How to calculate cost of AA accumulator charge? I would like to calculate how much it will cost to change AA accumulator. Is it really cheaper than usage of batteries (don't consider ecology question as of now)?
Let's say I have the following


*

*accumulator: GP Rechargeable NiMH AA HR6 270AAHC 2700 series (2600
mAh);

*battery charger 1: GP PowerBank Smart 2 (GPPB14, pdf)

*battery charger 2: Technoline BC700 (pdf).


In accordance with BC700 data, accumulator currently is in the following condition (?): 200 mA, 1.26V. 
The cost of electric power is 3.18 per K.W.H..


*

*Is there any difference in terms of cost (besides time of charging) which battery charger is used and in which mode?

*How to calculate cost of charging?

*How to calculate possible cost of accumulator refresh (=recovery)? Believe, it will depend on number of charges and discharges.

 A: I agree with David that the question is a bit off topic, but there is a physical principle that you have to take into consideration so it's worth a brief answer.
The capacity of the battery is an amount of energy and the KWhour is also a unit of energy, so to calculate the cost of charging you just need to calculate the battery capacity in KWHours. The capacity of your battery is 2600 mAh, which means it can provide a current of 2.6A for one hour. The voltage of an AA NiMH battery is $1.2\,V$, so the power $W$ is voltage $V$ times current i.e.
$$\begin{align}
W &= V\cdot I \\
  &= 1.2\,V \times 2.6\,A \\
  &= 3.12\,W \\
  &= 0.00312\,kW
\end{align}$$
This is the power the battery can produce for an hour, so the energy is simply 0.00312 KWHours, and the cost is therefore $0.00312 \times 3.18 \approx 0.01$ currency unit. In practice charging a battery is not 100% efficient, but even so the power used will be a tiny amount. You don't say what the units of currency are, but unless you live in a country with a very unusual currency the cost of charging the battery is likely to be negligable.
