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How do you evaluate battery damage?
4307 30 2015-5-16
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jimhare
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We all know LIPO batteries can be dangerous.   If a LiPo gets damaged it's not worth the risk of burning your house down.
Got it, we're all on the same page there.

Question - how do you evaluate if your battery has been damaged and when you should stop using it?   

First sign of a little dent?   If it starts acting funny?

At $270 (Australian) a TB-48 is not something you want to dispose of every time it gets a small ding in the case.  Wouldn't take long to get into the $thousands.

I'd be very interested to know how everyone evaluates battery damage.   
2015-5-16
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SAFAERIALS
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It's a good question!

The good thing is now with the inspire you can see how each cell are and in case a cell its not as the others check and see if theres  swelling, but it would be nice to know when it's the right time to through them away...
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dundee
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The inside of the TB47
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Flight 1
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My use with LiPo batteries was in pro video cameras. I would always feel them after charging. Slightly warm OK. Very warm I would keep an eye on it and when it didn't perform as well as others throw them out. Ive only had the I1 for a couple of months and bought it to have a bit of fun in retirement but now with all the battery problems and flyaways I'm reading about am wary of doing to much with it. I guess as you said if it starts acting funny its usually a sign somethings wrong.
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TimG
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Funny you would start this thread. One of my TB-48 batteries just failed today. I flew with it about a week ago, discharging it to about 15% when I landed. Tried to charge it today and it won't accept the charger nor will it light up at all when pressing the button. I'm headed off to Drones Plus in Las Vegas tomorrow. I'll ask them about your question and see what they say and report back. Have you seen this?



Scary as all hell. Just bought some lipo bags on Amazon.
2015-5-16
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jimhare
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TimG Posted at 2015-5-17 10:55
Funny you would start this thread. One of my TB-48 batteries just failed today. I flew with it about ...

Man!   That's the first time I've seen one go up in flame that wasn't charging.   Just minding its own business sitting on the desk for hours and BAM!

Scary as Hell, ordering LiPo bags today and going to keep them all in there.
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jimhare
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Flight 1 Posted at 2015-5-17 10:10
My use with LiPo batteries was in pro video cameras. I would always feel them after charging. Slight ...

I have a lot of pro batts for my RED EPIC but they are LI-ION, not LiPos.
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RichJ53
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Here is some Do's and Don'ts (Safety) regarding normal (non DJI) LiPo batteries: Most of this is common sense but use as a guideline.  I charge my standard LiPo's in a charge bag. So far, I have not used a bag for these DJI intelligent batteries.

DO: Use a charger that is specifically designed to charge Li-Po batteries. Using chargers that are not Li-Po-specific can be an extreme fire hazard.

DO: Li-Pos don't develop memory or voltage depression characteristics like Ni-Cds. Charge them without the worry of cycling or discharging them first.

DO: Store Li-Pos at least partially charged. Li-Pos will maintain their performance levels over time, even during non-use, much better than Ni-Cds, and there's no need to cycle them.

DON'T: Never fully discharge your Li-Po battery pack. Most electronic speed controls have a voltage cutoff that will prevent over-discharging the battery, but were designed for Ni-Cd & Ni-MH batteries. Be sure that your ESC features the proper Li-Po cut off voltage of 3V per cell (6V for 2-cell packs, 9V for 3-cell packs and so on). Discharging a Li-Po cell beyond its critical minimum voltage will cause damage to the battery.

DON'T: Shorting a Li-Po pack for even an instant can cause damage to the battery. Whether the pack has been shorted when new, while adding or changing the connector, when fully charged or fully discharged, the pack should not be charged without extreme caution. Be sure to take care when soldering connectors and during handling or charging to prevent shorts.

DON'T: If you have a crash and the battery is damaged, don't put the battery in your car or house immediately after a crash. It's possible that a chemical reaction can take place in the damaged battery that could cause a fire. Put the battery in a safe place for at least one hour.
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DJK
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jimhare Posted at 2015-5-17 11:29
I have a lot of pro batts for my RED EPIC but they are LI-ION, not LiPos.

Think I'll order some bags also and keep the batteries in a separate case from the quad.

These batteries are likely not just your ordinary dangerous LiPO, but a hybrid design using LiPV technology that is less understood. I have seen posts that there are more cells in the battery than originally thought in earlier posts.

