Critical low voltage with 44% battery remaining

[SolidP]

Upload your DJI GO log here and post the link back here.

Hi. Here is the link. DJI Phantom 3 Log Viewer - Phantom Help

Doesn't till me to much. Happy if you can read something interesting from it.

 

[SolidP]

Solid,
just read your issue and your problem wasn't due to cold weather, it was because the battery had already gone into auto-discharge mode and you took off without charging it back up. 65% is the level the battery will read when it has auto discharged but for some reason it will go into critical battery mode if you try to fly with out charging. I have been able to override the auto land when this happened to me, but I was perhaps just lucky. Bottom line here is if the battery doesn't show all 4 lights, CHARGE IT.

Good to know. Had no idea about this 65% limit. Hopefully that's what happened!

 

[SolidP]

When now reviewing the flight I see that some propulsion warning came on quite early which I did not see. Never had that warning before and I was watching the drone... Don't even know what that message meen? Maybe someone can enlighten me?

I used to live in a warm country and just moved to a cold one. Thats why I thought it might had something to do with the cold...

While on the subject.. Any specific warm up procedures that I should do when flying in cold weather?

 

[Mark The Droner]

Personally, when I fly in cold weather, I like to have my batteries toasty warm before I start. I try to get the battery to around 30 C (86 F) before inserting it into the aircraft.

 

[msinger]

Doesn't till me to much.

It tells me the following:

- You took off with a low battery.
- The propulsion output was limited because you ascended too quickly on a low battery (this prevented your battery from shutting down)
- Your Phantom auto landed because the battery was critically low (you should be on the ground by 3.3V).

If the battery was at 100% on takeoff, you would have been okay flying that same route.

 

[fastsmiles]

Yes, that's what I've read elsewhere. DJI knows about this anomaly and has reproduced it. The same problem has been experienced in Inspire craft also. I read that DJI has already released new firmware for Inspire batteries but it hasn't fix it 100%, only partially, whatever that means. I would assume they are still working on fixing the battery firmware.

In my opinion, and I believe DJI's too, a craft should not fall out of the sky as some have reported due to sudden unexpected battery failure with little to no warning. It's logical the controller should give a low battery warning at least 2 to 3min before it goes into auto-land. No way should the motors stop and the craft fall from the sky, that's just wrong, definitely flawed. Anyone that thinks that is OK is way out in left field, IMHO. The fact that most forum members know about this anomaly makes it clear, right now it's absolutely imperative to charge to 100% before all flights, which I do anyway, but annoyed that's it's so critical, apparently. However owners that aren't part of this forum may not realize there is a subtle firmware flaw that DJI is working on, and as a result lose their craft in water, or other catastrophic results, virtually not knowing what happened, possibly thinking it got attacked by a bird, etc.

I'm just wondering, does this occur by flying a battery only 80% charged? 75%? 65%. I can see very easily some guy trying out various lens ND filters, going up for 4 min, taking some shots, coming down and changing a filter, going up again for 4min, coming down, up, down, etc. Do we really know that wouldn't trigger this anomaly? Are we absolutely sure the battery must be removed and re-inserted at partial charge to run this risk? It's unclear to me, but I know I won't be doing anything like that for a while, until it's fixed.

The other question I have, do we really think DJI will announce this fix, explaining what it fixes, or will they just introduce new battery firmware with no information (which has been known to happen)?

These smart batteries need some schooling, because today it appears they act moronic in certain circumstances.

I do mostly still photos and I also take a lot of pictures of the P3 in flight, so I am constantly taking off for short flights with a partially discharged battery, moving to a new location and flying again, and I have never had a problem unless the battery had been idle for several days between flights.
It's only happened to me once, that the P3 went into auto land with a battery that still had 46%.

 

[SolidP]

It tells me the following:

- You took off with a low battery.
- The propulsion output was limited because you ascended too quickly on a low battery (this prevented your battery from shutting down)
- Your Phantom auto landed because the battery was critically low (you should be on the ground by 3.3V).

If the battery was at 100% on takeoff, you would have been okay flying that same route.

Great answer. Thank you! I have only been flying down to what the app says is 10% and not even then did it auto land so i was a bit puzzled about this sInce i had a lot of battery left according to the app... I have never even thought about keeping track of voltage..

