Does anyone do battery deep cycle discharges on their lipos?

[helpubuild]

Than

I agree with everything you've said here, yep. 30-60% would be fine. Lipo nominal voltage is 3.7v per cell and they like to be stored at nominal at 25°C, if we're being picky. But they'll handle a range as stated without adverse effects.

What does hurt them is being fully discharged for long periods of time (though this is still not the end of the world), but what really seems to kill them is being left full. They really don't like that!
Well, perhaps just don't charge them until you're ready to fly. Ideally you store them at 60%,but if you're regularly flying every 2 to 7 days (like me, really) then the best compromise might be to charge them before you fly rather than after you fly. Yeah, don't leave them empty if you flew to 10% remaining or so, but if you're like me, after a flight you have between 25% and 70% remaining, which is far better to be left at than being fully charged and left at 100% for most of their lives, only discharging briefly during that weekly flight before copping a full charge again.

-

Bottom line, compromise might be the way to go given we don't have a convenient Storage charge option like I do for all my other lithium batteries. The best compromise would be one that we're actually going to stick to and one that doesn't leave the batteries always full.

So, the best policy might be to charge before a flight rather than after a flight. That probably is the answer to most situations here, I reckon.

(Quick edit to add, don't forget about the controller! It's also lipo powered I believe, so it wants to be kept 30-60% ideally. Charge before you fly and do the controller only when the leds are showing one or two before a single flight, perhaps. Fully charge it if you're going to fly all your batteries, I guess. It also can be used to charge your phone while it's on, so that might be a convenient way to discharge it a bit)

*all of the above is based on my experience and knowledge as an electronics hobbyist who also does relatively basic electronics repairs in a small business as part of a greater service (fix the thing so it can be accessed in order to do the job). I don't have formal training with battery technology but do have years of experience working with lipo, li-ion, nimh, nicad and Pb battery chemistries. The advice here is my best guess rather than engineering fact, so please use your best judgement!

I've been working with lithium polymer batteries for over a decade and for various projects and uses here I have over 50 of them in varying sizes.

Categorically, discharging a LIPO battery completely will have a detrimental effect on its total capacity potential and on its remaining service life. They will survive this, as long as they're not left fully discharged for long, but it isn't good for them.

However, the dji batteries have circuitry in them that may need a cycle to reset for accuracy after some months. So, in this case, do what the manual says and run the batteries down to cut-off voltage and then charge again every few months. They're best stored at around 60% charge.

I wish there was A Storage function on the chargers that would allow me to put the batteries at 60% without having to charge them and then run them down to that level. The circuitry does it to 65% after 10 days, yes, but for a LIPO battery, that's a long time to be sitting at full charge before dropping to Storage voltage!

Thanks for your advice, really useful insight regarding our batteries. Rgds

 

[RCdancer]

Yes i do. I had a short flight once, like 15 minutes and i got the low battery warning. I wrote dji and they said to discharge it to 7% let it cool off and recharge fully. If you go to dji downloads they have a battery safety manual. In there it states on how and when to discharge the batts. Also they stated to put the bat into the drone and check the charge in % that its fully charged. I have one of those adapters that allows you to plug in 4 bats but it chargets only one at a time. Well guess what. It only charged the bat 94% on all three batts. At the field i did notice it but Didn’t have an answer and since it was 94% i flew it.
I dont use the adapter anymore If you tried to connect the bat direct to the charger it wouldn’t charge due to the fact it was on a high percentage. So now. One bat at a time for a 100% charge

hmmmm ..... I believe I have that same charger. I'll have to pay attention.

 

[Mossiback]

...I have one of those adapters that allows you to plug in 4 bats but it chargets only one at a time. Well guess what. It only charged the bat 94% on all three batts. At the field i did notice it but Didn’t have an answer and since it was 94% i flew it.
I dont use the adapter anymore If you tried to connect the bat direct to the charger it wouldn’t charge due to the fact it was on a high percentage. So now. One bat at a time for a 100% charge

I use the same quad charger and get 100% charge. Perhaps now that your batteries have been charging at 100% they are now "conditioned" and will fully charge using the quad adapter.

