Over Discharging TB50 Batteries

[Jerry Laurence]

Perhaps foolishly, I decided to deep discharge my TB50 batteries after updating the I2 firmware. I hovered above my landing pad and was going to take the batteries down to 5% before landing. However, the aircraft shut down before 5% was reached. Now, I cannot charge three of my six batteries and I get a solid red light on the charger. When pressing the batteries’ status button, I get a single LED showing and, if I hold the button down, all four LEDs flash for a few seconds, so the batteries are showing some signs of life.

What can I do to get these batteries to recharge? I thought they were intelligent enough to protect themselves from over discharging...

Thanks for any help.

 

[markfothebeast]

I'm not an Inspire 2 owner. But on the Inspire 1, the manual clearly states to drain the batteries till' the drone turns off (every 10 cycles) Now, on the Inspire 1, there's 12 Li Poly cells. 2 packs in series for 6 total cells that the system can sense. However, the batteries being in parallel pairs may begin to unequally charge resulting in a false sense of capacity - unless the Inspire 2 actually monitors EVERY cell.

So, don't be alarmed. The "below 5%" scare is complete BS. I've read that on this forum many times. Don't fly at 5% but let that battery drain so the cells can fully recharge more accurately. As a matter of fact, don't even trust the percentile readout. Read the voltage output for yourself. Research the output if a Li Poly cell voltage output during it's cycle.

 

[Jerry Laurence]

I'm not an Inspire 2 owner. But on the Inspire 1, the manual clearly states to drain the batteries till' the drone turns off (every 10 cycles) Now, on the Inspire 1, there's 12 Li Poly cells. 2 packs in series for 6 total cells that the system can sense. However, the batteries being in parallel pairs may begin to unequally charge resulting in a false sense of capacity - unless the Inspire 2 actually monitors EVERY cell.

So, don't be alarmed. The "below 5%" scare is complete BS. I've read that on this forum many times. Don't fly at 5% but let that battery drain so the cells can fully recharge more accurately. As a matter of fact, don't even trust the percentile readout. Read the voltage output for yourself. Research the output if a Li Poly cell voltage output during it's cycle.

Yes, thanks for the info, but I can’t get the batteries to charge.

 

[markfothebeast]

Yes, thanks for the info, but I can’t get the batteries to charge.

Have you updated the firmware on the remote and drone? I'm not familiar with the I2. If it is nearly new, call DJI (If they speak English). This is an Asian company and their products have been a little iffy.

 

[markfothebeast]

On my I1 charger. I have to give her a little wiggle literally every time to get a charge.

 

[markfothebeast]

On a side note; there's been some issues here and there (with I2) before but a new firmware update was just released... I just read that a few minutes ago actually.

 

[eldorado]

However, the batteries being in parallel pairs may begin to unequally charge resulting in a false sense of capacity

This is an interesting problem as Inspire 1 DJI battery status does not report a battery with .10 volt variance between cells as an issue.

ie 5 cells report 4.20v and one cell 4.10.

Further the stock chargers do not address the issue.

I don't know if this is the same situation with the I2 system.

 

[Casey53]

Jerry, this is a problem with their Intelligent Battery system. With their Phantom series, if the battery gets too low, the charger will not connect and the no charge is the result. Many of the Phantom batteries sit too long on dealer shelves and are DOA when the new owner tries to charge them and need to be exchanged.

Some of the I1 owners have tore into the I2 battery to get s "boost charge" into them and then their DJI chargers will work. The I2 batteries may be more difficult to do it.

Personally, I never let them get that low as you are flirting with the "Charger will not see them" territory so they go to the trashcan. I will toss mine back on a charger even when sitting around when I see a couple of LEDs on hitting their test button. I set the drain to 10 days too in case they might sit longer than their 3 day drain cycle and then self-discourage on their own to below what the charger needs to see them and activate the charging cycle.

With my old RC planes Li-Pos, they last forever and the smart chargers for them can get them back into a running state - and some of those batteries are years old too. I'm not enamored with the current DJI intelligent methodology at all and do not trust their system as it currently is so I keep the batteries up more than they prescribe.

 

[Jerry Laurence]

Thanks Casey, that all make sense (unfortunately for me). With three batteries in this state I can only hope they can be revived, even if it means sending them back to DJI, although that what cost? I was hovering a foot off the ground, waiting for the batteries to discharge to 5%, when they suddenly died. I intended to charge to 100% later that day to recalibrate and now I have nothing. I don’t think I was being irresponsible by doing this. If the batteries are ‘intelligent’, you’d think this problem would be factored into the firmware. But...

 

[Casey53]

Thanks Casey, that all make sense (unfortunately for me). With three batteries in this state I can only hope they can be revived, even if it means sending them back to DJI, although that what cost? I was hovering a foot off the ground, waiting for the batteries to discharge to 5%, when they suddenly died. I intended to charge to 100% later that day to recalibrate and now I have nothing. I don’t think I was being irresponsible by doing this. If the batteries are ‘intelligent’, you’d think this problem would be factored into the firmware. But...

If they are less than six months old, they may honor the warranty and replace them. Otherwise...$$$.

DJI really annoys me that they take forever with an update (P4 took 7 months, and yet it still has faults!) and it seems almost a ploy to get the things out of warranty both. I'm glad DJI doesn't build cars!

Think I'll go toss mine on the charger right now too as that last update was a whopper!

Quick thought added:
Given the RC had the suggested idea to hold the power button on while plugging in the charger so it would begin charging, why not try the same idea with the I2 battery? Hold the button down on the battery while shoving it into the charger. Couldn't hurt in their current condition. (I just tried it with mine too!).

Good luck!

 

[slim.slamma]

Discharged mines below 0% three separate occasions, once since the update, no problems with charging.

