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

[Anthony Romano]

Good summary Karl. A lot of noise to wade through for that. 

Most dischargers are very slow. I wire a male battery connector to female duplex adapter so I can plug my packs into a power strip. Then I plug a couple of old soldering irons and incandescent lamps into the power strip for resistance. With a watt meter inline you can monitor the load and voltage to terminate discharge. 

3.7 volts is pretty typical storage voltage but some will say anything below 4.0 volts is sufficient. Many do store in the fridge to slow the natural chemical decay of the cells but do allow them to reach room temperature before charging. 

As with most advice in pattern someone will contradict me shortly. Try what sounds logical to you and decide for your self. 

Good luck,
Anthony  

Sent from my iPad

> On Oct 11, 2015, at 4:37 PM, "Karl Watts via NSRCA-discussion" <nsrca-discussion at lists.nsrca.org> wrote:
> 
> 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> 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; 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> wrote:
>> 
>> 
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