 

[IgorD2]

Story #1
Would like to share some experience, year ago I charged P2 battery to 100%, its was in the good condition prior, no puffing. Weather was bad and since I can fly only during the weekends soon I have forgot that I have charged it. Checked it in one month or two (I know, I know, pls dont blame me, forget things from time to time ) , cant recall anymore, and it become slightly puffed. Still keep the voltage and can fly quite good but P2 give the signal of low voltage when I climb up fast, probably because P2 draw too much at that moment and voltage drops. So, I can confirm that keeping batteries at 100% for extended period of time is no good.

Story #2
Being a quite picky person few days ago I went thru the battery maintenance / checking routine. Have few dumb quads, one P2 and one Mavic and Im trying to check voltage from time to time, recharge etc, you know the drill. One of S1 batteries become puffed (it was like that since the purchase, it was 15 euro "drone with the "camera" ) so I wanted to charge it and then fly a bit to bring it to 50%, anyway after I landed it was bit over 50% so I left it connected with drone lights on because I wanted it to enter storage zone at about 3.70-3.80 V. Problem is that I have forgot about my plan and kept it that way for hours. When I saw what I did it was too late, battery was at like 0.02V. Knowing the minimal voltage for li po I believed that its over, no chance to charge it, but I connected the battery and slowly charged it back to normal voltage during the few hours. Charger was displaying that battery is not good any more but I persisted with frequent controlling of the battery temperature. After the battery reached normal voltage charger (its a simple usb charger with jst connector) did not show signals about the bad battery any more. Performed a test flight after that, it was just as before so no damage occurred during that short time loss of charge.

Hope that my experience will help someone.

(Perhaps many will say just dump those puffy batteries, why not just purchase new ones. Im in the Bosnia and its very hard to purchase even smallest LiPo here)

question to mod/admin: why some of my messages need approval of the admins?

 

[cragv]

I have a 300mah 2S and 3000mah 3S battery that just spent 4 days stuck high in a tree (long and embarrassing story) and when I got them down, both were thoroughly discharged. Like you, I slowly put power back into them and eventually got them to storage voltage.

They no longer hold that charge as accurately as they used to and the total capacity has diminished to 70% or so of what it was, the smaller battery faring worse than the bigger one.

In any case, lipos don't like being discharged, but that's still a safe prospect than over charging them! Cheers

 

[Former Member]

Ok here's a quick question. If you let a DJI battery sit for a year, what might happen?

 

[RCdancer]

Ok here's a quick question. If you let a DJI battery sit for a year, what might happen?

It's a year older?

 

[Former Member]

It's a year older?

Yes, that . But leaving a lipo around for a year without maintaining it might cause the battery to drop below the minimum charge needed to activate the firmware thats embedded into the battery PCB. If that happens, good bye battery.

Thats how I feel about running batteries until they are below 3.7vpc, or discharged enough that they wont power up the drone. There is a great risk of discharging past the point of no return, and then you have an $80 paperweight.

In the old days of dumb lipos, you could run it all the way down to around 2.7 under load, and it might still bounce back when charged. Back then, the batteries didnt have any logic themselves, and woiuld allow themselves to be discharged entirely if you werent using an LVC (external low voltage cutoff). These days, with Intelligent Batteries, the battery will do everything it can to protect itself from the pilot including turning the drone off before the pilot damages the battery, and landing when it calculates the drone will crash if it doesnt land at that point in time.

The more drones I repair, the more I find how much the drones try to protect themselves from inexperienced, or negligent owners. Obstacle avoidance, redundant IMU's return to home. All these features are trying to make sure that the drone survives the owners operator errors.

 

[mnis]

Ok here's a quick question. If you let a DJI battery sit for a year, what might happen?

