18650 Li-ion at $145 per KiloWatt Hour!

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DrkAngel   100 GW

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18650 Li-ion at $145 per KiloWatt Hour!

Post by DrkAngel » Mar 11 2011 10:14am

3.7v 3800mah Li-cells available for less than $2 each!

Batteries to complete a 37v 26.6ah pack for $140 @ about 8lb!
Charger & circuitry extra.
"Pack" build method?
Soldering? Wired "rack"? ???


That equals $145/kwh - @ less than 10lbs. A 20kwh battery pack, for less than, the weight of a 200lb passenger!!!

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... K:MEWAX:IT

"** Large Quantity ** of UltraFire 18650 3800mAh Rechargeable Battery are available to purchase.
Please check out other Quantity items on sale.
If you do not see the "Quantity" you need. Please contact us and we can open an auction for you to buy.
More Quantity, More Discount!"

Price per 100 is noticeably more, due to:
Weight limitations of air mail?
Li-ion shipping safety regulations?

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... K:MEWAX:IT

I have tested, lower capacity, UltraFire 18650's, previously, and found them to be of reasonable quality and to be "rated" responsibly.

I would recommend purchasing a limited quantity, and testing before committing to, large scale, purchases.

I will, of course, post my test results as soon as possible ...
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Re: 18650 Li-ion at $145 per KiloWatt Hour!

Post by Doctorbass » Mar 11 2011 10:56am

I heard about these 3800mAh cells a year ago.

I am curious to see if these veryfire are really 3.8Ah at 1C, 2C or 4C... or just at 0.5C or maybe 0.2C like many of these high energy density cells...

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Re: 18650 Li-ion at $145 per KiloWatt Hour!

Post by spinningmagnets » Mar 11 2011 1:24pm

Is the 18650 designation the chemistry, size, or shape (or "X")? Here's an awesome battery pack using 18650's, but they are 2200 mAh and also from Sony instead of Ultrafire. http://endless-sphere.com/forums/viewto ... 90&start=0

The pack arrangement is similar to advice and pics from DocBass...

Label and test each cell, rate them for true mAh, toss the weak cells, juggle the combinations of cells in each string until each string has the same amount of mAh (individual cell mAh vary slightly), then connect the parallel-strings in series for the final voltage.

edit: Doc, to test individual cells...I charge them to full charge, drain to LVC, then charge again, and write down the MaH that the charger says the battery was able to swallow?
Last edited by spinningmagnets on Mar 11 2011 9:54pm, edited 1 time in total.

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Re: 18650 Li-ion at $145 per KiloWatt Hour!

Post by John in CR » Mar 11 2011 1:37pm

They're simply not 3.8ah and whatever the actual ah, the c rate will be very low. 18650 cells weigh about 40grams. Do the math and that's 350wh/kg. Even the best batteries aren't hitting 200wh/kg yet, so it's just not possible that the cheapest lithium batteries we've ever heard of can have that kind of energy density. That's 2.5 times the energy density of the RC lipo folks are using, and over 3 times the ED of LiFePo4. I look forward to the day that's it's true, but unfortunately today isn't that day. :x

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Re: 18650 Li-ion at $145 per KiloWatt Hour!

Post by DrkAngel » Mar 11 2011 2:00pm

John in CR wrote:They're simply not 3.8ah and whatever the actual ah, the c rate will be very low. 18650 cells weigh about 40grams. Do the math and that's 350wh/kg. Even the best batteries aren't hitting 200wh/kg yet, so it's just not possible that the cheapest lithium batteries we've ever heard of can have that kind of energy density. That's 2.5 times the energy density of the RC lipo folks are using, and over 3 times the ED of LiFePo4. I look forward to the day that's it's true, but unfortunately today isn't that day. :x

John
Yes, I highly recommended that you test these cells, before buying a large quantity!

But, Li-ions do typically have twice the energy density of LiFePO4's.
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Re: 18650 Li-ion at $145 per KiloWatt Hour!