Just one thought. Why is the app showing 50% battery if it's not. If it was showing near empty I would not have taken off...

 

[SolidP]

Personally, when I fly in cold weather, I like to have my batteries toasty warm before I start. I try to get the battery to around 30 C (86 F) before inserting it into the aircraft.

How do you heat them if out and about? Thinking body heat but it might look weird walking around with batteries in my pants..

 

[Mark The Droner]

I don't heat them out and about. I usually fly from right outside my back door.

I haven't posted this yet because people might think I'm crazy, but then again, maybe I am.

I would only do the following on cold days.

I've tested this several times and this is the method I came up with:

I place the battery in my kitchen oven. I turn on my kitchen oven on its lowest possible setting for exactly 90 seconds. I actually set the timer and stand next to the oven for 90 seconds.

The timer goes off.

After 90 seconds, I turn the oven completely off. I leave the battery in the oven for 15-20 minutes. Again, I set the kitchen timer - this time for 15-20 minutes.

When the timer goes off, I remove the battery.

I've tested this a number of times. Basically, I'm cooking the battery like it was a roast. By the time I turn the oven off after 90 secs, the oven temp is at 68 F, according to the meat thermometer I also placed in the oven. But while it's off, the heat in the oven continues to increase from 68 F to over 100 F approaching 140 F. The hottest it has ever gotten is 138 F, and then the temp begins to recede.

After 20 mins I remove the battery, and when I check the temp of the battery, and it's always at about 86 F (30 C). Then I slap the battery into my aircraft and fly.

I do not recommend this method. At least not without first doing multiple oven temperature tests on your own oven - coupled with a mental health evaluation.

 

[Imabiggles]

Good to know. Had no idea about this 65% limit. Hopefully that's what happened!

In looking at a self discharged battery, yeah - it says it stops at 65% or so, but actually is more like 30%. My self discharged batterys take way more than 40% capacity in mAh when charged. I think its do to the low amperage self discharge, the LIPO drops cell voltage slowly to settle in to a very good storage per cell voltage. HOWEVER, as soon as you put a load on them, voltage sags way down. That is the nature of LIPOs. It is not a firmware bug. You can use voltage as a 'gas tank gage' if you are discharging at significant amperage over a short period of time. You can not use it for very slow ma discharges over a long time. All my LIPOs behave this way. The solution is to never take off with a self discharged battery.

If you wish, you can charge P3 batteries on a smart charger - set to Pb battery at 18 volts (traxxas adapter works for P3 battery). That way you can see exactly what capacity is pumped into the battery. I did this when I got my P3 so I can characterize the battery at various states and conditions. When my fixed wing battery goes critical, it aint no big thing. When my quad does, it sucks.

 

[alokbhargava]

I don't heat them out and about. I usually fly from right outside my back door.

I haven't posted this yet because people might think I'm crazy, but then again, maybe I am.

I would only do the following on cold days.

I've tested this several times and this is the method I came up with:

I place the battery in my kitchen oven. I turn on my kitchen oven on its lowest possible setting for exactly 90 seconds. I actually set the timer and stand next to the oven for 90 seconds.

The timer goes off.

After 90 seconds, I turn the oven completely off. I leave the battery in the oven for 15-20 minutes. Again, I set the kitchen timer - this time for 15-20 minutes.

When the timer goes off, I remove the battery.

I've tested this a number of times. Basically, I'm cooking the battery like it was a roast. By the time I turn the oven off after 90 secs, the oven temp is at 68 F, according to the meat thermometer I also placed in the oven. But while it's off, the heat in the oven continues to increase from 68 F to over 100 F approaching 140 F. The hottest it has ever gotten is 138 F, and then the temp begins to recede.

After 20 mins I remove the battery, and when I check the temp of the battery, and it's always at about 86 F (30 C). Then I slap the battery into my aircraft and fly.

I do not recommend this method. At least not without first doing multiple oven temperature tests on your own oven - coupled with a mental health evaluation.

Too risky for us to follow.

 

[msinger]

Why is the app showing 50% battery if it's not.

I'm not sure what you're referring to. According to your log, the app showed 61% at takeoff and 56% when you landed.

 

[SolidP]

I'm not sure what you're referring to. According to your log, the app showed 61% at takeoff and 56% when you landed.

