Well, the worry should be considered reduced to nothing, but yes, I think you are right when you say some end up trying to “convert” others as a form of validating their own likes and beliefs. But I think we all still pretty much have fun regardless.
Why would you use the blue label Tenergy? They are pretty much junk. I have the white ones and they hold there own against any 18650. What 18650 light can hold its turbo mode the way the TK70 does? I think the reason most people move on from Nimh isn’t because they suck but because that is what most people feel safer with when they start out. Just because someone does not like the TK70 anymore is kinda irrelevant, it is still is a great light to some. I sent mine to Vinh and had dedomed XML2 put in it and it would eat that tank of a light BTU up for breakfast
I think batteries in handphone or laptop are not good examples to compare to 18650 we use.
Handphone batteries are all single cell that is 3.7v. It is safer than multi cell that many flashlight use nowadays especially for high lumens output.
Laptop batteries are multi cell. And if you open laptop batteries before, you can see that they put a lot of temperature sensors to detect abnormalities. And their safety testing is much better than our 18650. But there are still cases of laptop batteries explosion.
In my opinion, NIMH is much safer than LI-ION for multi cell usage. For single cell usage, safety of LI-ION is closer to NIMH but still need protection circuit just in case.
You have to look at the watt hours of the batteries. A Tenergy LSD NiMH D cell is 8000 mAh and 1.2v nominal voltage. A Panasonic NCR18650B is 3400 mAh and 3.6v nominal voltage.
NCR18650B: 3.4ah x 3.6v = 12.24 watt hours
Tenergy LSD NiMH D: 8ah x 1.2v = 9.6 watt hours
An NCR18650B has more energy inside it than an LSD D cell and the same energy as a NiMH D cell. This is a sad truth I found out. I used to look at my TK70 and be like “this thing has soooooooooooo much power inside.” Now I just look at it and frown lol.
Thanks Toph but they are in my home state and I would have to pay sales tax so it’s not a great deal for being a used light. I had rather buy a new one.
But how many D lights have just one battery? Only one I know of. The TK70 has four. Even something as simple as my Malkoff Mag has three. And although it’s bigger than an 18650 light (which I don’t mind), the fact is that it can kick out maximum brightness for around five hours (that large size also means the light doesn’t overheat).
One other thing. An 18650 certainly doesn’t have more POWER than a NiMH D. At least not if we’re talking LiCo. Although voltage is low in comparison with a D cell, NiMH D’s are amp monsters. 30-40A is not too much of a problem from a quality cell. And at a modest draw like 4-5A, a good cell doesn’t even get warm.
Something like a sheath for a knife is not really a good comparison to a protection circuit on a Li-Ion battery. The very nature of a knife is that it cuts things. That’s what you use a knife for. And if you’re not careful with it, it will cut things that you don’t wnt to cut. Likewise, the heating of hot water is inherently dangerous to a degree. And you need a pressure relief valve. But if we consider the direct action of a battery, this is in most cases not too dangerous. True, if you short a necklace on a NiMH D battery, it can melt it down and possibly start a fire. But that’s the extent of the danger that a battery (at least a smaller one) can do just by virtue of being a battery. LiCo is different. And the dangers have NOTHING to do with the electrical output of the battery. The design is flawed in the sense that it has a flammable electrolyte in contact with a moderately oxidizing material (cobalt oxide). This is NEVER a good idea! Venting with flames has NOTHING to do with stored energy in the cell and everything to do with oxygen being liberated and causing the electrolyte to burn. So protection circuits DON’T protect you from the cell inappropriately releasing energy. They easentially protect you against a design flaw.
I agree that an NiMH D cell is an amp monster for sure. You said they have “insane capacity.” I was merely pointing out the fact that a lot of people see an NiMH D cell with 8000 to 10000 mAh and directly compare that to the capacity of an 18650 without understanding the difference between watt hours and amp hours. For instance, A Fenix TK75 with NCR18650B’s has 48.96 watt hours on tap with a single battery pack containing 4 x 18650’s. A Fenix TK70 (which I own and love) has 38.4 watt hours on tap with 4 Tenergy Centura 8000 mAh LSD NiMH D cells. So you actually get more juice on tap in a smaller package with the TK75. With a BTU Shocker, you get 36.72 watt hours with 3 NCR18650B’s, which is very close to the TK70, and it actually has basically the same exact head, except with an aluminum reflector, rather than a plastic one in the TK70. Theoretically, it should be better at dissipating heat than the TK70, while having around the same capacity.
I know you made the point that NiMH cells are much safer and I agree 100% with that statement. I just believe that at this point, NiMH cells have been completely dethroned by lithium ion cells in high end lights. Granted, the TK70 is the only high power light I own that I always leave batteries in due to their safety over lithium ion.
I would not fault anybody for buying a TK70 at this point, though. It is still an absolutely fantastic light and I doubt I will ever sell mine.