And with luck, you can save some energy in it

It's been a long time ... But I had replaced countless single-cell batteries in MP3 players and other portable devices. Some were so swollen, probably just before bursting. I pricked them with a needle to release the pressure, put a sticker over the hole, and then I recycle these batteries. Other batteries looked good, but the performance was already 50 percent of the original capacity. I also got devices that were not used for more than a year, but its batteries still looked good. I tested these batteries and got very different results between 30 and 80 percent. All batteries were equipped with single cell protection. All of these batteries could be charged, despite voltages between almost zero and 2.5 volts. But the battery cells with the lowest stored voltages definitely had the lowest capacity.

 

[mnis]

And with luck, you can save some energy in it

It's been a long time ... But I had replaced countless single-cell batteries in MP3 players and other portable devices. Some were so swollen, probably just before bursting. I pricked them with a needle to release the pressure, put a sticker over the hole, and then I recycle these batteries. Other batteries looked good, but the performance was already 50 percent of the original capacity. I also got devices that were not used for more than a year, but its batteries still looked good. I tested these batteries and got very different results between 30 and 80 percent. All batteries were equipped with single cell protection. All of these batteries could be charged, despite voltages between almost zero and 2.5 volts. But the battery cells with the lowest stored voltages definitely had the lowest capacity.

Oh, I had overlooked it, the question explicitly referred to DJI Batteries ...

Then you should better regularly every 1 to 3 months to see if the Smart Electronics still gets enough juice

Because when Smart gets nothing more power, then maybe only helps the violent opening of the battery for resuscitation attempts

 

[Former Member]

Oh, I had overlooked it, the question explicitly referred to DJI Batteries ...

Then you should better regularly every 1 to 3 months to see if the Smart Electronics still gets enough juice

Because when Smart gets nothing more power, then maybe only helps the violent opening of the battery for resuscitation attempts

Yes! I have tried a few times to open a Mavic battery, and got nowhere.

 

[mnis]

Yes! I have tried a few times to open a Mavic battery, and got nowhere.

Would you say:
There is no way to replace a dead cell pack?

But maybe it would be, if a pack is exchanged for a new, so to speak, an operation on the open (beating) heart ...

 

[Former Member]

Would you say:
There is no way to replace a dead cell pack?

But maybe it would be, if a pack is exchanged for a new, so to speak, an operation on the open (beating) heart ...

I dont think there is a way to open the battery, and put it back together again!

 

[mnis]

I dont think there is a way to open the battery, and put it back together again!

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Obviously here is the BMS of the Mavic used for the 18650er of LG...

 

[Former Member]

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Obviously here is the BMS of the Mavic used for the 18650er of LG...

He made his own battery! I think his drone can fly for 2 hours!

 

[Former Member]

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Obviously here is the BMS of the Mavic used for the 18650er of LG...

I think it is easier to mod a Mavic with an OEM battery to start, and then 2 external dumb lipos for added endurance.

I dont like to use Dumldore unless I have to, which is almost never. Too many things to consider.

 

[mnis]

He made his own battery! I think his drone can fly for 2 hours!

You do not kidding me?
He flew with these batteries for 16 minutes ...

Edit:
I like you Rob A big dream bursts. I could get fresh LiHv's 3S / 11.4V / 59.3Wh for less than 60 euros :-(

 

[Dingo]

assuming after a flight you have 20-30% when you get home set a timer for 15-20 minutes and charge for this long.Turn off the 240 volt charger at the power point dont remove battery while charging.This will give you approx 50-60% storage charge . Top up when you intend to fly. DJI gave me that advice. works well for me

 

[j.r.r.]

I went easy way about it, bought Inspire, Mavic and Phantom Angel for my Mavic Pro batteries. Easy to use, works very well and take guessing out of battery maintenance process.

 

[Marko9219]

Yup. I discharge to sub-10% then do a full recharge. I do it a few times a year. I store it at about 50% when not flying.