Based on owning a Chevy Volt, deep discharge reduces battery life. I never go below 30%. I have 5 batteries for over an hour of flight time.
Battery Discharge/Charge question?
- Thread starter jakeaheli
- Start date
Sorry but not true. The auto discharge function is specifically designed for storage level charge.
As to this myth of magically resetting capacity - it is only a calculation based on voltage level and can never be regarded as accurate. The production factory states capacity based on load test and even that is quoted as a 'safe' number subject to variance.
Seriously. It is a fact that factory's test the packs and often they exceed the labelled capacity. But if it is found to be below - then they either scrap or downgrade the pack. Quite often those packs get into hands of online sellers such as some ebay'rs.
Capacity like voltage is Nominal value.
Nigel
Why do people worry so much about what capacity is stated on Go ? The important value is voltage as that will decide if model flies or not.
You can have a battery showing full mAh but unable to power a lightbulb !!
Battery's have a factor termed Internal Resistance. This comes from physical make-up of the cell. As iR increases over llife of the cells, one or more cell will find it harder to provide the voltage / amps needed. Heat is developed worsening the iR until finally pack cannot deliver and it does not fly. But you can still see full mAh capacity.
Deep discharging can result in damage that incurs heat whenpack ois called to perform ..... iR then climbs .... Doing often enough and you will irreparably damage the pack.
General lipo use does not include deep discharging. Just because DJI fit a charge control doesn't change the basic point.
Nigel
You can have a battery showing full mAh but unable to power a lightbulb !!
Battery's have a factor termed Internal Resistance. This comes from physical make-up of the cell. As iR increases over llife of the cells, one or more cell will find it harder to provide the voltage / amps needed. Heat is developed worsening the iR until finally pack cannot deliver and it does not fly. But you can still see full mAh capacity.
Deep discharging can result in damage that incurs heat whenpack ois called to perform ..... iR then climbs .... Doing often enough and you will irreparably damage the pack.
General lipo use does not include deep discharging. Just because DJI fit a charge control doesn't change the basic point.
Nigel
I don't think he was trying to make the point that it reset the batteries capacity, but reset electronics like software and/or sensors that calibrate the capacity in terms of a percent. He went on further to state he thought maybe an update in the firmware no longer required this. In my opinion it probably never did work to begin with and they finally came to realize they needed to update the battery manual.
I was probably not so clear ... I don't mean the battery itself is reset ... but I meant that the control board will not be reset by such action.
I have difficulty with this sensing of capacity item as it needs two definite points to determine it ... ZERO and FULL. Any intermediate point is worthless to determine as even the best gear in the world only averages rates when charging / discharging etc. So how can the real capacity be referenced ?
At best its an approximation. Trouble is - it has 'developed' its own momentum in having people quote this myth too often. So often in fact that it now has joined the supposed world of fact.
The fact is that when you buy a recognised brand of LiPo whether DJI ... Overland ... Turnigy ... Hyperion or whatever - the capacity stated on the label is what is MINIMUM expected and most in fact are slightly more. This is where the differences in labels comes from. You can take an original DJI and it says 4480mAh ... and an identical cell clone says 4500mAh or even higher in some cases. There is NO difference in actual capacity - just in the reporting of g'teed minimum as DJI / recognised brands do or as clones do by quoting the tested mAh by the production. So where does that leave the little control board on the battery pack ? It reads a voltage and assumes a capacity, based on DJI formula programmed in - it can do nothing else.
Nigel
I have difficulty with this sensing of capacity item as it needs two definite points to determine it ... ZERO and FULL. Any intermediate point is worthless to determine as even the best gear in the world only averages rates when charging / discharging etc. So how can the real capacity be referenced ?
At best its an approximation. Trouble is - it has 'developed' its own momentum in having people quote this myth too often. So often in fact that it now has joined the supposed world of fact.
The fact is that when you buy a recognised brand of LiPo whether DJI ... Overland ... Turnigy ... Hyperion or whatever - the capacity stated on the label is what is MINIMUM expected and most in fact are slightly more. This is where the differences in labels comes from. You can take an original DJI and it says 4480mAh ... and an identical cell clone says 4500mAh or even higher in some cases. There is NO difference in actual capacity - just in the reporting of g'teed minimum as DJI / recognised brands do or as clones do by quoting the tested mAh by the production. So where does that leave the little control board on the battery pack ? It reads a voltage and assumes a capacity, based on DJI formula programmed in - it can do nothing else.
Nigel
Like you said, a battery needs two points to determine capacity. So obviously zero volts is not an option. Voltage at 30% vs 100% is ok, but voltage at 8% vs 100% is better because the batteries smart technology now knows what a nearly depleted voltage looks like. I'm not saying it's a good thing to run your battery to 8%, especially since DJI does not recommend it, but this reasoning is why DJI recommended it in older manuals.
I agree with your last statement but have to highlight that DJI batteries are "smart", meaning that the input variables (voltages) per capacity are not fixed at the factory, but deduced from battery performance. If every battery was identical, and stayed the same indefinitely, smart technology would not be needed.
But I think this is where the matter breaks down ... so far with tests conducted by myself and others i am in contact with - the 'smart' function is not as 'smart' as expected.
Tests have shown that balancing does not occur in anyway close to what a bog standard LiPo charger would achieve, and that's only one example.
The 'smart' as far as myself and others involved in the tests have determined is DJI have instigated this format to try and solve the problem of idiots who do not understand LiPo's and get a safer use.
