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Used Inspire 2 - Battery Advice Wanted

Would you replace the batteries?

  • Yes

    Votes: 1 50.0%
  • No

    Votes: 1 50.0%

  • Total voters
    2
Joined
Dec 1, 2020
Messages
18
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18
I am getting about 8-9 minutes of flight for each battery set before I land at about 50% battery (I will explain why I do that at the end). That is a far cry from the 13.5 minutes (half of 27 minutes) that is advertised, so I am curious as to where I am getting my penalties from ...
  • Payload: Zenmuse X5S (346g) and Panasonic Lumix 15mm/1.7 lens (115g), for a total of 461g. This is 82.2% more than the Zenmuse X4S (253g)
  • Batteries (age/cycles): I got a grab bag of eight batteries. Their date of manufactures range from late 2016 to early 2019; and they have anywhere between 22 to 38 cycles.
Or ... is that normal?

I am also wondering if I should replace all the flight batteries. I currently have two reasons for doing so and one reason against doing so:
  • Against - Cell deviation for each pack is no more than 0.02 Volts.
  • For - Uneven wear between batteries.
  • For - Suspect battery packs are swelling: If I were to place the outward-facing side of the batteries on a flat surface and gently rocked them, they are definitely not flat.
Why I like to land at 50% battery: That puts the batteries in an ideal state of charge for long-term storage and gives me margin to fight headwind on the way back in. Wind speed vs. the amount of power to overcome it is a cubic relationship: 2x the wind speed = 8x the amount of power required to overcome it.
 
If your batteries are swelling, replace them! There is no reason why they should with the low usage so I would look at your storage and maintenance and see what you can do there to improve that in the future. But you are putting way to much thought and calculations into this and you are going to end up losing your drone. All my batteries have been charged over 30 times and I still get 22 minutes out of them.
 
If your batteries are swelling, replace them! There is no reason why they should with the low usage so I would look at your storage and maintenance and see what you can do there to improve that in the future. But you are putting way to much thought and calculations into this and you are going to end up losing your drone. All my batteries have been charged over 30 times and I still get 22 minutes out of them.
Thank you. I will trust my instincts and replace the batteries; but cut me a break, man! I bought the aircraft used — I received the batteries in this condition! First thing I did with it was do the 50-hour/200-landing inspection, clean it, and replace the gimbal dampers. But you’re right ... I find the previous owner’s practices to be questionable. Thank you for helping me confirm my suspicions.

Here’s how I treat my Mavic 2 Pro batteries, and the way I plan to treat my Inspire 2 batteries. I’ll search the forums this evening to see how far off I am:
  • Plan to land with 50% state of charge.
  • Store battery at 50% state of charge.
  • Store batteries between 69F and 77F (indoors, air conditioned).
 
Last edited:
Thank you. I will trust my instincts and replace the batteries; but cut me a break, man! I bought the aircraft used — I received the batteries in this condition! First thing I did with it was do the 50-hour/200-landing inspection, clean it, and replace the gimbal dampers. But you’re right ... I find the previous owner’s practices to be questionable. Thank you for helping me confirm my suspicions.

Here’s how I treat my Mavic 2 Pro batteries, and the way I plan to treat my Inspire 2 batteries. I’ll search the forums this evening to see how far off I am:
  • Plan to land with 50% state of charge.
  • Store battery at 50% state of charge.
  • Store batteries between 69F and 77F (indoors, air conditioned).
This issue was discussed to death during last 5 years, but here we go again:
1. The one and only, relatively reliable way to determine DJI battery health is to observe individual cells voltage drop under heavy load. This can be done on dedicated page of DJI Go 4 app mid-flight with fully charged battery and solid throttle up. Fast voltage drop below safe green level indicates exhausted/deteriorated cells, simple like that. Significant temperature rise (hot to touch) is another indicator of aged battery.
2. No need to land at 50%. Simply charge ASAP to 55-60% (3rd LED blinking) for storage and fully charge just hours before planned flight. Check storage level every 2-3 months, pump it up a bit if necessary.
3. Don't rely on self-discharge feature. It's a last resort, rather desperate attempt to elongate the battery life span and may kick back at the worst moment mid-flight. Always, always fully charge before flight!
4. Badly swollen TB50 battery (rare) will not go in easily! Don't force and retire it ASAP.
 
