Battery Care - OK to keep on charger?

[GeraldV]

Hi,

I have a question regarding battery care which I would like to have some inputs on.

Being a Dad of three with limited time to go and fly I often plan to get some flight time so charge up the batteries only to find the trip cancelled due to family, weather, etc. This then results in the batteries going through their automatic discharge and then requiring charging again. Would it be better just to leave the batteries on the charger so they dont go through this cycle and then they are available fully ready when the opportunity arises to go flying? In the past couple of months I must have charged the batteries ready for every weekend, but only hasd the opportunity to go out once.

Appreciate your thoughts!

J

 

[msinger]

Would it be better just to leave the batteries on the charger so they dont go through this cycle and then they are available fully ready when the opportunity arises to go flying?

No. And that won't work anyhow since the batteries will stop charging after they have been fully charged.

It would be better to only charge the batteries when you are planning on using them. Check out this guide for additional battery tips:

HOW TO: Maintain and store your DJI Mavic batteries

 

[GeraldV]

No. And that won't work anyhow since the batteries will stop charging after they have been fully charged.

But once they start to deplete wont the charger kick back in and prevent the drainage for another 10 days?

 

[msinger]

No. And you wouldn't want to attempt that anyhow since charging batteries unattended could be dangerous. People have burned their houses down doing that

 

[deleted member 877]

But once they start to deplete wont the charger kick back in and prevent the drainage for another 10 days?

No, the charger won’t restart charging. The battery will discharge over 10 days as per normal.

 

[m0j0]

Being a Dad of three with limited time to go and fly I often plan to get some flight time so charge up the batteries only to find the trip cancelled due to family, weather, etc.

This happens to everyone.

This then results in the batteries going through their automatic discharge and then requiring charging again.

This is an undesired circumstance. Remember that these batteries are only good for so many cycles. You don't want to discharge them without using them in flight.

Would it be better just to leave the batteries on the charger so they dont go through this cycle and then they are available fully ready when the opportunity arises to go flying?

Here is what I do. I purchased a charger that can charge all the batteries at once. the charger also has a switch that allows you to charge to storage which is 65%. So I fly my batteries down to about 20%. Then as soon as I get home I charge them to storage and leave them there until I know I am going to fly then I top them off prior leaving. Takes about 35 minutes to get them ready to go.

This drastically reduced the number of times I charged the batteries fully and had to let them self-discharge.

 

[GeraldV]

This happens to everyone.


This is an undesired circumstance. Remember that these batteries are only good for so many cycles. You don't want to discharge them without using them in flight.



Here is what I do. I purchased a charger that can charge all the batteries at once. the charger also has a switch that allows you to charge to storage which is 65%. So I fly my batteries down to about 20%. Then as soon as I get home I charge them to storage and leave them there until I know I am going to fly then I top them off prior leaving. Takes about 35 minutes to get them ready to go.

This drastically reduced the number of times I charged the batteries fully and had to let them self-discharge.

This sounds ideal. Do you have a link or more details regarding the unit to limit the charge to 65%.

 

[msinger]

Do you have a link or more details regarding the unit to limit the charge to 65%.

The RCGEEK parallel battery charger has a switch that can be toggled to charge the batteries up to 100% or 65%.

 

[GeraldV]

The RCGEEK parallel battery charger has a switch that can be toggled to charge the batteries up to 100% or 65%.

View attachment 75769
View attachment 75770

That looks ideal! Like the idea of being able to charge all three batteries at the same time which would mean being able to charge them all in less than an hour before going out. Many thanks!

 

[Randall8686]

I dont know a great deal about the Mavic 2 pro yet as i have only just purchased it however i have been using and working with LiPo batteries for a long time (since they became commercially viable) and leaving your batteries fully charged damages them as does leaving them fully discharged. General rule of thumb if you want your rather expensive batteries to last the longest is dont discharge them below 20% now i dont know what DJI have programmed the drones software at so 0% in the drone could be 5/10/20% of the Lipo Voltage range i have no clue on this however they have put a safety margin in so i would say try not to go below 10% during a flight. once done allow batteries to cool and then charge them as soon as you can (after any warmth has gone). now if you plan on NOT flying the pack again only charge to 40% or as close as you can. Its hard with these packs to know where 40% is, but 40% capacity is storage voltage or to be exact 3.85v per cell. i have run various tests including 1 very long test. I used some LiPo's for 50 cycles and then put them at storage voltage and chucked them in my loft for....3 years! and then started using them again (i have a lot of LiPo's) they performed perfect and i am still using them in various RC models.

