What to do with days old batteries?

[Erroll]

I agree with most of what you say. Just fly it if its full and don't worry about how long its been since it was charged.

However, you are incorrect about the battery not having memory. They do, in fact, know how long its been since the prior charge and record additional statistics including number of times charged. These are fairly sophisticated units as far as batteries are concerned and more then a simple chemical battery; they have circuitry and a micro-controller and indeed have flash memory. This is how they "know" to auto-discharge after a certain number of days.

I agree.

In addition - I have five batteries and use them in sequence, with the discharge periods set to 3 days. I am also more intelligent than any battery. If I want to fly and the next battery in the rotation is only showing 3 LEDs, I make a conscious decision based on my intended flight. If I plan on doing a 5 minute test for example, I will use that battery and take off and fly gently, and if I want to fly a full mission I will either top up the battery or use the next one in the cycle, depending on time available.

Most often, it is the burst of full-power with batteries which are not fully charged that causes the voltage drops responsible for so-called critical battery conditions.

I fly a lot (well over 2 million feet on GO alone), and I have never had any unexpected battery issues.

 

[GadgetGuy]

I don't know but can only speak to my own experience. Where does DJI recommend only using batteries charged in the past 2 days? People come up with the strangest things to explain their crashes.

But I subscribe to what RedHotPoker just said -- just top your batteries off before the flight, certainly can't hurt. But I find after a week or so in storage after a charge my batteries are only down 4-5% at most, therefore starting the flight at better then 95%. And I've not observed strange sudden drops in the %, seems to be linear and predictable no matter the starting point.

Once you get down into the 15% range, the drop is no longer linear, and can drop much faster. Avoiding reaching the 10% critical battery autoland is key. Every % point counts. Topping off to 100% just before flying gives you an extra margin of safety that 95% may not, in case you run into a headwind or crosswind on the return flight. If it autolands at 10% into saltwater next to the pier, while you panic, trying to use full left stick to get it back above the pier, I promise you, you will wish you had had that last 4 or 5%! Safety first.

 

[GadgetGuy]

I'm a battery expert, so listen to me. It's simple, push the button one time on your battery. If it flashes 4 bars solid then go out and fly. The battery doesn't have memory, it doesn't know how long it has been left uncharged. It just knows how much power it has.

4 bars solid merely means that it is above 75%, and hasn't lost enough to reach 75% yet. The remaining battery power will depend upon the time since last charge.

 

[bobmyers]

I'm a battery expert, so listen to me. It's simple, push the button one time on your battery. If it flashes 4 bars solid then go out and fly. The battery doesn't have memory, it doesn't know how long it has been left uncharged. It just knows how much power it has.

What? Huh? Really? Battery Expert? Should everyone listen to the "expert" or DJI who engineered, designed and produced the P3 and the present Smart Batteries. They designed them to be fully charged before flying with them. So if it was ok to go out and fly with 4 solid bars 24 or 36 hours after charging, that would probably have been written into the recommendation.

All of this expert opinion is complete nonsense. Why would anyone want to chance going against DJI's recommendations and fly with batteries that are less than fully charged-- especially after letting them sit overnight. It just does not make and sense. Fly at your own risk. There is enough that can go wrong without adding to the list.

 

[alokbhargava]

I'm a battery expert, so listen to me. It's simple, push the button one time on your battery. If it flashes 4 bars solid then go out and fly. The battery doesn't have memory, it doesn't know how long it has been left uncharged. It just knows how much power it has.

80% charge can also light those 4 LEDs.

Problem is not how much charge is left on the battery, the real issue is can SW compute the battery discharge curve and thus the remaining charge/ time? If the discharge follows predetermined curve, you will get the correct alarms else you may miss the alarm or you will get the false alarm.

 

[snowghost]

I've had my batteries sit a week at full charge.When firing up the Phantom they'll show around 95% or so. Never had an issue. I wouldn't use a 50% battery unless I was purposely draining it for a full discharge.

 

[TC Malker]

What? Huh? Really? Battery Expert? View attachment 37570Should everyone listen to the "expert" or DJI who engineered, designed and produced the P3 and the present Smart Batteries. They designed them to be fully charged before flying with them. So if it was ok to go out and fly with 4 solid bars 24 or 36 hours after charging, that would probably have been written into the recommendation.

All of this expert opinion is complete nonsense. Why would anyone want to chance going against DJI's recommendations and fly with batteries that are less than fully charged-- especially after letting them sit overnight. It just does not make and sense. Fly at your own risk. There is enough that can go wrong without adding to the list.

Omg, I flew at 99% battery and my bird crashed! You were right I should have listened to you.

 

[alokbhargava]

Omg, I flew at 99% battery and my bird crashed! You were right I should have listened to you.

Are you kidding now?

 

[shockwave199]

So according to many on this forum your not supposed to use a charged battery if you haven't used it in a few days.

Well what are you supposed to do with the 100% charged batteries that are sitting around for a few days and haven't started discharging yet? I tried connecting it to the charged before use, but it doesn't start charging it because it is already fully charged.

