UPS Advice needed

[Silver-0-surfer]

Hi,

I am really needing some help here.

This is the scenario.

I have a routerboard that is currently plugged into my combi. Its connected via 3g and provides a wireless signal to users on the road. works pretty well.

Now, the problem is the way that it is wired means that when the combi is off, the routerboard goes off. thats the way I want it so that its not forgotten on or something. However I want it to stay on the the combi is off for like 10-15 minutes so I was thinking of getting a UPS...not as easy as I thought.

All the UPSes are massive and I don't think I can even supply enough power to it.

Do you guys know of any small ups that will give power to the ap and then when power is lost, let it run off of battery and when power is back it should then charge battery and continue to supply power?

Max Power consumption: 10W

any advice would be great

 

[RoganDawes]

You're asking the wrong question, I think.

It sounds to me like you have an inverter connected to your Combi's battery (e.g. via the cigarette lighter socket), and you are then powering the routerboard from that, using the standard wall wart?

My advice would be to verify the voltage that the routerboard uses (i.e. that the wall wart supplies), and then find a converter that will supply the same voltage from the car battery. Odds are good it is 12V, which is nominally what your car battery supplies anyway, which would mean you could eliminate the inefficient inverter and the wall wart completely. (You may want to get a regulator to limit the voltage to 12V just in case, as a car battery can go up to about 14V under some circumstances).

Then, the problem becomes one of making sure that a) you can find a connection to the battery that remains on permanently, as well as one that is switched by the ignition, and b) a method to make sure that the routerboard gets turned off after a set period of time after the ignition is turned off.

For b), you could try something like http://electroschematics.com/5476/timer-light-switch/

 

[RoganDawes]

For what it is worth, letting a UPS drain completely every time you turn it off is a sure fire way to destroy its battery in a hurry. Unless you are planning to get one with a USB cable that you can connect to your routerboard, and let the routerboard monitor it and turn itself off after a certain period has elapsed . . . .