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Serious Defect: Too Much Fun

rktman

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Really.

I've been flying DJI drones for 7 years. Never, not ONCE, has this ever happened to me.

I was just out, flying at home, launching off my back deck. Flying with the MC, I was an Ace in an fighter jet. Having a blast.

RTH kicked in for safe return, I was close to home so I canceled it and started heading back on my own (about 1200 feet away), Well, started having too much fun with the MC on the trip back, forgot what I was doing. The short of it is, I ended up at critical battery, forced landing, not in a good place.

I was lucky. 0% battery, starting at 250ft altitude, and just close enough to get it back over houses and trees to the court in front of my house. All the while descending without any choice. It was close with really no margin to spare.
 
I know what you mean about having to much fun! It's a blast! I fly off my back patio sometimes but I always keep an eye on my battery %.

I have been flying long enough for the RTH to kick in but wasn't that far out. The thing is, your having so much fun seems like the battery lasts no time!
 
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Hi, I do not have the Dji fpv so am just making assumptions. With a traditional fpv drone you must not fly until it drops. The battery will be severely damaged and the quad may catch fire. Although the Dji fpv has more safety features, say it is bad to fly it down to 0% but now it also has to descend from 250ft.
Can it show battery voltage and is it setup where you should stop at 25% or at 0%?
 
It shows battery percentage, remaining time, warns you to come back when needed based on distance and current battery level, then initiates auto return if you ignore it... It does a lot to ensure you never get below 10% but there will always be people ignoring all of it.
 
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Well, to be fair (to me 😁 ) I didn't ignore it, just decided to fly back myself.

The problem came about when I was having too much fun doing that, forgot what I was supposed to be doing, and got a shocking whack to the head when critical battery alert hit.

Never happened in 7 years, I'm an experienced pilot, but I guess not with the thrill of FPV. The thrill got away from me 😁.

Any fun people here, or just scolding critics? No harm no foul, lighten up gang. Hope someone else can learn from my close call.
 
Ya I'm not a FPV flyer until the little DJI appeared. I'd agree, it's a challenge, and a Blast! It's easily added a new level of non-work pure fun! After 5 paks, I'm feeling mentally drained and I'm not even doing acrobatics... yet!

The DJI batteries, when at 0% are not at the minimal voltage threshold... their IC circuitry protect going under minimal voltage specifications of the LiPo that cause damage.

Actually that's true for other DJI batteries too, you won't go into minimal voltage threshold at 0 %. Normal practice on cinematic platforms is to land prior to 10 percent to allow amperage draws sufficient to fly the craft home, manuver and to maintain a safety margin to dip into amps if needed. But on occasion deep recycle practice and allow battery to balance fully, I'll often hover a Matrice, Inspire,etc to depletion of 6-4% then land it and leave it on til 2 or 3%. Cool it and recharge without damage.

Standard LiPo lacks any IC Circuitry and will allow voltage to go below the minimum voltage threshold (varies depending on number of cells).

As fast as this little craft draws and drains the amps, I'm sure that calculation is in the IC Circuitry... I haven't measured it at 0% percent on bench... but I'd assume there was additional allowance programmed into this battery FW. The "percentage" doesn't directly equate to voltage and 0% can have different low voltage parameters with different platforms. Heavier platforms tend to have 0% further from minimum voltage than lighter DJI platforms.

I routinely override the FPV's RTH and land around 8-9%... sometimes lower. I'd personally like to modify the RTH value a bit further out before it activates... I'm normally watching it and preparing to stop and override... that 6 second count down routine... I'd prefer a normal RTH warning where you can immediately cancel the popup and continue. I've also experienced the forced land procedure while hovering above LZ... I think that activates in the 4-5% area. No option other than going down once kicked in... although you can leave it on, motors off if desired for a deep cycle discharge still.

More importantly is to allow the lipo gel to "cool" before recharging... I personally give then 1 hour minimal. Charging hot lipo gel accerlates the LiPo gel decay and increases IR value. If it's warm on the battey case, it's hot internally. Recharging a hot pak can motivate shorter life much more than low battery percentage programmed into FW. Hot recharge of any LiPo and dipping below minimum voltage are the 2 things that will effect battery life. Ya can't stop the LiPo decay, but you can slow it's rate. Hot accelerates decay, and below minimum voltage effect the gel chemistry to accept a charge.

Yep, the little craft is a Blast!
 
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Ya I'm not a FPV flyer until the little DJI appeared. I'd agree, it's a challenge, and a Blast! It's easily added a new level of non-work pure fun! After 5 paks, I'm feeling mentally drained and I'm not even doing acrobatics... yet!