This issue was discussed to death during last 5 years, but here we go again:
1. The one and only, relatively reliable way to determine DJI battery health is to observe individual cells voltage drop under heavy load. This can be done on dedicated page of DJI Go 4 app mid-flight with fully charged battery and solid throttle up. Fast voltage drop below safe green level indicates exhausted/deteriorated cells, simple like that. Significant temperature rise (hot to touch) is another indicator of aged battery.
2. No need to land at 50%. Simply charge ASAP to 55-60% (3rd LED blinking) for storage and fully charge just hours before planned flight. Check storage level every 2-3 months, pump it up a bit if necessary.
3. Don't rely on self-discharge feature. It's a last resort, rather desperate attempt to elongate the battery life span and may kick back at the worst moment mid-flight. Always, always fully charge before flight!
4. Badly swollen TB50 battery (rare) will not go in easily! Don't force and retire it ASAP.
Thank you for your patience. I absolutely never use the self-discharge feature; and so far, all the batteries slip in easily. Batteries are cheap, so I will plan on getting some new ones.

Good put on observing the cells when I go full throttle up ... I'll definitely try that! Do I have to put the aircraft in the air, or can I leave the props off, have the motors spinning, and throttle up?
 
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Reactions: Phillip DeVore
Thank you for your patience. I absolutely never use the self-discharge feature; and so far, all the batteries slip in easily. Batteries are cheap, so I will plan on getting some new ones.

Good put on observing the cells when I go full throttle up ... I'll definitely try that! Do I have to put the aircraft in the air, or can I leave the props off, have the motors spinning, and throttle up?
"Do I have to put the aircraft in the air, or can I leave the props off, have the motors spinning, and throttle up?"

o_Oo_Oo_O

Off course you must perform normal lift off procedure! Spinning propeller-less motors on your desk requires almost no effort and will render no conclusion ...
 
I’ve got several sets of TB50 batteries that have more than 50 cycles on them and I always get at least 22 minutes from them. A couple sets have 100+ cycles and I still get 20+ minutes from them also.
Battery maintenance is extremely important for maintaining healthy batteries. Discharge and deep cycling them at the appropriate time is also something that you might consider. Personally I keep a battery maintenance logbook for all my batteries so that I can keep track of them.
There are lots of great YouTube videos on this subject that you might want to check out. Good luck with your batteries.
There is also the Phantom Angel battery maintenance device that helps you to maintain good battery maintenance.
 
Last edited:
  • Like
Reactions: cyeung
This issue was discussed to death during last 5 years, but here we go again:
1. The one and only, relatively reliable way to determine DJI battery health is to observe individual cells voltage drop under heavy load. This can be done on dedicated page of DJI Go 4 app mid-flight with fully charged battery and solid throttle up. Fast voltage drop below safe green level indicates exhausted/deteriorated cells, simple like that. Significant temperature rise (hot to touch) is another indicator of aged battery.
2. No need to land at 50%. Simply charge ASAP to 55-60% (3rd LED blinking) for storage and fully charge just hours before planned flight. Check storage level every 2-3 months, pump it up a bit if necessary.
3. Don't rely on self-discharge feature. It's a last resort, rather desperate attempt to elongate the battery life span and may kick back at the worst moment mid-flight. Always, always fully charge before flight!
4. Badly swollen TB50 battery (rare) will not go in easily! Don't force and retire it ASAP.
I fully agree with you on this subject. It’s been discussed ad nosium!
 

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