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discharging/storage charge question

Old 08-01-2016, 02:55 AM
  #1  
Fishbonez
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Default discharging/storage charge question

Ok it may be a common sense answer but none the less I was curious.
We all know that for safety reasons never charge a lipo unsupervised.
However is it the same with discharging or putting on storage charge? I would assume yes with a battery that may be damaged but I mean just an everyday battery that may not have gotten used that day during flights etc
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Old 08-01-2016, 03:16 AM
  #2  
fhhuber
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Best to not discharge unsupervised....

Its more likely to damage the LiPo due to overdischarge than any other issue. Fire risk is much lower than charging.

I like to discharge via a high power model which trips LVC at 3.7 to 3.8 v/cell at WOT. Appx 3 min to take a full pack to storage.
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Old 08-01-2016, 10:35 AM
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solentlife
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I know I will get stick for this - but I cannot watch my lipo's totally, so I do have occassions of them alone.

I have just binned a 5S pack after connecting to take to storage though not using at site - I could feel the pack getting warm. The discharge rate was only 4A. Turned out to have a faulty cell and even the low rate discharge was showing signs of distress.

I am one who works in a Paranoid industry that Safety is drummed into us so much that in fact I believe has opposite effect. Fine for bosses and company's to say - WE train our people etc. but reality is over emphasis leads to turning people off.
This I believe is case with LiPo's as well. The level of paranoia and info to religiously stand over LiPo's and charge in earthernware pots, ammo cans etc. etc. is such that I can see it being counter productive. This is my personal view and I know will not gel with many.

Answer to post 1 ... LiPo's should be attended during any phase of changing state. IMHO

Nigel
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Old 08-01-2016, 01:01 PM
  #4  
JetPlaneFlyer
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IMHO it depends where the discharging is taking place. If it's in your home with lots of stuff that could catch fire in the vicinity then most certainly watch them like a hawk (or better yet do it somewhere else)

On the other hand if they are in a safe environment where there is no chance of a fire escalating then what's the worst that can happen? Bear in mind though that during discharging it's the charger/discharger that is more likely to burst into flames rather than the battery itself.

Discharging with the average charger can take hours, so practically it's hard to watch them all the time. I've made a discharge setup that will discharge at a constant 40A / 1000W so it will discharge most batteries in a few minutes. This makes the process a lot safer IMHO as you can easily keep an eye on them. Discharging in the model is ok but can cause overheating of the motor/ESC due to reduced airflow, plus I have large helis which cant be run up indoors if you like to keep your limbs attached.
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Old 08-01-2016, 06:16 PM
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Good rule of thumb is to never leave a lipo unsupervised if it is hooked to any kind of power source.
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Old 08-01-2016, 10:29 PM
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I'm with fhhuber on the discharge technique. I just anchor a big plane to the bench and let it run down. Wattmeter in-line and run the amps at an appropriate level.
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Old 08-02-2016, 06:38 AM
  #7  
solentlife
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$15 and a 3in1 battery discharger from MyRCMart does good job with auto shut off at user settable cell voltage.

Nigel

Last edited by solentlife; 08-03-2016 at 02:50 PM.
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Old 08-03-2016, 02:26 PM
  #8  
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I realize I am at a bit of risk, but I have a lot of faith in my expensive PL8 charger, which has been worth every penny, and commonly leave it unattended in my studio for short periods. I would be less likely to leave it unattended if I were dealing with a battery that was in questionable condition.
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