Battery Info

[WithTheBirds]

For comparison, here is how it comes out when I view it from within my own AirData account - the charge cycle count reads 55.
View attachment 93740
The absence of temperature data is something I enquired about a long time ago and never got an answer. Interestingly, I get temperature data when flying with Litchi and I can see the temp readings by going into the battery menu in flight when flying with GO4. I don't know why temp readings are not included in the flight log data


Yes, I too fly an MA but there is a simple explanation to that; OP's takeoff altitude=215.6m asl, my altitude is 1819.9m asl. I have significantly reduced flight time across all my batteries due to the altitude.

I haven't missed that and agree a period of careful monitoring is important before anything can be concluded (normally). But I would personally not fly with a battery like that even based on what can be seen from this single flight. But that is me, I choose to err on the side of caution.

Agree 100% you caution is wise with any flying models. I wouldn’t venture high or far with this particular battery until such time as the performance and telemetry could be further assessed. I might make a decision to retire the pack now if there was more information on its use and history available.

I don’t know about your experience but out of many lipo’s in many applications I have never had one that improved in performance (particularly cell voltage imbalance) during use other than in cold ambient conditions. If the IR is significantly higher (almost always the case with a failing cell) the V imbalance will increase exponentially.

 

[Prismatic]

... If the IR is significantly higher (almost always the case with a failing cell) the V imbalance will increase exponentially.

Say what? ?

What tool do you use to measure the internal resistance (IR) of a DJI drone battery?

I only have DJI hardware and tools, and I don't know how any of it can tell me the IR of one of my Mavic Air batteries.

Am I missing something?

 

[WithTheBirds]

Say what? ?

What tool do you use to measure the internal resistance (IR) of a DJI drone battery?

I only have DJI hardware and tools, and I don't know how any of it can tell me the IR of one of my Mavic Air batteries.

Am I missing something?

I never said anything about measuring the Mavic battery cells IR. I made a generalisation about LiION chemistry. IR is one of, if not the best, indicator of cell health -AND- the low cell in a series connected battery will be the one with the higher internal resistance. The higher the current demanded from the battery the quicker the lower voltage cell will deplete and collapse. In the OP’s scenario it seemed the voltage imbalance became less significant as the flight progressed. Doesn’t support a weak or failing cell as being the explanation.

 

[phototom1]

The telemetry from a pack flown for less than a minute from around 50% SOC won't give you the full picture. Do you disagree?

My comment didn't relate to the second log posted.

Looking at the second log I wouldn't be so hasty to sign the retirement papers for the battery.

For the second half of the flight deviations were of little to no concern. Health is reported by the BMS as 100% with reported capacity being close to as new spec.

I would keep an eye on it however there I don't think we have reason to say it is "shot". The fact Airdata has flagged 70mv cell deviation as "major" shouldn't given too much weight. The more accepted figure is 100mv plus.



@phototom1 What was the time duration between charging the battery subject of your second log posted and the flight?

 

[phototom1]

The telemetry from a pack flown for less than a minute from around 50% SOC won't give you the full picture. Do you disagree?

My comment didn't relate to the second log posted.

Looking at the second log I wouldn't be so hasty to sign the retirement papers for the battery.

For the second half of the flight deviations were of little to no concern. Health is reported by the BMS as 100% with reported capacity being close to as new spec.

I would keep an eye on it however there I don't think we have reason to say it is "shot". The fact Airdata has flagged 70mv cell deviation as "major" shouldn't given too much weight. The more accepted figure is 100mv plus.



@phototom1 What was the time duration between charging the battery subject of your second log posted and the flight?

Appro 2 hrs from full charge to flt.

 

[AirShark]

Did you fly in cold weather and discharge your battery significantly? Did this with a Typhoon H and ended up killing 1 cell. It would show good voltage but not long after launching the battery would drain significantly. Took a multi meter to it and found one cell 2.7 volts. Try recharging the battery and take if for a close flight. Get some stick time. You'll know soon enough if the battery is bad. Heard that sometimes an unbalanced battery can be rebalanced.

 

[phototom1]

Did you fly in cold weather and discharge your battery significantly? Did this with a Typhoon H and ended up killing 1 cell. It would show good voltage but not long after launching the battery would drain significantly. Took a multi meter to it and found one cell 2.7 volts. Try recharging the battery and take if for a close flight. Get some stick time. You'll know soon enough if the battery is bad. Heard that sometimes an unbalanced battery can be rebalanced.

Not cold here I live on the edge of Fort Worth this flt was prob in the 80-90 degree ambient temp. I plan to use it this week and will fly it close and low for extended time then check the battery info on the controller as well as check the txt log post flt. I will keep posting results.

 

[phototom1]

The telemetry from a pack flown for less than a minute from around 50% SOC won't give you the full picture. Do you disagree?

My comment didn't relate to the second log posted.

Looking at the second log I wouldn't be so hasty to sign the retirement papers for the battery.

For the second half of the flight deviations were of little to no concern. Health is reported by the BMS as 100% with reported capacity being close to as new spec.

I would keep an eye on it however there I don't think we have reason to say it is "shot". The fact Airdata has flagged 70mv cell deviation as "major" shouldn't given too much weight. The more accepted figure is 100mv plus.



@phototom1 What was the time duration between charging the battery subject of your second log posted and the flight?

 

[phototom1]

Did you fly in cold weather and discharge your battery significantly? Did this with a Typhoon H and ended up killing 1 cell. It would show good voltage but not long after launching the battery would drain significantly. Took a multi meter to it and found one cell 2.7 volts. Try recharging the battery and take if for a close flight. Get some stick time. You'll know soon enough if the battery is bad. Heard that sometimes an unbalanced battery can be rebalanced.

About 2 hrs between charge and flight

 

[phototom1]

Cont with the question of battery health here is a recent flt log with fully charged battery the one I have had a question on. Extended flt until battery said low battery warning I did not go to great heights stayed close made a few maneuvers. cell 3 shows all red in log however as I was flying and checking battery it would go between green and red. see what you people think. thanks

 

[slup]

Cont with the question of battery health here is a recent flt log with fully charged battery the one I have had a question on. Extended flt until battery said low battery warning I did not go to great heights stayed close made a few maneuvers. cell 3 shows all red in log however as I was flying and checking battery it would go between green and red. see what you people think. thanks

No, I'm sorry... that battery have not a healthy behavior, my earlier advise sticks... only good for ground duty if you want to avoid bad surprises mid air.

 

[AirShark]

One of the cells in the battery is dead. Once that happens the battery is dead. It might show decent static voltage but under load it will drop very fast. Not worth loosing your drone.