I am going to cross post a interesting statement from a Prius chat thread on recharging batteries.

I think this charger (which appears to not come with any accessories, proper leads etc. which will require a trip to a Radio Shack or a electronics store)  is the one charger for almost all of the tool driven batteries we commonly use. Appears to work with almost any battery per their literature.

Here is the manf. link.  I see it for around $140 on other sites (do a Google on MRC 989)

http://www.modelrectifier.com/search/product-view.asp?ID=6863

Note from Prius chat member extolling the virtues of this charger:

“One unexpected result of using the MRC 989 is the ability to quantify
the actual capacity of my digital camera batteries. The traditional
‘temperature cut-off’ chargers probably have been destroying my NiMH
camera batteries. This 989 handles charging and discharging in a much
more sensible way using the dV cutoff. I’m able to pull the cells out
without them being warmed up.

One lesson learned is it appears the conditioning cycle should charge
current limit to 1/2 the rated mAhr of the battery and the discharge
current should be full current for actual battery rating For example,
a 2000 mAh -> 2 A for discharge and 1 A for charge. This measures the
residual capacity without risk of seeing the batteries overheat. BTW,
I’m seeing some of the marginal batteries come back with a significant
fraction of their original capacity.”

Jim Flood