The LiFePO4 Headway cell 38120P TEST REPORT inside

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Doctorbass   100 GW

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The LiFePO4 Headway cell 38120P TEST REPORT inside

Post by Doctorbass » Feb 13 2008 2:22am

I received 3 LiFePO4 38120 cell of 3.2V 8.0Ah.

I will test those 3 identicals cells with my lab equipment soon and will post some true specs. I asked 3 for having better and realistic results acuraccy.

Here are some spec from Headway:

Oem specs
3.2V
8.0Ah
300g = 85.3Wh/kg
25.6Wh/cell
80A continuous
160 peak
2.8mohm


See the pics:


Doc
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Last edited by Doctorbass on Apr 02 2008 10:28pm, edited 2 times in total.
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Re: The 38120P cell from Headway

Post by drewjet » Feb 13 2008 5:50am

This should be interesting!

Do you have a price and source for them?

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Re: The 38120P cell from Headway

Post by Ypedal » Feb 13 2008 7:40am

:shock:

woooooo.. looks nice !

Testing, testing.. 1... 2... testing !.... :wink:
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Re: The 38120P cell from Headway

Post by fechter » Feb 13 2008 10:40am

I can't think of a better person to test them. :twisted:

Do you have any idea what the price on those will be?
"One test is worth a thousand opinions"

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Re: The 38120P cell from Headway

Post by RLT » Feb 13 2008 11:54pm

Dang!
Lately, I've been working with some 32650 'old style chemistry' LiIons rated at 3.6V 5000 mAH, /2C (4.8 AH @ < @ 5A or under and .... 3.8AH @ 12A, actual, according to my CBA) , and thought the ~$12.50 (including shipping from China) I paid for them, made them the best AH per dollar deal available,.... I have 30 now, ordered another 60 of them a month ago; (Should be here next week or so.)

Wish I'd known about these. Price is competitive; safer chemistry and better high current capacity. I sure wish I had bought 60 of these instead.

Hope they turn out to be as good as they sound!

If so, I'm afraid I'm going to spend another thousand dollars on batteries.

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Re: The 38120P cell from Headway

Post by OneEye » Feb 14 2008 1:52pm

Where are these available commercially?

I assume that someone sent them to you for independent testing to verify their claims as they market them to the masses...but we couldn't find them available for purchase after the ZEVA reports on these cells came out. Maybe I'm not looking in the right places though.

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Re: The 38120P cell from Headway

Post by recumbent » Feb 15 2008 2:43am

Nice format size, and at $18.00 per cell, nice price.
Only 1000 cycle lifespan, maybe the chemistry needs a little tweeking.
Still, the cost benefit is worth overlooking some of the negatives.
Ebike in use:
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Power: 58V, 16 amp/hr, lipo batteries.
max speed: 52 km/h (30 mph),
max range: 40 km's, incl stop&go few times, minimal pedaling.
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Re: The 38120P cell from Headway

Post by A1234LIFE » Feb 19 2008 10:01pm

Hey Doc,

Any progress on the testing for these cells?

Steve

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Re: The 38120P cell from Headway

Post by Doctorbass » Feb 19 2008 10:35pm

I'm designing a 50A constant current load to add parallel to my cahrger that only disch to 5A.
when i will finished it i will begin the tests.

from now, i did a short test just for fun about capacity at 5A disch and the internal resistor.

i measured 8230mAh from a fully charged cell at 23 degree C at 5A down to 2.5V the nominal is 8Ah :)

Also i tested 6mohms instead of the 2.8 mohms from the nominal spec :|
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Re: The 38120P cell from Headway

Post by A1234LIFE » Feb 20 2008 12:03am

Great. Thanks for the update. I have my doubts about the cells being able to handle a 10c continuous discharge, but if they could handle 5 or 6c continuous discharge that would be great. Some tests with a 50 amp load is exactly what I am interested in.

Steve

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Re: The 38120P cell from Headway

Post by Ypedal » Feb 20 2008 8:29am

Hey Doc

When you have the time, do me a favor, put one in the oven, or heat it up to 35 celcius and do the same test for IR.. :?
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Re: The 38120P cell from Headway

Post by Doctorbass » Feb 20 2008 11:06am

Ypedal wrote:Hey Doc

When you have the time, do me a favor, put one in the oven, or heat it up to 35 celcius and do the same test for IR.. :?
In the oven?? :shock:

Ypedal.. my oven can only stabilizt starting to 70C...

I have a vetter and secure ides.. the top of a computer CRT screen or the fan output of a pc power supply when playing to need for speed underground at 1280x1024 :wink:

or maybe my Jobmate heatgun using my IR thermometer :wink:

but an oven... :!: ischhh...!
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Re: The 38120P cell from Headway

Post by Doctorbass » Feb 20 2008 11:11am

Also.. about the IR, i observed that it is not only the heat that affect it!

If you measure it immediatly after charging it, it will be higher then i you leave it few hour after charging and then measuring it!

To be valid and accurate, Capacity and IR need to be taken to a very close range of environmental and process parameter!!
that is actually the most difficult to acheive about my 360 Li-Mn Konion cells.... i measure around 15-20 a day at 5A disch but the temperature of my room affect the results...

