making a cordless dremel cord-ed

[drow_elf]

after burning out the battery on my cordless dremel by leaving it in the charger for too long (DOH! ) i decided that before blowing $20-30 on a new pack i would try and direct wire it to a DC power source- that way it would never run out of juice

i used a grinder and 4 large headed nails to make "posts" to connect the wiring to
(sorry for all the pics modem ppl (LOL- i'm on a modem too!))

this first one shows the back half of the of the battery pack and a radioshack connector that i butchered to attach wires to so that i could use a radioshack DC source

[drow_elf]

heres a pic of the guts i dont know why i decided to solder the copper wires across the nail "posts" instead of just stripping the wire and wrapping it around them both
the solder jobs are really crappy, but thats because i had to move the copper wires so everything would fit together
also there is a whole stick of hot glue in this picture :-D

[drow_elf]

well i hooked it up a 800ma transformer- i have juice for the lower speed setting but i cant cut anything yet- it has no power and i cant use the higher speed setting at all- the transformer just whines
do i need more I? i dont see 6 AA sized NI-CDs putting out so much juice... or might it be my small solid-core wires that i used to connect to the nails- ie too much R (a small effect shouldnt matter since the whole thing is .3V overvolted)

i did continutity testing on the dremel (man i wish i knew how it was wired in there- it seems complex)

the leads that connect to the battery pack are somewhat complex the results of my testing show
lower speed (yellow symbols on the picture)- all 4 leads have 0 ohm resistance no matter the combination
higher speed (orange) only diagonals connect (ie a + connects to a non-adjancent -) all others possiblities show up as infinity on my ohmmeter
*sorry for the crappy pic* (dang its hard to focus inside that thing! note: picture was sharpened 5 times.....)

i'm not sure what that 1 diagonal wire/trace/thingy in the middle is.....

what do you guys think?
is the:
800ma to low?
resistance from added wiring to high?
dremel somhow screwed up?

edit- removed pic because of excessive uglynness; all it shows is 8 connectors- half of which are negitive and the other half positive

[The Spyder]

1. Too small of a transformer
2. Bad idea with the 2 wires bridged
3. You can ruin your dremal this way.
SPyder

[drow_elf]

hmm thats a good point.... i cant remeber if they set all 6 batteries or only 3 in series.... hmm no matter... ill i need then is a big bad 4V transformer

Update: after much thought i think i figured it out- in the lower setting the two sets of 3 batteries are hooked up in parralell- meaning the motor gets 3.6V in the fast setting the two sets of batteries are in series- so the motor gets 7.2V the beauty of this design being it needs no resistors to waste battery power and you drain both sets evenly

thus it follows that in the high setting the transformer was being shorted and in the low setting it was running at full speed (like in the high setting since it was getting 7.5V) but the transformer couldnt provide enough current to give the motor any ommph!

i'm leaving for 2wks this Sat. so i wont be able to try it out with a new transformer but i'm confident that it will work- in the meantime does anyone know how much current this thing CAN draw?
its a Dremel Multipro Cordless model 770...