Autonomous charging station for Spark

[Vlad]

Is there an autonomous charging solution for spark on the market?
I've noticed that the portable charging station charges the spark with a battery attached through a contact on the 2x2 metal grid on the battery itself. So if the spark landed and was positioned over this contact then it should be able to charge. The purpose is to have the spark land, charge, take off and repeat autonomously throughout the day. There are some commercial solutions that involve heavier drones and I understand the perception of having a more robust done, however I'd prefer to use several sparks rather than one expensive heavy drone.

 

[Spark 317]

Hello from the Hoosier Heartland, Vlad.

Considering the cost of multiple Sparks, it would be cheaper to get a bunch of batteries and swap them out within a minute verses landing and waiting for a complete charge cycle.

There are tethered power source options for larger drones to keep them flying longer, but is probably a waste of time on the Spark.

Welcome to the Forum.

 

[edkrisiak]

I bought this one. So far so good. Amazon.com: BonFook Intelligent Battery Charger Port-Handle Multi Parallel Charging Hub Compatible with DJI Spark(Includ Cable and Adapter,Not Included Car Charger and Battery)-White: Toys & Games

 

[Vlad]

Hi Spark 317 and edkrisiak, thank you for your answers. The use case I have is letting the drone take off and land continuously throughout the day from the top of a building, taking photos of the same scene and feeding these photos to a cloud server (I'm assuming Litchi might do part of this). There will not be anyone around to swap batteries, hence the need to make it autonomous. There are solutions for larger drones, hangars the size of a freezer, that open and close to let the drone out and these are expensive (about $20K+). Whereas the spark portable charging station almost does the job for $150 - so before doing a mod on this I'm hoping something already exists.

 

[Spark 317]

Whereas the spark portable charging station almost does the job for $150 - so before doing a mod on this I'm hoping something already exists.

Maybe you could hack an iRobot Roomba and incorporate the feature of returning to the charging station when low on power with the Spark. ?

 

[Vlad]

Maybe you could hack an iRobot Roomba and incorporate the feature of returning to the charging station when low on power with the Spark. ?

That's a good analogy.

 

[Andre Levite]

If you wanted the Spark to fly for hours at a time you would need the equivalent of 5 Spark batteries for each hour (average flight time of 12 minutes). So a 3 hour flight would need the capacity of 15 batteries. The Spark couldn't lift that weight. A continuous charger is essentially just a bigger battery that transfers its energy to the smaller on board battery.

Hours of continuous flight and the added weight would lead to overheating anyway. The Spark cooling system wasn't designed for that. It would cook the processors and the motor.

 

[Vlad]

If you wanted the Spark to fly for hours at a time you would need the equivalent of 5 Spark batteries for each hour (average flight time of 12 minutes). So a 3 hour flight would need the capacity of 15 batteries. The Spark couldn't lift that weight. A continuous charger is essentially just a bigger battery that transfers its energy to the smaller on board battery.

Hours of continuous flight and the added weight would lead to overheating anyway. The Spark cooling system wasn't designed for that. It would cook the processors and the motor.

One example would be to have it go up once every 15 minutes for a 2-3 minute flight and spend the other 12 minutes resting and recharging. I haven't done the calculations so it might be a longer rest with shorter flights, however the idea is the same. For more frequent flights I'm also considering having multiple drones, so they take turns while the others rest.

 

[Andre Levite]

One example would be to have it go up once every 15 minutes for a 2-3 minute flight and spend the other 12 minutes resting and recharging. I haven't done the calculations so it might be a longer rest with shorter flights, however the idea is the same. For more frequent flights I'm also considering having multiple drones, so they take turns while the others rest.

Oh. I understand now. Not actually continuous flight for hours at a time but rather autonomous for hours at a time.

You still have the obstacle of excessive weight of massive auxiliary battery that the Spark can't carry.

Are you actually going to watch it continuously and directly during these flights? The FAA specifically forbids autonomous flight out of VLOS unless you are granted a waiver.

 

[H3Alpha]

He wouldn't need a massive battery; only the standard battery. He wants it to take off and fly for a few minutes, then land and recharge before doing it again in about 15 minutes. So he's only flying for a few minutes, then recharging, then flying, then recharging...

That said, there is also the issue of letting the battery cool before it will even accept a charge, which can take 5-10 minutes. One of the problems that I see, even if you could design & build a "landing pad/charging station" that charged through those bottom contacts, is that you would still need the Spark to shut down to allow the cooling/charging cycle, then power back up to resume flight; I don't think it will charge while turned on, and I don't think that shutting it down/powering it up is possible without manually doing it. Another issue would be getting it to land accurately enough; I doubt that could be accomplished either. Interesting idea, though.

 

[Fred Abaroa]

What are the 4 copper square on the battery? I always guessed they were for charging. Am I way off?

 

[Andre Levite]

What are the 4 copper square on the battery? I always guessed they were for charging. Am I way off?

Those 4 squares on the Spark's battery are the contacts for the DJI Portable Charging Station pictured below...

