Looks like the new 15ah headway are available

[BMI]

Any new news on the Headway 15AH cells? I remember reading a while back that Doc was getting 1-2 for testing? Sure like to see some specs, tests and pricing on these.

If you want the full specs just email me at info@lifetechlithium.com and I will send you the full specs and discharge curves. The discharge curves for these cells are just superb and are just as flat or even flatter than an A123 cell discharge curve.

 

[Doctorbass]

Any new news on the Headway 15AH cells? I remember reading a while back that Doc was getting 1-2 for testing? Sure like to see some specs, tests and pricing on these.

I never received any 15Ah cells

just the known 10Ah cells

Doc

 

[AndyH]

If you want the full specs just email me at info@lifetechlithium.com and I will send you the full specs and discharge curves. The discharge curves for these cells are just superb and are just as flat or even flatter than an A123 cell discharge curve.

Please consider this 'alternate means'.

From: Mail Delivery System [mailto:Mailer-Daemon@server.twg-server-1.net]
Sent: Saturday, November 21, 2009 9:32 AM
To: #####@satx.rr.com
Subject: Mail delivery failed: returning message to sender

This message was created automatically by mail delivery software.

A message that you sent could not be delivered to one or more of its
recipients. This is a permanent error. The following address(es) failed:

armin@ihug.com.au
(ultimately generated from info@lifetechlithium.com)
SMTP error from remote mail server after initial connection:
host as-av.iinet.net.au [203.0.178.180]: 554-inbound.icp-qv1-irony-in3.iinet.net.au
554 Your access to this mail system from 67.19.8.106 has been rejected due to the sending MTA's poor reputation. If you believe that this failure is in error, please contact the intended recipient via alternate means.

 

[liveforphysics]

luke was making the argument for how internal resistance is heating the cells at the rates he calculated using (I^2)R.

do we know that the heating is from classic ohmic heating or is internal resistance a different type of 'resistance' similar to active devices and not passive devices such as a resistor?

i am of the impression that the internal resistance is related more to the mobility of the electrolyte inside the cell or the mobility of the ions through the elctrolyte, and maybe the separator material too. i just have doubts that we can assume the relationship is the same as a passive device and corresponding ohmic heating. all jmho, interested in other ideas too.

I don't think cells are ohmic. The amount of predicted heating doesn't seem to closely correlate to the cell's equilibrium temperature. But it seems to a be good measure for predicting voltage output under a constant load.

Search for a test on RC forums performed about 6years ago with cells sealed up in a ziplock sitting under water in a calorimeter. It was NiMH or NiCd, I don't remember, but they measured very precisely the amount of heating vs the resting voltage drop. The tests all came out inside of 5% of what the calculated ohmic resistance heating would have predicted, and the 5% was on both sides of things, indicating it was inside the margin of error for the testing equipment.

 

[julesa]

I see two email problems there. Andy's sending mail server at 67.19.8.106 is listed as a source of spam at a dnsrbl called backscatter.org. If that's your server you should contact backscatter.org to get unlisted. And find out why they think you're a spam source. Or if it's your ISPs server (The Planet?), contact them and let them know that IP address is listed at backscatter.org.

The other problem is on Armin's side. Blocking email just based on a single dnsrbl listing is a bad policy. You don't know the people who run all the dnsrbls (some of them are nuts and flakes) and you're giving them the power to block your communications at a whim. If it's your ISP's policy I'd start looking for a new ISP.

 

[Lessss]

I wonder if Headway would make a 14AH cell if we asked them? After all they are not under contract for that size are they? Perhaps Call it the ES14?

 

[europa81]

Why aren't the specs and discharge curve published here ? Afraid of too much drooling ?

 

[patrickza]

Why is the price such a secret?

 

[swbluto]

luke was making the argument for how internal resistance is heating the cells at the rates he calculated using (I^2)R.

do we know that the heating is from classic ohmic heating or is internal resistance a different type of 'resistance' similar to active devices and not passive devices such as a resistor?

i am of the impression that the internal resistance is related more to the mobility of the electrolyte inside the cell or the mobility of the ions through the elctrolyte, and maybe the separator material too. i just have doubts that we can assume the relationship is the same as a passive device and corresponding ohmic heating. all jmho, interested in other ideas too.

I don't think cells are ohmic. The amount of predicted heating doesn't seem to closely correlate to the cell's equilibrium temperature. But it seems to a be good measure for predicting voltage output under a constant load.

Search for a test on RC forums performed about 6years ago with cells sealed up in a ziplock sitting under water in a calorimeter. It was NiMH or NiCd, I don't remember, but they measured very precisely the amount of heating vs the resting voltage drop. The tests all came out inside of 5% of what the calculated ohmic resistance heating would have predicted, and the 5% was on both sides of things, indicating it was inside the margin of error for the testing equipment.

