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Old Mar 28, 2015, 05:40 PM
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Leaving a lipo charged

Hi all,
I have some lipos that I have had sitting around for a while fully charged. I realize that this is a big nono but I dont really have a choice because my charger does not have the ability to take the batteries down to storage voltage. My question is how much much of a change in performance will this make? I will be pretty mad if I wrecked $120 worth of batteries.
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Old Mar 28, 2015, 05:44 PM
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Depends on the specific battery and storage temperature. Some survive such abuse, some don't. If you have the means to test internal resistance, you can tell straightaway whether you've damaged your packs.

"I dont really have a choice because my charger does not have the ability to take the batteries down to storage voltage."

You do have a choice. http://www.myrcmart.com/rcx-3in1-bat...ng-p-4767.html
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Old Mar 28, 2015, 05:54 PM
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Quote:
Originally Posted by mrforsyth View Post
Depends on the specific battery and storage temperature. Some survive such abuse, some don't. If you have the means to test internal resistance, you can tell straightaway whether you've damaged your packs.

"I dont really have a choice because my charger does not have the ability to take the batteries down to storage voltage."

You do have a choice. http://www.myrcmart.com/rcx-3in1-bat...ng-p-4767.html
Thank you. They are the Turnigy A-Spec 4s batteries with the very high c rating. I odnt know if you know anything about them in particular. What I meant by i dont't have a choice is that it hadn't really occurred to me until today and my current setup doesn't allow me to discharge them.
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Old Mar 28, 2015, 06:54 PM
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Can you run them on the bench? A few minutes run time can bring them into storage voltage. But take the time to hook up a voltmeter so you don't discharge them below about 3.8v/cell.
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Old Mar 29, 2015, 03:13 AM
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Unfortunately very high C ratings are usually WORSE for degradation. And it obviously depends and how long "a while" is. Couple of days, not much problem, couple of months, very likely a problem.

Steve
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Old Mar 29, 2015, 07:42 AM
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Unfortunately very high C ratings are usually WORSE for degradation. And it obviously depends and how long "a while" is. Couple of days, not much problem, couple of months, very likely a problem.

Steve
Yeah unfortunately it has been closer to a couple of months. What kind of ill effects can I expect?
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Old Mar 29, 2015, 08:58 AM
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What kind of ill effects can I expect?
Increased internal resistance and reduced capacity. This will result in less available power and shorter flight times.
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Old Mar 29, 2015, 12:39 PM
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Quote:
Originally Posted by mrforsyth View Post
Increased internal resistance and reduced capacity.
I have to argue that it's a matter of reduced usable capacity at the current loads we demand to spin props and rotors. And for the sake of this argument, I have to define capacity as the ability of a pack to provide adequate voltage at those high current loads.

BUT:

It's been my experience that the pack capacity at reduced loads remains largely unaffected. I say this because I have a long history of re-purposing my LiPo packs once the voltage drop at a required load becomes excessive which, btw, is the #1 symptom of high IR. My most common use for old packs is external power for camera strobes, LED video lighting, and camcorders. Packs that are no longer up to the task of spinning props will usually serve well in that new role; often for several more years.

And charge/discharge test cycles at the reduced current they now need to supply indicates that they haven't lost the ability to store energy. They've simply lost the ability to release the energy at high rates.

Pete
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Old Mar 31, 2015, 08:09 AM
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Originally Posted by mrforsyth View Post
Increased internal resistance and reduced capacity. This will result in less available power and shorter flight times.
Thanks all for your replies,
Am I in any danger if I use them? Ie any danger of a lipo fire
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Old Mar 31, 2015, 08:32 AM
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You can't say there is "no danger" of a lipo fire as that's always on the table, but the chances are very low. Store and charge in a firesafe place and enjoy.
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Old Mar 31, 2015, 11:07 AM
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I rarely use the storage feature of my charger. My flight time is such that the batteries end very close to the storage voltage then I just put them away until next use.
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