Post by Doctorbass » Mar 11 2011 2:02pm

spinningmagnets wrote: Doc, to test individual cells...I charge them to full charge, drain to LVC, then charge again, and write down the MaH that the charger says the battery was able to swallow?

Yes.

It is better to leave the cells to sit for few hours after the charge to let them stabilize. This will also give you another data:`after these few hours measure their voltages no load. note that value. That will give you a good idea of the cell health. The cells with better sitting voltage are good and the cells with lower voltage are the worst..

Often charger will also calculate the RI of the cells.. this is also a good indication of the cells health. Lower RI = better cell.

Doc
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Re: 18650 Li-ion at $145 per KiloWatt Hour!

Post by Doctorbass » Mar 11 2011 2:05pm

DrkAngel wrote:
John in CR wrote:They're simply not 3.8ah and whatever the actual ah, the c rate will be very low. 18650 cells weigh about 40grams. Do the math and that's 350wh/kg. Even the best batteries aren't hitting 200wh/kg yet, so it's just not possible that the cheapest lithium batteries we've ever heard of can have that kind of energy density. That's 2.5 times the energy density of the RC lipo folks are using, and over 3 times the ED of LiFePo4. I look forward to the day that's it's true, but unfortunately today isn't that day. :x

John
Yes, I highly recommended that you test these cells, before buying a large quantity!

But, Li-ions do typically have twice the energy density of LiFePO4's.


I would correct that afirmation: Lithium cobalt do typically have twice the energy density of LiFePO4's


LiFePO4 cells ARE lithium ion type
-
LiFePO4 ( lithium phosphate) ( and.. badly called lithium polymer in china)
-LiMn04 ( lithium manganese)
-LiCo ( lithium cobalt)
-LiPo ( lithium polymer)

are ALL lithium ion

Doc
CURRENT PROJECT: 2WD duo MXUS/Max-E ebike 32kW
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Re: 18650 Li-ion at $145 per KiloWatt Hour!

Post by Ypedal » Mar 11 2011 2:35pm

I'm ordering some of the 3800mah and the 2800mah, i don't expect them to be true to spec but will test them for the hell of it.. ( at least i can use them in flashlights ) .

curious to see how they stack up against the dealextreme one's.
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Re: 18650 Li-ion at $145 per KiloWatt Hour!

Post by Doctorbass » Mar 11 2011 2:54pm

Ypedal wrote:I'm ordering some of the 3800mah and the 2800mah, i don't expect them to be true to spec but will test them for the hell of it.. ( at least i can use them in flashlights ) .

curious to see how they stack up against the dealextreme one's.
With my 900lm 33$ flashlights, i'm using the Konion all the way. I had bought the veryfire or truefire from them ( the 2400mAh) and the used 1.5Ah konion last more time!

I guess it is due to the lowert RI that the konion have that make teh cell loosing less energy in heat at 2.9A draw fro the LED...



I'm 99% sure they are not 3.9Ah anyway... imagibne... 3.9Ah x 3.7V = 14.4Wh for a cell of 2$... that's 7Wh per $... difficult to believe...


Doc
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Re: 18650 Li-ion at $145 per KiloWatt Hour!

Post by John in CR » Mar 11 2011 6:40pm

Ypedal wrote: ...( at least i can use them in flashlights )...
I think even the flashlight gurus slam the UltraFire's as bogus.

Twice the gravimetric ED of the heaviest Lifepo4 is reasonable since there are some lipos that have that, but the cheapest cell available claiming to have over 3.5 times that ED sets off all of my BS alarms at the same time. Thanks for being the guinea pig though, so we can put it to rest. I'll bet you need a low power LED as your load to get to even 2ah. :mrgreen:

Be sure to test it in a safe place, because my first search turned up one that exploded in a laser pointer. :shock:

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Re: 18650 Li-ion at $145 per KiloWatt Hour!

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Re: 18650 Li-ion at $145 per KiloWatt Hour!

Post by John in CR » Mar 11 2011 8:48pm

Two posts about them. Do we have the seller in our midst?

