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would anyone be interested in long-term cycling test of A123 and Headway cells?

3K views 10 replies 4 participants last post by  pm_dawn 
#1 ·
I am thinking of doing long-term comparative cycling tests of A123 cells and Headway cells. The idea is to cycle them under exactly the same conditions until they die. Not only until their capacity degrades to 80%, I want to cycle them until their capacity decreases to 0! Which can mean over 10000 cycles. That is to make a graph of how exactly the capacity degrades in relation to the number of cycles, sort of the one here on page 9:

http://batteryworkshop.msfc.nasa.gov/presentations/11_Dev_Batt_Packs_Space_Appl_DCarmen.pdf

I am interested in cycling at 4C charge/4C discharge.

The cells I want to test are:

H-38120P from http://stores.headway-headquarters.com/-strse-2/lifepo4-Headway-batteries,-EV,/Detail.bok

and:

APR18650M1A from http://www.a123rc.com/goods-102-Nano-Phosphate+LiFePO4+Original+A123+APR+18650+M1A+Cell.html

Testing at 4C/4C would go like this: 15 minutes charge, 15 minutes rest, 15 minutes discharge, 15 minutes rest. Total 1 hour per cycle, 417 days per 10000 cycles.

The device I want to test it is: FMA Cellpro PowerLab 8: http://www.fmadirect.com/new_applications/pl8_features.html
Two of such devices are needed, one for A123, one for Headway. 8 cells in series of each type would be tested. Every 1 second, the voltage of each cell, the current, mAh in/out, and cell temperature would be recorded.

Now, while I would very much like to know the results, I can't afford to finance the equipment and batteries alone, as the cost would be at least: 2 * 240 USD for PowerLab chargers + 8 * 2.16 USD for A123 18650s + 8 * 18.75 USD for Headways, that makes already about 650 USD, and still doesn't include at least 4 CellLogs like this: http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=9282
(1 per cell pack for voltages, and one for currents by measuring voltage across a shunt resistor). And something to measure and log temperature. Its all about a 1000 USD or more and the test would go on for over a year.

That's too much money for 1 person to pay just to get this knowledge, but what if several interested people pool money, we could do this? I could run this under my desk. Partial results would be published every week or so.

Is there anyone interested in this knowledge also, and willing to participate in costs?

On a related matter, is anyone here from the USA willing to reship me a charger from US to Germany? There is an auction of a Cellpro PowerLab 8 now: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=290556126136
But the seller is unwilling to ship outside USA (I e-mailed him).

Is anyone here would be willing to receive the package in USA and reship it to me to Berlin (I'd Paypal you the shipment cost of course)? I'd bid and pay from my account, just add your address in USA. I would only bid on this up to a price which is significantly lower then list price of a new device, this way more affordable equipment for the test could be gathered. If the price of this auction would be reaching anything close to the list price I will not bid on this. Would anyone be willing to help?
 
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#2 · (Edited)
Sure, but only if I do the testing. I wouldn't want someone who is new to the EV world (and batery technology) to set up the tests and "promise" to give me the data, and then return the equipment at the end of the cell testing. I'm fairly well established (worked for EVComponents, Manzanita Micro, Brooklynmotorized, Elithion).

I'll pay for one of the Powerlabs (I have A123 cells and Headway cells already), and bill you for:
- 1/2 of the time spent on setting things up
- 1/2 of the time spent on parsing the data (once a month)
- 1/2 of the time spent on publishing the results (once a month)
- 1/2 electricity costs (for keeping my computer running and the devices running for over a year)
- 1/2 of the shop space rental for the entire year
- 1/2 of the insurance (in case something shorts, melts, fries or starts a fire)

Sounds fair to me, but it'l exceed the cost of doing it yourself.

Then again, if $650 is too much for you, then I suggest you get out of this hobby, just sayin.
 
#3 ·
Then again, if $650 is too much for you...
I am thinking of gathering at least 10 people interested in this, each pays 10% of the cost. Anything less then 10 people it makes it too expensive per head.

It doesn't matter for me if I do this and people pay me, or I put some of my money into a pool for someone else to do this.

If I where to do this, everything besides the equipment and batteries would be free of charge. I won't charge anybody for time, electricity, shop space - WTF, maybe you forgot to charge for the air you breathe while doing these tests?

I don't plan returning the equipment, simply after this 1.5-year test is over (cells die), I'd start another test with another type of cells (there are plenty of brands/models to test). Other types of A123's, other high-current LiFePO4 which might appear till then. Or testing the same cells again, but from newer production batches, to check if they degraded or improved in specs.
 
#7 ·
First off I'd suggest not testing under your desk -- if you are doing unattended testing I'd suggest you do it with fire safety in mind.

Secondly, do you really need the rest periods? If you are watching temperature, don't do a rest period until it is needed.

Third, just buy 1 or 2 cells, an RC charger, a few relays, maybe light bulbs for a load, and an arduino. Get smart cheaply and simply. BTW some RC chargers will do cycling.