 

[Jerry Laurence]

Discharged mines below 0% three separate occasions, once since the update, no problems with charging.

That’s interesting.

 

[slim.slamma]

Rushed home to check after reading this post. My batteries took the update at around 30% then I drained them to 0.
Now they charge.

 

[traderdmb]

Same issue. Tried to deep discharge as advised in the go4 app. Aircraft shut down and dropped (only 6 inches) and now batteries are toast. Dji said too bad so sad American stoopid.

 

[davidjmurray]

I found this thread today looking to see if an issue I have with the fancy $1199 DJI Battery Station has been raised elsewhere. Seems not, and I may start another thread to make sure others see it. But it seems related to this thread too, so I'll post briefly here:

I expected this charging station to have an option to deep discharge the batteries, since the marketing material lists "Quick and Simple Discharging" as one of the features, and goes on to say "This intelligent, easy-to-use discharging feature improves battery maintenance to lengthen the life of your batteries". I erroneously assumed that was a reference to deep discharging, but apparently not. According to the user manual (yes, I know I should have read it before buying!), the device can discharge to "25% ... for safe transportation" and "50%...for safe long-term storage", but there's no option for a deeper charge.

I made this device for deep discharging my I1 batteries (not my design):

.
Worked well enough. But I was hoping the Battery Station would provide a more elegant solution for my I2 batteries.

 

[NickU]

If you're that desperate to run your batteries down then set the critical warning level on the I2 to 7%, hover it till it force lands and then leave it on until it shuts down itself.

You can also buy the simple TB50-rc charger lead and use it to top up the charge on your RC from the residual charge in the TB50.

 

[davidjmurray]

If you're that desperate to run your batteries down then set the critical warning level on the I2 to 7%, hover it till it force lands and then leave it on until it shuts down itself.

You can also buy the simple TB50-rc charger lead and use it to top up the charge on your RC from the residual charge in the TB50.

Oh my, thanks Nick. I had no idea that I could run down the batteries (slowly and inconveniently) using my drone or RC. ;-)

Seriously, this has nothing to do with being desperate. Its about efficiency and convenience. Deep discharging is a recommended activity every 10 charge cycles. As a pretty busy solo commercial operator with well over 200 hours of flight time on my I1, I've followed this procedure pretty faithfully. I don't know for sure that it has contributed to my batteries' health, but I've got 8 TB48 Inspire 1 batteries that each have >150 charge cycles on them and still work ok.

If periodic deep discharging is actually important, then doing it conveniently and efficiently matters to me. Since that was one of the benefits I hoped to gain from the Battery Station, I figured others might be in the same boat, and appreciate the heads up.

 

[NickU]

Can you point me to where DJI recommends the deep discharge every 10 cycles for the TB50's? As far as I'm aware, that advice is for the previous generation of 'dumb' batteries, not the current range of 'intelligent' batteries.

I've never had an I1 or any tb47/48's or any other of the 'dumb' Dji batteries, just the intelligent ones for the Phantom 4 and I2. In the 2yrs/15 months of respective use across 180hrs flight time, so far the combined 17 batteries have been fine without any special charge conditioning regimes. The only thing I do do with them is make sure they're regularly used. I've had a 2 month hiatus with my TB50's use due to Dji being slow to do some repairs, so it'll be interesting to see if the batteries have suffered from their rest once I've got the bird back. They've auto discharged to storage level a week after the bird went in, and so far I've only recharged one pair as their level had dropped lower according to the leds on them. I've been considering buying the battery station solely to make sure they can be charged & discharged as per the 3 month recommendations from Dji.

I think the big difference is in the 'intelligence' that Dji have integrated into the newer batteries, meaning we don't have to do the micromanagement. I might be wrong in this, if there's someone with a greater depth of knowledge on the tb50/55 design and use, then I'm happy to be corrected

 

[davidjmurray]

Can you point me to where DJI recommends the deep discharge every 10 cycles for the TB50's? As far as I'm aware, that advice is for the previous generation of 'dumb' batteries, not the current range of 'intelligent' batteries.

Well, now that I've looked again, I can't! Seems I was incorrectly assuming the same basic care/maintenance requirements as for my I1 batteries (which DJI also describes as Intelligent, but it's all relative...).

Thanks very much for making me aware of my misunderstanding (no sarcasm this time). This would explain why that feature is not present in the Charging Station. It will also save me time/concern. Much appreciated.

To reinforce NickU's statement above, "If there's someone with a great depth of knowledge on the Tb50 design and use..." please chime in.

Thanks again.

 

[The Editor]

The problem with ‘Intelligent’ lipo packs is....... they’re not.

DJI originally introduced them to weed out the idiot gene a few years ago and have been attempting to refine the ‘intellegence’ or algorithms since introduction with varying levels of success.
The problem is, no amount of clever software can accurately predict the deterioration of a lipo pack. There are simply too many variables.
By periodically discharging a pack all the way down to LVC you are ‘reteaching’ the software where the empty point is (or zero percent). This point is forever moving as a pack ages and is dependent on multiple criteria. This is why you will often fly a pack down to ‘zero percent’ indicated and yet the aircraft will fly for a further two or three minutes! The software just isn’t accurate without some sort of calibration every so often.
The DJI software simply makes a best guess when it displays a percentage and the algorithms err on the side of caution which is why you see your pack life diminish faster than you would like. (It’s also designed to get you to purchase more batteries).
Although DJI do not mention periodically discharging a pack to LVC it is still advisable/necessary to get a more accurate fuel gauge percentage readout (if that’s what you fly by).
DJI have been wrong in their advice many times before - they used to say ‘calibrate your compass before every flight’ until they released they were talking utter rubbish and it was actually more likely to cause problems than calibrating and leaving well alone.