Bi-exponential function fitting in Origin Lab SW

[Jakub]

I can't understand the exponential function fit for this set of data works well:
ExpDec2 exponential function fit
0 3,04
10 2,77
20 2,52
30 2,27
40 2,09
50 1,92
60 1,75
70 1,62
80 1,51
90 1,43
100 1,36
110 1,29
120 1,24
130 1,19
140 1,14
150 1,09
160 1,05
170 1,02
180 0,99
190 0,97
200 0,95
210 0,93
220 0,91
230 0,89
240 0,87
250 0,85
260 0,83
270 0,82
280 0,8
290 0,79
300 0,78
310 0,77
320 0,73
330 0,71
340 0,7
350 0,69
360 0,67
370 0,66
380 0,64
390 0,63
400 0,62
410 0,61
420 0,63
430 0,59
440 0,57
450 0,56
460 0,55
470 0,54
480 0,54
490 0,53
500 0,52
510 0,52
520 0,51
530 0,5
532,5 0,5

But this set with the same settings gives me the following error:
0 4,1
10 3,63
20 3,29
30 3,05
40 2,74
50 2,51
60 2,29
70 2,07
80 1,91
90 1,75
100 1,62
110 1,52
120 1,44
130 1,37
140 1,3
150 1,26
160 1,21
170 1,16
180 1,13
190 1,08
200 1,04
210 1,01
220 0,98
230 0,96
240 0,93
250 0,92
260 0,9
270 0,89
280 0,87
290 0,86
300 0,85
310 0,84
320 0,83
330 0,83
340 0,82
350 0,81
360 0,8
370 0,79
380 0,78
390 0,77
400 0,76
410 0,75
420 0,73
424 0,73
Fit did not converge, because mutual dependency exists between parameters. The model is over-parameterized, so the fitter cannot find a fixed parameter value. Try simplifying the function, or fixing several parameter values.

I have several similar sets of data, this one is the only one that makes problem. This is confusing. Any help pls

 

[Jakub]

I can't really change the type of function since I need it in the form y = A1*exp(-x/t1) + A2*exp(-x/t2) + y0

The one that did not converge has too big bonds
y0 -21656,44468 ± 215638,46693
A1 3,1442 ± 0,02977
t1 70,10402 ± 1,29334
A2 21657,39982 ± 215638,46692
t2 4,32545E7 ± 4,30752E8

To compare here is the good one
y0 0,78075 ± 0,01839
A1 0,68676 ± 0,07776
t1 9,97927 ± 1,98029
A2 3,51012 ± 0,06242
t2 86,08062 ± 2,56822