EVO II battery instantly went to ZERO!

[Steverino]

For the second time in as many months, I had a battery instantly drop from about 50% to 0% and the EVO II did an automatic landing. Unfortunately, it landed in the river. The battery had about 90 discharge cycles on it and the last battery that failed also had about the same number of discharge cycles. I expected I could get about 200 discharge cycles out of these batteries since Autel warranties them for 200 cycle within a year after purchase. Both of these batteries were about a year and a half old so they were out of warranty.

My question is, should I just discard an Autel EVO II battery when it get's 90 discharge cycles on it? What has been the experience of others here with these batteries? Prior to each failure, there was no indication what so ever that the battery near the end of its life. However, interestingly, on both flights, I noticed the battery was just over 50% right after I started the flight. This was unusual because I normally charge the batteries after each flight. I assumed I forgot and kept flying but planned to keep both flights short. Of course, I wasn't expecting the battery to suddenly go to zero. I'm wondering if perhaps a sign of a faulty battery is when it looses about half it's charge within a couple of days of being charged. I don't know for sure that the batteries had been charged but I'm about 90% sure they had been. I fly frequently and don't recall ever forgetting to charge the batteries prior to flight and the only two times I noticed the batteries were already almost half discharged, both batteries instantly went to zero within the first two minutes of flight.

The video of the crash was corrupt but I was able to recover all but the last few seconds. If anyone is interested, here it is:

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I added stock footage at the end to simulate the crash.

 

[AirStag]

Sad. I worry about that happening on every flight. I lost a Mavic Air a few years ago when it did almost the same thing, except I had no control. It just announced "landing" and slowly descended into the Ohio River. Most of my Evo II batteries are > 50 cycles, so.......

 

[lugin]

For the second time in as many months, I had a battery instantly drop from about 50% to 0% and the EVO II did an automatic landing. Unfortunately, it landed in the river. The battery had about 90 discharge cycles on it and the last battery that failed also had about the same number of discharge cycles. I expected I could get about 200 discharge cycles out of these batteries since Autel warranties them for 200 cycle within a year after purchase. Both of these batteries were about a year and a half old so they were out of warranty.

My question is, should I just discard an Autel EVO II battery when it get's 90 discharge cycles on it? What has been the experience of others here with these batteries? Prior to each failure, there was no indication what so ever that the battery near the end of its life. However, interestingly, on both flights, I noticed the battery was just over 50% right after I started the flight. This was unusual because I normally charge the batteries after each flight. I assumed I forgot and kept flying but planned to keep both flights short. Of course, I wasn't expecting the battery to suddenly go to zero. I'm wondering if perhaps a sign of a faulty battery is when it looses about half it's charge within a couple of days of being charged. I don't know for sure that the batteries had been charged but I'm about 90% sure they had been. I fly frequently and don't recall ever forgetting to charge the batteries prior to flight and the only two times I noticed the batteries were already almost half discharged, both batteries instantly went to zero within the first two minutes of flight.

The video of the crash was corrupt but I was able to recover all but the last few seconds. If anyone is interested, here it is:

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I added stock footage at the end to simulate the crash.

Wow how did you recover it? Did it float? Sorry to see that happen. Thats why I'm always afraid to fly it over water!

 

[Bonanzaman]

I suspect when enough of the current batteries reach end of their service life, we will see these packs get rebuilt……I’ve been doing this for a few years now with good success in regular rc fixed wing craft. Should be pretty easy to do, as the cells in these packs are mounted individually with air space between them for cooling. We just need enough working history to figure out how many cycles are a reasonable service life, before pulling them out and rebuilding….might be able to squeeze in a few more mah’s capacity as well ! In fact, now that I think about it….Anyone who has depleted packs, I’d be willing to buy ‘‘em for reconditioning…just pm me.. well, let’s start with 1 anyway and see if I can source some suitable cells!

 

[Andrew01]

For the second time in as many months, I had a battery instantly drop from about 50% to 0% and the EVO II did an automatic landing. Unfortunately, it landed in the river. The battery had about 90 discharge cycles on it and the last battery that failed also had about the same number of discharge cycles. I expected I could get about 200 discharge cycles out of these batteries since Autel warranties them for 200 cycle within a year after purchase. Both of these batteries were about a year and a half old so they were out of warranty.

