• Networking

  • Question regarding Router + 12v battery setup

I honestly have no idea where to post this thread so bare with me admins.

I recently purchased a UPS from Ketranji to power my router and cordless phone during cutoffs. It's 650 VA and I bought for 50$ including the removal of the alarm sound. My router's ac adaptor draws 0.35amps at 220v and the cordless phone draws a mere 0.1 amps.

The UPS says has a max output of 2.3 amps, but it lasts a bit over 3 hours which is pefect for Beirut. However it takes 8 hours to fully recharge.

I'm planning to power the same router in the mountains (i.e: 4 hour cutoffs) and this ups isn't going to cut it,

Being the cheap bastard I am who loves DIY jobs, I was thinking about connecting the router to a 12v 9amp battery which would last me for 8 hours or so before the voltage drops below 12v. But the main thing that's stopping me from implementing this plan is that I have no idea about what would happen if I connect a 1amp 12v adaptor to it at all times. I'm worried about overcharging the battery and am looking for an adaptor that automatically turns off once the battery is full and charges it when the voltage drops below 13.8v.

Do you have any experience with this kind of setup and what do you recommend?

This option is way cheaper and effecient than using a ups because there is no invereter or adaptor to waste energy and no need to endager my electronics with the square wave current.
Issue solved, I made a little tutorial for those interested. I Passed by Ketranji this afternoon and got:
- 12v 9amp battery
- 12v 1amp 3 stage charger
- Alligator wire clips
- 2 Male and 1 Female DC plugs

The battery's voltage will stay above 12v for 9 hours powering my router (draws 0.5 A at 12v) and when the electricity comes back on the charger kicks in and refills the battery at a steady 0.5A while also powering the router. Because this is a 3 stage charger I no longer have to worry about supercharging the battery.

As for the DC plugs, I cut the router's DC charger's wire in half and connected the a female and male plug on each side. The female plug is now connected to the wire containing the plug that goes into the router. Whereas the male plug is on the wire with the DC adapter.

Then I used the alligator wire clips I bought and connected them to a Male plug.

Now we can easily switch between the DC adapter and the 12v Battery in case we decide to discard the battery or any other reason.
I would be concerned about brownout, and battery service life(should not drop below 10V , or sometimes 11)
Just get a digital voltmeter gauge and monitor or a cut off circuit, as the power system in routers uses smps, would heat up and die if its running under operating voltage by a large margin.
Be AWARE of how you are powering the devices directly, for example, running the router directly from the battery while the ups is plugged in to mains interferes the charging circuitry of the battery, e.g: battery won't reach 13.7. Or, certain line interactive ups (use transformer as a regulator) have the primary center tap connected to the battery, few spikes would reduce the router's life easily.
Just get a basic 12v 7-14ah battery charger+ battery and use your diy skills, like a simple relay switching circuit with its own 12power supply according to your router's specs.
I did that with a 12 v Battery , a 12 volt charger 1 A and the connector of the router 12 volt i just attached them positive line to positive on battery and negative then checked original router charger negative and positive and attach them to the battery and seal them with electricity tap and charge it for 12 hours without connecting the router then connect it back .
don't worry for over charging because the 12 volt charger is a slow charger .
it can last you from 12 hours to 24 hours .
PS : do it on your own risk .
Do you guys have any idea what this is called? It switches between 2 power sources, but I can't seem to remember its name in Arabic or English.

it is a power switch "degentor i think we used to call it :P" there are now automatic ones
4 months later
TPR0 wroteI would be concerned about brownout, and battery service life(should not drop below 10V , or sometimes 11)
Just get a digital voltmeter gauge and monitor or a cut off circuit, as the power system in routers uses smps, would heat up and die if its running under operating voltage by a large margin.
Be AWARE of how you are powering the devices directly, for example, running the router directly from the battery while the ups is plugged in to mains interferes the charging circuitry of the battery, e.g: battery won't reach 13.7. Or, certain line interactive ups (use transformer as a regulator) have the primary center tap connected to the battery, few spikes would reduce the router's life easily.
Just get a basic 12v 7-14ah battery charger+ battery and use your diy skills, like a simple relay switching circuit with its own 12power supply according to your router's specs.
It took me months to figure out that all I needed was a simple relay. I'm stopping by Ketranji and getting one today. The old setup didn't work as expected, I had o manually manually switch between the battery and AC adapter since the battery's "smart" charger is getting confused while powering both the modem and battery. So when they were connected like that, the battery drained and the modem shutdown even though it was connected to the mains at all times.

I'll keep you guys updated!
@random-username your posted picture is called a "knife switch" in arabic "HAWES" and the new automatic ones are Contactors
@NAM what you are talking about is Disjoncteur or Breaker but that's another story