Using recently discovered polyrotaxanes (mechanically interlocked molecules) as a durable binder than can withstand volumetric changes: https://phys.org/news/2017-07-battery-breakthrough-nobel-prize-molecule.html
If you have a weak battery the other batteries will run it down quick and even reverse its polarity as happened to Chris.
I would trash the one that keeps getting discharged. Even better if you have an analyzer and can test capacity and internal resistance.
Can you tell the connection of the battery holder? Are Is there an intermediate voltage tap (possibly for maintaining memory)?
Any chance the batteries are old and mismatched? Do you have a way to measure capacity and internal resistance?
Re: GearBest New Arrivals (2015.7.30 update)
Question on the ZanFlare F6:
I have two, the whistle does not work on one of them. As a 46 yo man I can barely hear the good one but my 35yo girlfriend screamed from downstairs that it sounded like a dentist's drill.
I noticed the thin insert in...