A123 System cells.

[65535]

cane be had at horizonhobby.com, and they are coming out with you guessed it 18650 sized cells in 2 packs, for outrageous amoutns of electricity. For the story:

This weekend is the RCX (Remoted Controlled Expo) and A123 decided to send a couple reps. to go to horizon hobbies booth, well after talking for 15 minutes I feel enlightened more about lithium cells, A123 systems will not ignite without external combustion, they have excellent high current charging and discharging capacity, 30C continuous and 60C intermitten. Plus 5C charging you heard right 15 minute charging. They have their standard large cell, but are also going into smaller 18650 sized cells, but for the bad news they are only 1.1mAh capacity, so you basically are getting 17500 performance, but on the bright side you can drain them at up to 33amps continuous, and 66 intermitten, and for you USL guys the larger cells can sustain 69 amps and peak at 138 amps, so now you have the ultimate 15 minute charge 2 minute discharge extreme light, with 100's of cycles. They currently aren't pracitcal for long runtime lights, but are excellent for Show offs and other high short drain usage.

QUestions?

 

[LuxLuthor]

How much $$$ ?

 

[65535]

They are pricey, single cells are just under $17, they haven't released 18650 prices yet.

 

[AndyTiedye]

Does an A123 26650 fit in a C-sized Maglite? (It's longer than a C, I know, just wondering about the diameter).

 

[DMC]

http://www.a123systems.com/html/products/ANR26650M1specs.pdf

25.85 mm x 65.15 mm

 

[luckybucket]

Just ordered 8 of the 26650 cells from batterystation.com and they came shrinkwrapped in green plastic. They look exactly like the picture at battlepack.com. I was gonna order from battlepack, but they didn't have the charger and adapter I needed so I ordered from batterstation. I got great service and they showed them in the standard cardboard they use in the dewalt battery packs even though they came shrinked.

Just thought people should know. And yes, they fit perfectly in my C cell light which is about 2.5 years old.

 

[Russel]

The best place that I've found to purchase 2300mAh A123 cells is the Dewalt DC9280 battery pack from Toolking.com The packs are occasionally on sale at a discount. I purchased one for 39.99 plus tax and shipping, adding up to about $50. The pack contains 8 cells, so that comes to $6.25 a cell.

 

[luckybucket]

Now that's a low price! The website states it is sold out and I bet that happens a lot. I tried to find that particular product just by browsing the website and even found a link for 28v dewalt batteries but it says no items to list. I think I checked that site a long time ago but only looked at the 36v models and saw a more normal price so I stopped browsing.

 

[bshanahan14rulz]

You see 'em on ebay from time to time...

 

[jasonck08]

What lights do you guys use these in? I assume mostly modded maglites, but which what bulbs / LED's?

I'm interested in testing some of these out, because I have heard so much good about them!

 

[Battery Guy]

The best place that I've found to purchase 2300mAh A123 cells is the Dewalt DC9280 battery pack from Toolking.com The packs are occasionally on sale at a discount. I purchased one for 39.99 plus tax and shipping, adding up to about $50. The pack contains 8 cells, so that comes to $6.25 a cell.

Get them while you can. Black and Decker is dumping A123:

http://batteryfeeds.com/index.php/e...nd-decker-just-not-that-into-a123-lately-aone

Why? Because the competing power tool manufacturers and beating their pants off using high power lithium-ion cells made with more conventional cathode materials.

The only reason to use A123 cells is if you are concerned that you might overcharge your lithium-ion cell. If you want that peace of mind, then by all means go for the A123 cells. However, from a performance standpoint, they have substantially lower energy density (Wh/l) and specific energy (Wh/kg), and high power cells from Bosch, Milwaukee and others beat the A123 cells with respect to power capability.

Here is a Ragone Plot for cells removed from various power tool battery packs:

Cell sizes:

Milwaukee Ni-Cd: sub C
Milwaukee Li-ion: 26650
Bosch Li-ion: 18650
DeWalt Li-ion: 18650 (A123 cells)

Because the cells are different sizes, I have plotted energy density and power density for an apples-to-apples comparison.

