Testing the big 15 and 20Ah LiFePO4 cells is tough! *Pics*

[liveforphysics]

I got a chance to go over one of the large packs that a123 uses and it seems that they sandwich the cell between two sheets of aluminum for heat syncing. and between each of those sandwiches ~~mmmm, lithium sandwich~~ there is a layer of a neoprene like material to allow for expansion. I was told that the cells can expand about 10%, have you seen anything like that in your tests?

I've not personally measured or observed any cell expansion, but I've not been looking for it either. I assume the expansion is purely a thermal thing, and not related to SOC?

I will sandwich a cell between some of my fancy carbon fiber sheets, heat it up, and document a rate of thermal expansion.

Luke, my hats off to you! Stunningly great test, the thermal images are priceless. Glad the FET switcher electrically held together. Sure appears that without any doubt these cells are the real deal

Ohhhh, how I love the aroma of high power electronics in the morning

Ah, I really like the thermal images Luke, can you share which model Fluke Imager that is? What's the interface to get the thermal images out of it? How flexible is setting up the image to print the localized temps over the thermal map? The more I look at your pix, the more fascinated I am with the images.

It's this little guy:

http://www.tequipment.net/FlukeTi40FT.html

With one click you can set it to lay a grid over any IR image that shows the temps at every interval spacing that you set. It always makes the IR photo look like a spread-sheet with a colored background though. lol Otherwise, you click the "manual temp tag" button in the fluke software after the image is on your computer, and it throws a temp ID marker anywhere you click, so it's just as quick and easy as clicking a mouse.

Focus is bizzare with IR, and the angle you hold the camera in relation to the object you're viewing can cause some bizzare artifacts that show up as silver-grey blocks. I'm actually a certified Infrared Thermographer. lol It just means you sat through a couple 8hr classes while a bone-head instructor talks to you like you've never before heard of the concept of wavelength and emmisivity... On the bright side, I think at the end of the course, the instructor had a better understanding of the subject he was teaching. I politely asked a couple of questions that lead him toward gaining a deeper grasp of the subject he taught.

For things that fit into my lunch bag, it's very easy for me to get IR pics of them if you have anything you want to see in action. It's a high security datacenter, so it's very tricky to bring in larger things like cell testing equipment lol, but small things are cake.

 

[bigmoose]

Nifty, do you recall which lens you used on the TI40FT? The 10mm/20mm/54mm? Which lens would you recommend for general electronics work with a filed of view say 12x12 inches.

 

[liveforphysics]

I've got the 20mm, and I have to almost stand on my tippy-toes and hold the thing way up high to focus in on a 12x12" area. It's less than ideal for close-up electrical board inspections.

We have it because in a datacenter, we've got about 100,000 or so screw-lug terminals for power on critical equipment. With the IR gun, you open up an electrical box with hundreds of connections, make a quick scan over the connections, and if you've got a loose one somewhere, it sticks out like a sore thumb, and can be tightened down as needed before it becomes an issue.

I would recommend trying to find one on Ebay used for cheap if you're looking to buy one for personal use. We trained on some units that were only like $6,000usd new in the IR training class, and they honestly did everything this unit does that costs twice as much. They don't have any moving parts in them (no shutter!), so it's not like a used one will be worn out or something.

 

[liveforphysics]

I checked out the specs on this little guy:

http://www.dotmed.com/listing/777286?utm_source=base&utm_medium=search&utm_campaign=Base

It's 1/16th the price, and on paper at least, it looks like it would do equally as good of a job as the fancy one I've got at work. Those FLIR I40's are normally about $4,500-5000usd, so at $850, I would jump on that if you're serious about getting one.

Even if it's off by 5deg or something, it doesn't really matter too much for electronics work, because the emissivity differences on the surfaces of the parts are going to give a few percent margin of error for any IR imager, and the most important part is finding the relative differences between hot and cold areas, which is something they will all do accurately.

 

[johnrobholmes]

Boy, these cells look like just the ticket for about 99% of the people wanting high power!

 

[liveforphysics]

Boy, these cells look like just the ticket for about 99% of the people wanting high power!

