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Batteries Not Auto Discharging

SixStarsDrone

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The last time I charged my EVO II Pro V2 batteries was on 5/9. As of today, one battery is at 92% and the other is at 94%. Both batteries have the latest firmware update and I’ve got them set to auto discharge after 6 days. By my calculations, that’s 11 days, almost double the discharge setting. What am I missing?
 
The last time I charged my EVO II Pro V2 batteries was on 5/9. As of today, one battery is at 92% and the other is at 94%. Both batteries have the latest firmware update and I’ve got them set to auto discharge after 6 days. By my calculations, that’s 11 days, almost double the discharge setting. What am I missing?
First rule is Never store your batteries fully charged.
Storage level for our 3s (evo 2) batteries is 11.6 volts! That's less than 50%!
 
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the self discharge uses some resistors on the bms board to literally burn off the excess voltage.. the curent capacity is tiny otherwise there would be some excess heat and safety concerns.... this means it will take some time to bring the voltage down... if we assume the discharge circuit can handle 0.5W (no idea what it actually consumes) then it will take about 3.5 days to get to 50% SOC... unless I missed something...

It is difficult to know how fast the discharge occurs unless we know the circuit wattage.. but it is certainly a few days.
 
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First rule is Never store your batteries fully charged.
Storage level for our 3s (evo 2) batteries is 11.6 volts! That's less than 50%!
Where did you find the recommended storage voltage?

How do you reduce the voltage to that level if they are full? Example: you fully charge your batteries for a job and that job gets cancelled and the batteries are going to sit for several days or an extended period of time.

Do you power up the aircraft and let it sit running down the voltage? I know the easy answer may be to simply fly the aircraft but that’s not always an option especially if you have multiple batteries.
 
the self discharge uses some resistors on the bms board to literally burn off the excess voltage.. the curent capacity is tiny otherwise there would be some excess heat and safety concerns.... this means it will take some time to bring the voltage down... if we assume the discharge circuit can handle 0.5W (no idea what it actually consumes) then it will take about 3.5 days to get to 50% SOC... unless I missed something...

It is difficult to know how fast the discharge occurs unless we know the circuit wattage.. but it is certainly a few days.
As I mentioned at day 11 I’ve only lost 6% and 8% so I don’t have much confidence in the auto discharge that’s set at 6 days.
 
Where did you find the recommended storage voltage?

How do you reduce the voltage to that level if they are full? Example: you fully charge your batteries for a job and that job gets cancelled and the batteries are going to sit for several days or an extended period of time.

Do you power up the aircraft and let it sit running down the voltage? I know the easy answer may be to simply fly the aircraft but that’s not always an option especially if you have multiple batteries.
I use a 3rd party (after market) charger for my EVO batteries that has a storage setting. It will charge or discharge to proper Voltage. Had to make adapter for using EVO connector. Haven’t used OEM charger in over a year.
As you stated, flying them down is faster / easiest.
 
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As I mentioned at day 11 I’ve only lost 6% and 8% so I don’t have much confidence in the auto discharge that’s set at 6 days.

I have always had that problem, flying them down takes way too long so now I try to charge no more than what I absolutely need and only the day before the shoot in case it gets cancelled, it is a balancing act because if you charge too few you might come up short on the job, if you charge too many you are left with a full battery that won't discharge.

The other problem is that I frequently only need a few min in the air which leaves the battery with 95% remaining when I land.

For me there is no easy answer and I just have to price in the cost of replacement batteries into my project quotes while trying to minimize wasted charging cycles.
 
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I have always had that problem, flying them down takes way too long so now I try to charge no more than what I absolutely need and only the day before the shoot in case it gets cancelled, it is a balancing act because if you charge too few you might come up short on the job, if you charge too many you are left with a full battery that won't discharge.

The other problem is that I frequently only need a few min in the air which leaves the battery with 95% remaining when I land.

For me there is no easy answer and I just have to price in the cost of replacement batteries into my project quotes while trying to minimize wasted charging cycles.
Do your batteries auto discharge as they are supposed to?
 
Just curious... in my DJI batteries the SOC indicator is not reliable after a few weeks and the batteries need to be turned on to see the true SOC and typically the indicator level drops... (e.g. will drop from 3 LED's to 2 LED's)

Maybe this is happening here as well?
 
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Just curious... in my DJI batteries the SOC indicator is not reliable after a few weeks and the batteries need to be turned on to see the true SOC and typically the indicator level drops... (e.g. will drop from 3 LED's to 2 LED's)

Maybe this is happening here as well?
Good thought. I tried powering on the batteries and all 4 bars are still lighting up.
 

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