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Flight Battery advice needed
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1405 40 2015-12-21
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mike.wildlight
Second Officer
Flight distance : 5623 ft
Australia
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Recently was about to fly on a freshly charged battery (that morning) and noticed that it was only reading 95% and dropped to 91% whilst the aircraft was warming up. When I went in to check the battery it was showing 15 Times Charged and a Battery life of only 55%. I did a short flight with no dramas.
A few hours later I've hooked up to examine the issue and am getting:
Battery Charge (Main Display):38% which may be about right to a little low from flight time
Battery Life = 79%
Times Charged: 15
From the "history" there are 31 records all saying "Normal" except Record #03, Record #11, Record #18 which all say "Time to discharge". I have always assumed this is when the auto-discharge function was started.

My Question is:
Should I been concerned about this battery?
Why after only 15 charges would this Battery be at only 55% or even 79% of it's life?

Thanks in advance!
2015-12-21
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Geebax
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It should not be down to that level, try and get it exchanged under warranty. I would not fly with that battery any more.

I bought two new batteries through Kogan, and one of them showed 'Damaged Cell' on the first flight after charging. I went through the laborious Kogan return procedure and am still waiting for them to agree it is a warranty problem.
2015-12-21
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mike.wildlight
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Geebax Posted at 2015-12-22 14:44
It should not be down to that level, try and get it exchanged under warranty. I would not fly with t ...


I've checked all my other flight batteries now and they are all still 100%

I'm wondering if an early deep discharge of the problem battery might be in order?
2015-12-21
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Geebax
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mike.wildlight Posted at 2015-12-22 15:48
I've checked all my other flight batteries now and they are all still 100%

I'm wondering if an ea ...

I can't say, but I did do exactly that with the problem battery I had, in fact I did it twice. I just left it in the aircraft with the motors running, but no props. Eventually the motors stopped and I let it power the aircraft for some time later. Then charged it up again. But it still reported the same error.
2015-12-21
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Rebel
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2015-12-21
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Geebax
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Thanks, that can sit here and alert everyone on this forum to what a useless POS troll you actually are.
2015-12-21
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Rebel
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2015-12-21
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Rebel
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2015-12-21
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DJI-Patrick
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Hi ,Mike
Do a full discharge /charge  as they both suggested . But please don't join the fight ! Thank you !
2015-12-21
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mike.wildlight
Second Officer
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DJI-Patrick Posted at 2015-12-22 17:04
Hi ,Mike
Do a full discharge /charge  as they both suggested . But please don't join the fight ! Tha ...

Thanks Patrick,
Have just completed the discharge with some interesting results.
One cell dropped lower than the others during discharge by .09 V all other cells were within .01, but weirdly the Battery Life has come back up to 100%
I'm going to let it cool overnight and charge it in the morning.
2015-12-22
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Geebax
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mike.wildlight Posted at 2015-12-22 19:12
Thanks Patrick,
Have just completed the discharge with some interesting results.
One cell dropped  ...

It is your choice, but I would not trust an expensive aircraft to that battery. We pay very high prices for these batteries, higher than RC people pay for theirs, so if it shows any signs of weakness I would file a warranty claim.
2015-12-22
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DJI-Patrick
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mike.wildlight Posted at 2015-12-22 16:12
Thanks Patrick,
Have just completed the discharge with some interesting results.
One cell dropped  ...

Hi ,Mike
Please charge the battery after it's discharged . Please Don't keep the battery discharged for too long .
2015-12-22
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aburkefl
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Geebax Posted at 2015-12-22 00:36
I can't say, but I did do exactly that with the problem battery I had, in fact I did it twice. I j ...

I haven't yet had to do this myself. However, when and if I do, wouldn't it be better to leave the props on while you're "discharging" the battery? I was under the impression the motors are somewhat cooled by the props. That could mean that running the motors for an extended period without the props might possibly overheat the motors.

Out of curiosity, after doing this, did your motors seem overly hot?
2015-12-22
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mike.wildlight
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aburkefl@gmail. Posted at 2015-12-22 23:17
I haven't yet had to do this myself. However, when and if I do, wouldn't it be better to leave the ...

