18650 Li-ion at $145 per KiloWatt Hour!

zEEz said:
..., your only option is to consider buying a few cheap *ORIGINAL* DELL Laptop packs ...

That's all I use, original Dell packs. I'm sure you already knew, the Sony laptop cells that you use are also Lithium Cobalt, not the spinel (Konion) variety.
 
SamTexas said:
That's all I use, original Dell packs. I'm sure you already knew, the Sony laptop cells that you use are also Lithium Cobalt, not the spinel (Konion) variety.

Yes, it is worth to repeat this! I got this important point some time ago while I was looking for alternatives to LiPO for an RC plane ...
You know! If you plan to bump crash your plane each 20 seconds (a foamy jet) , you would feel anxious about
exploding LiPOs :evil: ... their plastic pocket is soooooo thin :mrgreen:

There I saw Konions from 1100 to 2400 mAh ... with 15 - 18 A of peak current ....
But for me the standard chemistry of the computer packs was good enough:
.... and the plane was topping at 8A, luckily :roll:
MY POINT: they came for free :p
 
No hate on konions here, but picking up used ones from dell packs that are 1-3 years old is kinda iffy.
Remember that these usually last about 5 years in real laptop use though so when you buy them used, you're getting the hand me down.

Thus the comparison to mom's 12 year old grocery getter ( at least it was a Celica, but it was an automatic )

But if you can get them for next to nothing, more power to you. Guess i'm a big snob for wanting new batteries :D
 
I have a lot of these 18650 lithium-polymer cells, all different, purchased at different occasions with flashlights, headlamps, bike lights etc. Last week I did a test-drive for all types of cells I own with a charge-discharge-charge test. Note that, albeit in use, a single charge will last for a long time (in flashlights I mean) - up to a week, so even the most used cells were used maximum 50 cycles.

So, the results were discouraging. At first, most of these "ultra-something" cells have giant internal impendance - up to one ohm on the worst samples, 0.5 ohms usually. This means very low discharge and charge rates. For example, if you suck one ampere from such a cell, e.g. 3.7 watts, about 0.5 of them (14%) will be spent just to heat the cell. Another bad news is that their real capacity is usually twice lower than declared. Even that I have tested them at 0.1C discharge rate. Some cells had just 500mah capacity (while were declared as 2400). Most were 1000-1400mah. So, about the energy density of the "fake A123" yellow 18650's, but with a much higher internal impendance. Eek.

The best cells that I own were from a ebay seller (don't remember his nick on ebay) that were declared from the beginning as 2200mah. And - surprise - they were for real 2200mah (well, 2150 and such, but meh). They weren't "ultra-anything", they just have a paper label sticked on the cell body.

The resume is: I would never use these cells for a e-bike battery. The best of them (those marked 2200) are very good for flashlights and such, but not for serious loads.

If somebody is interested, I may post a photo of the cells I tested, with their real capacity.
 
I'd love to see your research!

BTW guys, you're right, the Ultrafire group is mixed. My latest batch was a buncha USED cells with the old spot welds ground off, rusting tabs, nasty green cells with spot welded plates on and new shrinkwrap to make it look all good.

I still stand behind the fact that "real" UF cells actually do perform decently.

However, this does bring up the question of where these UF's come from lol. Working out this issue with the seller, will post up any further advancements. If they aren't able to readily supply me with the correct cells that I've been using previously, I can only assume that UF really is a "passaround" brand for random peeps to shrinkwrap up old cells and sell them as "new" cells.

SANY0417.jpg

LEFT - Good "NEW" cells RIGHT - BAD USED rewrapped cells

SANY0418.jpg

LEFT - Good "NEW" cells with top cap removed RIGHt - BAD cell with rusting and old welds ground off

SANY0419.jpg

Close up of under the UF wrapper.

SANY0420.jpg

Yup..

SANY0421.jpg

Ugh...

All 40 of the 40 I bought were like this. The last ~150 I bought were not (they were all the same). Out of these 40, 10 were able to power a small 55w foglight (12v), and at full charge they read an average of 3.9v (vs 4.2v on all of the good cells from UF)... 7 of them didn't even read a voltage.
 
I don't know how many times I've gotta say it, but once more won't hurt I guess.

Ultrafire does NOT have a battery factory. Period.

They do not manufacture batteries. Period.


They buy lots of cheap cells (b-stock and/or QC fails) from people that do manufacture cells, and shrink-wrap them in Ultra-fire labels (and rip off tab welds and put little covers on the ends if needed to make it looks like a decent cell etc).

Totally fine for things like flashlights where nobody cares as long as it works.