It would be interesting if you had a link to this result. It'd be interesting to know how they determined the thermal capacity of the battery/cells, which would heavily affect the accuracy of their testing.

It doesn't seem like lead batteries follow an ohmic heating prediction, but they're special in other ways than other chemistries.

 

[swbluto]

I found this formula from a paper that analyzes heat generation in cells at http://www.nrel.gov/vehiclesandfuels/energystorage/pdfs/apesaran.pdf.

q = - I [T (dE/dT)] + I(E-V)

where:
q = heat generation rate (W)
I = current (A); I > 0 for discharge and I < 0 for charge
T = temperature (K)
dE/dT = temperature coefficient (V/K)
E = equilibrium cell voltage or open-circuit potential (V)
V = cell voltage or cell potential (V).

It seems heat does follow an ohmic heating prediction (the I(E-V) part), but the entropy decreases the amount of heat generation the greater temperature and current is so it's not all as straightforward as ohm's law would predict. It appears this model has an electric side (the right half) and a chemical side (The left half), which is what cells are. It's nice how that synthesis goes.

The experience for my observation had come from high temperature and high C-rate situations, where the cells seemed to be at least 50 degrees cooler than what ohm's law would predict.

I really wonder what the V in the V/K units for dE/dT represents. I didn't think voltage was a change in energy? Well, in any case, it seems a temperature coefficient would be something like change-in-energy/change-in-temperature would be Joules/K and not Volts/K.

But yet, the units seem to work out for the heat equation listed above.

 

[liveforphysics]

Why aren't the specs and discharge curve published here ? Afraid of too much drooling ?

Why is the price such a secret?

The cells were priced at $22 each from headways for the 2 days before they made an agreement to not sell them to anyone else.

As far as spec sheets and things go, the BMI guy likes to operate in a cloud of secrets and spy game type stuff. You gotta have a secret handshake and password. Then you can get emailed a graph of an A123 cell discharge test with the labels on things changed in photoshop to match whatever specs and cell model you asked about (it's a classic super-spy move to distribute as much dis-information as possible). I'm just giving him a hard time, seriously though, why on earth wouldn't you want to post up some spec sheets? (real would be even more cool).

It's strange to have a battery re-saler working so hard to fight against the grassroots electric revolution.

 

[BMI]

I see two email problems there. Andy's sending mail server at 67.19.8.106 is listed as a source of spam at a dnsrbl called backscatter.org. If that's your server you should contact backscatter.org to get unlisted. And find out why they think you're a spam source. Or if it's your ISPs server (The Planet?), contact them and let them know that IP address is listed at backscatter.org.

The other problem is on Armin's side. Blocking email just based on a single dnsrbl listing is a bad policy. You don't know the people who run all the dnsrbls (some of them are nuts and flakes) and you're giving them the power to block your communications at a whim. If it's your ISP's policy I'd start looking for a new ISP.

Thanks Andy and julesa for alerting me to this problem. I was aware that a few emails were not getting through but I thought the problem had been resolved. I will let my ISP know that a problem still exists.

 

[BMI]

Why aren't the specs and discharge curve published here ? Afraid of too much drooling ?

As far as spec sheets and things go, the BMI guy likes to operate in a cloud of secrets and spy game type stuff. You gotta have a secret handshake and password. Then you can get emailed a graph of an A123 cell discharge test with the labels on things changed in photoshop to match whatever specs and cell model you asked about (it's a classic super-spy move to distribute as much dis-information as possible). I'm just giving him a hard time, seriously though, why on earth wouldn't you want to post up some spec sheets? (real would be even more cool).

The website is still a work in progress and I haven't had the time to include all the technical information as yet.

It is the doubters such as yourself liveforphysics who seem to think that any information I provide such as discharge curves etc. are not real or have been altered in someway (as you claim in photoshop etc) who make me think why do I even bother to try to provide this information here? Perhaps I should go the same way as Don Harmon and not waste my time posting any information here anymore. I go to the effort to provide information here on ES since I would of thought many ES members would be interested in the latest developments in the LiFePO4 industry even if LiFeTech Lithium do serve the high quality/performance end of the market and are not in the affordability range for most people.
In the same way I still enjoy reading about the latest Ferrari even though I can only afford to drive a Toyota.

After all you may have forgotten but I readily provided 40138F1 cells to Doc for independant testing some months ago now so don't blame me for no published results from someone who you trust won't make alterations in photoshop when I have made these cells available (two test cells from two different sources from two different batches sent to Doc).
Of course after all this time the new 8Ah,10Ah,12Ah and 15Ah XPS cells have replaced the 40138F1 cells so it is not even worth publishing results of something which has been superceded by a newer, superior performing product.