Don't have objective evidence as to exactly what they are (would like to know), but the voltages they reach are not off the shelf LiPO numbers.

I guess what I am trying to politely say is that these batteries by all counts of the issues being posted are looking to be higher risk than the normal LiPO's
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jimhare
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RichJ53 Posted at 2015-5-17 11:43
Here is some Do's and Don'ts (Safety) regarding normal (non DJI) LiPo batteries: Most of this is com ...

Thanks Rich, good tips!

Would love to get some focus on minor crashes/hard landings.   

If a battery has a couple of tiny dents but has been functioning fine for weeks afterwards, any reason to be concerned?    I had a couple of bumps in the early days.

I absolutely don't want to risk a fire but I also absolutely don't want to lose $250 every time my battery gets a little bump.

Where do you strike that balance between conservative safety and flushing money down the toilet?
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DJK
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The question I would like answered is what other safety precautions, and what other use and storage requirements can we follow to reduce risk.

I leave my bird and case in the car while I am at work, and it could get to 110 or 120 deg F in the car. Does this use/storage create an increased risk of the battery exotherming on its own?

Is the only reason there are issues associated with these batteries mis-handling them?
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Flight 1
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jimhare Posted at 2015-5-17 11:29
I have a lot of pro batts for my RED EPIC but they are LI-ION, not LiPos.

Thanks for pointing that out. Didn't realise these LiPos could be so volatile
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RichJ53
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jimhare Posted at 2015-5-17 11:48
Thanks Rich, good tips!

Would love to get some focus on minor crashes/hard landings.   


Hi Jim,

We just need to weigh the risks of using damaged batteries in our 3K bird.

IMO and my experience, I keep track of each battery that I use for my aircraft and look at the investment for each one. A battery will react if the cell is damaged to some outside impact fairly quickly.

Other things that will cause them harm is over discharge or fast charge causing them to get hot. Normal hobby batteries have a C rating for maximum discharge and charge ratios. DJI doesn't tell us this information because they supply us the under sized power supply that comes with the purchase. A lot of us have been looking into some better options.  
1> They usually start to swell up from the out gassing from the cell chemistry inside the sealed envelope (each cell package). You can also check the battery temperature after discharge and during charging for issues. Then you can decide if the battery is ok or not.
2> Momentary short circuit can cause the batteries to gas or puff up. If you have a blade strike causing the ESC to force the motor to stop, this puts a huge load on the battery. It could cause a cell to discharge below the rest and eventually it can go bad.
3> Leaving your batteries out in the hot sun will also cause harm to them. Always keep them cool even after you use them!
4>  I have some batteries that have had some rough handling (not crashed) and are starting to puff up. These are going to get discarded for sure. The battery is cheaper than crashing your aircraft and any safety concerns you might have.

A "C" or "current" rating indicates the maximum recommended average discharge current for that pack and is used to help you determine the maximum discharge rate. To determine the maximum discharge rate, multiply the "C" rating by the pack capacity (i.e. 1900mAh cell x 6C rating = maximum discharge rate of 11,400mA or 11.4A).


I hope this helps, electric flight is nothing new and we are all learning the new battery technology at a very fast pace.

Rich
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Mistician
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jimhare Posted at 2015-5-17 11:48
Thanks Rich, good tips!

Would love to get some focus on minor crashes/hard landings.   

Hey Jim,
I had a major crash a few weeks ago, when my bird decided to stop taking commands and flew into the back of my car. The battery (TB-47) was expelled on impact and slammed into the sidewalk. I was unable to return the battery to DJI with the drone because it had a small dent in the side. DJI repaired my Inspire but wouldn't send a new battery, despite it being a warranty repair. I was left in a similar situation where I didn't know whether I could still trust my slightly bruised battery. My saving grace was talking to a very helpful tech at DJI on the phone. His "off-the-record" advice was that if the battery could still power on and off, still be charged, still fit in the Inspire, and didn't show any abnormalities in the individual cell report in the app, then I should have no problem with it. He told me to give it a couple test flights and if everything went well, I wouldn't have anything to worry about.
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jimhare
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Mistician Posted at 2015-5-17 13:28
Hey Jim,
I had a major crash a few weeks ago, when my bird decided to stop taking commands and fle ...

Hey Mistician, that's exactly the advice I was after!   Thanks so much for sharing your experience.