Terrible idea for an EV pack, where you're only as strong as your weakest cell group, and a single failure can take down a whole cell group.
 
True true... but I've gone far to look back. Crapstock or not, the "new" cells actually do perform decently IMO. I had a 5P1S pack, 3.7v actually turn over a forklift motor without even raising the batteries a degree in temperature LOL.... that was surprising.
 
oscaryu1 said:
das sum boalshiz. First batch like that. Let's see how this ends out..

Friends don't let friends buy ultrafires.. ;)
 
I love how they are all different colors from random batches, and unprinted/unlabled because they failed QC and were culled before continuing on to the labeling machine. Lol

It's funny how random reject cells get labeled as higher capacity than the best in the world are capable of achieving.

Kai has a good sense of humor.
 
Yep, the caps just sit on the end, touching the tiny high points from the residual spot welds that were ripped off.

Its ultrafire quality.
 
i use these for hobby apps that dont use tremendous draw and i find each battery has its own personality :) .i dont know if i would bundle a bunch for ebike battery.i hope it works!
 
oscaryu1 said:

Impressive work!
Would work nicely, as a "saddlebag" configuration.
Highly recommend-don't forget to, install a fuse, on each pack.

Also, I cover the sides of the pack with clear "boxing" tape. (after attaching balancing leads ... of course)
It will:
Add stability;
Protect from minor short dangers;
Still allow visual inspection.
 
For any interested... I recently picked up 50 of the UltraFire 3800mAh cells. I figured I would play with them to see what I could work out. First off... The ones that I got were not recapped and had no other signs of repackaging (only tore down a dozen, but got bored doing that). Second, I tested those dozen cells, and was getting pretty reliably around 3700mAh.
I sure am not gonna go saying that UltraFires are just fine, but from the sounds of it, they can be hit or miss...
I am working on a cheap reliable BMS now, and when that is done, I plan on really putting them through their paces.

P.S. I managed to pick mine up for $75 (about 11 cents per watt-hour)
 
thomas.smith said:
For any interested... I recently picked up 50 of the UltraFire 3800mAh cells. I figured I would play with them to see what I could work out. First off... The ones that I got were not recapped and had no other signs of repackaging (only tore down a dozen, but got bored doing that). Second, I tested those dozen cells, and was getting pretty reliably around 3700mAh.
I sure am not gonna go saying that UltraFires are just fine, but from the sounds of it, they can be hit or miss...
I am working on a cheap reliable BMS now, and when that is done, I plan on really putting them through their paces.

P.S. I managed to pick mine up for $75 (about 11 cents per watt-hour)


You do not have 3700mAh 18650 cells.
 
:lol: yup...

Panasonic is not even up to that density in an 18650 cell yet. They're up to.. i think.. 3.4AH for the Tesla Model S?

Run it through a graphing RC charger or CBA-2/CBA-3 and you'll learn the ugly truth.
 
thomas.smith said:
For any interested... I recently picked up 50 of the UltraFire 3800mAh cells. I figured I would play with them to see what I could work out. First off... The ones that I got were not recapped and had no other signs of repackaging (only tore down a dozen, but got bored doing that). Second, I tested those dozen cells, and was getting pretty reliably around 3700mAh.
I sure am not gonna go saying that UltraFires are just fine, but from the sounds of it, they can be hit or miss...
I am working on a cheap reliable BMS now, and when that is done, I plan on really putting them through their paces.

P.S. I managed to pick mine up for $75 (about 11 cents per watt-hour)

Please do tell us more about how you tested the cells !!

we love pictures ! :p
 
I'd be content for now if I could get 1.5ah Sony US18650V cells for that same $1.50/ea . That's the kind of deal we need to be looking for instead of this stuff with a minuscule C rate that is just a fire waiting to happen.
 
Ypedal said:
thomas.smith said:
Please do tell us more about how you tested the cells !!

we love pictures ! :p
Sorry it took so long to respond, my actual job (and now lack thereof) has kept me pretty busy.

Well, I picked up a cheap digital/analog IO board, and wrote a quick voltage tracker. Then I rigged a 14w (1C) load, charged the cell, attached to load/voltage tracker (cut off at 2.9v); repeat. It was taking an average of around 52 minutes to drop to 2.9v. Admittedly, hardly what could be considered a really reliable rig.

After my new gig spins up, I am planning to pick up a CBA3 (like neptronix suggested) and run them through their paces again.

P.S. Not sure if I mentioned it, but the cells that I got have no signs of repacking after tearing them down (hehe, I do have a blister for my lack of patience in waiting to discharge it before hacking it up though).
 
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