AW,
Look out for those circular references. When they get in a quote weird stuff happens. Someone had one of those the other day, and I clicked the link and was sent to "Post a Reply" in the other thread. Computers are afraid of circles...our only hope once skynet goes live.

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Re: 18650 Li-ion at $145 per KiloWatt Hour!

Post by Doctorbass » Mar 11 2011 9:27pm

Congrat to any buyer from E-S... You are loosing money to help us to discover the truth of the Magic mAh :lol:

No kidding... Does anyone checked the feedback comments from the ebay buyers about these cells?

Doc
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Re: 18650 Li-ion at $145 per KiloWatt Hour!

Post by amberwolf » Mar 11 2011 9:35pm

John in CR wrote: Someone had one of those the other day, and I clicked the link and was sent to "Post a Reply" in the other thread.
Most likely whoever posted the link copied it from the title in their Post Reply page, instead of the viewing-thread page. When that happens, it includes the Post Reply part in hte link, so that's where yoiu are taken when you click it. ;)

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Re: 18650 Li-ion at $145 per KiloWatt Hour!

Post by neptronix » Mar 11 2011 9:55pm

Oh yeah.

Those are the cells that dealextreme sells that are more like 1ah-2ah.
There are tons of ultrafire fakes out there too.

Ultrafire also never meet their rated capacity.

http://www.dealextreme.com/p/ultrafire- ... blue-19625

http://www.dealextreme.com/p/ultrafire- ... pack-21474
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Re: 18650 Li-ion at $145 per KiloWatt Hour!

Post by DrkAngel » Mar 11 2011 10:10pm

I went hunting for someone who has actually tested UltraFires. This is the only post I could find.

Quote, from flashlightnews.net
"MattK
Jr. Flashaholic
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Re: UltraFire 3000mah 18650 3.7V
« Reply #4 on: May 02, 2009, 07:44:22 PM »

The Ultrafire 3000mah cells are actually suprisingly good. We've run a bunch on the Cadex and we're seeing 2600-2700 actual capacity at .5C. At higher discharge rates like 1-2A we're seeing closer to 2300-2400mah so my advice is that for '3W' (750mah) or less applications go with the 3000's but for higher drain lights the extra capacity won't be realized and you'll be paying 40% more for only 10% more realized capacity.
Logged "
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Re: 18650 Li-ion at $145 per KiloWatt Hour!

Post by MadRhino » Mar 11 2011 10:42pm

Those cells are not very interesting for any performance use. Low resistance Lipo will be the the preffered choice for a while, although I'm tempted to try the 30 C Lifepo4 bricks that they sell at HK.
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Re: 18650 Li-ion at $145 per KiloWatt Hour!

Post by neptronix » Mar 11 2011 10:48pm

He seems to confuse the C and amp ratings.

I think he means 0.5amps per cell ( which would be < 0.2C ), which is.. worse output than a lead acid.. :P

At our use, where we are drawing 1C minimum.. and you would need a 100ah pack or something to get good output, lol..
It would be a cheap pack, but an extremely heavy one. And who knows about what kind of cycle life you can get..

I will await results from you guys who have bought these though.
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Re: 18650 Li-ion at $145 per KiloWatt Hour!

Post by DrkAngel » Mar 11 2011 11:04pm

Buffer the 18650s with a bank of 20c 5700mah Li-po!... If you need 100amp+ draw.

My Ezip cruises at 20mph on less than 10amps. (25.9v home made Li-ion)
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Re: 18650 Li-ion at $145 per KiloWatt Hour!

Post by neptronix » Mar 11 2011 11:15pm

I don't exactly think that would work.
You could cut the amp draw in half by sticking them in parallel with the lipos, but that won't help them any if they are truly < 0.2C. Even a 1C load is too much apparently if they are losing ~40% of their capacity at 2amps ( about 0.6c for those cells )

Your eZip may draw 10amps cruising, but it sure as hell doesn't draw that accelerating or going up a hill.
That is when you get many multiples of your cruising amp load.