So have you deemed your bruised battery fit for use or are you still waiting for the repair?

Jim
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jimhare
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RichJ53 Posted at 2015-5-17 13:21
Hi Jim,

We just need to weigh the risks of using damaged batteries in our 3K bird.

Hey Rich, more great info, thanks so much.

Yes, this is exactly the info I'm after to educate myself about the safe charging and use of the batteries.

Thanks for being a great contributor to the forum!

Jim
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RichJ53
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DJK Posted at 2015-5-17 11:55
The question I would like answered is what other safety precautions, and what other use and storage  ...

This is absolutely a bad practice. Please take your stuff inside the air conditioning while you are at work. Do not leave these things in hot temperatures!

unless you are needing a new car after the insurance company pays for the replacement of the one that burns to the ground.

Rich
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DJK
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RichJ53 Posted at 2015-5-17 14:03
This is absolutely a bad practice. Please take your stuff inside the air conditioning while you ar ...

Thanks Rich..Is this just a precaution due to their size? Are there other smaller non LiON but LiPO powered devices...GPS's etc. that might be also staying in the car.

I have also seen posts in the forum that lead me to believe that the batteries might have multiple smaller cells in the design, and using LiPV vs LiPO or some hybrid technology. Would the charging formulas be the same?
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DJK
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Mistician Posted at 2015-5-17 13:28
Hey Jim,
I had a major crash a few weeks ago, when my bird decided to stop taking commands and fle ...

This must be new...Where is the individual cell info?
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smcbrearty
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DJK Posted at 2015-5-17 20:00
This must be new...Where is the individual cell info?

The info is displayed in the APP.
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RichJ53
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DJK Posted at 2015-5-17 19:57
Thanks Rich..Is this just a precaution due to their size? Are there other smaller non LiON but LiPO ...


It's a well known fact that batteries do not like temperatures outside their sweet spot no matter which battery chemistry we are talking about. They do not produce the same power in the cold weather as they do on a nice summer day.

Here is a blurb from the internet to name one example
According to our research, lithium ion batteries perform optimally, and will last longer, if they are kept at temperatures between -10°C and +30°C. This range is consistent with findings by the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy (EERE).


Link to the battery university blog discussing the importance of how heat, loading etc can effect batteries. LiPo batteries have higher energy curves than LiOn and can be less stabile but the technology is improving everyday. Again this is based on the battery design and "C" rating as to how much heat they can handle during discharging and charging.
Link:
http://www.batteryuniversity.com ... educes_battery_life


This not new information, Dundee has posted this video for others to see what's inside the Inspire battery pack. From this you can see the layout of the battery pack and the way the cells are put together. Note, each cell has two individual cells in parallel to achieve the needed capacity for one cell.


Rich
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Mistician
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jimhare Posted at 2015-5-17 13:32
Hey Mistician, that's exactly the advice I was after!   Thanks so much for sharing your experience ...

I'm glad to hear his advice was helpful! I've successfully completed around 15 flights with the dented battery since talking to the tech. I've had no power drops or abnormal temperature fluctuations and each cell is still reading perfectly in the app. I don't want to jinx it or anything but I'd say I'm completely confident in its performance at this point.
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piotr.pawlowski
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RichJ53 Posted at 2015-5-17 11:43
Here is some Do's and Don'ts (Safety) regarding normal (non DJI) LiPo batteries: Most of this is com ...

RichJ

Could please don't give the incorrect advices regarding Li-Pos as soon as the DJI's manual says something opposite

I mean this statement:

DON'T: Never fully discharge your Li-Po battery pack. Most electronic speed controls have a voltage cutoff that will prevent over-discharging the battery, but were designed for Ni-Cd & Ni-MH batteries. Be sure that your ESC features the proper Li-Po cut off voltage of 3V per cell (6V for 2-cell packs, 9V for 3-cell packs and so on). Discharging a Li-Po cell beyond its critical minimum voltage will cause damage to the battery.

The INTELLIGENT FLIGHT BATTERY manual for Inspire's Li-Po clearly says:

Charge and discharge the battery completely once every 20 charge/discharge cycles. Discharge the battery until there is 0% of power or until it can no longer be turned on, then recharge it to the maximum capacity. This power cycling procedure will optimize the battery life.

So please all read the manuals before getting only truth from this forum.