No they didn't get hot but I took the precaution of putting the Aircraft into a cool air-conditioned environment for the duration.
I'm not keen on running motors with a finite lifespan to discharge the battery, so I'm looking in to some other options such as this: Battery discharger

2015-12-22
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mike.wildlight
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DJI-Patrick Posted at 2015-12-22 18:18
Hi ,Mike
Please charge the battery after it's discharged . Please Don't keep the battery discharged ...

It's about half-way through charging as I type

P.S. Not interested in the fight. I quite like a healthy debate on facts, but get very disappointed  when it deteriorates to personal insults between intelligent and well-intentioned people that share a common interest.
2015-12-22
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mike.wildlight
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Geebax Posted at 2015-12-22 18:17
It is your choice, but I would not trust an expensive aircraft to that battery. We pay very high p ...

I agree, but it's worth a try and it's not as if the issues hasn't been documented now for Battery s/n 6171152179317 ;)

Now that I'm aware I can keep a very close eye on it.
2015-12-22
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DJI-Ken
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Hi Mike,
If the battery is now showing 100% life, it seems things are back to normal. BUT,keep an eye on it, if you get any more errors on that particular battery. would contact DJI for an exchange
2015-12-22
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mike.wildlight
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DJI-Ken Posted at 2015-12-23 07:28
Hi Mike,
If the battery is now showing 100% life, it seems things are back to normal. BUT,keep an ey ...

Thanks Ken,
Battery is now showing 100% Battery Life, I'll test fly it a couple of times and see, one cell does seem to be a little down on the others, so will defo keep a close eye on it.
2015-12-22
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DJI-Ken
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How much is a little, if that cell is always lower by  .25 or something like that then it could be the start of that cell going bad.
Also, it may be better for battery calibration to discharge the battery as slowly as possible so the cells drain more fluidly.
Try to do a discharge again but us the Slow process in the manual. Basically take a full charged battery and power the aircraft on and just leave it until it turns off.
Then fully charge it and see if the cells are pretty exact then.
2015-12-22
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mike.wildlight
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DJI-Ken Posted at 2015-12-23 08:32
How much is a little, if that cell is always lower by  .25 or something like that then it could be t ...

Cheers Ken,
They're pretty good- all are within .05 at full charge.
This discharge I did was pretty slow Down to 38% on flight, when cool, down to 10% on idle, the just on until cells got to around 3.5V.
I'll give it a flight or two and see how it goes I think- If it still has issues I'll do the super-slow, if it has issues after that It'll probably be coming back
2015-12-22
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Geebax
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Hey Ken, nice work. You delete my post as 'offending content', when it did not contain a single profanity, yet Rebel's post 'Eat shit old man." remains.

Now that is a real model of consistency. That guy puts up offensive material all the time and in spite of being reported you do nothing about him. Way to go, that's how to run a forum!
2015-12-22
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Rebel
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2015-12-22
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aopisa
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I have been away from this forum for a few months. I was fairly active too. It's really a shame to see that there are a now couple of people on here that are making it a very unpleasant experience.
2015-12-22
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DJI-Ken
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I'm sorry, I was trying to delete both, but I guess it didn't do it. The offensive post is gone now.
2015-12-22
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DJI-Ken
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mike.wildlight Posted at 2015-12-23 07:52
Cheers Ken,
They're pretty good- all are within .05 at full charge.
This discharge I did was prett ...

That's good, within .05, you should have nothing to worry about. Just keep an eye on it.
2015-12-22
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DJI-Patrick
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mike.wildlight Posted at 2015-12-23 03:43
It's about half-way through charging as I type

P.S. Not interested in the fight. I quite like  ...

Seems like your battery is getting back to normal . Nice to hear that !
2015-12-23
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aburkefl
First Officer
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mike.wildlight Posted at 2015-12-22 14:38
No they didn't get hot but I took the precaution of putting the Aircraft into a cool air-condition ...

While that looks like an interesting gadget, it might be overkill, unless you're in a hurry. The self-discharging feature of the IFB is settable. However, if you're unwilling to wait a couple of days (or a week!) for them to discharge to storage level, a balanced "discharger" seems practical.

The Chroma batteries do not have the same kind of features as the IFB, but I bought an adapter that lets me discharge (with balancing) individual batteries.