I think the results speak for themselves. You may be interested to note that I maxed out my cell testing system on the Bosch 18650 cell at 45 W, and the cell still delivered 4.3Wh out of a total of 5.0Wh. Not too shabby!

So if you want to harvest high power lithium-ion cells out of power tool packs, I would look to Bosch and others if performance is your primary concern and if you know how to charge lithium-ion cells.

And as far as the longer cycle life goes, you can get the same cycle life out of high quality, conventional lithium-ion cells simply by charging to a lower voltage. Charge a conventional, high quality 18650 to 4.0 V and you will still have more energy than an A123 18650 cell, and you will get awesome cycle life.

Cheers,
Battery Guy

 

[Russel]

The nice thing about A123 18650 cells is that I can routinely charge them at 5 amps and discharge them at continuously at 30 amperes. The 26650 cells can be charged at 10 amps and discharged continuously at 70 amperes.

The way that I use the cells, short charge times and high continuous output current are more important than a slightly lower energy density. My tipical discharge is 4 to 8 minutes followed with an 8 to 15 minute charge.

A123 cells are absolutely amazing! They are incredibly durable when used at extreme current levels.

I agree though, for applications that don't require high current levels there are other choices that provide better energy density.

 

[Battery Guy]

The nice thing about A123 18650 cells is that I can routinely charge them at 5 amps and discharge them at continuously at 30 amperes. The 26650 cells can be charged at 10 amps and discharged continuously at 70 amperes.

The way that I use the cells, short charge times and high continuous output current are more important than a slightly lower energy density. My tipical discharge is 4 to 8 minutes followed with an 8 to 15 minute charge.

Take a very hard look at the Ragone plot. The cells from the Bosch and DeWalt (A123) packs are both 18650 cells, so you can do a direct comparison.

At a 40W continuous power discharge, the Bosch provides 4.38Wh and the A123 cell provides 2.3Wh.

A123 cells are absolutely amazing! They are incredibly durable when used at extreme current levels.

I suggest that you try high power lithium-ion cells from some other manufacturers. For example, the Sanyo 1500 mAh cells, or just go out and buy a Bosch lithium-ion pack and try those cells. I suspect that you be very surprised at how much they out perform the A123 cells. Seriously, take a look at the Ragone plot that I posted in this thread. It is very hard to argue with that data.

I agree though, for applications that don't require high current levels there are other choices that provide better energy density.

Well, I certainly agree that A123 has amazing marketing. They also have great connections to the US government, which is why US tax payers are subsidizing them by the hundreds of millions of $$$. However, the performance of their existing product is substandard by any metric.

Cheers,
Battery Guy

 

[jasonck08]

The Sanyo IIRC is NCM Chemistry, which contains lithium colbalt and lithium maganese oxide. Much safter then LiCo, but not as safe as Lifepo4.

I think the advantage A123 has is for more industrial applications such as hybrid cars. Some of there batteries have done 8,000 cycles before failing. But typically do 2,000 cycles max.

Where NCM cells are rated at 300-500 cycles.

 

[Russel]

Take a very hard look at the Ragone plot. The cells from the Bosch and DeWalt (A123) packs are both 18650 cells, so you can do a direct comparison.

At a 40W continuous power discharge, the Bosch provides 4.38Wh and the A123 cell provides 2.3Wh.

I discharge 3S 1100 mAh A123 packs at 70 watts, it looks like the Bosch cells might be able to do that and offer more capacity. What is the maximum charge rate?

I suggest that you try high power lithium-ion cells from some other manufacturers. For example, the Sanyo 1500 mAh cells, or just go out and buy a Bosch lithium-ion pack and try those cells. I suspect that you be very surprised at how much they out perform the A123 cells. Seriously, take a look at the Ragone plot that I posted in this thread. It is very hard to argue with that data.

