A while back I wrote a blog discussing flashlights and how flashlights are all about the connection between the battery, the switch and the bulb. I went into detail in that blog, but, I can sum it up easily. Battery connection surfaces, springs, bulb connection surfaces and switch connection surfaces are all subject to corrosion. The cheaper the flashlight, the more batteries involved, the more problematic the corrosion issues.
Sealed rechargeable flashlights with solid state lighting such as LEDs are hands down the most reliable flashlights.
The next most reliable flashlight has a sealed solid state bulb, a sealed switch and one battery.
Next comes just the sealed switch, a standard bulb and a single battery
Then comes a sealed switch, standard bulb and multiple batteries
Finally comes the unsealed switch, standard bulb and multiple batteries.
Batteries are all about connections, the more unsealed connections the less reliable the flashlight.
That is pretty simple electronics and logic.
When a flashlight is dim or goes out, someone bangs it in their hand and it comes on because the contacts in the flashlight changed, the motion made surfaces rub and the contact improved. Sometimes doing this will break the filament in an incandescent bulb and the light is toast.
Think about springs for a second. Who hasn't seen a rusty spring somewhere? Springs move, plating or paint flakes off and the spring corrodes or rusts. Ever try cleaning rust off a wire spring?
I like flat spring steel springs in flashlights. They are very rare, but, they can be found.
Eveready used to make a cheap, flat 2XAA flashlight that was nice because it used flat steel springs which could be cleaned. The switch sucked and it was hard to reach the springs in the bottom of the battery compartment.
Another company used to make a 2XAA flashlight that required a screw driver to take apart. The switch was not great, people would lose the screw changing the batteries.
I had a sliding side flashlight that had wire springs.
Sometimes I think the people building flashlights are really clueless. The reality is building a custom flat spring for the end cap of a Maglite would be expensive and the vast majority of people out there are ignorant of the benefits so the investment in such a spring would not have any return.
Maglite could replace the little foam bulb holder in the endcap with a scotchbrite pad that people could use to clean the contact surfaces when they needed to.
Would replacing the springs and the foam have any return on the investment? Would it help sell flashlights? No. People wouldn't understand. Using the scotchbrite pad would make it lose the springy protection for the bulb and people would be annoyed so they would never use it. How about putting a simple, small round hunk of scotchbrite on top of the bulb, inside the spring? I already do that, I'm sure others do too.
Look at the flashlights at any store. Think about all those connections that could corrode and screw up the flashlight.
Sometimes I ask people about flashlights. My brother for example. What is a good flashlight?
People describe brands but no one tells me what to look for in a flashlight, except "quality".
So go to a store and look at the flashlights. Does the $20 flashlight have better springs than the $5 flashlight? Is the switch sealed or is it cheap and crappy?
Ever think about holding a flashlight while you are walking or working? I hold flashlights with my mouth quite often. Can I hold the flashlight in my mouth?
How bright is the flashlight going to be? How long will the batteries last?
Do you know why the stats on how long batteries will last in a flashlight are not published? Because corrosion on the connection surfaces of batteries (and springs) is a variable that manufacturers cannot control.
So what does "quality" mean to the person who is giving someone else advice about a flashlight?
We could replace the springs and battery contact surfaces with iridium. Iridium does not corrode and would be great in flashlights. It runs about $1,000 to $1,200 bucks an ounce right now. Would you pay an extra $50 bucks for a flashlight with springs that can't corrode? Would advertising that issue mean anything to the vast majority of people?
The military uses a lot of gold contacts to reduce corrosion but contacts still get dirty, causing increased resistance and decreased battery life.
Flashlights are a good metaphor for most things in life. They are really simple, yet interestingly and infinitely variable. Most people don't think of spring tension or contact corrosion resistance when they buy a flashlight. Consumer quality is usually a subjective perspective.
People are ignorant about most things and we make decisions in ignorance. People criticize our decisions, and I have typically found that the people criticizing don't know any more than the I did when I made the decision. They just think they do. Occasionally, like me, they know what they are talking about. But! Does it matter?
Suppose ten million people read this blog and start looking at flashlights critically? How long will it take flashlight manufacturers to build better flashlights?
Never. A couple manufacturers, Maglite and Scotchbrite, might incorporate some changes in design or marketing, BUT, 10 million is a drop in the bucket when we are talking about a world wide market of between 6 and 7 billion. Capital Investment will still follow the majority of subjective consumers and we are still going to have to look at flashlights in the store and make guesses about which one will be "best".