Between 4 Phantom batteries, 3 Chroma batteries and an assortment of "brick-type" LiPo batteries, it looks like I've gone into the battery biz!

Sounds like you've got a good plan going. Good luck.

Art - N4PJ
Leesburg, FL
2015-12-23
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megax1985
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Hey, I hope it's okay that I borrow the thread a little. I have a question about my battery.

First I want to apologize if my English is not the best when I use Google Translate.

I enclose a picture of my battery status
You see that the battery life is 84% at the 47 charges only.
Or is it normal? I was out flying yesterday "10 ° C" then showed volts in 3.4 "as a red" But it worked as it should.
I have read that you should not fly under 3.2volt. I have read of the battery when I bought my phantom 3 advanced
before I started flying because I wanted to get my battery to keep as long as possible. But I still think 84% at the 47 charges seem a bit scary low?

what can I do, or the battery is fully healthy anyway?

thanks for the reply and Merry Christmas to you all out there.

Screenshot_2015-12-23-19-55-53.png

Edit: Battery in only 28% charged now if you want to nu
2015-12-23
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mike.wildlight
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aburkefl@gmail. Posted at 2015-12-23 22:20
While that looks like an interesting gadget, it might be overkill, unless you're in a hurry. The s ...

Cheers Ken,
wasn't so much getting to storage charge I was thinking of but doing the deep discharge every 20 cycles. I haven't really liked any method for that I've seen thus far.

I think the most elegant solution for these smart batteries would be a firmware update that does the deep discharge on a button combination. Ken? Patrick? How cool would that be?!
2015-12-23
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Geebax
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mike.wildlight Posted at 2015-12-24 06:26
Cheers Ken,
wasn't so much getting to storage charge I was thinking of but doing the deep discharg ...

That's a good idea, but one factor is the heat generated. The self-discharge routine is done at a very low power consumption, and can easily be done inside the battery, but doing a deep discharge means higher current, and that is harder to do in the battery without special cooling.
2015-12-23
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aburkefl
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Geebax Posted at 2015-12-23 16:43
That's a good idea, but one factor is the heat generated. The self-discharge routine is done at a v ...

Absolutely. Those who've flown with "standard-style" LiPo batteries will know exactly what you mean. The newer users who've never used anything except the "caged" battery the Phantom now uses have never seen the heat your charger generates when you discharge to storage level.

I think I own three different chargers for standard LiPo batteries and every one of them gets pretty hot when you use them to discharge a battery.
2015-12-23
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mike.wildlight
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Geebax Posted at 2015-12-24 07:43
That's a good idea, but one factor is the heat generated. The self-discharge routine is done at a v ...

A deep discharge doesn't necessarily mean higher current draw, it can be done simply with longer time periods in fact if you look at the way I did it above, I reduced the current draw as the battery depleted. An electronic way of automatically doing that would VDC (Very Damn Cool), either in firmware or by an external device.
You shouldn't ever be letting LiPo batteries get very hot in either charge or discharge and increasing current draw for a deep cycle is not a good practice. I'm very careful of this with my ordinary LiPo s been a while since I did them but IIRC I discharged <1C even though LiPos are designed to discharge faster than charge. The key of course as you mentioned temp.
Cheers
Mike
2015-12-23
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Geebax
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mike.wildlight Posted at 2015-12-24 11:23
A deep discharge doesn't necessarily mean higher current draw, it can be done simply with longer t ...

I agree, but the self-discharge cycle used in the DJI battery is very low current, and you need to draw down a somewhat higher current, this is why battery reconditioners have heatsinks in them.
2015-12-23
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mike.wildlight
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Geebax Posted at 2015-12-24 13:03
I agree, but the self-discharge cycle used in the DJI battery is very low current, and you need to ...


Not sure what you are getting at here mate, if you draw down at constant current 1 amp (for example)
The work in watts (read heat) actually get's less as the battery voltage drops.
i.e
Fully charged 4S @ 1A discharge is 16.8V * 1A = 16.8W
As it is discharged 14V * 1A = 14W

It's the same if you keep the load constant i.e. like a resistor or light bulb, as the voltage drops so does the current and the work in watts (read heat).

