The Batteroo got a lot of criticism because it make outrageous claims like extending battery life 800%. That is not true, but it does extend battery life. The concept of a voltage booster is also called Joule Thief. The concept is simple, but the key for the Batteroo was miniturizing the components to fit as a sleeve around the AA battery.
More Batteroos scheduled to be sold in Jan 2017. Stay tuned. I'll be testing one of these.
I haven't seen any Joule Thief flashlights out there. Most flashlights concentrate on guzzling power to get a high brightness to blind a UFO. But if you want a power-sipping LED light that works on dead batteries, go here to Etsy.
EDIT: Further Batteroo testing by several people revealed the Batteroo does nothing to improve battery life. So it appears it's not even a tiny Joule Thief.
- EEVBlog video here, with toy train test.
- EEVBlog post about the Batteroo testing. You will need a free account to comment.
- Wikipedia entry on Batteroo.
I assumed there was some potential here if they really miniaturized a Joule Thief, and improved battery life about 20-40%, but test results indicate that it's a total scam.
San Jose State University's Kiumars Parvin claimed, "We tested the Batteriser sleeve in our lab and we confirmed that the Batteriser taps into 80 percent of energy that is usually thrown away."Now if you don't know how marketers talk, you will totally misunderstand the above statement. The statement does not say "it uses up all of the other 80% of the battery power". It says "it taps into (uses some of) the wasted 80% of battery power."
In the test by UL (safety organization), a Garmin Golf GPS using Batteriser was shown to have a lifespan of 10 hours and 12 minutes, in contrast to the 1 hour and 43 minutes of operating time without a Batteriser. However, later the test was independently duplicated by TechnologyCatalyst to demonstrate that Garmin runs OK for over 17 hours on ordinary AA batteries, and the report by UL was based on the sloppy test design.Test design matters, quite a bit, apparently. A better test might be how many milliamps the device uses with and without the Batteroo. Power meters on different devices are designed differently and can be misleading.