Today I thought I’d do a rough and ready experiment to see how long it takes for one of the TS05b rechargeable batteries to run down.  I’m hoping this will give me some clue about how many new-style range events I can perform on one battery.

I have set the program to range once/sec, and I’m going to count how many seconds it is until the battery powered unit stops responding.

I put it into the TS05b to charge and measure it with the gas guage.  It measured 4.2V and 22157 Coulombs in the tank, when I transferred it to the DW EVK, at 6.18pm.

I don’t have an on-board RTC to print out the time when it stops, so I’m simply incrementing a 1Hz counter each time there is a successful range operation.

Results

The 900mAh battery pooped out at 3h 41m.  I put it back into the TS05b to measure it rather than using the Fluke(Doh).  It showed 3.5V.  The gas gauge said it had 10610C left in it.  That’s 1 Coulombe/range – an easy, but probably meaningless statistic?

Just as interestingly, about 20 minutes beforehand the range estimates increased by 20 cms.  So clearly I have to keep an eye on that detail.  Why does it increase though?  Clock slow?

So bottom line is that we can get about 12000 good range estimates.  That’s 3000 3D fixes at 4 ranges per fix.

But let’s assume we need to take the median of 4 ranges to get a good fix.  Then it falls to 750 fixes/battery.  That’s about 1 good fix per 1mAh!  Oh jeez, I have a problem 🙁

N.B. In the following, the first number is the number of times the software polls the DW between ranges, not particularly important.  The last two numbers are <elapsed seconds>: <range>

136733 Me:0 Other:100999205E37F8FD 11253: 1.02
136784 Me:0 Other:100999205E37F8FD 11254: 1.10
136717 Me:0 Other:100999205E37F8FD 11255: 1.05
136844 Me:0 Other:100999205E37F8FD 11256: 1.05

136714 Me:0 Other:100999205E37F8FD 12007: 0.96
136735 Me:0 Other:100999205E37F8FD 12008: 1.04
136754 Me:0 Other:100999205E37F8FD 12009: 1.00
136726 Me:0 Other:100999205E37F8FD 12010: 1.05
136802 Me:0 Other:100999205E37F8FD 12011: 1.08
136884 Me:0 Other:100999205E37F8FD 12012: 1.09
136830 Me:0 Other:100999205E37F8FD 12013: 1.07
136798 Me:0 Other:100999205E37F8FD 12014: 1.04
136748 Me:0 Other:100999205E37F8FD 12015: 1.03
136791 Me:0 Other:100999205E37F8FD 12016: 1.01
136810 Me:0 Other:100999205E37F8FD 12017: 1.02
136708 Me:0 Other:100999205E37F8FD 12018: 0.99
136705 Me:0 Other:100999205E37F8FD 12019: 1.08
136843 Me:0 Other:100999205E37F8FD 12020: 1.08
136808 Me:0 Other:100999205E37F8FD 12021: 1.05
136876 Me:0 Other:100999205E37F8FD 12022: 1.10
136824 Me:0 Other:100999205E37F8FD 12023: 1.08
136747 Me:0 Other:100999205E37F8FD 12024: 1.08
136714 Me:0 Other:100999205E37F8FD 12025: 1.08
136881 Me:0 Other:100999205E37F8FD 12026: 1.05
136778 Me:0 Other:100999205E37F8FD 12027: 1.04
136726 Me:0 Other:100999205E37F8FD 12028: 1.11
136720 Me:0 Other:100999205E37F8FD 12029: 1.03
136879 Me:0 Other:100999205E37F8FD 12030: 1.07
136737 Me:0 Other:100999205E37F8FD 12031: 1.11
136829 Me:0 Other:100999205E37F8FD 12032: 0.99
136820 Me:0 Other:100999205E37F8FD 12033: 1.03
251146 Me:0 Other:100999205E37F8FD 12034: 1.28  Something happens around here…
136881 Me:0 Other:100999205E37F8FD 12035: 1.25
136799 Me:0 Other:100999205E37F8FD 12036: 1.16
136795 Me:0 Other:100999205E37F8FD 12037: 1.21
136746 Me:0 Other:100999205E37F8FD 12038: 1.13
136814 Me:0 Other:100999205E37F8FD 12039: 1.09
136880 Me:0 Other:100999205E37F8FD 12040: 1.19
136707 Me:0 Other:100999205E37F8FD 12041: 1.10
136778 Me:0 Other:100999205E37F8FD 12042: 1.22
136886 Me:0 Other:100999205E37F8FD 12043: 1.18
136709 Me:0 Other:100999205E37F8FD 12044: 1.17
136828 Me:0 Other:100999205E37F8FD 12045: 1.11
136823 Me:0 Other:100999205E37F8FD 12046: 1.20
136868 Me:0 Other:100999205E37F8FD 12047: 1.24
136783 Me:0 Other:100999205E37F8FD 12048: 1.22
136737 Me:0 Other:100999205E37F8FD 12049: 1.26

136800 Me:0 Other:100999205E37F8FD 12050: 1.18

136756 Me:0 Other:100999205E37F8FD 13253: 1.54
136821 Me:0 Other:100999205E37F8FD 13254: 1.43
136715 Me:0 Other:100999205E37F8FD 13255: 1.46

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