UPS help please???

[davidclayton]

i'm looking for a UPS system for a webcam [with built-in modem]
it IS NOT for a pc, only the cam.

my question is:
can you get ups's for this low a power demand?
and, where are they?
it also needs to be pretty compact.

please help,
dave

[turkster]

You mean you just need to power the webcam/modem? Does it have a 240v input or is it powered by a transformer/voltage regulator?
Presumably a normal PC UPS will not do or is too expensive although it depends how long you want to run it without mains power. A normal PC UPS would run something like that for a long time though.

[davidclayton]

5V, 0.3A, 1.5W.
comes with transformer.
only need it to run unpowered for about 1 hour.

i was also gonna look into the systems that house alarms use
when the power goes out.

views?

[turkster]

Hmm doesnt take much power. The actual circuitry that is used to work a UPS seems rather unusual in every day applications and i doubt youd find something designed for an application so low powered. You could always make it up yourself if you have any electronics experience all youd need would be a smallish (preferably lead acid) battery and a relatively simple circuit on the low voltage side of the line. If you were willing to keep the battery charged yourself you could get away with just a few diodes i think.

I should imagine you could find designs for such a thing on the web.
I dont know about house security systems but they are probably decent sizes ie to power all the sensors alarms etc for possibly longish periods.

[davidclayton]

i'm spec'ing this for a few hundred units, so diy soldering is not an option.
i'm looking for a "black box" solution [pre assembled]

i found this, which is close to what i want:
http://www.apc.com/resource/include/...sku=BF350%2DUK

but i need a single plug version.


dave

[ed^chigliak]

You can get upgrade kits to turn an ordinary flourescent luminaire into an emergency luminaire so that it remain on in the event of a power failure. A emergency luminaire conversion kit looks nothing like what you want but it is similar in function. Good luck.

[turkster]

I found this which is relatively small but i couldnt find any decent specs probably only works on 110V or so.

This seems a bit more promising. It is small and works on the low voltage side of your circuit so no big sockets etc. (maybe that would be a disadvantage for you). The problem is you would need to pair it with a battery such as one of the smaller lead acids from herehttp://international1.farnell.com/a2...jhtml?PAGEID=1 and then put the whole lot in a small case which im sure you can also get from farnell. It would be a bit of work but still possible for c 100 units.

[davidclayton]

This is another option, which would get rid of the adaptor supplied with the webcam.

http://www.maplin.co.uk/products/mo...4486&Products=2

not enough info on this page, so i emailed asking for more info... we'll see.
anyone else knoe if this would be suitable?

[turkster]

Link doesnt work i'm afraid.

[davidclayton]

search for
"6V 4Ah Batteries and Charger"
on maplin.co.uk

1st one in the list

[turkster]

Yeah looks the job. But if all it is is a battery charger you might have trouble in that youll have to draw power from the battery at the same time that it is being charged which could confuse the charger. Ie the charger could be fooled into overcharging the battery because of the drain on the battery circuit during the charge or normal operation of the device.

I see what you mean about the provided specs I dont how anyone could buy it with just those!!