The DJI batteries, when at 0% are not at the minimal voltage threshold... their IC circuitry protect going under minimal voltage specifications of the LiPo that cause damage.

Actually that's true for other DJI batteries too, you won't go into minimal voltage threshold at 0 %. Normal practice on cinematic platforms is to land prior to 10 percent to allow amperage draws sufficient to fly the craft home, manuver and to maintain a safety margin to dip into amps if needed. But on occasion deep recycle practice and allow battery to balance fully, I'll often hover a Matrice, Inspire,etc to depletion of 6-4% then land it and leave it on til 2 or 3%. Cool it and recharge without damage.

Standard LiPo lacks any IC Circuitry and will allow voltage to go below the minimum voltage threshold (varies depending on number of cells).

As fast as this little craft draws and drains the amps, I'm sure that calculation is in the IC Circuitry... I haven't measured it at 0% percent on bench... but I'd assume there was additional allowance programmed into this battery FW. The "percentage" doesn't directly equate to voltage and 0% can have different low voltage parameters with different platforms. Heavier platforms tend to have 0% further from minimum voltage than lighter DJI platforms.

I routinely override the FPV's RTH and land around 8-9%... sometimes lower. I'd personally like to modify the RTH value a bit further out before it activates... I'm normally watching it and preparing to stop and override... that 6 second count down routine... I'd prefer a normal RTH warning where you can immediately cancel the popup and continue. I've also experienced the forced land procedure while hovering above LZ... I think that activates in the 4-5% area. No option other than going down once kicked in... although you can leave it on, motors off if desired for a deep cycle discharge still.

More importantly is to allow the lipo gel to "cool" before recharging... I personally give then 1 hour minimal. Charging hot lipo gel accerlates the LiPo gel decay and increases IR value. If it's warm on the battey case, it's hot internally. Recharging a hot pak can motivate shorter life much more than low battery percentage programmed into FW. Hot recharge of any LiPo and dipping below minimum voltage are the 2 things that will effect battery life. Ya can't stop the LiPo decay, but you can slow it's rate. Hot accelerates decay, and below minimum voltage effect the gel chemistry to accept a charge.

Yep, the little craft is a Blast!
Thanks Doug for the detailed information on lipo batteries.........I've learned several things on your explanation that I didn't know about lipo charging.

Yes, the fpv drone is a blast to fly but like you stated, the battery drains fast especially in sport mode.........Happy and Safe Flying!
 
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Just curious when the RTH triggers for other people. Since the last firmware update I found my flight time a lot shorter and when I fly close to me RTH triggers at 40% battery left.
 
Just curious when the RTH triggers for other people. Since the last firmware update I found my flight time a lot shorter and when I fly close to me RTH triggers at 40% battery left.
That's early RTH... I've been off the FPV a bit, on work tasks. Haven't seen a recent FW update, was one recently released? As of 2 weekends ago after updating a new craft, it flew as expected on battery percentage in the teens to kick in RTH notice. Wow, 40% Limit, on this craft that be reached quickly!
 
That's early RTH... I've been off the FPV a bit, on work tasks. Haven't seen a recent FW update, was one recently released? As of 2 weekends ago after updating a new craft, it flew as expected on battery percentage in the teens to kick in RTH notice. Wow, 40% Limit, on this craft that be reached quickly!
I think it was like a month ago or so for the firmware update. Now that I think about it what I get at 40% is not really RTH. It's a warning telling me that battery is low and I need to land now. Maybe I should push longer to see when RTH really kicks in.
 
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You are exactly correct Timeless.......after the last firmware I notice my RTH kicks in around 40% also. I just override it til it gets 20% or so depending on how far I'm out.

Gosh....... battery time is short enough already!!

There's bound to be a reason for for the change???
 
You are exactly correct Timeless.......after the last firmware I notice my RTH kicks in around 40% also. I just override it til it gets 20% or so depending on how far I'm out.

Gosh....... battery time is short enough already!!

There's bound to be a reason for for the change???
Maybe because it puts the battery right around the storage charge so they recommend to land around 40%. I'm getting more flight time out of my 3.5" quad on a 4S 850mAh battery lol.
 
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On both my DJI FPV's, latest FW (month or so ago), RTH doesn't appear until upper teens in percent (18% ??).
Are you getting the RTH Notice & the 6 Second Countdown to RTH or some other non-intrusive notice? The 6 second timer appears, hate how ya have to wait for it to fully timeout before canceling.