Regards

Piotr.
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piotr.pawlowski Posted at 2015-5-18 03:50
RichJ

Could please don't give the incorrect advices regarding Li-Pos as soon as the DJI's manual  ...

I noticed at 0% the cells still have 3 volts each!! so it is actually not totally discharged

To correct the tracking error that occurs, a “smart battery” in use should be calibrated once every three months or after 40 partial discharge cycles. [See Battery Calibration: BU-603]  This can be done by a deliberate discharge of the equipment or externally with a battery analyzer. A full discharge sets the discharge flag and the subsequent recharge establishes the charge flag.


A “smart” battery can be seen as consisting of two parts: the electrochemical battery and the digital battery. The electrochemical battery is known as the actual energy storage vessel and the digital battery is the circuitry that predicts state-of-charge (SoC) and monitors other information. The digital battery provides the readouts but the truth lies in the chemical battery.  Figure 1 illustrates the typical drifting away of the digital battery from the electrochemical battery and how periodic calibration corrects the error. The values are assumed and accentuated.

http://batteryuniversity.com/learn/article/how_to_calibrate_batteries
The SMBus has other limitations, and a major one is the inability to display capacity. This creates a false sense of security by assuming that a recharge will always deliver a full runtime. An older battery with only 50% capacity will give a 100% SoC indication in the same way as a new pack would. The SMBus cannot make the user aware of the shorter runtime when the capacity gets low.
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DJK
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RichJ53 Posted at 2015-5-18 00:35
It's a well known fact that batteries do not like temperatures outside their sweet spot no matter  ...

Thanks again Rich for responding.

I have seen the video for the 47, but have not seen what is inside the 48, and assume there is some difference to reach the additional capacity in the same space.

I agree that environmental temperatures affect the realized capacity.

The battery can and does operate at higher temperatures than the car gets, so one would expect that this temperature is not inherently dangerous. I would also assume you are correct with respect to the "long term" storage temperature.

What I am not clear on is the specifics differences as they relate to LiPV which these are or a at least some hybrid of them.

I will no longer leave the batteries in the car for due diligence, until we know more about them and why there have been unexplained exotherms.

We really need some "Root Cause Analysis" to identify the true contributors to these incidents, otherwise we are all speculating.
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nilsblix
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I consider buying Lipobags - any adivice ?
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RichJ53
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DJK Posted at 2015-5-18 04:47
Thanks again Rich for responding.

I have seen the video for the 47, but have not seen what is ins ...

Agreed, you are correct and we will wait to see how DJI answers the situation.

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RichJ53
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piotr.pawlowski Posted at 2015-5-18 03:50
RichJ

Could please don't give the incorrect advices regarding Li-Pos as soon as the DJI's manual  ...


Piotr,

You are correct the manual for the DJI Inspire has information about the intelligent battery and operation.  I was only providing general information and cautions for batteries, this is not misinformation but fact. All of this info is not related to the DJI LiPo's and is intended to be helpful not negative.  Sorry for any confusion this may have caused you.

DJI has the last word for their hardware.

Rich
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TimG
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So I went to Drones Plus today. It's a candy store for us geeks. They have the DJI Ronin and it's quite an impressive stabilizer. I've always thought that drones will be the death of the Jib and Production Crane. Now I wonder if this Ronin could replace the Steadicam.

I was there because one of my TB48 batteries refuses to charge. They will have their best tech take a look at it tomorrow but all they could do today was confirm that it wasn't taking a charge.

Jim, I asked their tech about your battery question and like Mistician posted, he said that if it isn't seriously damaged, he would suggest (off record) to just keep an eye on how it performs. If it takes a charge normally and gives you good flight time AND it checks out in the DJI app then he said it's most likely fine. He said that the vast majority of failing batteries will  start to perform poorly and that will be the sign to replace it. Again, this is just him talking off the record and from his own personal experience.
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jimhare
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TimG Posted at 2015-5-18 14:22
So I went to Drones Plus today. It's a candy store for us geeks. They have the DJI Ronin and it's qu ...

Fantastic, thanks Tim!
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Mistician
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TimG Posted at 2015-5-18 14:22
So I went to Drones Plus today. It's a candy store for us geeks. They have the DJI Ronin and it's qu ...

Hey Tim, I'm glad to hear I wasn't the only one who had received this off-record advice. It makes me feel better about having followed it so dutifully!
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