First, a plea to the mods. There have probably been many topics on this subject before, but I cannot find one that deals with the specific question I am going to ask, so please let me put this up.
Ok, I have a Mini 4K and 3 batteries. Assuming the intention is to be able to fly for a whole day using a power station, meaning over 6 hours of flytime, at 30mins per battery, this means that, if I start out with 3 fully charged batteries, then replace the first with the second after ballpark 30 minutes, then the second with the third after another 30, I would need to be able to fully recharge the first battery in 60 minutes, then have rolling fully charged replacements until the power station becomes depleted and needs a mains connection to recharge. For 6 hours of flying I would need to cycle the batteries 4 times, but would finish with two fully charged batteries.
Is that correct, meaning can it be done, and what sort of equipment would be needed? My knowledge of this subject is next to non-existant, but if that it correct it seems like a big ask; will any portable power station out there do it or would it be more practical to buy another 9 batteries at £50 a pop? Could buy a good number of betteries for the cost of a DJI power station!
I can’t realistically afford either option, but a compromise might be feasible. I need to know more about this, but the wattages and amp/hours figures are meaningless to me, so please, bear with…
I use a lesuire battery in the car boot, and a 300 watt inverter. I then plug the charger in as normal. I have a Mavic 2 Enterprise and this allows me to fly all day, the drawback, however is I need to be near the car. I hope that’s of help.
Hi John, AFAIA you dont drive so that option would be out. You are also possibly forgetting a couple of things, namely your phone and also the controller ? How good does the charge last in them when your flying ? My phone has a decent battery so would probably stand up to it but the controller on my potensic Atom would probably need a charge as well. I have a power bank ( well I have several but thats a different story) my main powerbank is 20000mah so quite beefy and will charge an individual battery and will charge the controller. I know it WILL. Charge them but no idea how long it would take. It will charge my phone up 4-5 times depending how depleted it is. Given the idea though, next time I get to fly I will see how quickly the bank will charge a battery and how much power that uses up.
I’ll keep it simple but you’re gonna need to grasp the maths here or if not, buy a shed load of batteries!!!
A 12v batt with mah capacity of say 20000 is described as have a storage capacity of (12x20000/1000) Watt Hours…thus 240Wh.
A mini 4k batt is a two cell LiPo with DJI stated capacity of 2250mah. So doing the simple maths, it has a capacity of 17.3 Wh (calculated as 7.7v (that’s the nominal voltage of a 2 cell
Lipo) x 2250/1000).
So you could charge a mini4k battery 240/17.3 about 13 times. However, the power needed to actually process and manage the charging cycle means you might get 9-10 charges from a 12v 20000mah battery.
if you’re still reading and I haven’t confused you too much, be aware the Amps needed by a mobile phone (if you’re using a typical
phone charger as your power source) are relatively small compared to Amps for charging Lipo batts… so charging could take a lot longer unless you have a decent charger and your source can provide higher current
That looks like a good black friday deal. if you bought a battery, you have another half hour flying. If you bought that power bank you have the possibility of charging the batteries you aleady have, on the move or you could charge your phone, or the controller if necessary which you CAN’T do, if you buy the battery. I think personally I’m going to hold off on buying another battery until I see how my power bank performs, as if it works well, I get more benefit from having the bank with me, rather than an extra battery. Sparky have you used that particular power bank yourself with the drone stuff ? If so how did it perform ??
Seems like you might want a read through this post.
I didnt find the DJI chargers were quick enough for continuous flying like you want because even when you have put the second battery in the charger it hasnt started charging it until the first is done, Also realistically the 30 minutes is actualy 20-25 minutes on a still day so you may also need to look at a fast chargers which are aftermarket.
Yes, I agree that real-world Mini 4K battery life is more like 20 minutes, but went for 30 minutes in my ‘calculations’ (if they are worthy of that title; maths and me ‘have history’) in order to give the setup a bit of safety margin/wobble room, and the ability to cope in a ‘worst case scenario’. I am in practice quiel likely to break for tea/coffee/beer/ice cream/chips between flights as well, which is a further help to the idea of charging batteries quickly enough for continuous flying with 3 (or perhaps 4) betteries. 4 batteries will increase the time available to charge the first battery by half an hour to 90 minutes, which feels a bit more possible!
With the system suggested, I only need to charge one battery at a time, and keep feeding depleted batteries in to the charger as soon as charged ones are removed. It is, of course, not essential that the last 3 charged batteries are replaced in the charger in this way, as we are now winding the system down ready for finishing flying for the day.
4 batteries last for a theoretical 2 hours at 30minutes each, so an 8-hour session will need the charger to be functionining for 6 hours charging 1 battery at a time. It charges a total of 13 batteries over the 8-hour session.
Much of this is theoretical. I can’t seriously see me wanting to fly for 8 hours a day very often, and the existing ‘fly more’ set up of 3 batteries for 3 near-half-hour flights will be fine for most of my needs. But there will occasionally be times when 3 fully charged batteries that get depleted during a session are not enough, and I will be stuck with no working batteries; I am looking at possible potential ways around this.
There should be an equilibrium between batteries and charger that would enable continuous flying (ok, you’ve got to land to change tbe batteries every half hour, but you know what I mean) for longer than the 90minutes afforded by the fly more kit. Maybe 6 hours, or 4 hours, would be sufficient for nearly all of the time.
Gentlemen, you have given me much to absorb and ponder; many thanks for your input!
Hi,
I purchased an Anker C200 this week n the sales, charges a flat mini 4 pro battery easily within the hour and not to cumbersome to carry around. From the power banks first total charge the indicator left me on 93% left, so lots of charges to follow. Cost £109.99 from Anker UK.
I had a few minutes to spare so I looked. A complete charge of a mini 4k battery can take up to 1 hour 22 minutes in the charge hub. So it all depends on how much you land with too. In practice what youre hoping wont quite work.
So say you fly battery 1 to yellow and put it in the charger, then you fly 2,3 and 4, battery 1 may just be ready to use by this time and 2 starts to charge. By the time you have flown battery 1 for the second time 2,3 and 4 arent ready to use so your system falls behind if that makes sense.
Best way to look at it will be are you really going to want to fly non stop for many hours. Thats a lot of fatigue mentally and not much time to warm your fingers between flights at this time of year. Depending how much you want to fly in this way a faster charger is the way to go. Or you can get away with the charge hub and have plenty of breaks between
Thank you Dave, sounds pretty close to what I think I might be looking for. If it can charge a flat Mini 4 Pro battery in an hour, it should be able to ace a 4K battery in less time. One 4 Pro battery taking 7% off it suggests that it should be capable of another 14 batteries, perhaps more 4K batteries. That equates to about 5 cycles of 3 batteries, 7.5 hours flying time, adequate I’d say!
All good points; as I said I am looking at this from a theoretical viewpoint at the moment, wondering what might be possible and practicable. In practice a full day’s flying would include many breaks for refreshment, sustenance, and brain-rest; flying requires a good bit of concentration, which is why it is relaxing, it distracts you completely from your everyday problems and worries, but it is mentally tiring.
I think I’m starting to get a handle on the numbers to do what I want; 20k amp/hours at 200W, like the Anker powerbank suggested by Dave681, though searching Amazon for Anker C200 brought up a lamp!.
I bought an Energizer PPS 320W1 power station in my local Go-outdoors for £70 in their closing for relocation sale! Primarily for use in the motorhome but I reckon it’ll be handy for drone battery recharging too. I already use a small power bank so this should be just the job.
