Why not more lithium batteries?

[Daekar]

So I've been looking around and trying to learn more about battery choices, and I find myself wondering why there aren't more lights (especially larger ones) constructed to use things like 18650 or 17670 cells. These are the advantages as I seem them - please add/correct if I've left anything out or I'm mistaken on any point:

1 - Comparatively good energy density.
2 - Little to no voltage/charge loss when left to sit over time.
3 - Offer voltages and capacities such that they're useful to light single LEDs either by themselves or in pairs.
4 - Small enough that in a larger light they could be used in greater numbers to power multiple LED arrays like in Milkyspit's Project M lights.

Based on all of this, I'd really like to see (and once I learn the electronics I'll be trying to make my own) custom lights offered that take advantage of these factors. I know one of the major determining factors in my decision to purchase a Lumapower M1 was the excellent runtime using 18650s, and I'd be more than happy to purchase an even larger more powerful light which used multiples of that size battery... I have a feeling if it were constructed properly, it would be possible to cram as many as six 17500s, 17670s, 18650s, etc. into something the same size (give or take a bit) as a 2D maglite.

BTW - I have a feeling that the number names mean something but I don't know what exactly. As in 18650 - 18 would be nominal diameter in mm? And 650 would be...the length with an extra zero tacked on to make it look pretty? Clue me in!

 

[Illum]

compared to the forum, the general consumer markets only begiining to learn of this cr123A cell...introducing these "numbers" batteries would certainly draw confusion

 

[VidPro]

18 would be nominal diameter in mm? And 65mm would be the length and 0 means its round. Learned that here.

18650s are excelent power sources, and they come in CORRECT protected versions, both mechanically, and electronically.

the done correctally part about jamming in many in series, is the part i doubt they will do right :-(
single cell lights DESIGNED for 18650s with protected batteries are perfect. just stuff a charger on the back, some levels, and FOCUS capability.

 

[LuxLuthor]

When you introduce a whole other battery, it takes a long time for them to catch on to the mainstream. The RC crowd started using Lithium Polymer for their light weight and high energy storage. There has not been much of a market for all the various Li-Ion cells that AW is selling yet because not many things are made to accept their custom sizes. Most electronic things are made to fit D, C, AA, AAA, 9V Transistor, and a few less common Alkaline, NiMH, NiCd sizes.

Then there is the different voltage of Li-Ion 3.7V, Li-FeS2 @ 1.5V, Li-MnO2 @ 3.0V, Li-PO4 @ 3.2V, etc which gets hard to sort out which to use for what.

Then with most except the new LiPO4 (A123/Saphion), there is a significant fire/explosion risk that is most commonly triggered by charging incorrectly. That's why I think most will move to the safe Li Phosphate chemistry.

 

[LiteTheWay]

please tell us more about LiPo4. do you have a link?

 

[Effulgence]

I'm currently use Wolf-Eyes brand and AW cells now but I have 6 Tenergy 18650's with protection. These Tenergy cells won't power up my lights, so I was wondering if I should take the protection off to gain the single click or some advantage. They're quite useless as is... I was wondering if taking the protection off these cells could be used in a hotwire or something. Is this a good idea or am I asking for trouble? Thanks everyone.

 

[VidPro]

I'm currently use Wolf-Eyes brand and AW cells now but I have 6 Tenergy 18650's with protection. These Tenergy cells won't power up my lights, so I was wondering if I should take the protection off to gain the single click or some advantage. They're quite useless as is... I was wondering if taking the protection off these cells could be used in a hotwire or something. Is this a good idea or am I asking for trouble? Thanks everyone.

it indeed is usually the protection itself that is keeping you from using them in this situation, because one aspect of protection is to insure that the discharge rate is not to high.
but that same protection is what makes it "safe" to use in series. if you toss the protection or use unprotected cells, you will be able to run a hotwire, but you will LIKLY cause the batterys problems, and then yourself.
read up on the specs of the cell, and analise how you would keep EACH cell in that series set from going beyond those specs without protection.

a Incadescent bulb may be rated to best work at a specific voltage, but it draws a LOT of juice even when the batteries are depleated beyond li-ion specs.