The numbers on these cells don't look good thus far.
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Re: 18650 Li-ion at $145 per KiloWatt Hour!

Post by DrkAngel » Mar 11 2011 11:20pm

DrkAngel wrote:I went hunting for someone who has actually tested UltraFires. This is the only post I could find.
"The Ultrafire 3000mah cells are actually suprisingly good. We've run a bunch on the Cadex and we're seeing 2600-2700 actual capacity at .5C. At higher discharge rates like 1-2A we're seeing closer to 2300-2400mah so my advice is that for '3W' (750mah) or less applications go with the 3000's but for higher drain lights the extra capacity won't be realized and you'll be paying 40% more for only 10% more realized capacity.
Logged "
neptronix wrote:He seems to confuse the C and amp ratings.

I think he means 0.5amps per cell ( which would be < 0.2C ), which is.. worse output than a lead acid.. :P
Pay better attention! The following explanation fits the post better, and makes a lot more sense!

Looks like he meant to say: "2600-2700 actual capacity at .5C. At higher discharge rates like 1-2C we're seeing closer to 2300-2400mah".
Meaning, 2600-2700mah at 1.5a draw, and 2300-2400mah at 3-6amp draw.
This post was for last years 3000mah model, if present 3800mah model is comparable then equivalent would be:
3800mah=3300-3420mah at 1.9a draw, and 2900-3040mah at 3.8-7.6amp draw.


Just noticed. 10% below rated, at .5C and 20% below rated, at 1-2C.

Compare this to SLA, where 1C rate produces 40% below rated. 1C draw = empty in 36 minutes.
Last edited by DrkAngel on Mar 13 2011 3:41pm, edited 1 time in total.
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Re: 18650 Li-ion at $145 per KiloWatt Hour!

Post by DrkAngel » Mar 12 2011 9:28am

When testing the performance of Li-ion's, remember that they should be "broken in" first.
Manufacturers, typically recommend, that cells should be fully charged, then discharged, at a moderate rate, to the 50% capacity point, then repeat several times. They point out that failure to properly break in a battery might result in "poor performance characteristics".

Li-ion (Lithium Ion), Li-Po (Lithium Polymer), also, have a median voltage of 3.7v. Fully charged = 4.2v, & safety cut off varies, but near, 3v.
LiFePO4 (Lithium Iron Phosphate), alternately, is a vastly different type. Due to safety considerations, capacity is greatly reduced, performance - somewhat. Working voltage is much different! Median voltage is 3.2v. Fully charged = 3.65v & safety cut off is near 2v.
On all types:
Voltage cut off is below minimum recommended, "usable voltage".
Most chargers will charge above the "full" voltage. Before testing, batteries should be allowed to "rest", so that this "excess" voltage may dissipate - to allow accurate testing.
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Re: 18650 Li-ion at $145 per KiloWatt Hour!

Post by Ypedal » Mar 12 2011 9:43am

canadian dollar is 1:1 on par with USD right now.. cool !
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Re: 18650 Li-ion at $145 per KiloWatt Hour!

Post by DrkAngel » Mar 13 2011 10:32am

"Tab" 18650's are also available, (for easy soldering).

Tabbed 3800mah, & 4000mah are available, but at a much higher price!
About $4 each

3800mah
http://cgi.ebay.com/10-UltraFire-18650- ... 483f72ae3c

4000mah
http://cgi.ebay.com/12-Rechargeable-186 ... 4cf53ad6a1
Last edited by DrkAngel on Mar 13 2011 3:57pm, edited 1 time in total.
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Re: 18650 Li-ion at $145 per KiloWatt Hour!

Post by grindz145 » Mar 13 2011 11:18am

Theres really no reason to break in cells of this type.even the high quality lico cells have low discharge rates.its a function of the cell impedance.if you're interested I'm building a 2+ kwh pack then these might make sense, but that's still a ton of cell terminations to make, not to mention the safety risk. Just things to consider.

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