BatterySpaces 4000mah 26650 cells Graph

[cmacclel]

Cells look to be actually rated properly! I have only tested at 1 & 2 C and they have exceeded there labeled rating.

4amp
69F Start
76F 15 Min
78F 30 Min
80F 45 Min
84F 60min

8amp
66F Start
92F 15 Min
104F 30 Min


Cells measure

66.5mm Length
26.3mm Diameter

 

[TexLite]

Thats Awesome,

Thanks for the graph Mac!

-Michael

 

[LuxLuthor]

Mac, your graphs drop a bit more than the pdf presentation from BatterySpace.com, but I agree it looks pretty close.

Personally I would not buy these cells because of the 6 month life listed in table 2.2; item #13. That is going to be 6 months after their factory ships them. They appear to have about 150 cycles at 8A discharge if used during the first 6 months, after which they have about 70% capacity left.

They don't list the deterioration drop off (approaching and beyond 6 months) over time if used minimally. In the other thread, these were initially listed as 40A cells (unless OP was mistaken).

 

[lolzertank]

Mac, maybe you could run the test again now that a month's passed? Then we could try to extrapolate the capacity loss after 6 months to see how bad the capacity loss really is.

 

[Mjolnir]

Are these the same as IMR cells? How do they differ from these cells, as well as AW's IMR C cells?

 

[lolzertank]

These are IMR, though they have very high capacity compared to most IMR cells and a lower max current rating.

 

[Mjolnir]

Any idea why they would be listed as having a shelf life? Why would these cells degrade more than others? DO all IMR cells have a "shelf life?"

 

[cmacclel]

Mac, maybe you could run the test again now that a month's passed? Then we could try to extrapolate the capacity loss after 6 months to see how bad the capacity loss really is.

Loss is negligible if at all after 32 days.

 

[TexLite]

Loss is negligible if at all after 32 days.

Thanks again Mac, that's interesting.

At this price point I'm willing to accept a shorter cycle life in favor of the large capacity and safer chemistry, at least until something better comes along.

Hopefully by the time these cells come up short, an improvement will be made to cycle life.

12-18mos from now I may think differently, but that's my take for now.

-Michael

 

[Mjolnir]

Any idea if this would flash the 3854 H bulb? From Lux's destructive bulb testing it seems that it can stand about 8.5 V before flashing, but this cell doesn't seem to go higher than 4.1 from the graph, which would put 2 of them at about 8.2 V at the highest.

 

[cmacclel]

Any idea if this would flash the 3854 H bulb? From Lux's destructive bulb testing it seems that it can stand about 8.5 V before flashing, but this cell doesn't seem to go higher than 4.1 from the graph, which would put 2 of them at about 8.2 V at the highest.

There would be a great possibility for an instaflash. These cells can put out alot of amps. If you charged them to 4.0 instead of 4.2v you may be OK.

Mac

 

[VidPro]

cmacclel :twothumbs thanks for comming back with the update info , of the one month stats

 

[Mjolnir]

Does this mean that the 6 month thing is not an issue?

 

[cmacclel]

Does this mean that the 6 month thing is not an issue?

It appears that way......but I guess we will really find out in 6 months

Mac

 

[Patriot]

I'm not sure what to make out of the 6 month thing or why they chose to rate it so conservatively. It appears they're performing great according to your latest test.

Thanks for the helpful info Mac.

 

[Mjolnir]

These seem like a pretty good option instead of 18650's for my ROP (since they should be about the same length).
Any ideas of how to charge these with a PILA IBC? I don't think making a charging cradle out of a C battery holder would work, since these are larger than C cells. Maybe a D cell battery holder would work? I would rather not have to make magnetic charging leads.

 

[metlarules]

I would imagine that they will last longer if the discharge is 1a or less like most LED lights. It would be nice if you could run this test once a month so we could see the degradation of the cell over time. Thanks for the graphs.

 

[lolzertank]

Thanks! If the 6 months to 70% capacity loss was constant, the capacity should already have dropped about 200mah.

I don't think the shelf life rating means what we think it is. I noticed Emoli has a prismatic Li-ion cell rated at only 1 year of shelf life which seems pretty doubtful as well.

Once my wallet decides that it isn't so empty for flashlights (Discrimination! Bad wallet!) anymore,

 

[metlarules]

Now if only we can get Fivemega to make one of his Surefire tubes in single 26650 size. Can you imagine the runtime on a multimode drop-in on low with this battery? :thumbsup:

 

[lolzertank]

Can you imagine the runtime on a multimode drop-in on low with this battery? :thumbsup:

Yeah, just hand over the calculator. About 25% longer than how long a AW C Li-ion lasts? And those were pretty high capacity to begin with...