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loker
09-14-2005, 02:38 AM
im somewhat new to lipos. I use mainly thunder power. does anyone know, assuming I charge and discharge correctly, how many times the batteries can be used before they are no good? thanx

Tweet
09-14-2005, 04:52 AM
I've heard the number 300 mentioned. My most used battey so far is a TP 3S3P with 60 cycles that shows no sign of deteriorating so far.

Red Scholefield
09-14-2005, 10:45 AM
Cycle life is greatly impacted by depth of discharge, rate of discharge, and balancing of individual cells. Balancing being the most important. I have been told by one manufacturer that without balancing you can have as few as 50 cycles :( , balancing will get you well into the 100s of cycles.:D

Greg Covey
09-14-2005, 12:54 PM
The On-line FMA LiPo Handbook is a complete resource for understanding Lithium Polymer technology and its application in the R/C industry. The document purpose is to disseminate knowledge about Lithium Polymer technology, safety, and technical issues by using factual data, charts, and graphs, along with a comprehensive write-up.

Section 1 (https://www.fmadirect.com/support_docs/item_1177.pdf) focuses on FMA LiPo systems and building LiPo packs.

Section 2 (https://www.fmadirect.com/support_docs/item_1178.pdf) focuses on evaluating and selecting Lithium cells.

Section 3 (https://www.fmadirect.com/support_docs/item_1179.pdf) focuses on safety, charging, and discharging.

Geoff_Gino
09-14-2005, 01:06 PM
Hi Greg

Which is the best way to store LiPo's - charged or dis-charged?

Geoff

Greg Covey
09-14-2005, 01:49 PM
Hi Geoff,

You're going to make me answer another "best" question, huh? :)

The image that comes to mind is from a new t.v. show called E-Ring about the Pentagon where Dennis Hopper says, "Do as I say, not as I do!"

Here is a link to the best way to store Lithiums if you were a cell.
http://www.batteryuniversity.com/partone-19.htm

Now, if you are a busy person and have limited time or no access to cold temperatures or lots of money, etc. The best for you can be a sub-set of these conditions.

For me, I leave my packs charged for the most part and dump them in my garage during the long cold Winter months of upstate New York. It has been my experience that newer, better cells keep coming out so my expectations for Lithium packs is two years tops.

Unbalanced prop
09-14-2005, 08:17 PM
For me, I leave my packs charged for the most part and dump them in my garage during the long cold Winter months of upstate New York. It has been my experience that newer, better cells keep coming out so my expectations for Lithium packs is two years tops.

Ditto the above. Anything over two years is out of date and something two or three times better is being sold. I do have a couple packs that have gone through a couple summers (flying 2 to four times a week), but they need replaced.

Doug

Tweet
09-14-2005, 10:48 PM
You know, I guess this problem really gets solved if volume and/or technology allows battery prices to come down. At that point we'll be less concerned with how long they last.

Geoff_Gino
09-15-2005, 07:27 AM
Hi Greg

Sure made you do it ;) and thanks for the answer. I have always thought it best to store any battery charged.

Geoff