I would fly it but I would be more conservative about the flight. I wouldn't send it out on a 4k' run, let's put it that way. It could be just fine though, but since I have multiple batteries I'd have one freshly charged for my flight and use the one that's been sitting for a few days for a closer in flight- not too high and not too far just in case it decides to misbehave. I might even be inclined to hover it for five minutes in the back yard down to 80% or so and then charge it. I personally don't like flying a battery that's charged outside of a 24 hour period. It's what I would do, not necessarily what anyone else would do.

 

[Erroll]

...DJI's recommendations...

DJI also recommends not to fly over water, and I have no doubt you follow that recommendation very strictly? I know I don't.

Most of DJI's recommendations are pure CYA, especially in the US.

 

[Hung]

You need to turn it on before connecting the charger

The company recommends not turning on the battery when charging it. Just use it into 50% power then charge it.

 

[alokbhargava]

The company recommends not turning on the battery when charging it. Just use it into 50% power then charge it.

If batteries are 95% charged and you want to charge more to 100%, it's recommend to turn on battery before charging.

 

[alokbhargava]

DJI also recommends not to fly over water, and I have no doubt you follow that recommendation very strictly? I know I don't.

Most of DJI's recommendations are pure CYA, especially in the US.

You should not fly over water if you are only 10-12' above as VPS system may not be stable over water. There is no problem in flying over water if height is 20' or more.

 

[GadgetGuy]

80% charge can also light those 4 LEDs.

Problem is not how much charge is left on the battery, the real issue is can SW compute the battery discharge curve and thus the remaining charge/ time? If the discharge follows predetermined curve, you will get the correct alarms else you may miss the alarm or you will get the false alarm.

I've seen no evidence of inaccurate remaining charge/time from not topping off, but it will happen if you don't discharge to 8% after every 20 flights.

80% is a problem because it removes the top 20% you may need to safely get home if the wind changes, or RTH gets activated, or Autoland kicks in at 10% over water. That 10% Autoland over water would otherwise be a very safe 30%. It's your bird and your risk, but I always top off before flying. Heck, even at 100%, by the time everything warms up, you are already at 95-97% before getting into the air.

 

[GadgetGuy]

If batteries are 95% charged and you want to charge more to 100%, it's recommend to turn on battery before charging.

Not only "recommended" but absolutely necessary, as otherwise it won't top off. Same is true on the DJI battery hub. It ignores any battery at 95% or higher, unless you first turn them on.

 

[GadgetGuy]

You should not fly over water if you are only 10-12' above as VPS system may not be stable over water. There is no problem in flying over water if height is 20' or more.

Or just turn off VPS in DJI GO if you think it will be an issue within 9 feet or so of the water, which is when it will kick in, only if it determines that the water is ground. I think the lateral stability over water is the issue, as their is no shape or contrasting linrs to use to maintain position over water, like there usually is indoors and over ground.

 

[bobmyers]

DJI also recommends not to fly over water, and I have no doubt you follow that recommendation very strictly? I know I don't.

Most of DJI's recommendations are pure CYA, especially in the US.

Flying over water and flying with a partially charged battery in not analogous with regard to what causes crashes. Water for the most part does not cause crashes unless you get too close to it-- but flying with a partially charged battery may certainly cause the P3 to fall out of the sky. I don't even know why we are arguing this point. It is a senseless argument and serves no good purpose.
Cheers

 

[Erroll]

Flying over water and flying with a partially charged battery in not analogous with regard to what causes crashes. Water for the most part does not cause crashes unless you get too close to it-- but flying with a partially charged battery may certainly cause the P3 to fall out of the sky. I don't even know why we are arguing this point. It is a senseless argument and serves no good purpose.
Cheers

I wasn't attempting to draw any analogy. I tried to show that just because DJI recommends something does not mean you (or your quad) are doomed if you don't follow that recommendation, as you tried to assert.

Think about it. When DJI want to enforce something, they do so. Consider no fly zones as an example. If there was a sound scientific reason for not allowing take-offs with batteries which are not fully charged, they would have enforced that too rather than just recommended that you don't.

Although common sense is not as common as one would expect, there is plenty of room for it.

 

[RedHotPoker]

I bought a second 100w charger, and find it very convenient to always maintain my battery levels at peak performance for the very best flying experiences. It's so easy to turn on the radio, drone and go app, to check "exact" battery levels, and top them up accordingly, before heading out to fly.
Why would you want to lose any of your most precious flying time, by deliberately going to fly with battery levels below full percent of charge? ;-)
Unless you are charging while driving. . .
Always Top them Up, and get the most out of each and every flight.

RedHotPoker

 

[Erroll]

Why would you want to lose any of your most precious flying time, by deliberately going to fly with battery levels below full percent of charge? ;-)
Unless you are charging while driving. . .
Always Top them Up, and get the most out of each and every flight.

RedHotPoker

Two days ago I upgraded from an iPad mini 3 to an iPad Air 2. After I had confirmed that all my apps had been restored and were the latest versions I wanted to test them. All my batteries had been auto-discharging for two days or so. I simply picked the next battery in the cycle, tested all three my apps, confirming proper video and signal feed, RTH etc. It took about 5 minutes of flying time.

I got everything I wanted out of those flights with about 65% charge on the battery, without having to waste time by first fully charging it first.

As I have said before, I made a conscious decision to fly with 65% and I flew accordingly - gentle take-offs and no full bursts of power.

Anyway, this subject has been beaten to death. To each his own.