Doc
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-Succeded to haul a 19200 pounds schoolbus!
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Re: The 38120P cell from Headway

Post by TylerDurden » Feb 20 2008 11:39am

Image
"Bonnet Dryer"

Mix cool air as needed for stable temperature over long periods.
Have a Nice Day,

TD

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Re: The 38120P cell from Headway

Post by Ypedal » Feb 20 2008 12:11pm

Geeeeez... you sarcastic bunch.... :D

Sunny window, heating pad, your crt monitor, sit on it for a while and incubate :wink: lol..

:mrgreen:
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Re: The 38120P cell from Headway

Post by TylerDurden » Feb 20 2008 12:34pm

Hey... I'm not joking. :D

You want stable temperature for at least 15min. The heating pad is hard to accurately control temperature. You can run the hairdryer hose into a clear plastic box and mix cool air into the hose while watching the temp.

That's how I would do it...
:mrgreen:
Have a Nice Day,

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Re: The 38120P cell from Headway

Post by Doctorbass » Mar 31 2008 10:38pm

I'm testing Headway cells now 8) (I just received my CBA-II battery tester today.

First test running now;

Cell no 3/3

-10A charging terminated to 50mA
-now 8A discharging capacity test. First result: ended at 8.29Ah at 26.6degreeC :wink:

Coming next dishcarge rate: 16A, 24A, 32A, and 1A (C/8)for absulote C rating.

Doc
Last edited by Doctorbass on Apr 01 2008 10:01am, edited 1 time in total.
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Re: The 38120P cell from Headway

Post by Toorbough ULL-Zeveigh » Apr 01 2008 8:20am

Ok, I get it now.
At first blush my thinking was preconceived that it resembled a douchebag.
Which should answer the question OneEye asked.

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Re: The 38120P cell from Headway

Post by olaf-lampe » Apr 01 2008 12:55pm

Doc, you must be absolutely fearless! Watch the last picture on top of this thread: putting a metall ruler so close to the tabs! :twisted:
How many weld-spots do the tabs have? Do they look trustworthy? I wonder if they can handle these rated amps?
-Olaf

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Re: The 38120P cell from Headway

Post by Doctorbass » Apr 01 2008 1:41pm

olaf-lampe wrote:Doc, you must be absolutely fearless! Watch the last picture on top of this thread: putting a metall ruler so close to the tabs! :twisted:
How many weld-spots do the tabs have? Do they look trustworthy? I wonder if they can handle these rated amps?
-Olaf

they have more than 20 spot. home made style (not regular or symetric)
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Re: The 38120P cell from Headway

Post by Doctorbass » Apr 01 2008 11:37pm

I had time to do some others test on the cell:

Cell no 3/3

-10A charging terminated to 50mA

-Results of 16A discharging capacity test. ended at 8.16Ah at 27.4degreeC
-Results of 8A discharging capacity test. ended at 8.29Ah at 26.6degreeC
-Results of 1A discharging capacity test. ended at 8.39Ah at 25.1degreeC (C/8)for absolute C rating.

Coming next dishcarge rate: 24A, 32A,
Doc
CURRENT PROJECT: 2WD duo MXUS/Max-E ebike 32kW
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-Fastest 1/4 mile@ 114km/h on flat and 16.316 sec
-Succeded to haul a 19200 pounds schoolbus!
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Re: The 38120P cell from Headway

Post by disadvantage » Apr 02 2008 10:06am

Good work Doc, keep it up!

I'm especially interested in the higher amp-rate discharge tests.

Do you think a single series string would power an ebike, or would 2 or more in parallel be required?

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Re: The 38120P cell from Headway

Post by Doctorbass » Apr 02 2008 11:07am

From now, for sure only one would be ok.

I tested this morning all 3 cells internal resistance i left them alone last night from the previous charging to stabylise.

I got exactly 6 miliohm from each of the 3 cells

INTERNAL RESISTANCE TEST
Cell 1: 6 miliohms
Cell 2: 6 miliohms
Cell 3: 6 miliohms


I think that is great news from these cells.

Also what i discovered is that their no load voltage from 3.600 immediatly after i charged them droped to 3.412V 10 hours after. It seems that their nominal voltage is really 3.2V like the manufacture claim instead of 3.3 like most common LiFePo4

I will do a discharge test them at 24 and then 32 and 40A soon

I will also torture them at 60, 80 and 100A with heavy resistive load soon. bring popcorn with you next time, that will become interesting!! :wink:

Doc
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-Succeded to haul a 19200 pounds schoolbus!
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Re: The 38120P cell from Headway

Post by slayer » Apr 02 2008 1:13pm

Yeah ok interesting but you never said anything about prices ...the only time a saw a price was that link earlier in this thread by someone else that stated 17 something american dollar is that so or is it with the link you get would get them for by andy at 35 $

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Re: The 38120P cell from Headway

Post by Doctorbass » Apr 02 2008 2:14pm

slayer wrote:Yeah ok interesting but you never said anything about prices ...the only time a saw a price was that link earlier in this thread by someone else that stated 17 something american dollar is that so or is it with the link you get would get them for by andy at 35 $

That's not determined from now.
CURRENT PROJECT: 2WD duo MXUS/Max-E ebike 32kW
http://endless-sphere.com/forums/viewto ... =3&t=65764
-Fastest speed record 117 km/h on flat
-Fastest 1/4 mile@ 114km/h on flat and 16.316 sec
-Succeded to haul a 19200 pounds schoolbus!
113kmh Gianthttp://www.evalbum.com/3406
Mongoosehttp://www.evalbum.com/1947
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