My question is, should I just discard an Autel EVO II battery when it get's 90 discharge cycles on it? What has been the experience of others here with these batteries? Prior to each failure, there was no indication what so ever that the battery near the end of its life. However, interestingly, on both flights, I noticed the battery was just over 50% right after I started the flight. This was unusual because I normally charge the batteries after each flight. I assumed I forgot and kept flying but planned to keep both flights short. Of course, I wasn't expecting the battery to suddenly go to zero. I'm wondering if perhaps a sign of a faulty battery is when it looses about half it's charge within a couple of days of being charged. I don't know for sure that the batteries had been charged but I'm about 90% sure they had been. I fly frequently and don't recall ever forgetting to charge the batteries prior to flight and the only two times I noticed the batteries were already almost half discharged, both batteries instantly went to zero within the first two minutes of flight.

The video of the crash was corrupt but I was able to recover all but the last few seconds. If anyone is interested, here it is:

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I added stock footage at the end to simulate the crash.

I would reach out to Autel support and try to get them to send you another one and honor their warranty. This has been an open question for a while as to whether or not they'll actually do that (I haven't seen a response from them on the subject yet) , and it'd be valuable to all of us to know where they stand on it.

Always always record your screen as well when flying, so if there's a mishap you have more evidence to prove what happened.

 

[moodman]

I suspect when enough of the current batteries reach end of their service life, we will see these packs get rebuilt……I’ve been doing this for a few years now with good success in regular rc fixed wing craft. Should be pretty easy to do, as the cells in these packs are mounted individually with air space between them for cooling. We just need enough working history to figure out how many cycles are a reasonable service life, before pulling them out and rebuilding….might be able to squeeze in a few more mah’s capacity as well ! In fact, now that I think about it….Anyone who has depleted packs, I’d be willing to buy ‘‘em for reconditioning…just pm me.. well, let’s start with 1 anyway and see if I can source some suitable cells!

I've been saying for a while that anyone who figures out how to rebuild drone batteries will make a fortune. Essentially, our expensive drones are worthless without the proprietary batteries that run them. There is a YouTuber who took apart one of the Evo1 battery packs and shows what's inside. When (not if) my batteries go bad I will try to rebuild them myself. I have nothing to lose, but I would also consider paying someone who knows how. (hint hint)...

 

[GeoDrone SRL]

For the second time in as many months, I had a battery instantly drop from about 50% to 0% and the EVO II did an automatic landing. Unfortunately, it landed in the river. The battery had about 90 discharge cycles on it and the last battery that failed also had about the same number of discharge cycles. I expected I could get about 200 discharge cycles out of these batteries since Autel warranties them for 200 cycle within a year after purchase. Both of these batteries were about a year and a half old so they were out of warranty.

My question is, should I just discard an Autel EVO II battery when it get's 90 discharge cycles on it? What has been the experience of others here with these batteries? Prior to each failure, there was no indication what so ever that the battery near the end of its life. However, interestingly, on both flights, I noticed the battery was just over 50% right after I started the flight. This was unusual because I normally charge the batteries after each flight. I assumed I forgot and kept flying but planned to keep both flights short. Of course, I wasn't expecting the battery to suddenly go to zero. I'm wondering if perhaps a sign of a faulty battery is when it looses about half it's charge within a couple of days of being charged. I don't know for sure that the batteries had been charged but I'm about 90% sure they had been. I fly frequently and don't recall ever forgetting to charge the batteries prior to flight and the only two times I noticed the batteries were already almost half discharged, both batteries instantly went to zero within the first two minutes of flight.

The video of the crash was corrupt but I was able to recover all but the last few seconds. If anyone is interested, here it is:

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For more detailed information, see our cookies page.

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I added stock footage at the end to simulate the crash.

I had last year one experience like yours....but without crash...
I have inserted a battery that showed 100% at check (full led, also 99% in AE)...The battery was not charged in last 8 days, discharging is set for 5 days at all my batteries...
I have started to fly and do some tests for a mapping mission...after only 8 minutes, I have the message with "Critical Battery! Auto-Landing!"....The drone was at 50 meters away, in a field...so I was able to get it back and land it as it was in Forced Landing already...
What I believe it happened:
- Somewhere was a bug and the battery did not refreshed the actual charge...just showed 100%...At moment of fly, internally was actualized to new value at the moment it reached the minimum V and reported low battery...
I had refreshed the firmware using the BIN on microsd...I had made another 2 flights with that battery watching for discharge rate and balancing of cells...All is fine...so...was unable to replicate the error.
The point is:
- At each flight, recharge your battery that you will use with less then 24h before take off...In this way you will prevent any discharges and misreported values...

