[NSRCA-discussion] LiPo Fun Fact 'O The Day

Sun Oct 11 18:40:38 AKDT 2015

As far as discharging, the Turnigy Reaktor I have ( http://hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=70272 ) has a regenerative discharge feature.  It can discharge at the full rate it can charge at as long as you use a battery to charge with. It will return the current back to your charging battery.  Really kewl and nice feature to be able to discharge your packs in 15-20 minutes.

-           Robert Beaubien
-           Sr. Software Architect
-           Kool Software LLC

"Dear Algebra, Please stop asking us to find your X.  She's never coming back and don't ask Y."

From: NSRCA-discussion [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Karl Watts via NSRCA-discussion
Sent: Sunday, October 11, 2015 1:37 PM
To: General pattern discussion <nsrca-discussion at lists.nsrca.org>
Subject: Re: [NSRCA-discussion] LiPo Fun Fact 'O The Day

Ok, so hearing all the discussion here I am trying to capture some take home points to use in the care of my batteries.
1.  Do not keep them at full charge for extended periods of time.  Charge prior to flying and the ones I do not use discharge after getting home.  My problem is it takes sooooo much longer for my charger (iCharger 208B) to discharge a battery to storage than to full charge a battery from storage.  Question - My charger will discharge a battery to 50% capacity for storage, is it OK to store them at lower capacity?  What is the low limit?
2.  Discharge for storage over the winter or in between flight sessions.  Question - Is it better to store them in the refrigerator for longer life?
3.  Warm up cold batteries before charging.  Warm up cold batteries before using.
4.  Do not discharge batteries below 25% capacity.
5.  Charge batteries at 1-2 C, no higher, to be on the safe side.  Note there is controversy with this point.

Is that all?

Karl - an enthusiastic intermediate pattern pilot

Sent from my iPad

On Oct 10, 2015, at 8:08 PM, Jeff and Claire via NSRCA-discussion <nsrca-discussion at lists.nsrca.org<mailto:nsrca-discussion at lists.nsrca.org>> wrote:
Yes, warm to at least 50deg F before charging.  Was charging at the field last winter and the Powerlab6 was stopping charge at  90% of capacity. Thought the charger was broken.  Turns out they use the internal temp sensor to check ambient as well and if below 50F, it will stop at 90% to keep from damaging the battery (with the assumption that battery is also <50F).  The Powerlabs allow lowering that threshold to 41F, once I did that started getting full charges (but made sure the batteries stayed warm before charge via thermo-nuclear fusion (truck dashboard).

>From FMA Revolectrix engineering group: Lithium is a poor performing battery in cold weather. If the pack is cold, the cell damage voltage reduces from 4.35V down to 4.20V. That means charging a lithium pack to 100% when it is below 50 deg F will reduce cycle life. Automatic temperature monitoring prevents pack over-charging at low ambient temperatures

They also say:   LiPo packs charged to 100% should not be cooled below room temperature. Cells at 90% or less capacity can be cooled below 32ºF (0ºC).

From: NSRCA-discussion [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Stuart Chale via NSRCA-discussion
Sent: Saturday, October 10, 2015 9:01 AM
To: chuenkan at comcast.net<mailto:chuenkan at comcast.net>; General pattern discussion
Subject: Re: [NSRCA-discussion] LiPo Fun Fact 'O The Day

What about if you store them in the fridge  during the week.  Should they warm to room temp before charging or is charging them cold OK?
On 10/10/2015 10:08 AM, Phil Spelt via NSRCA-discussion wrote:
Correct!!!  I don't do that...

________________________________
Apparently you guys never put them on charge when they're hot!!  Then they definitely cool down while charging.  :)

Sent from my average intelligence  phone

On Oct 9, 2015, at 8:44 PM, Robert L. Beaubien via NSRCA-discussion <nsrca-discussion at lists.nsrca.org<mailto:nsrca-discussion at lists.nsrca.org>> wrote:

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