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Internal resistance tests of older Q500 battery

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Until recently I only used the Yuneec "smart charger" that came with my Q500+. I really knew nothing about internal resistance and how it could affect battery and flight performance. I have Q500 5400 mAh batteries that are at least 5 years old. I now have an Onyx KX80 multi-chemistry charger that does all kinds of batteries and tests. I recently tested an old battery that came with my first Q500+ for internal resistance. I had made 4 flights this past summer and got good(not great) times from the battery. The readings for the 3 cells were... 17, 21, & 30. The battery is not puffy. I ran the battery down some in one of my Q's and then placed it on the new charger and set it for "storage" mode. When finished, I disconnected it and let it sit for about an hour and ran the resistance again. This time I got readings of 17, 20, & 28... some had actually gone down. Over the next 2 months I plan to weekly charge up and then discharge it for storage the following day. I want to see if the resistance readings go lower or higher over the time period. I'll provide updates to this post.

Update Nov 14, 2021... readings are now 17, 21, & 29. I plan to do two balance charge and storage runs before my next report.
Update Nov 21, 2021... after another charge/storage cycle readings are 17, 20, & 26.
Update Nov 24, 2021... after another charge/storage cycle, readings are 17, 18, & 24.
Update Nov 25, 2021... readings are now 17, 17, & 24.
Update Nov 28, 2021... On this day I fully charged the battery and decided to use it in a flight. I made it off the ground and about 15ft in the air and I got a red warning banner on my ST10+ that said battery depleted land immediately. I never got any other low battery warnings. It just went from showing a good 12.2 volts to nothing in less than 10 secs of flight time. The props were still spinning and I was able to safely land the A/C. I shut everything down and then restarted all and the battery again showed 12 volts. I started another flight and the same thing happened. Voltage went from good volts to no volts in about 10 secs. This tells me that this battery will simply not hold any meaningful current and it's time to retire it. The battery has given me about 5 years of good service.
 
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Steve Carr

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I don't know of any benefit to weekly charge and discharge the battery. But I've never tried it so your results will be interesting.
A reading close to 30 is troubling. New batts should be less than 10 and the resistance increases with age and usage. I just tested 5 batteries and only one had a reading close to 30.

20211109_215150.jpg
 
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I don't know of any benefit to weekly charge and discharge the battery. But I've never tried it so your results will be interesting.
A reading close to 30 is troubling. New batts should be less than 10 and the resistance increases with age and usage. I just tested 5 batteries and only one had a reading close to 30.

View attachment 26868
In the KX80 manual it does state that multiple charge/storage cycles can help to "refresh" a LiPo battery. Not sure if this will do much of anything to the resistance values. I also have some Venom 6000 mAh batteries about 4 years old that have 5, 8, 6 for values. These I trust more and use when flying out over water. Whatever comes of my tests I will post it here.
 
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In the KX80 manual it does state that multiple charge/storage cycles can help to "refresh" a LiPo battery. Not sure if this will do much of anything to the resistance values. I also have some Venom 6000 mAh batteries about 4 years old that have 5, 8, 6 for values. These I trust more and use when flying out over water. Whatever comes of my tests I will post it here.
let me ask you my two brand new batteries have done the exact same thing on two different occassions are you saying that both brand new batteries i just bought are bad
 

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let me ask you my two brand new batteries have done the exact same thing on two different occassions are you saying that both brand new batteries i just bought are bad
What batteries are you referring to?

What exact same thing are they doing?

What charger are you using?

Do you have a multimeter so you can make voltage measurements?
 
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let me ask you my two brand new batteries have done the exact same thing on two different occassions are you saying that both brand new batteries i just bought are bad
Brand new does not always mean freshly assembled.
Batteries you've bought could be old because they remained on the shelf for too long time....
 
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What batteries are you referring to?

What exact same thing are they doing?

What charger are you using?

Do you have a multimeter so you can make voltage measurements?
I WOULD CHARGE THEM AND VOLTAGE WOULD READ 12.6 AND ALL CELL READ 4.20 THEN GO OUT TO FLY IT AS SOON AS IT GETS OFF THE GROUND WARNING LOW VOLTAGE COMES ON THEN ONCE I LAND IT VOLTAGE BACK TO NORMAL AROUND 12.4
 
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I WOULD CHARGE THEM AND VOLTAGE WOULD READ 12.6 AND ALL CELL READ 4.20 THEN GO OUT TO FLY IT AS SOON AS IT GETS OFF THE GROUND WARNING LOW VOLTAGE COMES ON THEN ONCE I LAND IT VOLTAGE BACK TO NORMAL AROUND 12.4
I WENT OUT AND BOUGHT A BRAND NEW BALANCE CHARGER THINKING MY OLD ONE WASNT WORKING
 
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Pls don't write in upper case....it looks like you're screaming.
If voltage is correct, the problem is not the charger but the batteries.
First of all we need to know what batteries you are referring to: for what drone??
Second thing, your charger should show the amount of mA given to the battery during charge: how much mA at the end of the charge?
Third: not sure if your charger can check also internal resistance of the batteries. This parameter is the only that can give an idea of batteries conditions.
From the symptoms you describe, batteries no longer hold the charge, and as I wrote above, the fact that they are new to purchase does not mean that they are fresh from production, so they may have remained in stock for many months.
The advice I give you is to return them, if possible.
There is no way to recover them, they must be replaced.
 

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