack made for this tool is 4.8 vdc 700ma Ni-Cad battery pack. I have found that it maintains a useable current for about half a project, so before going into any project I usually have a couple of extra battery packs fully charged and ready to go.
Since the tool has such a low amperage draw I have always wanted to take a dead battery pack and convert it into a battery eliminating slug to be used with a "wall wart" battery eliminator power supply.
Today I found that one of my battery packs would not hold enough current to work under load. It charged to the proper voltage and would run the tool in a no-load condition, but once applied to the project it would simply grind to a halt. Finally I had a dead battery pack to experiment with.
The case was fairly easy to open. The case snaps together on the sides that do NOT have the retaining snaps (that hold it into the tool). By simply inserting a small flathead screwdriver between the inner and outer case and applying a small leverage, the inner square case will simply pop out. It can then be rotated into a fully "out" position.
I was fully expecting to find the standard Ni-Cad arrangement of several small "watch-battery" type cells soldered together and shrink wrapped, but when I popped the battery case open I found, to my surprise, 4 "AA" style cells.
At this point I decided to abandon the idea of an AC Slug and instead opt for simply replacing the batteries.
It is important to keep in mind here that these four cells create TWO fully independent 3 volt batteries! It is the shorting bar in the switch that chooses between low (2.4 - 3.0 v) and high (4.8 - 6.0 v) speeds so DO NOT SHORT ALL 4 CELLS TOGETHER INTO A SINGLE 6 VOLT BATTERY!
I just happened to have four fully charged Radio Shack "AA"1500 mah NiMH batteries which came with a battery charger I bought for my mother to take on her trip for the digital camera, so, using electrical tape, I taped a small piece of copper wire to act as a shorting bar between the positive terminal of one cell and the negitive terminal of the next to create a simple 3 volt cell. After doing the same to the other two batteries I was ready for re-assembly.
Now, not only does this rascle run like a champ, but the higher amperage batteries means it lasts literally TWICE as long! I now have plenty of juice to get through a project without having a platoon of batteries waiting in the wings.
The only drawback is that the new NiMH batteries must be removed from the pack to be recharged, but since it's a simple snap-in snap-out proposition that's not too tough.
WARNING! DO NOT PLACE A BATTERY PACK RESTUFFED WITH NiMH BATTERIES IN THE ORIGINAL CHARGER! (IT IS MADE ONLY TO CHARGE NI-CADS)
NEVER CHARGE NiMH BATTERIES IN A CHARGER MADE FOR NI-CAD BATTERIES!
1 comment:
NiMh will charge on the original NiCad charger. It of course takes longer, but what we're concerned with here is NiCad can generally take overcharge abuse than NiMh when these cheap chargers are forgotten about pluggen in for days. The NiMh will be ok as long as you don't forget about it and end up overcharging them. The damage is cumulative. Overcharge once and you probably won't even notice capacity loss. Some NiMh cells however are almost as resistant as NiCad to this damage, but they are not common. Overcharging NiCads is not the healthiest thing for them either. All in all you want to avoid overcharging any cell.
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