It would be fun to start with one cell about 1/2 the charge of the rest, and see if it would slowly equalize or stay locked at 1/2 the capacity.
I am thinking of doing long-term comparative cycling tests of A123 cells and Headway cells. The idea is to cycle them under exactly the same conditions until they die. Not only until their capacity degrades to 80%, I want to cycle them until their capacity decreases to 0! Which can mean over 10000 cycles. That is to make a graph of how exactly the capacity degrades in relation to the number of cycles, sort of the one here on page 9:

http://batteryworkshop.msfc.nasa.gov/presentations/11_Dev_Batt_Packs_Space_Appl_DCarmen.pdf

I am interested in cycling at 4C charge/4C discharge.

The cells I want to test are:

H-38120P from http://stores.headway-headquarters.com/-strse-2/lifepo4-Headway-batteries,-EV,/Detail.bok

and:

APR18650M1A from http://www.a123rc.com/goods-102-Nano-Phosphate+LiFePO4+Original+A123+APR+18650+M1A+Cell.html

Testing at 4C/4C would go like this: 15 minutes charge, 15 minutes rest, 15 minutes discharge, 15 minutes rest. Total 1 hour per cycle, 417 days per 10000 cycles.

The device I want to test it is: FMA Cellpro PowerLab 8: http://www.fmadirect.com/new_applications/pl8_features.html
Two of such devices are needed, one for A123, one for Headway. 8 cells in series of each type would be tested. Every 1 second, the voltage of each cell, the current, mAh in/out, and cell temperature would be recorded.

Now, while I would very much like to know the results, I can't afford to finance the equipment and batteries alone, as the cost would be at least: 2 * 240 USD for PowerLab chargers + 8 * 2.16 USD for A123 18650s + 8 * 18.75 USD for Headways, that makes already about 650 USD, and still doesn't include at least 4 CellLogs like this: http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=9282
(1 per cell pack for voltages, and one for currents by measuring voltage across a shunt resistor). And something to measure and log temperature. Its all about a 1000 USD or more and the test would go on for over a year.

That's too much money for 1 person to pay just to get this knowledge, but what if several interested people pool money, we could do this? I could run this under my desk. Partial results would be published every week or so.

Is there anyone interested in this knowledge also, and willing to participate in costs?

On a related matter, is anyone here from the USA willing to reship me a charger from US to Germany? There is an auction of a Cellpro PowerLab 8 now: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=290556126136
But the seller is unwilling to ship outside USA (I e-mailed him).

Is anyone here would be willing to receive the package in USA and reship it to me to Berlin (I'd Paypal you the shipment cost of course)? I'd bid and pay from my account, just add your address in USA. I would only bid on this up to a price which is significantly lower then list price of a new device, this way more affordable equipment for the test could be gathered. If the price of this auction would be reaching anything close to the list price I will not bid on this. Would anyone be willing to help?
 
#10 ·
First off I'd suggest not testing under your desk -- if you are doing unattended testing I'd suggest you do it with fire safety in mind.
Agreed!

Secondly, do you really need the rest periods? If you are watching temperature, don't do a rest period until it is needed.
Do you know if the Powerlab can actually measure temperature and cycle automatically (I am not familiar)? I don't know that its "that" configurable.

Third, just buy 1 or 2 cells, an RC charger, a few relays, maybe light bulbs for a load, and an arduino. Get smart cheaply and simply. BTW some RC chargers will do cycling.
They don't keep discharge current constant. As voltage drops, current increases. I mean, for me it'd be fine, but I think he wants more "accurate" data.

It would be fun to start with one cell about 1/2 the charge of the rest, and see if it would slowly equalize or stay locked at 1/2 the capacity
can you turn off balancing on the charger?
 
#8 ·
I could, but I'm gonna pass..... I'm not going to do the testing and post data once a week, as I'm too busy with finishing my electric motorcycle and my normal 40hr/wk job to parse the data every week and publish just because you want it more often. Manipulating all of that data takes a long time (if the powerlab even allows you to log that long), not worth it to do once a month.

you forgot the cost for two 1000W power supplies and electricity for running continuously..... (just note, you'll need two different 15A 120V power feeds, because 2 would be over the limit for residential wiring).

Around here, thats 7cents/kwh, you'd be paying $0.035 to run those every hour (15 min on, the rest its off/discharging). 1 cycle per hour. there are ~8760hours in a year. That would cost $300 annually, and that's not even finishing the test. Lets say it takes 1.25 years to finish, that's $375, plus the cost of two 1000W AC to DC power supplies to convert AC to 12VDC to run the powerlabs (add a couple hundred bucks each for those). Then add the cost of keeping a computer running that whole time, add another $200 per annum.

So:
~$152 for 8 headways
~$48 for 8 A123
~$480 for 2 Powerlab's
~$375 for electricity for a year for the power supplies
~$200 for electricity for a year for the computer
~$50 for a hard drive to keep all this data on for a continuous logfile

you're looking at getting together $1300 bare minimum.


Again, good luck.
 
#11 ·
The iCharger 306b and 3010b can do 30A on up to 10cells (3010b) it has regenerative discharge that can be run towards a BIG LA pack. It can run cylces on Li chems and you can logg everything using the logview interface to PC, I dot know if you can get the charger to output tempetature to the log but I think so. But it can only do 999 cylces at the time. Then you would have to start a new run.

It can't do 4C on the headways but atleast 3C.

I have one running a discharge test on TS 90ah cells right now.

I have not explored the logview output yet.

Best Regards
/Per
 
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