Probably was not a thing to observe, but I have realized in that day that I did not charged the batteries before flight (all other 3 batteries were at around 55-60%, only this one was remaining at 100%)....and as I have the Hub for charging all, was impossible to have one at 100%.

 

[Steverino]

I had last year one experience like yours....but without crash...
I have inserted a battery that showed 100% at check (full led, also 99% in AE)...The battery was not charged in last 8 days, discharging is set for 5 days at all my batteries...
I have started to fly and do some tests for a mapping mission...after only 8 minutes, I have the message with "Critical Battery! Auto-Landing!"....The drone was at 50 meters away, in a field...so I was able to get it back and land it as it was in Forced Landing already...
What I believe it happened:
- Somewhere was a bug and the battery did not refreshed the actual charge...just showed 100%...At moment of fly, internally was actualized to new value at the moment it reached the minimum V and reported low battery...
I had refreshed the firmware using the BIN on microsd...I had made another 2 flights with that battery watching for discharge rate and balancing of cells...All is fine...so...was unable to replicate the error.
The point is:
- At each flight, recharge your battery that you will use with less then 24h before take off...In this way you will prevent any discharges and misreported values...

Probably was not a thing to observe, but I have realized in that day that I did not charged the batteries before flight (all other 3 batteries were at around 55-60%, only this one was remaining at 100%)....and as I have the Hub for charging all, was impossible to have one at 100%.

Thanks for the information. It both cases, I had not recharged the battery within 24 hours and both batteries were partially discharged when I flew with them. I tend to try to use the batteries as much as I can before I recharge them to limit the number recharge cycles. I still have one of the batteries that went instantly to zero when it was at about 50% and I've tested that battery after recharging it and it now will last it least until it gets to about 20%. But I'm still afraid to use that particular battery, especially when flying over water.

 

[tvwxman]

Here's my battery update. I've owned this drone since Father's Day 2020, just over a year and a half. I have four batteries, but can't say for sure when each were bought, but based on the charging cycles, pretty easy to deduce their ages from oldest to youngest. For starters, I've had two REALLY close calls with, as logic would dictate, my oldest battery. Three weeks ago I was flying in near-freezing weather and when my low battery warning hit at 20%, five seconds later it alerted that it was landing and I looked down to see 0%. Fortunately it was only 30 feet high and near my original home point. I assumed the cold air had a lot to do with it, and did not give it more thought. Yesterday, I was once again flying very close and low altitude and I had just looked down and saw I had 30% on my battery and by the time I looked back up to decide on my next maneuver, the alert sounded and the drone landed with 0%, but safely.

So after two scary close-calls, I decided to do a long-overdue inventory on my four batteries, beginning with the oldest and most troublesome battery:

1. 88 cycles
2. 62 cycles
3. 44 cycles
4. 14 cycles

The battery with 62 cycles started swelling up on me post flights last summer and so I shelved it. Thus, it was probably bought with the original drone purchase but fell behind cycles since I benched it. I started using it carefully again recently in the cooler weather and it hasn't swelled up on me again (yet), but I'm using it with caution - not over water, not too far away from me. Despite the swelling last year though, it hasn't misbehaved in any other way.

Batteries 3 and 4 have been perfectly fine to date, no surprise.

In the early days, I would charge my batteries up to 100% after every flight. Rarely did they hit the six day discharge point since I was having so much fun and flying all the time.

Now with two weeks in between flights becoming more common, I'm not sure what is best. I've seen both sides of it with some saying they charge immediately after each flight and let it discharge, while others don't recharge their batteries until it's time to fly again.

But in terms of number of cycles, I guess I'm a bit disappointed with two batteries I own - both well below 100 cycles - already showing signs of fatigue.

 

[cholpuch68]

My battery story is as follows... I received my Evo 2 Pro on 10/10/20 with three (3) batteries. Accessorizing netted me an additional battery on 10/12/20. I write the in-service date on my batteries with a permanent marker. To date, I have had no battery issues. I have adjusted my "low" and "critical" battery charge levels to 20% and 10%. I began to keep flight records in 2021 and logged more than 35 hours over 84 flights. My average take-off battery charge level was 98% and 17% average charge remaining at landing. My average flight time was 25 min. 17 sec. I am in the practice of charging my batteries after each use and have set them to begin automatic discharge after 4 days. I will bring them up to full charge the day before a planned flight. My concern stems from the times I've charged the batteries in preparation for a planned flight but end up not "putting the bird in the air." Battery balance/use was fairly consistent through 2021 with 20, 23, 19, and 22 flight, but when I checked the batteries through the app I found 42, 45, 44, and 48 discharge cycles. I know I flew a few times at the end of 2020 but I'm sure it wasn't 95 times! Sharing thoughts, ideas, and previous experiences on the matter are encouraged and greatly appreciated.

