My device calls for a 9 volt, but that is too heavy... 1

[deenybird]

I'm using a wireless camera that is powered by a 9 volt. Its too heavy to be lifted by my rc helicopter and I'm wondering if i can 'create' a lipo battery that will fit the bill.

not knowing anything about batteries, i came here..

thanks for help.

http://www.rc-copter.com

 

[ScottyUK]

No hobby posts allowed on here, but as it is Sunday...

How much current does your camera need? What do you have available for your receiver and servos? It is possible that if the camera is not too thirsty you may be able to draw power from the servo battery. Obviously using that battery to power the camera will reduce the flight time, or at least the controlled flight time.


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If we learn from our mistakes I'm getting a great education!

 

[deenybird]

don't know what's wrong with a 'hobby' post, thought this was a battery forum...

camera calls for DV8V.
does that mean that any lipo putting out more than 8v will work?

http://www.rc-copter.com

 

[MikeHalloran]

I don't know what you mean by "DV8V" or "lipo".

If your camera requires 8VDC, then any battery or any series combination of cells that adds up to 8..9V open circuit voltage will power the camera.

The capacity of the cellls in mAh divided by the current demand in mA will tell you ~how long the camera will work, in hours. The capacity roughly scales with the physical size, and weight, but some chemistries provide more capacity per unit weight.

One crazy idea came to mind: Just take a regular 9V battery, put it in a diamond tile saw, slice off half its thickness (e.g. by cutting 2mm behind both of the biggest faces), and seal the cut faces with epoxy. It's a primary battery, so you're going to throw it away anyway, and 9Vs are cheap, so try a couple. Use distilled water in the saw, and work fast, and you may not lose all the capacity to the process. Splash protection and especially eye protection would be a real good idea.

Remember I said it's a crazy idea. There's a surprising amount of energy in a 9V battery, and you don't want to be surprised in a bad way.





Mike Halloran
Pembroke Pines, FL, USA

 

[ScottyUK]

Ain't my rules... if this thread vanishes don't be surprised.

DV8V makes pretty much no sense. DC8V seems reasonable though. Typo?

There will almost certainly be a tolerable range on the 8V nominal so it will probably work direct from a 7.2V or 8.4V Ni-Cad pack if you have either of them available. It probably won't be happy with 9.6 or 12V. You can get a regulator which will provide 8V from a higher input voltage. I don't expect the camera takes more than 100mA so something like the 78L08 regulator IC will drop a higher input voltage to your required level. The 78L08 has a 23V absolute maximum input: exceed it and the IC will die. If you need more current than 100mA then the 78M08 or the 7808 will give 500mA and 1A respectively, but come in a heavier package.

What the heck is LIPO an abbreviation for? Lithium Polymer?


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If we learn from our mistakes I'm getting a great education!

 

[deenybird]

lithium polymer batteries (abbreviated Li-poly, Li-Pol, LiPo, LIP, PLI or LiP) are rechargeable batteries which have technologically evolved from lithium-ion batteries.

most rc planes/copters use lipo's (li-poly batteries) because currently they are the battery that produces the most juice per ounce. weight is everything in flight.

no typo's, the camera says:
203CWAS - probably model #
2.4G - transmits at
DC8V

the battery that I am currently using to power my copter is a 3.7V lipo 1000mah. I can get 10 min of flight for a 2 hour charge.

only putting out 3.7v won't be enough to power my 8v camera right?

so if i get a lipo that is 8V (does the mah matter?) it will work?

in regards to slicing a 9V, i'm a battery noob, u really think this will work? i've noticed that when the 9v starts dying, my picture quality degrades greatly, and i'm soon left transmitting only audio. will 1/2 a 9v really do it?

thanks for all your help guys, none of my friends know anything about batteries...

http://www.rc-copter.com

 

[MikeHalloran]

If you run the camera from a 9V with a voltmeter and a milliameter in the circuit, you can measure the current flow while the camera is operating, and you can measure the voltage at which the video signal becomes unavailable. That gives you two design points for your next camera battery.

You probably should get help from an electronics engineer or a really smart high school kid with this stuff.

No, don't cut up a battery. It would work, but you might get hurt.



Mike Halloran
Pembroke Pines, FL, USA

 

[richs]

Hiya-

Well the OP mentions that he runs an electric RC copter as his choice for flying.

If I might suggest, that you research DC-DC converters that with some thought and measurement, can be used to "BOOST" the 3.7V or so voltage from the main battery to the 9VDC needed for the camera.

Of course, such a venture ought to be done with considerable thought as one does not want the camera, copter motor, radio, or battery to come to misfortune.

There are modules available that will convert (usually by means of switching) a lower voltage to a higher voltage. For your application you will be using a boost DC-DC converter. These, with maybe some post conversion DC regulation, will allow the camera to be run from the main Li battery.

Although I don't have any references handy, a search of the major supply houses (i.e. Digikey, Mouser, etc.) might prove interesting.

These little modules are just electronic components and have a very small footprint and are very light. You might want to consider using some filtering at both ends of the converter to allow for the high electrical motor noise on one side and the "clumps" of current draw from the camera side.

As MikeHalloran mentioned, you might need a friend to lend a hand with this. In addition to the list he mentioned, you might find a friend who is a ham radio operator who might be able to lend his/her thoughts to the issue. Maybe someone who has experience with low power ham repeaters (those that are solar powered for example). These guys have experience with boost circuits, going from the lower voltage solar arrays to a higher storage/operating condition.

As an added advantage, they might also have some thoughts on increasing the range of the "wireless" signal.

Hope this yields an avenue of research.

Cheers,

Rich S.

 

[MattNCSU03]

If you cut or pry the metal case from a 9V battery you will find it is made up of 6 AAAA cells connected in series. You could save weight by removing the metal case and using just the cells or a stack of watch batteries may provide enough juice for a few minutes of recording