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Cell Balancing TB48 Question
2042 12 2017-11-30
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Cabralkev
Second Officer
Flight distance : 1997861 ft
Canada
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Does anyone know how to balance the cells to the TB48 batteries? When I  fully charge the batteries, I turn them on while they're still in the  charging bay. Sometimes the batteries will actually start charging again  for a minute and shut off, even when it just finished charging full. Is  this cell balancing mode?                                                
2017-11-30
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DJI Elektra
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Hi, Cabralkev. Please try to drain your battery and fully charge it again. Thanks for your attention.
2017-12-1
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Cabralkev
Second Officer
Flight distance : 1997861 ft
Canada
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DJI Elektra Posted at 2017-12-1 00:18
Hi, Cabralkev. Please try to drain your battery and fully charge it again. Thanks for your attention.

I did. Should I stop turning on the battery after it charges full? I thought after it charges full and the lights turn off. Turning the battery on allows the cells to charge so it balances?
2017-12-1
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Mark Guille
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Guernsey
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Cabralkev Posted at 2017-12-1 09:46
I did. Should I stop turning on the battery after it charges full? I thought after it charges full and the lights turn off. Turning the battery on allows the cells to charge so it balances?

When the battery has been left charged for a while, it may drop to slightly under 100%, turning on before charging allows for "topping off" of the battery, back up to 100%. I hope this makes sense.
In the battery section of the DJI app, you can see the individual cell voltages, this is the best place to see how well the cells are un/balanced.

Mark G.
2017-12-1
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Cabralkev
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Canada
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Mark Guille Posted at 2017-12-1 10:19
When the battery has been left charged for a while, it may drop to slightly under 100%, turning on before charging allows for "topping off" of the battery, back up to 100%. I hope this makes sense.
In the battery section of the DJI app, you can see the individual cell voltages, this is the best place to see how well the cells are un/balanced.

Ah makes sense! I'll check the cells after my 2 batteries finish charging. I lost a lot of mAh as well. 1 of the batteries was at 4989 mAh :|. Pretty bad I may say lol
2017-12-1
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Mark Guille
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Jersey
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Cabralkev Posted at 2017-12-1 14:47
Ah makes sense! I'll check the cells after my 2 batteries finish charging. I lost a lot of mAh as well. 1 of the batteries was at 4989 mAh :|. Pretty bad I may say lol

It would be interesting to see what mAh you have after deep cycling, please let us know.

Mark G.
2017-12-2
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DTK
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Australia
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So what is your no of charge so far. DJI battery is not premium quality. Your charge capacity will keep dropping by about 30-50 mah, every time you recharge. It losses more if you have a deep discharge or deep recycle as suggested for every 20 charges. I set myself a rule to land the bird around 30% below 20% will lose more capacity each time. I don't suggest you to deep recycle every 20 charges but manually monitor the capacity of each cell in the app. Only deep discharge if it is unbalanced by more than 0.03 v. Of course, Mark and Rich has a battery balancing harness which will balance each cell more efficiently. With the harness, you don't even have to deep discharge in order to balance the cells. Your third party charger will look after this.
2017-12-2
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Mark Guille
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DTK Posted at 2017-12-2 23:52
So what is your no of charge so far. DJI battery is not premium quality. Your charge capacity will keep dropping by about 30-50 mah, every time you recharge. It losses more if you have a deep discharge or deep recycle as suggested for every 20 charges. I set myself a rule to land the bird around 30% below 20% will lose more capacity each time. I don't suggest you to deep recycle every 20 charges but manually monitor the capacity of each cell in the app. Only deep discharge if it is unbalanced by more than 0.03 v. Of course, Mark and Rich has a battery balancing harness which will balance each cell more efficiently. With the harness, you don't even have to deep discharge in order to balance the cells. Your third party charger will look after this.

Hi DTK,

Regardless of the harness, I still cycle my batteries every ten or so charges. I always fully charge each battery before AND after each flight and have set them to discharge after two days (never discharge them before storing them, they are programmed to do that themselves). I've just been checking my batteries and on average, I have lost about 10 mAh per charge so I guess I'm doing something right.

Mark G.
2017-12-3
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Cabralkev
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Flight distance : 1997861 ft
Canada
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No go guys tried deep cycling the 2 Tb48 batteries 4 times... Didn't work. Airdata.com states the life of both is 87%. 4 times deep cycling until battery shut itself off and I wasn't able to reach above 5000 mAh. Maybe because the batteries are old? Here are some pictures I took of the battery info.
FF3CA92F-A675-43A0-8234-20F6E566ADFD.jpeg
945038B2-7753-48C0-8385-E2164EF64F4C.jpeg
2017-12-3
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DJI Elektra
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Cabralkev Posted at 2017-12-1 09:46
I did. Should I stop turning on the battery after it charges full? I thought after it charges full and the lights turn off. Turning the battery on allows the cells to charge so it balances?

In this case, you can enter the app and check the battery status. If the difference between cell voltage is over 0.1, you battery is abnormal. If not, please continue to it. Thanks for your support.
2017-12-3
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Cabralkev
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Flight distance : 1997861 ft
Canada
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It says battery status normal. The aircraft status shows normal as well. I guess the battery is showing it's age then? I won't be able to get above 5000 mAh anymore?
2017-12-3
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RichJ53
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Flight distance : 1837356 ft
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United States
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Cabralkev Posted at 2017-12-3 19:56
It says battery status normal. The aircraft status shows normal as well. I guess the battery is showing it's age then? I won't be able to get above 5000 mAh anymore?


Hello, I was reading your post and information. All the battery cells look pretty even and from my 2 years using the Inspire 1 batteries the mAh capacity seems normal. They loose capacity with each use and will eventually not be usable. I have seen some comments that they will last over 200 cycles,not quite a buck for charge. I look at batteries as a consumable part and if you want to risk your Inspire 1 using an old tired out battery, then that's your call.  Deep cycling your battery will keep the DJI intelligent battery chip in sync with the decline of the condition of your battery (IMO).

In some cases new or slightly used TB-47, 48 batteries can become out of balance and the Intelligent circuit will not allow the battery to charge correctly. In some of these cases you can disassemble the battery and using a harness,,, the battery can be saved. It can also help restore a battery that has been acting up or over discharged.  See the thread link below if you would like to see more.

Looks like you are all good with your batteries, just keep an eye on your flight times.

Rich
Battery info link::  
2017-12-3
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Cabralkev
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Flight distance : 1997861 ft
Canada
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Yeah the cells look normal to me, I wasn't too worried about that. Just sad about losing so much mAh. I guess that's what I should expect from a 2 year old battery still kicking. Once I notice flight times is less than 10 minutes, I'll retire the 2 batteries. One of my batteries manufactured in 2016 is showing major deviations in cell 1. Seems like cell 1 is weak. So now I try and not stress the battery out by flying far distances. Does DJI still manufacture TB48 batteries? I'd like to buy a new one, not one made in 2015
2017-12-3
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