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?
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?