For a college competition we aren't given any wall outlets to power our devices. We are purchasing (we don't have it yet) the wireless camera kit in the following link and we need to rig up a portable power supply for the receiver base (shown in the link). I am trying to avoid splicing that cable as to keep its future usability. Another problem is that we have about 25$ left in our budget to rig something up - give or take.

Camera System: (Links have same system, but may display specs differently)

One idea was to buy a wall outlet by itself such as:

Then plug the camera receiver into this, and then wire a battery into the outlet's leads for portable power.

My questions are as follows:

  1. What battery should I use to power this receiver for at least an hour? It needs to be a Li-Po battery since thats what we have a charger for. I'm honestly not sure of the power requirements and was hoping someone could take a look at the link and clarify.

  2. Would there be a problem from AC-DC? Can an AC device run off of DC and vice versa? From what I understand, the power outlet from a wall is AC and batteries are DC. Would this conflict if I just plug a LiPo battery into the leads of the outlet shown in the previous link and plug in the receiver?

Does anyone have any other suggestions or recommendations to make this work?

Any help is appreciated, Thanks.


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  • 2
    \$\begingroup\$ The wall-warts accepts AC only, but the camera itself almost certainly uses DC. Just look at the specs on the wall-warts and make your power supply provide that. Then make your own DC power connectors and plug into the cameras. This is more efficient and cheaper than doing a useless DC-AC-DC conversion. \$\endgroup\$ – In silico Jan 30 '13 at 4:24
  • \$\begingroup\$ Powering the cameras themselves isn't the problem. They will be powered by 9v batteries using the battery clips provided in the box. I'm talking about powering the Receiver, the thing with 4 antennas. \$\endgroup\$ – DMor Jan 30 '13 at 4:27
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    \$\begingroup\$ I can almost guarantee the receiver itself also uses DC. (Note there are 5 wall-warts in the picture.) According to the link you've provided, the receiver needs a 5 volt, 1.5 amp power supply. This is relatively easy to provide for some time with current battery technology (unfortunately, I know close to nothing about how to size rechargeable batteries). \$\endgroup\$ – In silico Jan 30 '13 at 4:32
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    \$\begingroup\$ Take a look at digikey.com/product-detail/en/VYB10W-Q24-S5-T/102-2306-ND/… if the receiver is 5V 1.5A as per the link. You can connect that to an SLA or car battery and just use an auto charger, things you'll likely to either have or be able to borrow. \$\endgroup\$ – PeterJ Jan 30 '13 at 5:05
  • \$\begingroup\$ Our budget left over is about $27'ish \$\endgroup\$ – DMor Jan 30 '13 at 5:08

It's going to be very hard for $27. You wouldn't want to generate 110V AC to power a wall outlet, only to plug a transformer into it to convert it back into DC for your camera system. That's complex for no reason and less efficient than it needs to be.

Creating a battery power DC supply is much easier. However, to get some idea of the amount of energy required to run this for one hour, we can take the power specifications from the first link:

Power Requirement : 5V DC/1.5A Regulated.

To run this load, you need a battery capacity of 1500mAh, and a battery capable of delivering 1.5A. The Energizer D cell datasheet doesn't specify capacity beyond 500mA. They have some data for discharge rates as high as 1A, but the battery is going to be very inefficient at that discharge rate.

At the end of their life, battery voltage will be about 1.2V. That means you need 5 to get a voltage above 5V, and since you are exceeding the maximum current of a single battery, you will need another stack of batteries in parallel, so 10 batteries. That's most of your budget in batteries alone.

There are other battery types that are more effective, like NiMH or Lithium-ion, but they probably aren't any cheaper.

  • \$\begingroup\$ One of the competition requirements is for the batteries to be rechargeable. We are already getting a LiPo Charger, so someone else recommended: valuehobby.com/power-systems/lipo-batteries/3s-lipo/…. But are you also suggesting I use the converter from the previous poster: ebay.com/itm/… \$\endgroup\$ – DMor Jan 30 '13 at 13:13
  • \$\begingroup\$ @Dmor574 specifications for chineese goods on ebay aren't always the most accurate, but it does look like it would work. That battery lists the capacity as 2200mAh which should be enough to run your system for 1 hour, but manufacturers always have a way of stating there numbers in a way that doesn't account for practical use. Depending on the efficiency of that converter, and the accuracy of the capacity number, you could come pretty close to a dead battery after 1 hour. I'd get two, to be safe, but it may work. \$\endgroup\$ – Phil Frost Jan 30 '13 at 13:23
  • \$\begingroup\$ It'll only be in use for 5-10 minutes during the competition, I mentioned an hour just to be safe. I assumed 2200 mah would be much more than an hour. Thanks for the response \$\endgroup\$ – DMor Jan 30 '13 at 14:06

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