I'm referring to my battery being drained but still showing about 50%.

 

[SolidP]

I don't heat them out and about. I usually fly from right outside my back door.

I haven't posted this yet because people might think I'm crazy, but then again, maybe I am.

I would only do the following on cold days.

I've tested this several times and this is the method I came up with:

I place the battery in my kitchen oven. I turn on my kitchen oven on its lowest possible setting for exactly 90 seconds. I actually set the timer and stand next to the oven for 90 seconds.

The timer goes off.

After 90 seconds, I turn the oven completely off. I leave the battery in the oven for 15-20 minutes. Again, I set the kitchen timer - this time for 15-20 minutes.

When the timer goes off, I remove the battery.

I've tested this a number of times. Basically, I'm cooking the battery like it was a roast. By the time I turn the oven off after 90 secs, the oven temp is at 68 F, according to the meat thermometer I also placed in the oven. But while it's off, the heat in the oven continues to increase from 68 F to over 100 F approaching 140 F. The hottest it has ever gotten is 138 F, and then the temp begins to recede.

After 20 mins I remove the battery, and when I check the temp of the battery, and it's always at about 86 F (30 C). Then I slap the battery into my aircraft and fly.

I do not recommend this method. At least not without first doing multiple oven temperature tests on your own oven - coupled with a mental health evaluation.

THIS is seriously crazy

I've now started to keep it close to my body. Under the jacket. Works perfectly. Even if it's -4C outside my battery is heated to exactly 30 degrees Celsius. Good to go....

 

[SolidP]

FYI. I've been in contact with DJI support abut my auto landing despite showing battery stats in the 50%. VERY quick response time I must say! They have looked at flight data and explained the autolanding as an safety measure. They do however classify my battery to be in need of service. So all speculations aside. If they consider it to be a fault you should all contact them if this happens. Not settle with knowledge that your battery MIGHT be empty even if it indicates more then 50%. It's not an acceptable feature and I'm pleased to know they agreed.

And again. They have responded very quickly in our correspondence. Been reading a lot of negative stuff on DJI support but so far they've been excellent!

Good luck everyone!

 

[msinger]

Not settle with knowledge that your battery MIGHT be empty even if it indicates more then 50%.

Where are you seeing you're battery being drained? It was only drained down to 56%. If you're asking why it auto landing, it's because you were climbing straight up very quickly on a low battery. After the DJI GO app warned you with the propulsion limited warning, you continued to give her all she had, so your Phantom had no choice but to auto land. To prevent this from happening again in the future, you should fly with a full battery and watch your battery voltage so you can fly accordingly.

 

[Juhead]

Wasn't a way around this problem is to never let the battery auto discharge once as that messes up the battery permanently.

So only way is to set it at 10 day discharge and always switch it on before 10 days to reset the counter.

 

[msinger]

Wasn't a way around this problem

Which problem are you referring to?

 

[AP4me]

I do mostly still photos and I also take a lot of pictures of the P3 in flight, so I am constantly taking off for short flights with a partially discharged battery, moving to a new location and flying again, and I have never had a problem unless the battery had been idle for several days between flights.
It's only happened to me once, that the P3 went into auto land with a battery that still had 46%.

Was the one time when you didn't use the battery for a few days in between?

 

[SolidP]

Where are you seeing you're battery being drained? It was only drained down to 56%. If you're asking why it auto landing, it's because you were climbing straight up very quickly on a low battery. After the DJI GO app warned you with the propulsion limited warning, you continued to give her all she had, so your Phantom had no choice but to auto land. To prevent this from happening again in the future, you should fly with a full battery and watch your battery voltage so you can fly accordingly.

I didn't see that it was drained. Just people on here that said it's likely to be the case. That a battery left idle drains it self but will still show more then 50%. It's suggested that when it's drain to 65% it goes in to self depletion mode. Hence the need of "topping up". Speculations maybe but it sounds very close to what happened to me.

And. If it says 50 or more I don't expect the battery to in fact be empty. And as I said. I didn't se the first warning due to looking at the drone instead of the display. And SINCE it showed more then 50% battery I didn't expect it to do anything stupid. Full throttle has never ever given me any strange warnings or auto landing before. If the battery cant handle whats going on when showing more then 50% i find it to be something wrong. DJI seems to agree...