cordless devices - 2AA can opener, etc

[ps56k]

Most of the cordless devices I've taken apart usually have 2AA batteries and use a simple resistor+capacitor charging circuit in the stand.

Now I have a cordless can opener that runs fine when free wheeling,
but stalls when actually opening a can....
ie has volts, but lacking current draw.

So - if I pop this open and want to replace the existing 2AA nicd's -
should I just grab any of my nimh's and solder them as replacements ?
or go get some actual nicds ?
or use some nimhs - but coin toss for higher/ lower mah ?
or go with top line Eneloops ?

 

[Mr Happy]

If the device is on constant trickle charge it will kill NiMH cells. It will kill NiCd cells too, but it will take longer to do it. You are basically faced with bad product design here. Your least worst option is probably to find some of the NiCd cells sold for solar garden lights and try those.

Recently I have tried to find devices that take alkaline batteries and then use Eneloops in them. Successes have included toothbrushes, soldering irons, cordless screwdrivers, kitchen scales, cordless mice, frappe frothers and cameras.

But a recent experiment with a 4AA pencil sharpener was not so successful. It sucked at sharpening due to cheap design and lack of power in the motor.

 

[Lynx_Arc]

I have a cordless can opener that you can change batteries in that I use LSD nimh and it works well with them. If you want to use nimh in place of nicd you need to determine the charge current level, calculate time needed to charge and manually take it off the charger after that period of time otherwise each time you overcharge them it will reduce the life cycles of them.
As for using nimh in place of alkalines motors that use a lot of gearing to translate into torque need higher voltage to get the required revolutions up that is why they tend to not do as well.
A 4AA alkaline device may require 5 nimh to run it well if it doesn't fry it.