Yeah, it really makes a lot of sense for the power nuts, as well as the commuter EV guys. It's like having ~80% of LiPo performance capability, but in a safety chemistry, and with some insane cycle life like 8,000. lol In the long run, for a commuter EV, it's absolutely the most economical choice in battery by a long shot, as well as a very high performance battery for the folks who are performance nuts, or folks who just want a light weight bike with a ton of range.

Just a damn good product. I'm freaking pumped about these!

 

[CroDriver]

Boy, these cells look like just the ticket for about 99% of the people wanting high power!

Yeah, it really makes a lot of sense for the power nuts, as well as the commuter EV guys. It's like having ~80% of LiPo performance capability, but in a safety chemistry, and with some insane cycle life like 8,000. lol In the long run, for a commuter EV, it's absolutely the most economical choice in battery by a long shot, as well as a very high performance battery for the folks who are performance nuts, or folks who just want a light weight bike with a ton of range.

Just a damn good product. I'm freaking pumped about these!

I was playing with the cells and figured out that I can place 60 kWh of this cells under my car!! The pack would be just 8 cm thick and fit between the wheels. I can even make a second pack and swap them for long distance races

 

[liveforphysics]

Boy, these cells look like just the ticket for about 99% of the people wanting high power!

Yeah, it really makes a lot of sense for the power nuts, as well as the commuter EV guys. It's like having ~80% of LiPo performance capability, but in a safety chemistry, and with some insane cycle life like 8,000. lol In the long run, for a commuter EV, it's absolutely the most economical choice in battery by a long shot, as well as a very high performance battery for the folks who are performance nuts, or folks who just want a light weight bike with a ton of range.

Just a damn good product. I'm freaking pumped about these!

I was playing with the cells and figured out that I can place 60 kWh of this cells under my car!! The pack would be just 8 cm thick and fit between the wheels. I can even make a second pack and swap them for long distance races

OMG! That's the biggest EV pack I've ever heard of! Anytime you add weight to a car below the roll center of the car (determined by the suspension layout design and wheel height), you cause that part of the car to be countering the rest of the car's natural body-roll effect. In theory, an EV with it's pack super low like this could have extremely level handling through corners with out the need for loads of anti-sway bars and excessively stiff spring rates. That would be a big handling advantage.

If you road-race anything like I do, you had better slap a big ass sheet of CF or Titanium or something over the cells through! I cut every damn corner, drive over all the turn markers, blast through the dirt and gravel when I botch turns etc. lol I always thought I was a pretty big road-racing cheater until I went to watch American LeMans at Laguna Seca. I snapped some pics of those guys in lowered Ferrari's, Porsche's, GT1-2-3 cars, all flying off the damn corkscrew, cutting the entire turn out, and rallying it down the rocky dirt hill like a damn 4x4's. lol Sparks flying, rocks flying, bits of front-lips and rear diffuser carbon fiber laying all over the damn place. lol

Protect that pack if you're going to stick it down there.

 

[CroDriver]

OMG! That's the biggest EV pack I've ever heard of! Anytime you add weight to a car below the roll center of the car (determined by the suspension layout design and wheel height), you cause that part of the car to be countering the rest of the car's natural body-roll effect. In theory, an EV with it's pack super low like this could have extremely level handling through corners with out the need for loads of anti-sway bars and excessively stiff spring rates. That would be a big handling advantage.

If you road-race anything like I do, you had better slap a big ass sheet of CF or Titanium or something over the cells through! I cut every damn corner, drive over all the turn markers, blast through the dirt and gravel when I botch turns etc. lol I always thought I was a pretty big road-racing cheater until I went to watch American LeMans at Laguna Seca. I snapped some pics of those guys in lowered Ferrari's, Porsche's, GT1-2-3 cars, all flying off the damn corkscrew, cutting the entire turn out, and rallying it down the rocky dirt hill like a damn 4x4's. lol Sparks flying, rocks flying, bits of front-lips and rear diffuser carbon fiber laying all over the damn place. lol

Protect that pack if you're going to stick it down there.

You're right, I'll have to protect them really good. Maybe with a few sheets of carbon fiber (isolated of course).

