** BLF LT1M-Mini Project - The little Lantern! ( PM's sent today June 21, 2022)**

please see the picture below, compare the 26650 tube with 21700 tube. 21700 tube seems slimmer.

This is excellent news!!! Slim is good guys!! :+1: :+1:

Please sign me up for one additional BLF LT1M-Mini (for a total of three.)

I like the look of the 21700 tube version better. Looks a little lighter.

I had thought that 26650 cells on average had notably higher mAh than 21700 cells. But a recent sweep of batteries in the marketplace turns up something interesting — that while the highest 26650 cells are pushing 5300mAh, the highest 21700 cells have reached 5000mAh. That’s not a huge difference. Frankly, it doesn’t look to me like the 26650 has much of an advantage over the 21700.

Given this, I’d be more inclined to say that a 21700/18650 compatible tube would be preferable. Yeah, this means losing the 3xAAA battery carrier option (in a pinch), but frankly good planning on batteries would obviate the need.

Based on my (not that professional) capacity test, charge battery to 4.20v, then discharge battery at 1Amp until 2.50v (I’m using SkyRC MC3000 analyzing charger), the highest capacity 5000mAh 21700 batteries (eg. Vapcell T50 or Vapcell G50), can barely get 5000mAh capacity (from 4.20v down to 2.50v at 1A discharge current).

Whereas something like the Vapcell/Shockli 5500mAh 26650 (and also the Keeppower 6000mAh 26650, which appear to be using the same internal battery) batteries, using the same discharge test (4.20v down to 2.50v at 1Amp discharge current, yields around 5800-5900mAh capacity on the SkyRC MC3000). So the highest capacity 26650s are still nearly 1000mAh (around 18% more capacity, assuming discharge down to 2.50v). Although it’s difficult to get these “5500mAh” 26650 batteries. Although based on energy density, I recall reading that 26650 is still not as energy dense as high-capacity 18650 or 21700 batteries…)

Thank you, dta. This is enlightening. 18% is nothing to sneer at. And frankly, looking at the form factor differences on diameter, maybe it’s worth a slightly wider girth to have that extended 26650 cell capacity. I wonder if it would make sense to provide two different tube sizes as an option. Certainly it’s done commonly with 18650 & 18350.

I thought 26650 form factor was a great idea for both lantern stability as well as extra capacity

Yeah, a 26650 is about 42% bigger than a 21700, and at most has 15% more capacity (in 2021.)

Not a good trade-off, in my opinion.

And the ability to use 3 AAA batteries?

You're not going to get much runtime compared to a nice 21700 cell.

I do admit that a fatter lantern is more stable, but the 21700 lantern could come with a plastic anti-tipover disc that fits on the bottom of the lantern.

I am excited to see the new build. Its going to be perfect. :smiley:

For me personally, it’s more about who wants a skinnier lantern that will tip over easier with less battery capacity?
Does it need to fit into a pocket? No.
Does it need high discharge that 21700 can deliver? No

It’s a lantern, runtime and stability is paramount (for me anyway)
It’s not important that it runs off 3 AAA’s but it’s a nice little bonus that you probably won’t need until you do.

Using 3 AAA’s just doesnt make sense to me. If you are going to go to the trouble of taking 3 AAA’s ‘in case of emergency’ why not just go ahead and take spare 18650/21700s :question:

I think it makes sense from the standpoint of buyers other than those knowledgeable about flashlights. Don’t forget that Sofin wants to sell the mini to the mass market, many whom may think it’s a great feature to have or are afraid of li-ion batteries (I’m just speculating here and could be totally off base :stuck_out_tongue: ). Also in case of a true emergency (earthquake, floods, etc) the more option one has the better off one is. AAA’s are going to be much easier to scrounge than 18650/21700 batteries.

Naturally those using it for camping, etc will just bring extra batteries.

3xAAA flashlights are quite common. So lets say your Lithium Ion cell failed, you were unable to charge it for whatever reason, and you lost your spare. If someone in your group has a spare 3xAAA set, or you head into town and a cheap 3xAAA light is on the shelf — you’ve got a substitute.

The entire concept for this light originally was a small, backpacking oriented version of the LT1. If size isn’t a concern, use the LT1. The LT1 already has all the things you are looking for when size isn’t a factor. Heck, with a little ingenuity you could probably shoehorn a 3 AAA carrier into a LT1 if you wanted to. Where size is a factor though (the whole purpose of a mini version!?) the 26650 is unwelcome.

A "half a millimeter" (about 20 thousandths of an inch) larger in diameter 21700 battery tube could accept AAA battery cages:

https://budgetlightforum.com/t/-/60851/1225

I wouldn’t take AAA’s as an emergency, I would buy them anywhere, unlike lithium ion cells (of course I’d have several other lights with me as a backup too :smiley: )

Hmmmmm …………… Dont forget the backups for the backups :beer: :beer: :beer:

Interested for 2

This LT1M was intended to be more compact, (thinner) to better fill the need for campers, backers, canoeists, Kayakers, etc. The 26650 is an older format, & loosing popularity in favor of the newer 21700 thinner format. A base cap will likely be available for better stability.