 

[Andrew01]

My battery story is as follows... I received my Evo 2 Pro on 10/10/20 with three (3) batteries. Accessorizing netted me an additional battery on 10/12/20. I write the in-service date on my batteries with a permanent marker. To date, I have had no battery issues. I have adjusted my "low" and "critical" battery charge levels to 20% and 10%. I began to keep flight records in 2021 and logged more than 35 hours over 84 flights. My average take-off battery charge level was 98% and 17% average charge remaining at landing. My average flight time was 25 min. 17 sec. I am in the practice of charging my batteries after each use and have set them to begin automatic discharge after 4 days. I will bring them up to full charge the day before a planned flight. My concern stems from the times I've charged the batteries in preparation for a planned flight but end up not "putting the bird in the air." Battery balance/use was fairly consistent through 2021 with 20, 23, 19, and 22 flight, but when I checked the batteries through the app I found 42, 45, 44, and 48 discharge cycles. I know I flew a few times at the end of 2020 but I'm sure it wasn't 95 times! Sharing thoughts, ideas, and previous experiences on the matter are encouraged and greatly appreciated.

it'll still count as a cycle to the battery if it auto discharges, even if you don't fly. I have cycles I've "lost" because of weather problems, plans changing, or because "reasons" that kept me from flying. Ive found it to be best to keep them in storage level and charge only the day before a flight to minimize that from happening too. Of course things come up, but if you can find a way to "use" the cycle before it discharges via maintenance/test flights, firmware updates, etc, you can get the most of it.

 

[sidc3000]

We’re having the same discharge issue with a brand new EVO II Pro Enterprise. Two incidents, within a few weeks, where we had a rapid discharge of the battery mid-flight. The first incident we chalked up to a cold day with high winds. Today’s incident was a perfect 75 degree day. Both times the battery discharge within minutes and had emergency landings. Not sure what could be going on.

 

[mondodrum77]

For the second time in as many months, I had a battery instantly drop from about 50% to 0% and the EVO II did an automatic landing. Unfortunately, it landed in the river. The battery had about 90 discharge cycles on it and the last battery that failed also had about the same number of discharge cycles. I expected I could get about 200 discharge cycles out of these batteries since Autel warranties them for 200 cycle within a year after purchase. Both of these batteries were about a year and a half old so they were out of warranty.

My question is, should I just discard an Autel EVO II battery when it get's 90 discharge cycles on it? What has been the experience of others here with these batteries? Prior to each failure, there was no indication what so ever that the battery near the end of its life. However, interestingly, on both flights, I noticed the battery was just over 50% right after I started the flight. This was unusual because I normally charge the batteries after each flight. I assumed I forgot and kept flying but planned to keep both flights short. Of course, I wasn't expecting the battery to suddenly go to zero. I'm wondering if perhaps a sign of a faulty battery is when it looses about half it's charge within a couple of days of being charged. I don't know for sure that the batteries had been charged but I'm about 90% sure they had been. I fly frequently and don't recall ever forgetting to charge the batteries prior to flight and the only two times I noticed the batteries were already almost half discharged, both batteries instantly went to zero within the first two minutes of flight.

The video of the crash was corrupt but I was able to recover all but the last few seconds. If anyone is interested, here it is:

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I added stock footage at the end to simulate the crash.

This just happened to me. Did Autel ever get back to you? I have had 21 flights with the drone and the flight record showed it going from 80% to 3%. thanks

 

[Sam Stone]

For the second time in as many months, I had a battery instantly drop from about 50% to 0% and the EVO II did an automatic landing. Unfortunately, it landed in the river. The battery had about 90 discharge cycles on it and the last battery that failed also had about the same number of discharge cycles. I expected I could get about 200 discharge cycles out of these batteries since Autel warranties them for 200 cycle within a year after purchase. Both of these batteries were about a year and a half old so they were out of warranty.

