Testing a Brio Battery Powered Engine, Art# 33595, with the Batteroo sleeve. The tracks were glued with double-sided tape to the pertinax board, for same test conditions. Result: without the sleeve it ran for 127 minutes, with the sleeves for 59 minutes and using the sleeves on the dead battery of the first test, it ran for 4 minutes. The video shows all 3 tests in one shot, no editing, only time lapse when it is not interesting. In the small overlay at bottom right in the first half of the video, you can see the test with the sleeve, to compare it without the sleeve. At 6:28 you can see in the overlay how it dies with the sleeve, while it is still running without the sleeve at this time, and after this you can see the 4 minute run, and at the end of the video at 24:20. At 18:03 the original battery is removed from the toy and a new battery with the Batteroo sleeve attached is inserted and the test is repeated. You can also see that the train runs faster without the sleeve. Conclusion: The Batteroo sleeve has no advantage for this toy. More discussion about Batteroo sleeve tests: http://www.eevblog.com/forum/projects/batteroo-testing/ Someone counted the laps: http://www.eevblog.com/forum/projects/batteroo-testing/msg1096834/#msg1096834 I wrote a Python script, using OpenCV to verify it and to measure the individual lap times, and the counts are right: http://www.eevblog.com/forum/projects/batteroo-testing/msg1101162/#msg1101162 EEVblog has verified the test with a different train model, but the same bad results for Batteroo / Batteriser, see here: https://www.youtube.com/watch?v=Tl90m2KHbNk It is very likely that any toy with motors has the same bad performance, reduced battery life, if you use it with the Batteroo sleeve. ... https://www.youtube.com/watch?v=pj6GyGVWwto