I thought DJI was expensive, but Autel is almost twice the price for an >entry-level drone. The less expensive drone makers use C.R.A.P. technology >and other weirdness like not selling additional propellers and whatever
other parts. Can't believe how cheap lesser brand controllers are compared
to DJI. The phone holder on even $300 drones is a single plastic plunger
with a simple spring inside the controller for tension! You can hear the >spring creaking.
DJI messed up the firmware or software for the Mini 2, so I'm waiting to
get back into FPV flight with that one.
https://www.ebay.com/itm/175008269834
John Doe wrote:
I thought DJI was expensive, but Autel is almost twice the price for an >>entry-level drone. The less expensive drone makers use C.R.A.P.
technology and other weirdness like not selling additional propellers
and whatever other parts. Can't believe how cheap lesser brand
controllers are compared to DJI. The phone holder on even $300 drones is
a single plastic plunger with a simple spring inside the controller for >>tension! You can hear the spring creaking.
DJI messed up the firmware or software for the Mini 2, so I'm waiting to >>get back into FPV flight with that one.
https://www.ebay.com/itm/175008269834
Depends on what you want, I would not want that, only smartphone app
control? I have this:
http://panteltje.com/panteltje/quadcopter/index.html
added some stuff to it, auto pilot, HUD. Not been flying here, drone
flights are prohibited here close to the mil airport. No idea if it
still available and at what price.
Need high capacity (for removing and replacing a battery, don't know what
the current is), at least 10 V, small and light as possible.
https://industrial.panasonic.com/ww/products/pt/edlc-wound-type
That might be related to what I recall. Those gold capacitors have been >discontinued. As I recall, they looked much stubbier than those.
Need high capacity (for removing and replacing a battery, don't know what
the current is), at least 10 V, small and light as possible.
Thinking about using the stock battery circuit, putting a capacitor across >its power pins, with a battery plug out from that, so batteries can be >swapped on that plug without trashing the battery circuit. Assuming the >capacitor holds up during the swap, there would be a big jump in voltage
when the new battery is plugged in, but maybe that wouldn't trash the >circuit. Don't know if keeping that circuit plugged into the drone, or
not, would matter while swapping batteries at the plug point.
I remember long ago looking at digi-key capacitors and seeing gold >capacitors, like 1 farad, but a quick search shows no such results.
Capacitor weight or size might be an issue, too.
Or maybe a tiny battery with a diode and maybe a resistor.
Would be nice to know the input impedance, bias current, whatever.
John Doe wrote:
Or maybe a tiny battery with a diode and maybe a resistor. Would be
nice to know the input impedance, bias current, whatever.
Diode should work, I have done that as backup in an other project, but
you lose a few hundred millivolts.
Use a Schottky diode perhaps, those have very low voltage drops.
John Doe wrote:
Or maybe a tiny battery with a diode and maybe a resistor. Would be
nice to know the input impedance, bias current, whatever.
Diode should work, I have done that as backup in an other project, but
you lose a few hundred millivolts.
Use a Schottky diode perhaps, those have very low voltage drops.
Jan Panteltje wrote:
John Doe wrote:
Or maybe a tiny battery with a diode and maybe a resistor. Would be
nice to know the input impedance, bias current, whatever.
Diode should work, I have done that as backup in an other project, but
you lose a few hundred millivolts.
How long without the drone battery?
This would be no more than seconds, while swapping batteries.
Use a Schottky diode perhaps, those have very low voltage drops.
The reverse leakage current won't destroy a CR3032 (or smaller) battery?
The drone battery starts at about 14 V.
John Doe wrote:
Jan Panteltje wrote:
John Doe wrote:
Or maybe a tiny battery with a diode and maybe a resistor. Would be
nice to know the input impedance, bias current, whatever.
Diode should work, I have done that as backup in an other project, but
you lose a few hundred millivolts.
How long without the drone battery?
No idea, my drone uses 10 amps at 7.4V (2 cells)
http://panteltje.com/pub/hubsan_h501s_current_test_full_throttle_IMG_6290.JPG
http://panteltje.com/pub/hubsan_h501S_current_test_idle_IMG_6281.JPG
This would be no more than seconds, while swapping batteries.