How fast can Sanyo 1500 mAh cells be charged? That is one of the important characteristics of A123 cells I appreciate. I charge 18650 A123 cells at 5 amps. Is this the Sanyo 1500 mAh cell you are talking about? I can't find any 1500 mAh Sanyo cells that can be charged fast. Can you post a link to the ones you are refering to?

 

[jasonck08]

Those Sanyo's can be charged at up to 3A... But its recommended to charge them at 1.5A.

 

[Battery Guy]

The Sanyo IIRC is NCM Chemistry, which contains lithium colbalt and lithium maganese oxide. Much safter then LiCo, but not as safe as Lifepo4.

That particular Sanyo cell uses a blend of two different cathode materials: NCM and manganese spinel.

I think the advantage A123 has is for more industrial applications such as hybrid cars. Some of there batteries have done 8,000 cycles before failing. But typically do 2,000 cycles max.

Where NCM cells are rated at 300-500 cycles.

With respect to both safety and cycle life, it is important to note that the A123 cells have substantially lower total energy than other lithium-ion cells. If you were to charge a Sanyo 1500mAh cell to the same energy as the A123 cell, it would exhibit similar safety characteristics and the cycle life would be amazing.

The advantage that A123 has is that the cell cannot be overcharged. Apparently they can also be charged REALLY fast for a lithium-ion battery. Russel indicates that they can be charged at a 4C to 8C rate, which is truly phenomenal for a lithium-ion cell. I know they had been making claims about rapid charging, but this is the first time I heard independent confirmation.

So, the advantages of A123 are that they can be charged quick and cannot be overcharged. The price you pay is 1.6x-3X lower energy.

Cheers,
Battery Guy

 

[Battery Guy]

I discharge 3S 1100 mAh A123 packs at 70 watts, it looks like the Bosch cells might be able to do that and offer more capacity. What is the maximum charge rate?

I honestly don't know what the maximum charge rate on the Bosch cells is, or even who makes them. However, I would not think that they can be charged in 8 to 15 minutes like you are doing to the A123 cells. Quite frankly, I am not aware of any lithium-ion cell that be charged that fast repeatedly and not have problems with lithium plating. So if you are able to do that with the A123 cells and are not seeing reduced capacity, then the A123 cell may be your best bet if rapid charging is critical for your application.

How fast can Sanyo 1500 mAh cells be charged? That is one of the important characteristics of A123 cells I appreciate. I charge 18650 A123 cells at 5 amps. Is this the Sanyo 1500 mAh cell you are talking about? I can't find any 1500 mAh Sanyo cells that can be charged fast. Can you post a link to the ones you are refering to?

Yes, those are the cells. The specification says they can be charged at a 1C rate, and I tend to follow manufacturers specifications. jasonck08 says they can be charged at 2C (3A), but I don't have first hand experience doing this or measuring how this would affect cycle life.

I think you got me on this one. Yours might be the first application where I am convinced that A123 cells are the best choice, given your rapid charging requirements. Both the Sanyo 1500mAh and Bosch cells would give you more run time, but neither of them can or should be charged as fast as you are charging the A123 cells.

Cheers,
Battery Guy

 

[jasonck08]

Yes, those are the cells. The specification says they can be charged at a 1C rate, and I tend to follow manufacturers specifications. jasonck08 says they can be charged at 2C (3A), but I don't have first hand experience doing this or measuring how this would affect cycle life.

One trend I've noticed with the Sanyo datasheets is that if it says "Standard charge rate" then you double that for the max charge rate. I've seen data sheets that confirm that for other Sanyo cells. But this one may be an exception. I'm just assuming that it can be charged at 2C, but that statement is still speculation at this point based on previous datasheet trends.

----------------

Also one advantage I see for A123 cells is that since its a Lifepo4 cell you don't really need to worry about balanced charging, as the cells don't care if they are over charged by a little bit. So this makes the electronics associated with A123 battery packs cheaper and easier to manufacturer vs other li-ion cells.

Did the Sanyo 1500's have a balancing circuit in the boch pack you opened?