My question is, should I just discard an Autel EVO II battery when it get's 90 discharge cycles on it? What has been the experience of others here with these batteries? Prior to each failure, there was no indication what so ever that the battery near the end of its life. However, interestingly, on both flights, I noticed the battery was just over 50% right after I started the flight. This was unusual because I normally charge the batteries after each flight. I assumed I forgot and kept flying but planned to keep both flights short. Of course, I wasn't expecting the battery to suddenly go to zero. I'm wondering if perhaps a sign of a faulty battery is when it looses about half it's charge within a couple of days of being charged. I don't know for sure that the batteries had been charged but I'm about 90% sure they had been. I fly frequently and don't recall ever forgetting to charge the batteries prior to flight and the only two times I noticed the batteries were already almost half discharged, both batteries instantly went to zero within the first two minutes of flight.

The video of the crash was corrupt but I was able to recover all but the last few seconds. If anyone is interested, here it is:

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I added stock footage at the end to simulate the crash.

Have the same with Mavic 2 Pro on lake O'Hara (BC). I lost my drone and switched to EVO 2 Pro V3 after.

 

[tvwxman]

There is another recent thread on here discussing sudden drops in battery charges, and the takeaway I got from those who posted is the batteries MUST be recharged to 100% before every flight if you want the most dependable and reliable performance from them, ESPECIALLY if they were allowed to self-discharge over time. Apparently LiPo batteries have multiple cells in them, and they can fall out of 'balance' when discharged, a dangerous situation. Recharging the batteries does a balancing routine on the cells at the very end of the charging cycle, so it's important to leave the batteries charging until the lights go off - again - not before since the balancing is the last thing that happens in the process.

 

[moodman]

There is another recent thread on here discussing sudden drops in battery charges, and the takeaway I got from those who posted is the batteries MUST be recharged to 100% before every flight if you want the most dependable and reliable performance from them, ESPECIALLY if they were allowed to self-discharge over time. Apparently LiPo batteries have multiple cells in them, and they can fall out of 'balance' when discharged, a dangerous situation. Recharging the batteries does a balancing routine on the cells at the very end of the charging cycle, so it's important to leave the batteries charging until the lights go off - again - not before since the balancing is the last thing that happens in the process.

Where did you get this info about "balancing being the last thing in the process"? Additionally, I am puzzled by this common theme being discussed here - that is, why is it that the batteries will suddenly drop to zero. Batteries just don't do that! Batteries keep discharging until their voltage goes to zero. They don't just "sudddenly" go to zero? I can only conclude then that what is happening is that the drone sees a certain voltage and interprets that as zero percent, but in fact it is not zero.
Therefore, I believe that Autel has preprogrammed their birds to just quit! I think this could be fixed by them programming their drones, instead of flying with "all or nothing", route the remaining battery voltage, whatever it is, into an emergency mode, in which all remaining battery power is directly routed to the prop motors (balanced out of course) so that the bird will land safely instead of just dropping out of the sky. A bonus would be maybe a mode in which it calculates which direction it came from and attempt to fly back to the takeoff point.
My question for Autel (and DJI too) is WHY CAN'T you do this? Surely you have some smart people in your company who can figure this out. Either this, or publish the schematics and wiring diagrams so us users can do it ourselves!

 

[tvwxman]

Here is the thread I referenced, pay particular attention to the post by 'herein2021'...

Drone crash when battery went from 21% to 0% in 10 seconds...

Hi team: So I did a short flight yesterday with my Nano plus (10month old). Taking off with a battery showing 61%. All is well until RTH is trigger when the battery is down to 24% after 5 minutes of flying. So I immediately started to fly back in a straight line. The battery was down to 21%...

autelpilots.com

 

[symphonyx314]

I have my evo2 pro 6k with me all the time, I fly almost dairy when im on vacations, yesterday 3 of my batteries when from 100% to 0% in less than 30 seconds after starting my flight, and I get the emergency landing warning, I was very near so I could resolve it , this never happen to me, and happen on 3 batteries I had 2 years of use, I put my new battery that has just 6 cicles and all perfect, the other 3 are 56, 48 and 55 cicles, this happen to me in very cold weather, -10 degree celsius, do I have to through away the 3 batteries ? and purchase new ones?

 

[Paxaran]

Hi- same issue here on both of my batteries on the Eve 2. Both have less than 30 cycles over the past year as I only use it occasionally. I was able to fly for less than 10 minutes today. Perhaps the cells are not being conditioned properly? Absurd. I have LiPo batteries for home built quadcopter that are still going strong 5 years later.

 

[Sam Stone]

The same thing happened to me with the Mavic 2 Pro. I was wearing glasses and did not have time to take them off to see the place of the fall. One consolation, the drone fell into the beautiful lake O'Hara BC. After that, I bought a Autel 2 pro but the problem does not seem will disappear ))