Use a Schottky diode perhaps, those have very low voltage drops.
The reverse leakage current won't destroy a CR3032 (or smaller)
battery?
The drone battery starts at about 14 V.
So almost 1 A idle... A coin battery won't do that, a small 2 cell (or 3
cell if 14 V) lipo with diode will, got a lot of those 1 cell lioos from ebay:
http://panteltje.com/pub/single_cell_lipo_protection_IMG_5486.JPG
Just put those in series.. That strip is a charge controller /
protection (MOSFET in it), also from ebay.
Jan Panteltje <pNaonStpealmtje@yahoo.com> wrote:
John Doe wrote:
Jan Panteltje wrote:
John Doe wrote:
Or maybe a tiny battery with a diode and maybe a resistor. Would be
nice to know the input impedance, bias current, whatever.
Diode should work, I have done that as backup in an other project, but >>>> you lose a few hundred millivolts.
How long without the drone battery?
No idea, my drone uses 10 amps at 7.4V (2 cells)
http://panteltje.com/pub/hubsan_h501s_current_test_full_throttle_IMG_6290.JPG
http://panteltje.com/pub/hubsan_h501S_current_test_idle_IMG_6281.JPG
I had one like that (H501S, with the big controller).
This would be no more than seconds, while swapping batteries.
Use a Schottky diode perhaps, those have very low voltage drops.
The reverse leakage current won't destroy a CR3032 (or smaller)
battery?
The drone battery starts at about 14 V.
So almost 1 A idle... A coin battery won't do that, a small 2 cell (or 3
cell if 14 V) lipo with diode will, got a lot of those 1 cell lioos from
ebay:
http://panteltje.com/pub/single_cell_lipo_protection_IMG_5486.JPG
Good soldering.
Just put those in series.. That strip is a charge controller /
protection (MOSFET in it), also from ebay.
I'm talking about swapping batteries. The thing is OFF, not idle. I will
know soon enough.
Mavic Air (1) batteries are outrageously expensive, but I got a new kit
for $300 (US). So the question is, how to use non-DJI lipos. Seems odd no
one else has tried.
There are some poorly made videos with insufficient instruction. There is
a Russian guy's video using a stock battery shell to hold 18650s.
Some use
an Air 2 (the sequel) battery in a stock battery shell. But seems to me we >can use a single stock battery shell and just swap the batteries. If it >works, that will be by far the cheapest method.
AFAIK, the only problem is keeping the battery management system (BMS)
V+ pin from dropping below some cutoff voltage, while swapping batteries.
John Doe wrote:
I'm talking about swapping batteries. The thing is OFF, not idle. I
will know soon enough.
Here I cannot follow you. If the drone is 'off' what difference does a
small voltage interrupt make when changing batteries?
There are some poorly made videos with insufficient instruction. There
is a Russian guy's video using a stock battery shell to hold 18650s.
I have tried that sort of batteries, and expensive liion Sony cells:
http://panteltje.com/pub/liion_cells_storage_IMG_6338.JPG
Not better but worse than lipos!
I thought DJI was expensive, but Autel is almost twice the price for an entry-level drone. The less expensive drone makers use C.R.A.P. technology and other weirdness like not selling additional propellers and whatever
other parts. Can't believe how cheap lesser brand controllers are compared
to DJI. The phone holder on even $300 drones is a single plastic plunger
with a simple spring inside the controller for tension! You can hear the spring creaking.
DJI messed up the firmware or software for the Mini 2, so I'm waiting to
get back into FPV flight with that one.
https://www.ebay.com/itm/175008269834
The seller accepted $300 for that old technology DJI Mavic Air (Arctic White).
Additional batteries are OUTRAGEOUSLY expensive, at least twice the price
of other DJI drone batteries.
Can the provided battery shell be used as a connector for homemade
batteries?
Of course there are only 2 terminals to the actual battery inside of the shell, so they can be connected to whatever batteries that will work
(Sanyo NCR2070C sourced enough current to work well in prior tests with another drone). Lipo is ideal, but that Sanyo "C" model sources lots of current.
