I have been checking out the forums posts for P7's and have yet to find somebody using Emoli cells in theirs. From what I read, they will fit in some older C body Mag's. I was thinking about building a single cell C body Mag P7 using the Emoli cell (with a tail switch), but have some reservations. It seems like direct drive is the way to go, but I may do a regulated setup, would that work with a single Emoli cell? Is there something else I need to consider with even a direct drive setup and the Emoli?
Also, any info on the Emoli's would be cool, I recall reading a long time ago that they were a safer technology, and I know they are built with much tougher than normal cases (steel). Do they also have the special liners to prevent runaway reactions?
Here is an absolutely gorgeous cut down Mag Chris MacClellan made that uses a 26700 E-Moli.
http://candlepowerforums.com/vb/showthread.php?t=191836
BatteryUniversity partone-5A has some interesting reads about this newer type cell. E-Moli cells have a slightly higher voltage, 3.8 vs 3.7 volts. They have lower internal resistance than cobalt-based Li-Ion's. That's why they are able to handle sustained charge and discharge rates at least 10 times higher than regular cobalt Li-Ion's. The lower internal resistance might suggest under heavy drain (2.8 amps from a P7), the voltage the battery puts out might be slightly higher than from a cobalt Li-Ion. That would of course make the LED draw more power. I haven't seen anything specifically saying this, but it's possible you can't use a spinel Li-Ion without a regulator on a P7, i.e. direct drive not possible. Certainly worth looking into. Also check out partone-5B. They say there spinel can take 100°C higher temp than a cobalt Li-Ion can before becoming thermally unstable. There's your safer technology.
http://www.batteryuniversity.com/partone-5A.htm
All that aside, I saw another post here on CPF where someone said his "I" voltage P7 drew slightly higher than 4 amps when he put three freshly charged NiMH D cells in his 3D MagLite. He didn't care that was cutting the 50,000 hour life span down to a few hundred hours. It would give him a good excuse to upgrade in a few months when something better comes along. If a MoliCel works OK direct drive with a P7, it'll definitely be the brightest on the block.
Manganese dioxide Li-Ion's do have slightly less capacity than cobalt. E-Moli's spinel type 18650 has a capacity of 1,400 mAh and the 26700 is 2,900 mAh. BTW, will 26 mm even fit in a C cell MagLite? Even if you stripped off the plastic which I guess you could do if you're using only 1 battery, it still might need boring out. E-Moli sells both manganese dioxide and cobalt type batteries. Look at the constant current discharge graphs of the ICR18650J and compare it to the IMR18650E. The manganese dioxide "power cell" at 5 amps puts out at least 0.3 volts more than the cobalt "energy cell" does on the 4.8 amps discharge curve. Hard to tell from these graphs how these two cells would behave at 2.8 amps.
E-Moli has a note on the page saying since these cells have no protection circuits, they're only for sale to OEM guys who assemble packs with proper balancers and protection circuits. Imagine a thermal runaway in a battery 26 x 70 mm.
http://www.molienergy.bc.ca/products.html
What about an A123 26650? At 3.3 volts and 2.3 Ah capacity, nanophosphate is a lower voltage than manganese dioxide. With an I voltage LED having a range of 3.25 to 3.5 volts, A123's might be perfect for direct drive of a P7. They can be drained to almost zero volts with no damage to the battery. No possibility of its venting with flames either.
http://www.a123systems.com/#/products/p1