leaving a LiPo that long in charged state and discharged resulted in a knackered pack. discharged ones ended in cells dropping to below recovery voltage. leaving a lipo fully charged for 10 days and waiting for the pack to discharge its self is also too long to maximize battery life. Ideally only leave them fully charged for 2/3 days. a good way to discharge them is use the USB power bank adapter. you can just charge phone's/tablets until they are around the 50% mark. or failing that buy a little USB Load tester for a few quick and put a 2amp load on the fully charged battery via the power bank adapter and it will discharge the pack over a few hours or of course the fun way is to fly the drone!

Sorry for the long reply however i cannot stress enough how leaving these batteries charged for long periods of time will drastically reduce the life of the pack. a well looked after LiPo will happily do 600+ cycles a poorly looked after LiPo can do as little as 50 Cycles. Its also a good idea if you dont use them for 2/3 months to just top them back up from storage voltage and then discharge them to storage voltage again.

I have worked with LiPo's in industry long enough and also in my hobbies too see people Kill LiPo's with poor use and then blame "crappy" batteries when in fact its all their own doing. I know its not ideal having to charge on the day but its best practice but as above if you get a parallel charger you can be fully charged from storage voltage to ready to go with all your batteries in under an hour. will save you Money in the long run.

 

[globetrotterdrone]

First off, I believe, DJI's didn't do itself a favour with disabling the time to discharge with the M2P batteries. Provided the soil for wild guess and lots of accessories. ?
For some, 10 days + 4 to discharge, are way too long. For the manufacturer (and seller) it seems viable (at least within the one year guarantee time).

For me it's a little bit too much vodoo. The provided batteries are marked as intelligent with their own set of rules, not to be compared to the early or simple LiPo cells you may buy. DJI lists their maintenance for optimal lifetime in the manuals, which include some very basic behaviour you can read here: Link

There is still no long-term evidence, that using the batteries within DJI's specifications will lead to significant or any drop of life expectancy.
One might suspect, that 10+4 days will stimulate sells of bloated batteries in the long run, but there's no proof.

I don't say, that you shouldn't care about, but you shouldn't care too much with charge, re-charge, discharge to certain % in normal conditions.
Follow the guidelines and sometimes anticipate your flight behaviour. The use cases are defined. There's not so much else to follow with common sense. But each to their own.
The quality provided with the LiPo cells is outstanding.

Happy and safe flying!

 

[Randall8686]

I have no doubt that the DJI rules are way better than most I’m just putting that info out there for getting the most out of your batteries. Also I believe that DJI only offer 6 months warranty on batteries? With a year on the drone it’s self?

Regardless of the quality of the LiPo the same rules apply to all LiPo’s if you want many years of fun out of them. If you happy to get a year or two out of them then their guidelines will do this. But doing the above will keep them good for much longer. Ultimately DJI want to sell you new batteries as they are a brilliant revenue stream not that I’m saying they are setting you up for failure as they are not they are doing their best to keep things simple for the consumer and self draining the batteries after 10 days is a very very good idea as they have been stored charged too long.

I have literally dozens and dozens of LiPo’s in various configs and brands some years old still going strong as I just look after them. LiPo is great performance but unfortunately to maximise life it is a little bit of a fiddle. I find it very strange DJI don’t offer a parallel charger of their own too! Would be a great addition to have a parallel charger that offers a storage setting like others do. Plug in 4 packs and press charge or storage. Instead we are stuck with 3rd party chargers to do this.

 

[John235]

The RCGEEK parallel battery charger has a switch that can be toggled to charge the batteries up to 100% or 65%.

View attachment 75769

View attachment 75770

Is there a version for the Mavic Pro?

 

[GeraldV]

Randall8686, post: 770930, member: 100057

Many thanks for your detailled and informative post! Looks like the third party option is the best way forward.