 

[Locutus40]

the problem i dont like with spark batts and dji batts is they let the internal bms charge the batts its been proven the bms on most boards dont fully charge batts and are poor at ballancing.. this is why hobby chargers are best but the spark only provides power in.. all a battery needs is 13.8 volts and the battery does the charging thats why if you see one put on a hobby charger its just giving it voltage its not ballancing or doing anything to it... and the 2 other ports on the top connector are for feedback ie temp and status there not for ballancing on any charger so these over priced chargers you see that claim all this crap is a lie you tear them down and see tonsssss of electronics again a lie to justify the cost.. a spark the 4 pins 2 arent even connected and the other ones are positive and negative lol so all you need is a brick power supply with some pins and supply 13.2 to 13.8 volts and thats it... you can make one outta a lab power supply and or a computer power supply with a step down etc..... i think someone did on here for like 5 bucks he bought a 10 amp step up converter and just 3d printed a holder and voila done...

 

[Andre Levite]

the problem i dont like with spark batts and dji batts is they let the internal bms charge the batts its been proven the bms on most boards dont fully charge batts and are poor at ballancing.. this is why hobby chargers are best but the spark only provides power in.. all a battery needs is 13.8 volts and the battery does the charging thats why if you see one put on a hobby charger its just giving it voltage its not ballancing or doing anything to it... and the 2 other ports on the top connector are for feedback ie temp and status there not for ballancing on any charger so these over priced chargers you see that claim all this crap is a lie you tear them down and see tonsssss of electronics again a lie to justify the cost.. a spark the 4 pins 2 arent even connected and the other ones are positive and negative lol so all you need is a brick power supply with some pins and supply 13.2 to 13.8 volts and thats it... you can make one outta a lab power supply and or a computer power supply with a step down etc..... i think someone did on here for like 5 bucks he bought a 10 amp step up converter and just 3d printed a holder and voila done...

My Spark batteries all work fine. I use the DJI 3-battery charging hub that comes in the Fly More Combo - it works fine as well. I'm really impressed by the performance and reliability. I've definitively gotten my money's worth with nearly 2 years of regular use.

Are you actually having a problem with your batteries and/or charger? Are you actually going to make a DIY charger with $5 of components to prove your point?

Or is your post an anti-DJI rant against their products and pricing?

 

[Vlad]

He wouldn't need a massive battery; only the standard battery. He wants it to take off and fly for a few minutes, then land and recharge before doing it again in about 15 minutes. So he's only flying for a few minutes, then recharging, then flying, then recharging...

That said, there is also the issue of letting the battery cool before it will even accept a charge, which can take 5-10 minutes. One of the problems that I see, even if you could design & build a "landing pad/charging station" that charged through those bottom contacts, is that you would still need the Spark to shut down to allow the cooling/charging cycle, then power back up to resume flight; I don't think it will charge while turned on, and I don't think that shutting it down/powering it up is possible without manually doing it. Another issue would be getting it to land accurately enough; I doubt that could be accomplished either. Interesting idea, though.

Focusing on one thing at a time - I'm concerned about automating the turn-off -> charge -> turn-on as I haven't tried charging the Spark when it is turned on. At the moment, I can only think of having a mechanism that holds the spark and performs a mechanical double click on the back - not ideal! Does anyone know of a software solution that can turn on and off the spark?

 

[Andre Levite]

Focusing on one thing at a time - I'm concerned about automating the turn-off -> charge -> turn-on as I haven't tried charging the Spark when it is turned on. At the moment, I can only think of having a mechanism that holds the spark and performs a mechanical double click on the back - not ideal! Does anyone know of a software solution that can turn on and off the spark?

The Spark would turn off by itself once the battery got low enough -- no double click necessary. It could then charge fully without any commands if it had docked properly.

Now comes the hard part...
Turning the Spark back on would require mechanical input such as a double-click of the battery power button. There is currently no software that can wake a powered off Spark -- that would require an always ready low power Sleep state -- that option does not currently exist.

For the moment we have overlooked the requirement for the Spark to precisely land in a waiting charger. That is actually an extremely difficult obstacle to overcome.

Several other members are looking for drones with the complete autonomy you describe. For now this is science fiction. But a few years that will be the norm.

 

[Vlad]

For the moment we have overlooked the requirement for the Spark to precisely land in a waiting charger. That is actually an extremely difficult obstacle to overcome.

I'm going to have a chat with these guys in a few days Drone Precision Landing: World's Smartest Vision Landing Solution regarding the precision landing. I'm not sure if they have it ready to go for Spark, if anyone has used them before please let me know.

 

[Uale]

Hi, I am going to revive this because I am quite interested in the same use case.

I would imagine that you do not need a very precise landing to achieve this if we use a design solution instead of an engineering solution. For example, we could 3D print a sort of basin design to allow the Spark to land within its whatever margin of error and by gravity or otherwise slide it to the centre after landing where the metal contact points are. That will also be the position of the mechanical pusher to power up the spark after a full charge. The required duration of coverage vis a vis charge time, battery endurance, distance to target, time required to let battery cool, etc is just a matter of math and more sparks.

Correct me if I am wrong but I remember seeing on youtube that the dji charging station automatically power down the spark when it is placed in the station. So maybe that auto-off function when charging via the metal contacts is already in place?

Let me know how you have progressed about with this!