Silver-zinc batteries feature a water-based chemistry and contain no lithium or flammable liquids.
Developed originally for satellite applications, these batteries are beginning to replace lithium-ion batteries in mobile phones, laptop computers, and battery-powered medical devices.
For example, some modern implantable hearing aids are powered by silver-zinc rechargeable batteries.

The data set {\tt silverzinc.dat|mat} goes back to the 1980's when silver-zink battery technologies have been
analyzed by NASA (Sidek et al, 1980; also Johnson and Wichern, 2007).
The response variable is cycles-to-failure, {\tt ctf}, while the predictor variables are
{\tt chr} - charge rate (in Amp), {\tt dchr} - discharge rate (in Amp), {\tt ddch} - depth of discharge (in \% of
rated Amp/hours), {\tt temp} - temperature (in $\deg$C), and {\tt ecv} - end of charge voltage (in Volts).



%--------------------------------------------------------------

  chr  dchr  ddch temp ecv ctf


 0.375 3.13  60.0 40 2.00 101
 1.000 3.13  76.8 30 1.99 141
 1.000 3.13  60.0 20 2.00  96
 1.000 3.13  60.0 20 1.98 125
 1.625 3.13  43.2 10 2.01  43
 1.625 3.13  60.0 20 2.00  16
 1.625 3.13  60.0 20 2.02 188
 0.375 5.00  76.8 10 2.01  10
 1.000 5.00  43.2 10 1.99   3
 1.000 5.00  43.2 30 2.01 386
 1.000 5.00 100.0 20 2.00  45
 1.625 5.00  76.8 10 1.99   2
 0.375 1.25  76.8 10 2.01  76
 1.000 1.25  43.2 10 1.99  78
 1.000 1.25  76.8 30 2.00 160
 1.000 1.25  60.0  0 2.00   3
 1.625 1.25  43.2 30 1.99 216
 1.625 1.25  60.0 20 2.00  73
 0.375 3.13  76.8 30 1.99 314
 0.375 3.13  60.0 20 2.00 170