Pushing battery to its limits?

[ImJim]

Hey bros,

Well all of us pilots know that we need to take care of our babies, and make sure to begin landing them when reaching 20%.

But... Is really 20% the absolute limit before you start ruining the battery life? DJI themselves allow us to choose 15%. What would you guys say about that? Of course, you might be thousands of feets away, and the time that your eagle comes back would take maybe 5% or 7%, draining the battery down to like 10% (if the warning is set to 20%).

So what average percentage should you really never exceed?

 

[msinger]

I always land by 30% or when the first battery cell reaches 3.4V. See more details about that here:
http://www.phantompilots.com/thread...y-voltage-to-watch-for-signs-of-failure.43313

Keep in mind that your Phantom will auto land at its current location if the battery reaches the critical low level. There is no way to abort that landing.

 

[ImJim]

Thanks a lot for the thread

Keep in mind that your Phantom will auto land at its current location if the battery reaches the critical low level. There is no way to abort that landing.

Seems logical I may have to choose 20% if the drone is far away from me!

 

[4wd]

There is no way to abort that landing

You can delay it by throttling up and still continue returning to a chosen landing site.
However, the battery chemistry seems to have a feature where the remaining charge drops progressively faster, in other words dropping from 100% to 70% takes significantly longer than dropping from 50% to 20%
In short, you can easily be caught out if not close to home soon after the first warning.
It is rarely worth the risk.

 

[ImJim]

You can delay it by throttling up and still continue returning to a chosen landing site.
However, the battery chemistry seems to have a feature where the remaining charge drops progressively faster, in other words dropping from 100% to 70% takes significantly longer than dropping from 50% to 20%
In short, you can easily be caught out if not close to home soon after the first warning.
It is rarely worth the risk.

So you advise 20% in most situations?

 

[N017RW]

You're right 4wd.

The LiPo has a steep discharge curve after ~3.4 - 3.6v/cell.
Pretty close to the 50% level.

 

[AmirChar]

I don't think it hurts the battery to drain it below 10% or even 5%, in fact, I believe you are supposed to drain it all the way down every so often. Lipo batteries (at least the speed controller on my RC cars), have logic that will turn them off before allowing them to be discharged below the minimum threshold. I would have to believe that the 0% level on the Phantom battery level is that threshold (i.e., the bird will shut off at 0% to prevent over discharging, so yes you could crash so you need to be reasonable on how low you let it get, but it won't physically hurt the battery to go that low).

 

[ImJim]

I don't think it hurts the battery to drain it below 10% or even 5%, in fact, I believe you are supposed to drain it all the way down every so often. Lipo batteries (at least the speed controller on my RC cars), have logic that will turn them off before allowing them to be discharged below the minimum threshold. I would have to believe that the 0% level on the Phantom battery level is that threshold (i.e., the bird will shut off at 0% to prevent over discharging, so yes you could crash so you need to be reasonable on how low you let it get, but it won't physically hurt the battery to go that low).

Really interesting, thanks. Funny because I saw posts saying the exact opposite thing... Some said that you should never drain the battery till "death" before recharging it, cause for some reason going from maybe 2 or 3% to 100% was bad for the battery.