I may have a battery related notice at times, but it appears 2-3 seconds then goes off.
No reason for a 40% RTH... unless there is some FW dealing with Overheating: Sport / Acrobatic, Hot Ambient temps, etc. Just guessing.
 
You have control over what percentage of charge the craft kicks rth and critical level in the goggles. Also, look at the batteries they are not LiPo they are LiOn, so not quite as finicky, you can beat them a little harder, doesn't mean you can drain them again and again, but are a little more compliant and safer.
 
Really.

I've been flying DJI drones for 7 years. Never, not ONCE, has this ever happened to me.

I was just out, flying at home, launching off my back deck. Flying with the MC, I was an Ace in an fighter jet. Having a blast.

RTH kicked in for safe return, I was close to home so I canceled it and started heading back on my own (about 1200 feet away), Well, started having too much fun with the MC on the trip back, forgot what I was doing. The short of it is, I ended up at critical battery, forced landing, not in a good place.

I was lucky. 0% battery, starting at 250ft altitude, and just close enough to get it back over houses and trees to the court in front of my house. All the while descending without any choice. It was close with really no margin to spare.
Really.

I've been flying DJI drones for 7 years. Never, not ONCE, has this ever happened to me.

I was just out, flying at home, launching off my back deck. Flying with the MC, I was an Ace in an fighter jet. Having a blast.

RTH kicked in for safe return, I was close to home so I canceled it and started heading back on my own (about 1200 feet away), Well, started having too much fun with the MC on the trip back, forgot what I was doing. The short of it is, I ended up at critical battery, forced landing, not in a good place.

I was lucky. 0% battery, starting at 250ft altitude, and just close enough to get it back over houses and trees to the court in front of my house. All the while descending without any choice. It was close with really no margin to spare.
I hear you , way to much fun with the motion Controller you gotta stay focused or you will go goose 😂
 
You have control over what percentage of charge the craft kicks rth and critical level in the goggles. Also, look at the batteries they are not LiPo they are LiOn, so not quite as finicky, you can beat them a little harder, doesn't mean you can drain them again and again, but are a little more compliant and safer.
Nice, I'll have to check that in Goggles. Last time I walked through the options RTH battery level wasn't available. Thanks for that one!
 
You have control over what percentage of charge the craft kicks rth and critical level in the goggles. Also, look at the batteries they are not LiPo they are LiOn, so not quite as finicky, you can beat them a little harder, doesn't mean you can drain them again and again, but are a little more compliant and safer.
Actually they are LiPo, all DJI batteries are identified as Lithium Ion Polymer, which is a LiPo battery, not a LiOn.
That is confused at times... a Lithium Polymer / LiPo includes Lithium Ion Polymer. The Polymer is the key substance as a Gel.

Look at all DJI batteries, they all say Lithium Ion Polymer.
A Lithium Ion isn't normally presented in a Gel.

"Drain them again & again" is fine as long as you don't go below the rated Minimal Voltage, and on DJI batteries, that's always significantly below the Firmware's 0% rating. At the same time, I normally target 18-20% on most DJI Batteries and comfortable with 10% on the FPV since it's close to home.Screenshot_20210731-182107_Gallery.jpg
 
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You have control over what percentage of charge the craft kicks rth and critical level in the goggles. Also, look at the batteries they are not LiPo they are LiOn, so not quite as finicky, you can beat them a little harder, doesn't mean you can drain them again and again, but are a little more compliant and safer.
Where in the google settings can you change that? I didn't see any option. Flew again this morning and got the land promptly warning at 40%, decided to ignore and see when RTH would kick in. RTH literally kicked in few seconds after the warning and I was only 40m away from the home point
 
RTH also consider battery level regarding to height.. if very high altitude it will easily kick in "early".
 
I looked through the manual, found no reference to RTH battery setting, only Altitude. Although if new feature, it'd be after manual.

While scanning manual, the RTH has 3 modes.
Smart RTH, Battery RTH, Failsafe.

Just some thoughts, remote but possible.
Exploring other options... If you have more than 1 battery, is it triggering the same for all batteries? Possibly bad battery or IC reading. Prior to RTH trigger, what does the flight time indicate... also low or normal. Another option, was craft flown agreessivly going Out, and could distance and heavy draw equate to smart RTH calculating more battery than needed to fly back? Looking at battery specs in above post,, the draw can be up to 10c... that's a hefty draw if hammered outbound. Any time do you loose video signal, indicates that too will trigger RTH.

Screenshot_20210731-173925_Google PDF Viewer.jpg
 
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