Besides measuring temperature, what other connectors might be related to
the battery? I suppose any temperature sensor can be left hanging (with
the appropriate caution).
I suppose they could defeat battery mods by trying to communicate with the battery circuitry, but apparently not since there is AFAIK no mention of
that by anybody who has tried connecting batteries to it.
I can get into the battery firmware using "DJI Battery Killer" (or
similar) and a hardware interface "CP2112" from my PC to the drone
battery.
But not sure if using one battery management system (BMS) while
swapping batteries to that BMS is possible, at least not without
adding two more capacitors (or whatever stuff might be needed).
I can get into the battery firmware using "DJI Battery Killer" (or
similar) and a hardware interface "CP2112" from my PC to the drone
battery.
But not sure if using one battery management system (BMS) while swapping batteries to that BMS is possible, at least not without adding two more capacitors (or whatever stuff might be needed).
It works! At least preliminarily. It requires 1 10 mF capacitor and 3 1/10
It works! At least preliminarily. It requires 1 10 mF capacitor
and 3 1/10 W resistors. The capacitor drains fast when the battery
management system is not in power failure mode (a bit
disappointing, but no big surprise), but not too fast. On a 3s
Mavic Air BMS, after unplugging the battery, the cap went down to
9.2 V before it was re-plugged. Still functioned. Maybe it can get
down to at least 9 V. In any case, that probably is enough time
to switch batteries, unless you fumble the operation.
That is for using only one BMS circuit board and switching
batteries to it, as opposed to using one BMS per battery. It might
be advantageous with only one BMS circuit board available. For a
Mavic Air, the required 10 mF cap is only 14 g, the 3 1/10 W
resistors are weightless. The resistors are used as a voltage
divider so the BMS thinks the battery midpoints are connected.
I wrote:
I can get into the battery firmware using "DJI Battery Killer"
(or similar) and a hardware interface "CP2112" from my PC to the
drone battery.
But not sure if using one battery management system (BMS) while
swapping batteries to that BMS is possible, at least not without
adding two more capacitors (or whatever stuff might be needed).
John Doe wrote:
It works! At least preliminarily. It requires 1 10 mF capacitor and 3
1/10
The 'm' stands for 'milli'
Jan Panteltje wrote:
John Doe wrote:
It works! At least preliminarily. It requires 1 10 mF capacitor and 3
1/10
The 'm' stands for 'milli'
Very good! At 14 g, a Rubycon PX 10 mF cap from Digi-Key seems to work.
Putting that cap across the V+ and V- terminals of the battery management >system seems to keep the BMS from dropping below its power failure mode >cutoff voltage (or doing any other mischief) when swapping batteries.
Usually a DJI drone user swaps batteries with each having an integrated
BMS circuit board, but this (preliminary) solution requires only one BMS.
Used 6.8 k resistors for a divider to the otherwise unconnected battery >midpoints. Maybe 10 k will work.
It works! At least preliminarily. It requires 1 10 mF capacitor and 3
1/10 W resistors. The capacitor drains fast when the battery management system is not in power failure mode (a bit disappointing, but no big surprise), but not too fast. On a 3s Mavic Air BMS, after unplugging the battery, the cap went down to 9.2 V before it was re-plugged. Still functioned. Maybe it can get down to at least 9 V. In any case, that
probably is enough time to switch batteries, unless you fumble the
operation.
That is for using only one BMS circuit board and switching batteries to
it, as opposed to using one BMS per battery. It might be advantageous
with only one BMS circuit board available. For a Mavic Air, the required
10 mF cap is only 14 g, the 3 1/10 W resistors are weightless. The
resistors are used as a voltage divider so the BMS thinks the battery midpoints are connected.
I wrote:
I can get into the battery firmware using "DJI Battery Killer" (or
similar) and a hardware interface "CP2112" from my PC to the drone
battery.
But not sure if using one battery management system (BMS) while
swapping batteries to that BMS is possible, at least not without adding
two more capacitors (or whatever stuff might be needed).
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