In it's simplest form, hook any battery up to a light bulb as time passes and the battery discharges the light gets cooler and duller.

All this is also true with respect to the internal heating of the battery itself which is due to the internal resistance within the battery.

The total work that must be done (Wh) is greater of course but the heat build up is the difference between heat generated and heat dissipated, so for any given dissipation capacity (affected by location ambients) the heat generated will become less  as the battery voltage diminishes.

Cheers
Mike
2015-12-24
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mike.wildlight
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megax1985 Posted at 2015-12-24 05:15
Hey, I hope it's okay that I borrow the thread a little. I have a question about my battery.

First  ...

Sorry mate,
haven't seen a reply to your post yet,
but based on the advice received for my issue, as a first step try the deep discharge if you haven't already done that. At 47 cycles you should've already done that twice.
2015-12-24
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Geebax
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mike.wildlight Posted at 2015-12-24 19:11
Not sure what you are getting at here mate, if you draw down at constant current 1 amp (for exampl ...

Sorry, I did not explain that very well. I used to design battery charge and reconditioning systems some years back, and the principles are much the same no matter what battery technology is used. The DJI Intelligent battery discharge system uses a very small load, whereas you need to do a good discharge cycle at around 0.3C, and if that was done inside the DJI battery, I doubt there would be any way to get rid of the heat produced, given it is a mostly enclosed plastic box. My point is that the load needs to be external.
2015-12-24
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mike.wildlight
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Geebax Posted at 2015-12-25 07:21
Sorry, I did not explain that very well. I used to design battery charge and reconditioning system ...

Right-o

That makes more sense, I didn't realise there was any advantage to a higher discharge for a LiPo in deep cycle and that a high load discharge risked a premature voltage drop. I always thought it was more about calibrating the "smart" aspect in these batteries.

What does this higher discharge rate do that's advantageous?
2015-12-24
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Geebax
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mike.wildlight Posted at 2015-12-25 09:57
Right-o

That makes more sense, I didn't realise there was any advantage to a higher discharge for ...

A higher discharge rate uses the chemical reaction that a battery is designed to utilise, whereas a very low discharge rate is not considered by the battery to be doing any useful work, akin to tickling it. It is a universal fact that batteries of all types like to be worked, not necessarily hard but worked nonetheless.

In a LiPo pack used by the RC guys, it is normal to bring out connections to the outside world from each cell. This allows charge balancing, and just as important, it allows you to monitor the discharge of each cell individually. When discharging, it is ideal to discharge each cell individually to around 0.5volts, but in a pack like the DJI Intelligent battery, all of that is supposed to be taken care of internally, so the individual cell connections are not brought out, just the main power and a serial communications connection.

If a LiPo pack is discharged too far, one cell may reach zero volts first, and if you continue to discharge the pack, that cell is driven into negative charge, which is damaging to the cell. Therefore, the safe route for DJI packs is to recommend a safe battery level that hopefully does not drive any cell into negative charge. Provided the cells are reasonably closely matched, 10% might be considered reasonably safe.
2015-12-24
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megax1985
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Hello,

After 3 days of reading and Googling, I have probably understood how the battery should be managed.
I have deep discharge it down to about 3% several times without results.
But today I charged it up fully and drove my P3 indoor to 5-7%, and then I let it cool to room temperature, and then I loaded it full again and now it was up to 87%. must be added that it was down to 81% after I posted the last picture.

So I have to thank for all the help I got from just reading all your threads about the battery.


Screenshot_2015-12-25-00-07-01.png


Right now we have winter here in Sweden.
But the weather is not as it should be at this time of year. we should have had -20°C / -4°F
but right now we have + 8°C / 46.4°F so than you can fly with P3. But there is little else to think about now at this time of year just for the battery.

But I'll take care of the battery as I do now and we'll see if I can reach over 90% battery life


Merry Christmas

2015-12-24
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DJI-Patrick
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mike.wildlight Posted at 2015-12-24 03:26
Cheers Ken,
wasn't so much getting to storage charge I was thinking of but doing the deep discharg ...

Sorry for late response . Thanks for your suggestion . It's a nice idea .
2015-12-24
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