Voltcraft IPC-1L

This is rather old news but let me have my say anyway.

To start with, it is how a battery charger should be done.

Once you use it, you will realize what a "cheap" simplification you had before. At least in my case, despite the fact that my old charger was among the decent ones, it had only 2 channels and other disadvantages. Anyway...

IPC-1L takes care for each battery separately. By default it charges with 200 mA current that will require about 16 hours to charge a common AA NiMH battery. You can select 500 and 700 mA as well that will, of course, charge faster. Once it is fully charged it will keep the battery full by topping it with low pulse current. And this is one feature that makes it quite useful and requires changing your usual habit of charging batteries.

Instead of charging the batteries, when they are depleted, you want to have a spare set that is slowly charged and kept ready at top capacity. Don't forget that NiMH batteries discharge themselves with time, that makes them somehow inappropriate for "low power over long period" devices like remote controls, watches, wireless keyboards etc. You need something that uses the batteries within 2-3 weeks.

About the advanced modes, here are some excerpts from the manual:

Charging mode 
Charge up the rechargeable battery, automatically switch to trickle charge after rechargeable battery is full. The default setting of the charger is in charging mode with 200mA charging current. 

Discharging mode

Discharge the rechargeable battery before charging it for minimizing the memory effect. After the rechargeable battery is fully discharged, the charging process will start automatically. 

Refresh mode 
Refresh the rechargeable battery to its maximum capacity by charging and discharging the rechargeable battery repeatedly. This process may bring the rechargeable battery back to the optimum condition for old rechargeable batteries or those have not been used for a long time. 

Test mode 
Check the rechargeable battery capacity (mAh). The battery capacity determined in the test mode refers to the capacity being discharged after fully charged. If the battery capacity is lower than the battery’s rating, the battery may reach the end of its useful life. 

Cons:

• bulky external power supply - it is not something that easily  fits together with other power plugs -this will cover at least 2 other holes...
  Some pictures to illustrate the variants that are on the market (usually this information is missing):
  http://n2.vatera.hu/photos/b4/1a/3f65_2_300.jpg - this one is like mine.
  
  http://www.auldies.euweb.cz/dev/IPC1.jpg - this one is just horrible.
  link - and this is how it would fit in a bag....
  more link | link |
  
  I have noticed that some of the original links do not work, so I have copy-ed them here, just in case.

Some notes:
Do not simply assume that you can replace regular alkaline batteries with rechargeable. For instance, if you need 4 batteries in some device, 4 new alkaline batteries will produce 6V, while four fully charged NiMH will start from 4.8V !!! I hope you get the idea how inappropriate are rechargeable batteries for use with digital cameras like this one: Konica Minolta Dimage Z3.
I can use my wireless mouse with decent new alkaline batteries for about 6 months (cheaper last less than that). usually you can't expect more than a month with rechargeable (you might need to recharge every 2 weeks in the worst cases).

Or if I can wrap it this way - this is perfect replacement for the original charger/s that came with your devices (wireless headphones, torches, walky-talky, etc. ).