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Old Feb 21, 2012, 02:27 PM
Southern Pride
everydayflyer's Avatar
Haralson County GA. USA
Joined Oct 2004
34,834 Posts
Yes the tread is a few years old however LiFePO4 ,Nicad and NiMH cells have not changed thier nonimal ,discharged,charged or voltage under load. The same rules of charging and balancing still apply and the data is as useful today as it was when first posted.

Quote:
but my 40th birthday is coming up soon and I can tell my mind it not very sharp anymore
Well I am pushing 67 and still know a thing or two about batteries and their use in RC applications.

Reduced to simpliest terms a 2S LiFePO4 is the best receiver battery there is for over 95% of applications.. Not all LiFePO4 cells (batteries) are created equal just like not all Nicad,NiMH or LiPolys are created equally.

Charles
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Old Feb 21, 2012, 02:28 PM
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Mikecam's Avatar
Canada, MB, Winnipeg
Joined Apr 2008
939 Posts
Thanks Charles, great thread for information. I noticed the thread started in the summer of 2008 and here we have the summer of 2012 coming around and A123/lifepo4 are still being discussed as in should I or shouldn't I. I only started in this hobby in 2008 and I can't believe that all Rx power applications have not gone to life chemistry.

It's the perfect battery for Rx power, the fact that it's safe, requires no extra regulator's, keeps it's charge for months and can last 1000 charges should be enough. I bought my first A123 from hangtimes in 2009 and they still discharge to within 15 mAh when new. I also always left them fully charged, even through 5 months of winter storage because until 2011 didn't know that A123 had a storage level. Even leaving them fully charged for 2 years didn't harm them.

People just don't like change. The old timers at my field still buy the nimh packs (would buy nicd if they could find them) and complain when they need to buy a new pack after 2 years and literilly 30 cycles. You can talk about life till your blue in the face but they still buy another nimh to replace it.

I talk to much, lucky I type 2 fingered or it could be pages.
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Old Feb 21, 2012, 04:45 PM
Southern Pride
everydayflyer's Avatar
Haralson County GA. USA
Joined Oct 2004
34,834 Posts
Only NiMH I use in RC are Sanyo Eneloops in my Transmitters and I even tried a Hyperion LiFePO4 battery in one of them . It worked fine but was not an improvement over the Eneloops and I prefer the more gradual discharge slope of the Eneloops.

I have a 2S K2 Energy Solutions 1250 mAh LiFePO4 receiver battery in my Sig fazer out in my shop that has not been flown or charged in over a year my guess is that it would take less than 50 mAh to top it off. They really are remarkable cells.

My cordless power tools which I converted to LiFePO4 from Nicad are allways charged and ready and never let me down. I did finally manage to kill one of my original A123 cells whic I purchased as a Developer Kit back in the very early days of A123s. Perhaps the fact that I abused the heck out of it including charging at up to 100 amps. had a bit to do with it.


One of my summary post from years ago

http://www.rcgroups.com/forums/showp...3&postcount=17
Charles
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Old Mar 14, 2012, 04:06 AM
Registered User
United States, NJ, Roseland
Joined Apr 2009
2,214 Posts
Using a bunch of hyperion 850mah LiFe RX packs but i have a question. At 3.6volts per call the pack tops off at 7.2 volts. This is a little risky as I am not running a regulator of any kind. I know the voltage quickly levels off at 6.4-6.5 volts. is there a way I could maybe charge the LiFe packs to 95% to keep it at the 6.5 volts?

Would that be the way to do it? You cant charge to 6.5 as its constant.....Any ideas?
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Old Mar 14, 2012, 05:54 AM
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United States, MA, Bristol
Joined Sep 2009
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Quote:
Originally Posted by hidaven View Post
Using a bunch of hyperion 850mah LiFe RX packs but i have a question. At 3.6volts per call the pack tops off at 7.2 volts. This is a little risky as I am not running a regulator of any kind. I know the voltage quickly levels off at 6.4-6.5 volts. is there a way I could maybe charge the LiFe packs to 95% to keep it at the 6.5 volts?

Would that be the way to do it? You cant charge to 6.5 as its constant.....Any ideas?
A 5 cell NiMH pack will read 7+Volts fresh off charge as well. I have used LiFE packs for over a year with no issues. Most modern servos are designed for the voltage.
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Old Mar 14, 2012, 07:54 PM
Jack
USA, ME, Ellsworth
Joined May 2008
17,140 Posts
Here is a recent thread about the 1100 mAh A123 18650 LiFEPo4 cells, it seems they are hitting the market at around $2 a cell now from a variety of sources (read the whole thread for the various links):

http://www.rcgroups.com/forums/showthread.php?t=1602710

Jack
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