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Old Dec 03, 2012, 01:00 PM
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Originally Posted by seefest View Post
Thats what I meant. Sorry if I wasn't clear. For determining capacity reasons.
When doing that I add 10% more than was determined by the discharge test to make up for the only going to 3.3V. Close enough for government work.
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Old Dec 03, 2012, 02:25 PM
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When doing that I add 10% more than was determined by the discharge test to make up for the only going to 3.3V. Close enough for government work.
thank you.
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Old Feb 11, 2013, 08:27 AM
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Originally Posted by TheWoodCrafter View Post
I know the iChargers do have an adjustable cut off voltage.
For $350.00 the icharger should wash and wax your car as well!
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Old Feb 11, 2013, 11:15 AM
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For $350.00 the charger should wash and wax your car as well!
That is the job for the girl friend (or wife)! Or both.

I have 29 worn out Li-Po battery cells (almost $290.00!). Some are Parkzone but most are ThunderPower and they failed at the 2 years warranty ending. Most are swollen and might catch on fire so I store them in a tin can. I should take them to the hazzardous waste dump.

My new E-flite 150mAh 25C batteries are inexpensive and are very good. They have newer 150mAh 35C cells but my local hobby store doesn't have them yet.

I use older E-flite 200mAh 25C 2S batteries in my UMX airplanes and they work fine. They have 35C batteries now but my local hobby store also does not have any.
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Old Feb 11, 2013, 11:37 AM
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Discharge the "worn" packs with a light bulb and in the US, it's acceptable to put in the trash.
http://www.rcgroups.com/forums/showp...3&postcount=27
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Old Feb 11, 2013, 06:38 PM
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So, I have a quadcopter and it uses a 3s 4000mAh battery

I hear about the 80% rule but don't know when I should actually start landing.

At what voltage?

I'm also a little confused as how voltage and mAH correlate with each other. Could someone clarify this for me?

Thanks!
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Old Feb 11, 2013, 08:24 PM
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See this thread http://www.rcgroups.com/forums/showthread.php?t=1287041
In post #2 look for "How Much Capacity Is Left In My Pack?"

Voltage several minutes after landing should be at 3.7V/cell (no load) (80% discharged) or above.
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Old Feb 13, 2013, 04:36 PM
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Originally Posted by hoppy View Post
See this thread http://www.rcgroups.com/forums/showthread.php?t=1287041
In post #2 look for "How Much Capacity Is Left In My Pack?"

Voltage several minutes after landing should be at 3.7V/cell (no load) (80% discharged) or above.
Is this equivalent to 3.3v underload?
So... I should be landing at around 3.4v?

edit:
Is there anyway I can measure how much mAh is left in my battery.
Since I have a 4000mAh battery.. it would be at 80% at 800mAh.

So if I could get my battery at 800mAh (or close) then I could read the voltage? And set LVC from there?
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Old Feb 13, 2013, 05:48 PM
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I would not fly till the LVC kicks in.

The 80% rule is usually done by timing the flight.

When the pack is fully charged, fly for 4 minutes.
This works well when your all your flights are similar in style.
Land, charge your pack and note the mAh put back in.
Divide it by the 4 min to get the average mAh/minute used.
Then divide the 80% of your battery (3200) by your mAh/min to get your total flight time in minutes.
It usually works out very well and has some cushion built in.
Way better than waiting for the LVC to kick in.
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Old Feb 13, 2013, 06:17 PM
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Originally Posted by TheWoodCrafter View Post
I would not fly till the LVC kicks in.

The 80% rule is usually done by timing the flight.

When the pack is fully charged, fly for 4 minutes.
This works well when your all your flights are similar in style.
Land, charge your pack and note the mAh put back in.
Divide it by the 4 min to get the average mAh/minute used.
Then divide the 80% of your battery (3200) by your mAh/min to get your total flight time in minutes.
It usually works out very well and has some cushion built in.
Way better than waiting for the LVC to kick in.
ohh.... good idea! Then.. depending on about how much mAH I use per minute... I can determine the time to land. Correct? 3200 / (mAh per minute) = total minutes to fly.

I have an LiPo alarm too. How should I use that?
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Old Feb 13, 2013, 06:21 PM
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Originally Posted by v00d0o View Post
Is this equivalent to 3.3v underload?
So... I should be landing at around 3.4v?

edit:
Is there anyway I can measure how much mAh is left in my battery.
Since I have a 4000mAh battery.. it would be at 80% at 800mAh.

So if I could get my battery at 800mAh (or close) then I could read the voltage? And set LVC from there?
I gave you the thread that shows you the chart of Voltage vs capacity. Didn't you look at it?

You can't go by the underload voltage as that varies with the load, the higher the load the lower the voltage.
As I said before, your packs should be above 3.7V/cell after landing "Voltage several minutes after landing should be at 3.7V/cell (no load) (which represents 80% discharged) or above."]
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Old Feb 13, 2013, 07:18 PM
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Originally Posted by hoppy View Post
I gave you the thread that shows you the chart of Voltage vs capacity. Didn't you look at it?

You can't go by the underload voltage as that varies with the load, the higher the load the lower the voltage.
As I said before, your packs should be above 3.7V/cell after landing "Voltage several minutes after landing should be at 3.7V/cell (no load) (which represents 80% discharged) or above."]
Sorry. I'm a noob at all of these lipo things. I just trying to setup the lipo alarm so I would know when to land. But being that underload and no load are completely different I'm not sure where to set my alarm to.

(I also printed your little chart out...just for reference)
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Old Feb 13, 2013, 07:29 PM
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How about starting out with LVC set to highest level and then when done flying use trial and error to hit the target 3.7 volts/cell. Continue to lower your LVC until the target is reached. Using the LVC is not a good way to tell one when to stop , but is good insurance when something goes awry with the timer. The timer isn't perfect either , but the two combined are a decent way to not ruin your lipos by discharging them too much or crashing the plane.

Varying one's flying routine , forgetting to charge battery, dimished battery capacity , wind, ghost load, ect are all things that can throw the timer off.
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Old Feb 13, 2013, 07:35 PM
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Originally Posted by v00d0o View Post
Sorry. I'm a noob at all of these lipo things. I just trying to setup the lipo alarm so I would know when to land. But being that underload and no load are completely different I'm not sure where to set my alarm....
You may find this past post helpful.

http://www.rcgroups.com/forums/showp...&postcount=194
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Old Feb 13, 2013, 09:26 PM
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Originally Posted by v00d0o View Post
Sorry. I'm a noob at all of these lipo things. I just trying to setup the lipo alarm so I would know when to land. But being that underload and no load are completely different I'm not sure where to set my alarm to.

(I also printed your little chart out...just for reference)
Set the alarm so that a minute after landing the voltage is 3.7V/cell. It's really just that simple.
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