Looking for DEAD Battery for Phantom 4 Pro

ctsti · Sep 19, 2018

Can anyone help me? I have a project in mind that will require a dead battery. If anyone has a paperweight they would like to get rid of I will gladly reimburse you for the cost of shipping.

Please email me jerry at molaver dot org

Thanks!

With The Birds · Sep 20, 2018

What sort of project?

ctsti · Sep 20, 2018

I am an amateur radio operator and want to see if I can use the drone tethered to earth with a combination antenna wire / power feed so the battery can be eliminated. I need a battery 'shell' with connector to 'seal the hole' and provide connection to the drone circuits.

With The Birds · Sep 20, 2018

Nice!!!! I suspect your considering some form of switch mode power supply so you can get away with a smaller gauge feed.

ctsti · Sep 20, 2018

With The Birds said:

???
hmmm on second thought looks like I'm going to need a voltage regulator in the drone so I can supply 25+ volts or so and have it reduced inside (after what may be a 10 volt drop in the circuit)

richw8341 · Sep 22, 2018

Is RF going to be an issue here?

ctsti · Sep 22, 2018

richw8341 said:

Should be easy to filter out at the aircraft end.

To tell the truth the more I look into this the less appealing it becomes. The thought of somehow the wire becomes disconnected, the power supply on the ground fails, etc is not encouraging me at all.

DOC 1500 · Sep 22, 2018

If you're lifting an antenna wire how much of it are you lifting is the Drone capable of doing that

ctsti · Sep 22, 2018

DOC 1500 said:

That is one of the issues. My plan evolved into supplying 50 volts or so thru the wires and downconverting it just below the aircraft so it any heat could be dissipated in the open, not in the drone. Even so using 100 ft (200 total ft) of 18ga wire is about 1-1/2 lbs + the weight of the downconverter. I need to see how much weight I can save by stripping out the cells of the battery.

With The Birds · Sep 22, 2018

You could hang a dipole below the Phantom that used an outer sheath for the lower element with a similar arrangement above the feedpoint- you could probably use the feedlkne to carry the DC power in a similar fashion to how phantom power is delivered to a microphone or other audio equipment. The heat dissipation consideration is probably irrelevant.

Dronefriend · Sep 23, 2018

I have a dead battery. It’s in Sweden, Europe

DOC 1500 · Sep 23, 2018

Even though you may not have to weight of the battery cells,
You do have the weight of the antenna the connection the coaxial cable and the power going to the bird.
Seems like a lot of thought and worry to get an antenna 100 feet in the air.
Still I'm interested to see what you come up with. I'm on MacGyver that likes to figure those things out too.

ctsti · Sep 24, 2018

This looks like a project that has reached quickly beyond my risk aversion level and the practicality to doing it. I appreciate the replies.
Coax cable (RG58) weighs over 1lb for even just 50' so its not really practical.

My 1st thoughts were for a 100' vertical. The IR loss at 10+ amps for wire is way too great for wire small and light enough to be supported and fed with close to battery voltage.

Going to 50+ volts and a voltage downconverter near the aircraft had some hope. Even 22 ga insulated wire would weigh .8lbs (200'). A suitable downconverter another .75lb https://www.amazon.com/Yeeco-Converter-Adjustable-Stabilizer-Transformer/dp/B06ZZG2GPR
Unless I could save 1lb by emptying the battery I wouldn't feel good about more that 8oz additional load continuously on the drone.

Let's face it, 22ga wire isn't the strongest element in the periodic table. The thought of a wire break and the ensuing dive to earth . . .

So for now this project has gone to back shelf. I may someday revive it. In the meantime thanks to all for the suggestions.