Capacity is fixed by physical construction and not by magical electronic wizardry.
OK ... I have had a number of occasions where a battery warning has been voiced by my Nexus ... BATTTERY ZERO % .... when I heard it first time - my heart near stopped !! BUT I kept flying .. I had full control ... APP showed ZERO battery ... and then miraculously recovered to show battery voltage again...
And before anyone asks .. that was with both DJI and clone batterys ... no difference. To this day I still cannot find out why it happens occasionally. But at least I now know the model still flies !!
Yes - I appreciate it is displayed voltage and not actually figures of what model gets ... so it must be a comms problem.
Nigel
Tests have shown that balancing does not occur in anyway close to what a bog standard LiPo charger would achieve, and that's only one example.
The 'smart' as far as myself and others involved in the tests have determined is DJI have instigated this format to try and solve the problem of idiots who do not understand LiPo's and get a safer use.
Capacity is fixed by physical construction and not by magical electronic wizardry.
OK ... I have had a number of occasions where a battery warning has been voiced by my Nexus ... BATTTERY ZERO % .... when I heard it first time - my heart near stopped !! BUT I kept flying .. I had full control ... APP showed ZERO battery ... and then miraculously recovered to show battery voltage again...
And before anyone asks .. that was with both DJI and clone batterys ... no difference. To this day I still cannot find out why it happens occasionally. But at least I now know the model still flies !!
Yes - I appreciate it is displayed voltage and not actually figures of what model gets ... so it must be a comms problem.
Nigel
I think we basically agree. It's too bad DJI doesn't tell more about their batteries.
Wow, that's a tad judgmental. Yes there is much information on recommended maintenance for these batteries and I have looked at quite a bit of it. What I hadn't seen (and thus the reason for my question) is what is the real world limpacton the life of these batteries of keeping them charged. That was what I was asking on a forum with a bunch of people with real-world experience with these particular batteries. Forgive me but I thought that was the purpose of these forums.
Thankfully someone took my question at face value and answered it. I appreciate your constructive criticism though.....
N017RW
Premium Pilot
If you monitor voltage during the charging you'll see it does not follow/apply the CC/CV profile recvommended for LiPos.
N017RW
Premium Pilot
Not judgmental but lazy. Why should I rewrite what is clearly already published all over the web by reputable sources? Take everything here at face value and do your own research to determine what you wish to believe or follow. This topic and questions have gone on here for years and will continue as new folks get into this hobby. I stand by my advice. DO YOUR OWN RESEARCH BEYOND ANONYMOUS CHAT FORUMS.
There is a lot of good information right here on these forms you just have to weed through some subjects that may have disagreements or different points of view. If by being anonymous you mean we're not posting our last name and address, that has nothing to do with the advice given by anybody. Often times when you search online you're getting YouTube, other forums, Facebook posts, blogs and Wikipedia, all of which are also anonymous. With a slight exception with Facebook which might actually have a person's proper name, but that doesn't make their opinion anymore correct.
Last edited:
N017RW
Premium Pilot
Anecdotal advice lacking supporting research.
I subscribe to the sentiment of the Russian proverb translated to 'Trust but verify'.
My advice to seek information backed by cite-able sources does not require 'weeding' but rather encourages researching the published works of industry professionals. In other words don't take my word for it.
Can't see how that hurts.
I took note of cell voltages Vs %charge on the app. This is for a P3A:
27% - 3.76v
15% - 3.72v
10% - 3.68v
5% - 3.65v
1% - 3.62-3.59v where past 3.60v voltage goes from green to yellow
Just reaching 0% - 3.59v
You can let voltage go below 3.59v but no matter how low it goes, % will stay at zero, no negative numbers. I did not go below 3.59v this last time, my observation was from a couple months ago.
This seems to confirm that DJI is conservative on the low end of charge level where little harm can come from critical landing at 10% or controlled landing between 20 and 10%
I found it interesting that the total battery capacity rose a bit from what I wrote down 4/7 and rose yet again when re-installing batteries that were 15-20% to recheck some numbers.
Variance was as much as 100mAH.
Bottom line: you don't seem to need to baby these batteries so much.
My experience in general with LiPOs is heat and constant charge. In other words older laptops and phones and car GPS constantly left on charge would get deteriorated batteries. Modern laptops and phones stop applying charge to the batteries though the device may get it's operating power from the power pack.
27% - 3.76v
15% - 3.72v
10% - 3.68v
5% - 3.65v
1% - 3.62-3.59v where past 3.60v voltage goes from green to yellow
Just reaching 0% - 3.59v
You can let voltage go below 3.59v but no matter how low it goes, % will stay at zero, no negative numbers. I did not go below 3.59v this last time, my observation was from a couple months ago.
This seems to confirm that DJI is conservative on the low end of charge level where little harm can come from critical landing at 10% or controlled landing between 20 and 10%
I found it interesting that the total battery capacity rose a bit from what I wrote down 4/7 and rose yet again when re-installing batteries that were 15-20% to recheck some numbers.
Variance was as much as 100mAH.
Bottom line: you don't seem to need to baby these batteries so much.
My experience in general with LiPOs is heat and constant charge. In other words older laptops and phones and car GPS constantly left on charge would get deteriorated batteries. Modern laptops and phones stop applying charge to the batteries though the device may get it's operating power from the power pack.
Similar threads