Btw. One thing I definitely have to do in my life - come to Laguna Seca and drive trough that corkscrew. Hell of a track.

Thanks for the test Luke, you're a big help

 

[liveforphysics]

My pleasure Mate I'm just down for anything that helps the EV revolution, as well as being a lover of all racing. That means I'm double aligned with your cause Mate.

-Luke

 

[olaf-lampe]

I was playing with the cells and figured out that I can place 60 kWh of this cells under my car!! The pack would be just 8 cm thick and fit between the wheels. I can even make a second pack and swap them for long distance races

That is roughly $45k for one pack
Is it for hobby racing or professional? I hope you have a good sponsor
Charging would take 8-10h with a 3~ charger and a whole weekend with a single phase charger :lol:

-Olaf

 

[CroDriver]

I was playing with the cells and figured out that I can place 60 kWh of this cells under my car!! The pack would be just 8 cm thick and fit between the wheels. I can even make a second pack and swap them for long distance races

That is roughly $45k for one pack
Is it for hobby racing or professional? I hope you have a good sponsor
Charging would take 8-10h with a 3~ charger and a whole weekend with a single phase charger :lol:

-Olaf

I would rather have a 1000 hp EV that I have built than a Buggati Veyron for 4 times the money. I could build the fastest and strongest EV ever. I think it's worth that $200-300k

Besides that, electric cars are the future so it's more like investing in research than just spending.

 

[jkirkeboe]

I was playing with the cells and figured out that I can place 60 kWh of this cells under my car!! The pack would be just 8 cm thick and fit between the wheels. I can even make a second pack and swap them for long distance races

That is roughly $45k for one pack
Is it for hobby racing or professional? I hope you have a good sponsor
Charging would take 8-10h with a 3~ charger and a whole weekend with a single phase charger :lol:

-Olaf

Uh, 8-10h ? Pretty low voltage and amps then ? The emerging standard for 3~ charging in Europe is 400V 63A, approx. 40kW. Charging time would then be 1.5 hours

 

[peterperkins]

Great discharge testing data. Thanks

Question though.

My application requires the cells be able to stand 50A charge current for several minutes at a time. How do we think they will hold up under that? Can you test it?

I need 100A discharge and 50A charge capability for my pack.

BMS will obviously prevent them going over or under V during use.

 

[jonescg]

I snapped some pics of those guys in lowered Ferrari's, Porsche's, GT1-2-3 cars, all flying off the damn corkscrew, cutting the entire turn out, and rallying it down the rocky dirt hill like a damn 4x4's. lol Sparks flying, rocks flying, bits of front-lips and rear diffuser carbon fiber laying all over the damn place...

Or if you're Rossi, you just cut through the corkscrew, overtake Casey on the dirt and win the race... and no-one complains 'cause you're Rossi :wink:

 

[cell_man]

Great discharge testing data. Thanks

Question though.

My application requires the cells be able to stand 50A charge current for several minutes at a time. How do we think they will hold up under that? Can you test it?

I need 100A discharge and 50A charge capability for my pack.

BMS will obviously prevent them going over or under V during use.

I haven't got anything here that will give that kind of current at the required voltage. I'm sure A123 26650s are rated for over 4C charge and 3.85V at the terminals during fast charge but proper info on these cells is a bit thin on the ground. I charge the 15Ah cells at 20A and the terminal voltages look very similar to what they do at 5A. I really cannot see an occasional 50A chrge causing any problems to be honest but I would like to hear some others thoughts.

 

[liveforphysics]

I snapped some pics of those guys in lowered Ferrari's, Porsche's, GT1-2-3 cars, all flying off the damn corkscrew, cutting the entire turn out, and rallying it down the rocky dirt hill like a damn 4x4's. lol Sparks flying, rocks flying, bits of front-lips and rear diffuser carbon fiber laying all over the damn place...

Or if you're Rossi, you just cut through the corkscrew, overtake Casey on the dirt and win the race... and no-one complains 'cause you're Rossi :wink:

With the amount of sack required to attempt that move, I'm suprized Rossi is able to walk.

[youtube]ZQ7sNEtYzlc[/youtube]

Great discharge testing data. Thanks

Question though.