 

[liveforphysics]

I applogize. I didn't know you had sent cells to DocBass. This is all we can ask from a vendor, to submit a sample to an independent tester like Doc.

I don't know why doc wont get off his ass and do some cell tests for us, but that's not your fault.

When a company sends a sample product to a trusted independent source for testing, it shows a lot about a persons faith in a product to perform as they claim, and does more to impress me than any amount of vender supplied datasheets could ever do.

Doc! Test cells! Pronto!

 

[BMI]

I applogize. I didn't know you had sent cells to DocBass. This is all we can ask from a vendor, to submit a sample to an independent tester like Doc.

I don't know why doc wont get off his ass and do some cell tests for us, but that's not your fault.

When a company sends a sample product to a trusted independent source for testing, it shows a lot about a persons faith in a product to perform as they claim, and does more to impress me than any amount of vender supplied datasheets could ever do.

Doc! Test cells! Pronto!

No problem. Apology accepted. One cell came came from my cell stock in Australia and the other cell was from stock mcstar kept in Texas.
There was a thread a while ago about aussiejester criticizing Doc for not publishing any test results after having test cells and testing equipment which members had donated the funds to Doc to purchase this equipment. Some members came to Doc's defence saying it was not his job to test cells and he would do it in his own good time. I am not here to criticize either way so long as people are aware that I made the cells available for testing (from memory about March/April) so as I say this was several months ago and these cells are no longer available having been replaced by the new XPS cells around August/September.
I am sure you can find the relevant threads concerning this is you do a search from a few months ago.

 

[AndyH]

I see two email problems there. Andy's sending mail server at 67.19.8.106 is listed as a source of spam at a dnsrbl called backscatter.org. If that's your server you should contact backscatter.org to get unlisted. And find out why they think you're a spam source. Or if it's your ISPs server (The Planet?), contact them and let them know that IP address is listed at backscatter.org.

The other problem is on Armin's side. Blocking email just based on a single dnsrbl listing is a bad policy. You don't know the people who run all the dnsrbls (some of them are nuts and flakes) and you're giving them the power to block your communications at a whim. If it's your ISP's policy I'd start looking for a new ISP.

My message was sent from my San Antonio Time Warner/Roadrunner account. The IP listed isn't one assigned to me by TW/RR. Thanks for the lookup. I made sure my business IPs were whitelisted but didn't think to check TW/RR's addresses...

 

[AndyH]

Physics - one tiny oversight oversight -- the cells sent were the 10Ah products made by PSI - not the new 15Ah cells made 'somewhere else'.

Armin - Doc has a 'real job' and a spousal associate - he tests on his own time. While I'm sure one could contract with him for testing, maybe Headway or someone at the Panjit Group could pony up some test results? Am I oversensitive, or might there be an attempt to redirect attention here?

 

[BMI]

Physics - one tiny oversight oversight -- the cells sent were the 10Ah products made by PSI - not the new 15Ah cells made 'somewhere else'.

Armin - Doc has a 'real job' and a spousal associate - he tests on his own time. While I'm sure one could contract with him for testing, maybe Headway or someone at the Panjit Group could pony up some test results? Am I oversensitive, or might there be an attempt to redirect attention here?

Of course I understand what Doc does is his own business. It was not me who was criticizing him. All I am saying is that there is no point in Doc testing a cell several months after he has received it and it has been replaced by an improved product.

It seems as though results published by Doc Bass are the only ones which are trusted since it is clear many members here don't believe anything which is provided by a manufacturer (or the belief that any information which is provided has been altered or changed in someway in photoshop). If people don't trust the results which have been available on manufacturer's websites for some time now then there is nothing I can do about that.

 

[tostino]

Well BMI there is good reason for not trusting everything a manufacturer says without independent testing. If we were to do that, TS cells would be used more than they are, because they look better on paper (the manufacturers paper that is) than reality shows. There are other instances of manufacturers slightly fudging data in their favor. I'd tend to believe a company like BMI/Headway over others, mainly because you did send out test cells, even if we didn't see the results yet, and you have a presence here.

I don't think anyone is trying to chase you off, or come off as rude.

And P.S. What happened to Don was his fault. He really tried to turn every battery thread into "lifebatt is better than this or that". It takes a certain fineness to not frock up customer relations on a public forum like this, and that is something Don did not have. There are plenty of vendors on here that can get along just fine, without turning everyone against them.

 

[BMI]

Well BMI there is good reason for not trusting everything a manufacturer says without independent testing. If we were to do that, TS cells would be used more than they are, because they look better on paper (the manufacturers paper that is) than reality shows. There are other instances of manufacturers slightly fudging data in their favor. I'd tend to believe a company like BMI/Headway over others, mainly because you did send out test cells, even if we didn't see the results yet, and you have a presence here.

