So the LD01 lasted 38.5 hrs on a alkaline battery. I took the battery to the meetings I was in for work today and peeked at it periodically. I was able to see it fully illuminated and then 10 minutes later looking dark. When I returned to the hotel in the evening I turned it back on and it produced full level low light for about 40 more minutes. It slowly died down to barely discernable light, and then I removed the battery and quickly measured. The battery had recovered to about 0.38V and rising. The review link below shows behavior of a version of the LD01 that looks very similar to what I observed. Operation down to 0.3V. I am thinking I don’t need to make a joule thief, I have one already in the LD01, which seems very efficient. I can’t verify the intensity level of this light but if the advertised 3 lumens is correct, then I got about 115 lumen hours out of a 4 year old alkaline battery. And the light does come back on at medium level resting during the time it took me to type this post.
I also did another voltage test of the E01 battery. It is holding tough at 1.26V after 116 hours. Just as a sanity check I put a new eneloop in to compare the light intensity which best I could tell had not changed since the test beginning. I can see that there is some slight dimming of the already dim light, but not much. The light is still useful finding your way around a dark room, still puts out enough light to read by, but maybe not fine print. I also found out that the mode memory timeout in the light is a function of the battery voltage, which is no surprise. When I took out the new eneloop and put ack in the old one, I observed (twice) that the light came on in medium mode with the old battery, and I had to switch to high then back to low mode. The first time I thought the light was just flaky, but after the second time I realized it is the short term mode memory. I tried two more times, both times waiting well beyond 10 seconds, and it came on at low in those cases. Also, it never came on above low when I put the new battery in. Fun stuff!!
I leave for the west coast way too early tomorrow morning, so I may not check any voltages for a day or so. I have no doubt the E01 will still be on, we will see about the e+lite, which continues to very slowly dim but is still putting light out.