My application requires the cells be able to stand 50A charge current for several minutes at a time. How do we think they will hold up under that? Can you test it?

I need 100A discharge and 50A charge capability for my pack.

BMS will obviously prevent them going over or under V during use.

My E-bike's LiPo pack's chargers can do 53amps continous, but I think 32v is the lowest voltage I can dial it down to. I could throw a discharged section of my E-bike pack in series with one of the cell_man cells and see what happens letting it charge at 50amps.

I've been normally charging them at 20amps, and they don't ever seem to even get warm or have any effect from it, so I wouldn't think 50amps should be much different.

 

[AussieJester]

^^ not one of Rossis finer moments IMHO, he is still without doebt the best rider of the modern era...possibly ever...

This is not the best footage of it Luke, but check the first video out on this url

Video: Rossi Vs Lorenzo – Catalunya, final corner pass:

THAT is the best pass i have ever seen in MotoGP in awhile... Last lap last corner ~200clicks room to fit the front tire is all The Doctor needs

STONER FTW in 2010! he should of pwned Rossi in 2009 if it wasn't for 'mystery' illness half season...Hes the only rider in MotoGP that can ride the Ducati to the limit...and beyond...hehee

KiM

 

[liveforphysics]

I would rather have a 1000 hp EV that I have built than a Buggati Veyron for 4 times the money. I could build the fastest and strongest EV ever. I think it's worth that $200-300k

Besides that, electric cars are the future so it's more like investing in research than just spending.

Agree 100%.

You can spend a hell of a lot more money and end up with less car by buying most any of the supercars on the market.
My civic beats most all of the supercars out there for 5-10% of the price.

With these cell_man cells making the cycle life and weight and volume of an electric car so damn good, it's got me thinking hard about doing my own electric racecar. Something as light as I can make it with as much battery and motor as I can tuck into it.

 

[olaf-lampe]

With these cell_man cells making the cycle life and weight and volume of an electric car so damn good, it's got me thinking hard about doing my own electric racecar. Something as light as I can make it with as much battery and motor as I can tuck into it.

How about our thorr? ( http://www.thorr.eu )
We are currently building a 75kW/150kW peak version and next will be a nominal 200kW/250kW peak version. Weights less than 700kg.

 

[liveforphysics]

With these cell_man cells making the cycle life and weight and volume of an electric car so damn good, it's got me thinking hard about doing my own electric racecar. Something as light as I can make it with as much battery and motor as I can tuck into it.

How about our thorr? ( http://www.thorr.eu )
We are currently building a 75kW/150kW peak version and next will be a nominal 200kW/250kW peak version. Weights less than 700kg.

OMG!!! Lotus7 style cars are my most favorite sportscar in the world!!!
The 200/250kw version is screaming my name!!!

Why on earth did I never hear of this car before???

Please PM me with price

-Luke

 

[olaf-lampe]

Why on earth did I never hear of this car before???

Because US media doesn't cover good ol' europe too often

Pricing starts at 55k€ but the option list is looong

No just kidding, we only built one car as a testplatform for our own developments. But there is a guy who has designed the EV frame version for us. Maybe he is willed to sell kits to the new world

-Olaf

 

[pm_dawn]

Hi !

No offense to you Olof.
@LFP: please take glance over at the Metric-Mind home page before ordering a thorr.
http://www.metricmind.com/audi/14-battery.htm at the bottom.
also
http://www.evdrive.com/BMW_project/specifications.html

They might have straightened up their business by now.

Best Regards
/Per

 

[olaf-lampe]

Hi !

No offense to you Olof.
@LFP: please take glance over at the Metric-Mind home page before ordering a thorr.
http://www.metricmind.com/audi/14-battery.htm at the bottom.
also
http://www.evdrive.com/BMW_project/specifications.html

They might have straightened up their business by now.

Best Regards
/Per

You're right Per, we were in trouble. But since last year september we have new investor
But the guy who builds the thorr frames has nothing to do with the evisol story anyways...

-Olaf

 

[pgt400]

These cells have fantastic specs...would love a 24S3P pack of 20AH units for my bike. But so pricey right now, hope they get cloned soon