 

[ROBERT MAVIC 55]

WILL IT BE THE SAME PROCEDURE FOR THE MAVIC PRO

 

[paulatkin73]

so, to add my 2c here - in the mavics go4 app, always add battery cell voltage to be shown. at the end of the day, when you are done flying, quickly go over your batteries and make drone hover for several minutes until voltage per cell gets down to the 3.9-3.8v level. it takes some time and is annoying, but, it is the only way to go, otherwise you will be shelling out on new batteries non stop. charging and discharging those packs non-stop is an unfortunate part of this hobby, but, so far, there is no other battery solution available yet. fully charged cells left laying around will puff, eventually, and will deteriorate quickly. again, a proper storage voltage is 3.8v per cell - for long term storage.
regular lipo has a 4.2v max cell voltage, those new cells in the DJI packs are so called HV cells - they are at 4.4v per cell. you need to make sure that pack is set to at least 4v per cell when you put it into bag for overnight sleep. i do not know why rcgeeks did not put a usual 'storage discharge' function into their charger - as it is a royal pain to do it manually with the drone - with my regular lipos i simply use a charger unit to deal with storage discharge, it has a special function for this task.
this new white rcgeeks unit has a function to charge up to 65% - and it is nice, but i do not think it has a function to discharge down to 65%. that would be ideal, but - ...

 

[paulatkin73]

WILL IT BE THE SAME PROCEDURE FOR THE MAVIC PRO

sure does. old pro uses 3 cell packs, new one uses 4 cells per pack , how to take care of those lipo cells is all the same set of rules.

 

[BigAl07]

First off, I believe, DJI's didn't do itself a favour with disabling the time to discharge with the M2P batteries. Provided the soil for wild guess and lots of accessories. ?
For some, 10 days + 4 to discharge, are way too long. For the manufacturer (and seller) it seems viable (at least within the one year guarantee time).

For me it's a little bit too much vodoo. The provided batteries are marked as intelligent with their own set of rules, not to be compared to the early or simple LiPo cells you may buy. DJI lists their maintenance for optimal lifetime in the manuals, which include some very basic behaviour you can read here: Link

There is still no long-term evidence, that using the batteries within DJI's specifications will lead to significant or any drop of life expectancy.
One might suspect, that 10+4 days will stimulate sells of bloated batteries in the long run, but there's no proof.

I don't say, that you shouldn't care about, but you shouldn't care too much with charge, re-charge, discharge to certain % in normal conditions.
Follow the guidelines and sometimes anticipate your flight behaviour. The use cases are defined. There's not so much else to follow with common sense. But each to their own.
The quality provided with the LiPo cells is outstanding.

Happy and safe flying!

Some SOLID advice. I think the 10-day start to discharge is a wee bit too long. If you only fly a 3 times a month you could, in theory have your batteries at 100% for approx 30 days (just an example). I like 5 days personally.

 

[globetrotterdrone]

I have no doubt that the DJI rules are way better than most I’m just putting that info out there for getting the most out of your batteries. Also I believe that DJI only offer 6 months warranty on batteries? With a year on the drone it’s self?

My comment was not meant to belittle your efforts - of course not, they all sound reasonable.
However, I guess most of they batteries will still be in the high 90 % capacity when people already bought the successor to the Mavic 2 ... so I assume DJI's guidelines are certainly a good choice between lifetime and "instant" availability to fly.

You were right about the 6 months guarantee for the batteries: expendable material is offered with a 6 months warranty, the drone itself one year.

Concerning the charging cycle: some people may argue, that charging to 65 % for storage and the rest shortly before the flight will count for 2 cycles rather then fully charge and use it within 10 days to fly.

So, I guess, some points are also personal preference - one need to face, they even with the highest care these batteries are not built for eternity.
I also don't know, why DJI is not putting parallel charger with more options on the table. Even with higher prices, I would rather buy them as some 3rd party device, where I am not sure about the quality of interior parts.

 

[globetrotterdrone]

Some SOLID advice. I think the 10-day start to discharge is a wee bit too long. If you only fly a 3 times a month you could, in theory have your batteries at 100% for approx 30 days (just an example). I like 5 days personally.

If I could set the timer, I probably would between 3 to 5 days for my liking.
But I can't. I also don't want to spent every day to care about the batteries. Charge, dis-charge to store, re-charge for tomorrow, etc.

I am somehow convinced, that I cannot ruin the batteries fast enough even with 10 days discharge time upon a new Mavic in the next 2 - 3 years.