Simplish maths question

[blobrana]

@kenny
ok you said...
T=time, in years
D=discharge (per year)
C=charge level (1 being full, 0 being empty)

I worked out that C=(1-D)^T, but got stuck trying to get it for T. But with your help:

T = ln(C)/ln(1-D)

Cheap alkaline or zinc chloride batteries, for instance, have a self-discharge rate of 4% per year, therefore:

T = ln(0.85)/ln(1-0.04)

= 3.98

So where did you get the value D from....

It`S a bit like saying D= 1 x (D x 1)

 :-)

[blobrana]

Ah,
you mean:

first year = 96% charge ( d=4%)
second year = 92.16 (96 - 3.84 , d=4%)
third year =  88.4736    (92.16 - 3.6864, d=4%)
forth year = 88.4736 - (88.4736  x 0.04 = 3.538944) = 84.934656%

 :-)

(rather than the rough  method of 15 / 4 = 3.75)

[blobrana]

@ Karlos
 @ kenny
You may be interested in this article I found, er, in Platinum Today...

“Scientists in the US have succeeded in breaking through the "oxo-wall" to forge multiple stable chemical bonds between oxygen and platinum.
The breakthrough is being widely hailed as a significant achievement because the process was previously thought to be impossible because oxygen is extremely unstable when combined with certain metals”

I wonder what the properties that would have,

 Ect…