I don't think anyone is trying to chase you off, or come off as rude.

And P.S. What happened to Don was his fault. He really tried to turn every battery thread into "lifebatt is better than this or that". It takes a certain fineness to not frock up customer relations on a public forum like this, and that is something Don did not have. There are plenty of vendors on here that can get along just fine, without turning everyone against them.

Tostino, I agree with your comments entirely.
Yes I agree that the vast majority of Chinese battery manufacturers claims about the performance of their products are lies.
I know I am honest about the products I supply but it makes it so much harder to convince people you are telling the truth when the customer has had bad experiences from other suppliers who have misled them and now they are wary as a result.
When I was providing BMI cells on ebay at least everyone could see I have 100% positive feedback and there was not a single negative customer comment regarding either the product I supplied or my service.
Perhaps some kind of similar reliability/honesty rating system for suppliers and manufacturers would be helpful here?

 

[AndyH]

Of course I understand what Doc does is his own business. It was not me who was criticizing him. All I am saying is that there is no point in Doc testing a cell several months after he has received it and it has been replaced by an improved product.

It seems as though results published by Doc Bass are the only ones which are trusted since it is clear many members here don't believe anything which is provided by a manufacturer (or the belief that any information which is provided has been altered or changed in someway in photoshop). If people don't trust the results which have been available on manufacturer's websites for some time now then there is nothing I can do about that.

It's easy to say something is improved but with no data at all to back it up, it's just smoke and mirrors. There are numerous requests for information in this thread and all of them have been ignored. The only tech info on your site is discharge C ratings. The data on the LiFeTech page has only a 5C 10Ah cell. I found a single reference to cell testing in an article about Panjit Group's purchase of LiFeBatt Productions/LiFeTech but it was reference to US testing of cells made by PSI.

You said that you would provide data on request. You have requests. Do you have data?

 

[The Mighty Volt]

The surface area to radiate heat is a non-factor for the methods used in typical Ebike pack construction which encloses the cells. If you wanted to make cells cool better, its not the surface to worry about, but rather using some passive or active system to encourage airflow. Otherwise internal pack temps act like a closed system with the outside pack material (often very insulative) exchanging heat with the air around the pack.

The much better way to control cell temps is by having low Ri.

If these cells are 10mOhm, it means when pumping out 100amps, there is 100w of heating for the cell.

If they are 5mOhm cells, then 50w of heat.

If 2.5mOhm cells, then only 25w the amount of heat.

If 1mOhm cells, then just 10w of heat, but generally it would take Lipo cells to see that from only 15Ah.

Okay then, here is where I wanted to ask a question....Suppose I "P" , say, three of these cells into a 45Ah pack.

Now to get 100Amps the C rate is reduced from 6.66 to 2.22 recurring.

But the physical mass of the system has increased three fold, which would increase, presumably, resistance.

THUS: where is the happy medium between keeping C rates low, and keeping internal resistances low, with a view to keeping heat dissipation as low as possible.

I hope this makes sense.

Thanks.

 

[Kin]

^I think that is not the right way to think of it. Because although you are "increasing" the sum total of the internal resistances, you are also dividing the amount of current that is going through each battery. Basically, all things considered, it's the same thing.

From what limited amount I understand about batteries, I do believe there is some relation between what C you're pulling and the resistance from the cell. A 6.66C rating will have more heat wasted because the internal resistance should be slightly higher at 6.66c than 2.22c. Within the operating parameters (of 10C) this might be marginal, though.

 

[ninjamik]

I have just received a set of 12, (36ah pack) headway 42160 15ah's...I bought them before joining E.S...( i just went for the highest AH lifepo4 for the best cost)....I too have been trying to find out the verdict on these cells, as my build to test them is still just beginning....I also want to know if it would be possible to series them up with an a123 pack? say(36v) for a total 72v pack output.
if anyone would like the specs on them i can give you the "manufacturer ones" 150a discharge 60a charge (peak I think)...each cell is 3.3v...i may have had a little dyspraxia and got the 5 and 6 the wrong way round in that...
they're in the workshop atm.

so did the doc never get any then?? i may be able to arrange getting the meter out for some testing....but i am a little new to e-bike battery tech!..my dads a qualified electrician though so i'm sure it may be possible..(god i sounded like a kid then hehe

gotta build my pack first I bought it as a DIY kit with BMS..so i can change the construction method to get a much more aesthetically pleasing/aerodynamic shape to a power brick..

I promise i don't work for a battery manufacturer i'm just a e-bike enthusiast with his own build on...