How to make a 5 volt battery?

[JonathanEngr]

I have a wireless network camera that I want to mount in a location that doesn't have an outlet (the camera I own is the D-Link DCS-900G, and details can be found here:

http://www.dlink.com/products/?sec=0&pid=459).

Anyway, the users manual states that the power supply cord is a 5-volt, 2.5-Amp power supply. I know so little about electricity, but if I remember correctly I could get 6 volts by placing 4 1.5 volt batteries in series, correct? However, would 6 volts damage the unit? If I did create a 5-volt battery system, doesn't the voltage on a battery drop as it's used? How long would batteries run the camera? (Obviously it depends on battery size and type, but I have no clue where to begin).

Anyway, I just need to work up some way to get some juice to the camera, and a 50-foot extension cord running through the middle of my front yard is an option I'm sure my wife isn't going to go for, and I have no desire to pay someone to run electricty to the site. Thanks!

 

[itsmoked]

You want to google "low head" voltage regulator. You would take your 6V and regulate it down to 5V. Alternatively you could use a silicon rectifier to dump 0.7V by placing it in series with the the 6V.

Other things to consider.

A bunch of 1.5V dry cells aren't going to last long.

A six volt lead acid battery will last far longer.

Six volt LA batteries put out more than 6V.

Six volts would probably damage the unit but 5.2 - 5.3 probably wouldn't.


Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[MikeHalloran]

You can probably get it to work for a usable time period with four NiCd cells and no regulator, or five NiCd cells with a regulator.

If you charge the cells while they are in the circuit, e.g. with a trickle charger, you _must_ use a voltage regulator, because it takes something like 7V to charge a 6V lead-acid battery, and probably a bit more than 5V to charge a 4.8V NiCd battery. Most 5V devices will tolerate some undervoltage, but not overvoltage.

OR, run it from the specified AC adapter (no warranty issues), and run _that_ from a computer UPS, which should be good for a couple of days.



Mike Halloran
Pembroke Pines, FL, USA

 

[B3188]

Spec sheet in back of manual says its 5V 2.5 amp. Also says 5 watt. Numbers dont add as 5 V at 2.5 Amp is 7.5 watts.

So to Battery. Nicad or NiMH are 2000 maH for the
very high capacity AA size, 1.2 votl per cell,
will last about 3/4 hour

Enersys X cell (fat D sealed lead acid)
is 5 amp hours 2 volts per cell (2.14 charged).
3 in series would provide a couple hours and last
through about 300 charge discharge cycles.
Cost is more than $10 a cell on the open market.

Golf cart battery is 6 volt, 220 Amp hour, Weight less
than 75 pounds... About 1 foot cube last about
2 - 3 days at that rate (100 hours or so.)

Gives you an idea of your trade offs.
Low drop out regulator for 2.5 amps is going to take a heat sink etc etc. This little puppy is power hungry.

 

[tinfoil]

Look at these:

http://www.pacificsites.com/~brooke/BTPS.shtml

http://www.adorama.com/BOY4DC.html

http://www.electronicsoutfitter.com/store/AC4009-541.html

You've hinted that this is an outdoor application. Have you considered powering this puppy with solar cells?