Optimising battery use

[malbowski85]

So i've had my MM for about a year now and when I fly, I tend to keep it in the air until the battery is low, getting what shots I can in the 20 mins or so per battery then bring it down. Im wondering if it would be better to send the drone up, get the shot, then bring it down and save some juice. Just not sure if this uses more battery life taking off and landing, powering down/up again.

I have a big trip planned where charging time will me minimal so want to get the most out of the batteries.

TIA

 

[StantonZ]

If possible, it's best to cycle any Lithium based battery (like the LiPo's in our drones) between 30%-80%. Obviously, that's not always possible, so the critical points are:

• don't let it "sit" at full (<90%) or empty (<20%) for very long
• let the battery pack cool before/after charging

For example, I charge my batteries up the night before...and then typically use them down to ~50% (perfect for storage). If I'm toward the bottom end of the window above, I charge them a bit after cooling for storage. Rinse and repeat.
While DJI battery packs "self-discharge" if stored above 70% or so (after a few days), it's best to keep the props going a bit (either hover or on the ground) to reach ~50% during the flight.
Hope that helps.

 

[old man mavic]

@malbowski85 ,it really depends how many shots you are intending to take at a given location
in the grand scheme of things it is not going to gain you much in increased flight time ,as each time you land ,and then have to climb up and compose your shot is going to use X amount of juice, it would be better if you can just move from shot to shot at a given location ,also remember that as lipos get to below around 35% charge then the voltage drops a lot quicker than a fully charged one ,from the moment you turn on the battery its voltage is dropping depending on what current demands are being asked of it ,even just sitting on the ground

 

[Lurch003]

Against all recommendations, I charge mine and keep them at 100% so always available should I need them. Didn't fly for 6 months or so over the winter and they obviously lost charge.
Charged them back to full when I wanted them again, as though I'd used them the day before. Flown them a fair bit this year with no decrease in flight time or degradation from what I can tell. Airdata shows no errors/warnings/or anything to suggest they're not exactly as they were 12 months ago.

You're told to do this, that, and the other which I haven't done but haven't suffered at all for it. Just my experience, not recommending or anything

 

[StantonZ]

Against all recommendations, I charge mine and keep them at 100% so always available should I need them. Didn't fly for 6 months or so over the winter and they obviously lost charge.

You are lucky DJI implemented a "self discharge" protocol in the BMS...or your batteries would most likely have already lost significant capacity (and possible even failed).
LiPo is a much more fragile chemistry than (for example) LiOn (like what's in my car).

 

[Lurch003]

from what I understand, the mini batteries aren't intelligent so don't self discharge

 

[StantonZ]

from what I understand, the mini batteries aren't intelligent so don't self discharge

You are absolutely correct and I missed that without any equipment list in the OP sig.
So: everything I said about storing ~50% is even more important.

 

[scro]

Op states its a MM (ie not a mini 2) so the batteries don't auto discharge and they're li-ion, not lipo like most other DJI drones. I have several li-ion and lipo camera batteries that are 10yrs old and have received no proper care. They still easily hold enough capacity to be perfectly usable, and hold it for months. Admittedly they don't face quite as harsh a use cycle as drone batteries. While it's still good practice to take proper care of batteries I think we can easily fall into the trap of getting too hung up about it.

OP was more about whether it is better to fly up, take a few photos then land, or fly up and stay up until the battery runs out, with regard to getting as many photo opportunities...

I find that planning the flight, what angles and shots are wanted before getting airborne is the best way to maximise use of a few batteries. If all the shots you want are within a small distance (say a few hundred meters) of each other then you may be best getting up to height taking the shots and simply flying between each location. If you only need a few shots in 1 location and then need to move a bit more than several hundred meters for the next one then it is probably more effective bringing the drone down, carrying it and relaunching. Its a trade-off between the battery power needed to fly between locations and the battery power needed to fire up the drone, get GPS, and get up to altitude and back down. Again, planning out the flight and what shots you want beforehand will help a lot.

 

[Lurch003]

OP was more about whether it is better to fly up, take a few photos then land, or fly up and stay up until the battery runs out, with regard to getting as many photo opportunities...

Ha ha I misread that totally !!! Think I got too hung up on the misinformation being dished out...