HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Jan 29, 2013, 02:38 PM
AMA Life Member 'Ezflyr'
Tewksbury, MA
Joined Nov 2004
86 Posts
Discussion
Capacity Testing XPS

Hi All,

I have a pair of 2S, 2300 mAH A123 packs I purchased from XPS about a year ago. At the time I fully charged them with a Thunder Power balancing charger. I'm about to use these packs now, so I'd like to capacity check them first. When I attempt this, I end up with a ridiculously low capacity of 75 mAH or something like that. When I recharge the packs, that is approximately the same amount being put back in. I assume I'm not discharging them properly, and probably ending prematurely. What is the per cell cutoff voltage that is appropriate to these A123 batteries?

Anything else I might be missing?

Thanks,

John
ezflyr is offline Find More Posts by ezflyr
Reply With Quote
Sign up now
to remove ads between posts
Old Jan 29, 2013, 03:15 PM
Registered User
E_ferret's Avatar
Launceston Arpt, Tasmania, Australia
Joined Jan 2004
564 Posts
Quote:
Originally Posted by ezflyr View Post
Hi All,

I have a pair of 2S, 2300 mAH A123 packs I purchased from XPS about a year ago. At the time I fully charged them with a Thunder Power balancing charger. I'm about to use these packs now, so I'd like to capacity check them first. When I attempt this, I end up with a ridiculously low capacity of 75 mAH or something like that. When I recharge the packs, that is approximately the same amount being put back in. I assume I'm not discharging them properly, and probably ending prematurely. What is the per cell cutoff voltage that is appropriate to these A123 batteries?

Anything else I might be missing?

Thanks,

John
You can use your computer for more than communicating with Jim!
required information is only one click away;
http://www.a123systems.com/Collatera...ta%20Sheet.pdf
E_ferret is offline Find More Posts by E_ferret
Reply With Quote
Old Jan 29, 2013, 06:35 PM
Registered User
crazy8s's Avatar
Pennsylvania, USA
Joined Sep 2008
358 Posts
Quote:
Originally Posted by ezflyr View Post
Hi All,

I have a pair of 2S, 2300 mAH A123 packs I purchased from XPS about a year ago. At the time I fully charged them with a Thunder Power balancing charger. I'm about to use these packs now, so I'd like to capacity check them first. When I attempt this, I end up with a ridiculously low capacity of 75 mAH or something like that. When I recharge the packs, that is approximately the same amount being put back in. I assume I'm not discharging them properly, and probably ending prematurely. What is the per cell cutoff voltage that is appropriate to these A123 batteries?

Anything else I might be missing?

Thanks,

John
I apologize in advance if this sounds insulting (not meant to be) but you ARE using a charger that has a LiFE setting on it, right??
crazy8s is offline Find More Posts by crazy8s
Reply With Quote
Old Jan 29, 2013, 10:13 PM
AMA Life Member 'Ezflyr'
Tewksbury, MA
Joined Nov 2004
86 Posts
Quote:
Originally Posted by crazy8s View Post
I apologize in advance if this sounds insulting (not meant to be) but you ARE using a charger that has a LiFE setting on it, right??
Hi,

Yes, the Thunder Piwer TP-610C does have a LiFe setting! The default cell discharge voltage is 3.3V, so I was seeing virtually no capacity after a full charge. Once I saw the discharge curves, I realized I could set the cut-off to 2V, and now I'm measuring rated capacity!

Thanks!

John
ezflyr is offline Find More Posts by ezflyr
Reply With Quote
Old Jan 30, 2013, 01:32 AM
Registered User
Doffen24's Avatar
Norway
Joined Sep 2008
229 Posts
Quote:
Originally Posted by ezflyr View Post
Hi,

Yes, the Thunder Piwer TP-610C does have a LiFe setting! The default cell discharge voltage is 3.3V, so I was seeing virtually no capacity after a full charge. Once I saw the discharge curves, I realized I could set the cut-off to 2V, and now I'm measuring rated capacity!

Thanks!

John
Do not go as low as 2V. Minimum Voltage should be 2,5V. Almost no difference in capacity between 2,5 and 2,0 volts due to steep discharge curve. Your batteries will last longer though....
(said that, a couple of my A123 cells where discharge completely -due to forgot turning off-, and I got it back to ŽlifeŽ again after a couple of cycles . They never seem to stop surprising me)
Doffen24 is online now Find More Posts by Doffen24
Last edited by Doffen24; Jan 30, 2013 at 01:35 AM. Reason: trying to get it in Engliscsh...
Reply With Quote
Old Jan 30, 2013, 09:05 AM
Xtreme Power Systems
Lake Havasu, AZ
Joined Jun 2005
15,702 Posts
3.3v is the normal operating voltage. A123 cells will retain their voltage for a very long time and then suddenly they will rapidly drop all of the way to zero. Cut-off at 2.5v and that will give you your capacity.
JimDrew is offline Find More Posts by JimDrew
RCG Plus Member
Reply With Quote
Old Jan 31, 2013, 07:36 AM
AMA Life Member 'Ezflyr'
Tewksbury, MA
Joined Nov 2004
86 Posts
Hi All,

Actually, I misspoke. The minimum cut-off voltage on the Thunder Power Charger I'm using in LiFe mode is 2.5V per cell. At that setting, I am getting rated capacity from my XPS A123 packs!

A special thanks to E_ferret for pointing out all the new-fangled things I can do with these computers !

John
ezflyr is offline Find More Posts by ezflyr
Reply With Quote
Old Jan 31, 2013, 03:26 PM
Registered User
E_ferret's Avatar
Launceston Arpt, Tasmania, Australia
Joined Jan 2004
564 Posts
Quote:
Originally Posted by ezflyr View Post
Hi All,

Actually, I misspoke. The minimum cut-off voltage on the Thunder Power Charger I'm using in LiFe mode is 2.5V per cell. At that setting, I am getting rated capacity from my XPS A123 packs!

A special thanks to E_ferret for pointing out all the new-fangled things I can do with these computers !

John
You are welcome! If you need further help, I cut my teeth (so to speak) on IBM 407s, so if you need help with point-to-point wiring, I'm the man.
E_ferret is offline Find More Posts by E_ferret
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Sold Royal Evo 7 Pro, XPS Evo module iva Aircraft - General - Radio Equipment (FS/W) 5 Jan 31, 2013 01:58 PM
For Sale 13 XPS Receivers Joel Rosenzweig Aircraft - General - Radio Equipment (FS/W) 2 Jan 22, 2013 08:34 PM
Discussion Dedicated flight video battery capacity Altimat Multirotor Electronics 7 Jan 15, 2013 09:00 AM
Question How to test Lipo capacity? fmidgett Batteries and Chargers 2 Sep 19, 2004 08:23 AM
Testing Battery For Mah Capacity Steven9026 Power Systems 5 Feb 26, 2002 11:27 AM