Ideally charge or top off a few hours before you fly, morning for and afternoon flight kind of thing. No rigid rule, but not days, as the battery will have lost some charge. Night before is fine as necessary
Best way to use batteries
- Thread starter martinetti
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Just hours .... if I charge day before - I try to charge again before flight. My auto is set to 2 days and in theory I should be ok leaving overnight and still use - but I have metered my batterys and I am not so happy that self-discharge is higher than I expected to see BEFORE auto discharge.
It may only be 5 - 8% charge ... more if it was charged previous morning ... but to me that is charge safety margin I prefer to have.
I have car charger as well as my Programmable LiPo chargers I can power from car 12V source.
Nigel
I know the conventional wisdom is to not power down on a partially discharged battery then power back up and fly again with that same battery.
My question:
If I fly for a while then land and power down at, say, 72%... then 5, 10, 15 minutes later power back up and the battery level still displays in the app at 72% and the individual cell voltages are exactly the same as before I powered off, how is the battery sensor 'out of kilter'?
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If you have that ... then I wont argue.
The age old problemm with ESC's and batterys was the LVC. Originally because ESC's came from NiCd / conventional battery techno - the % LVC was based on starting voltage. You can imagine this is not a good system as :
Full charge LiPo normally 4.2V per cell. So a 3.3V LVC setting would equate to x% defined by ESC. Now imagine you put a partial charged battery in ... it expects 4.2V ... but its lower ... therefore that x% will LVC at much lower voltage. Later evolution ESC's changed so that LiPo's auto detected by cell count / voltage would LVC on a specific set voltage per cell and not a %. But those ESC's if used ith NiXX would still LVC on a %.
It appears that DJI may have a bit of a problem here ... I would expect that the ESC's used are modern and use specific Voltage IF allowed to fully operate ... but the control FW may not be so inclined.
We have reports of partial charged batterys shutting down too early and AC landing out. Why ? I don't think anyone can really answer that. I don't think my explanation of ESC and evolution is the real answer either. It has to do with how FW etc. see's the battery and operation.
Of course the simple answer is to not use partial charge battery !
Nigel
Thanks for the lesson on ESCs and battery evolution. I think that the more one knows about the evolution of a product they're using, the better they understand the current version.
Though I still can't imagine why the LVC ( low voltage cutoff?) would be based on a percentage of starting voltage, as you said. I'm sure it must have something to do with the battery chemistry of the day.
So you think the FW may be the 'culprit' here?
I think it may have to be ... ESC's generally only use % on NiXX batterys with LiPo on specific voltage.
I wonder if its because LiPo will fall between two specific voltages based on 3.3 - 4.2 (4.35 for DJI HV) range empty to full but a NiXX can be 0 - 1.35V ?? With that - its easy for ESC to do voltage for LiPo ... but with NiXX more difficult - so % of initial.
I know if you get a dud cell or one very low below LiPo threshold - you can get some weird effects from ESC's.
I still have some ESC's that use % for LiPo ... so not something to casually dismiss.
Whatever the reason ... as said - try not to fly with partial discharged batterys.
Nigel
O believe me, heeding the advice of the long-timers around here has served me well in my short one year of Phantom ownership.
But I soak it all in, mix it all up, and come up with my own -hopefully logical- conclusions.
O believe me, heeding the advice of the long-timers around here has served me well in my short one year of Phantom ownership.
But I soak it all in, mix it all up, and come up with my own -hopefully logical- conclusions.
We are human ... so we all arrive at our own solutions. I know I have made some really awful decisions in past !!
Yes totally agreed.
Nigel
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That appeared to be an issue with the Phantom 3 firmware around 2016. Unless the battery was fully charged, the controller couldn't figure out where it was in terms of battery capacity. That and issues with the auto discharge logic starting to drain the battery gave erroneous results when using a partially charged battery.
That seemed to be in the context of partially using the battery on one day, putting the bird to bed and starting out again the next day (or several days) ON THE SAME BATTERY WITHOUT RECHARGING IT. That lead to some dramatic failures.
DJI revamped the battery logic to the point where this doesn't crop up as a complaint now.
So, you can take a fully charged battery, fly around. Land, rinse, lather and repeat without any problem except the slowly diminishing voltages as the battery is used. If you shut down for the day, you REALLY should charge the batteries (why wouldn't you?) but with modern firmware you should be able to follow the battery voltages downward safely.
And remember to look at the voltages, not the % remaining.
That all said, I agree with the concept that 'batteries are cheap'. I try to swap out a fresh battery every time I land. Murphy's Law will come into play and you will find that the picture of a lifetime pops up just as soon as the battery hits 30%.
Question:
I topped off my batteries with the intention of flying in 2 days, but wind postponed the flight probably for another 3 days, so it would be 5 days since charging. My batteries are set to discharge in 4 days to 50%. If I turn on each battery will is reset the timer and give me another 4 days before discharging?
Yes it will, but you don't even have to turn them on... just pressing the power button once resets the discharge timer.
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