UKE 2AAA LED performance
I ran some voltage, current and light output tests for mine that might prove 'enlightening' (sorry, couldn't resist):
,8 Volts, 3 mA, 3 cp
.9 7.7 11
1.0 10 21
1.1 12 31
1.2 15 42
1.3 17 53
1.4 20 65
1.5 23 79
1.6 26 100
1.7 30 117
1.8 32 131
1.9 34 156
2.0 37 167
2.1 40 185
2.2 45 220
2.3 51 256
2.4 57 280
2.5 63 326
2.6 70 364
2.7 77 386
2.8 84 419
2.9 93 457
3.0 104 475
3.1 107 519
3.2 115 534
3.3 124 572
3.4 135 585
3.5 146 597
3.6 157 603
Several things seem clear, at least to me. Yes, there is electronics in there, no, it's not regulated (as it's normally defined) and under the 'time to half original birghtness' test 19 or 20 hours seems highly unlikely.
Let's assume 3.0 Volts to start, 100 mA more or less, 475 cp as I measured it. Half level is at 2.2 Volts, 45 mA. Let's assume an average current of say 75 mA from the two AAA cells. Average voltage is 1.3 Volts times .075 Amps is 100 mW load per cell. Using the Energizer E92 curve for 100 mW looks like a bit under 400 minutes to 1.1 Volts, under 7 hours, more like a third that time.
Doug Owen