Battery backup for router/modem etc.

[girishso]

Ok.

I am looking to build uninterrupted battery backup to power the router, modem, raspberry pi etc.

Both my router and modem use a 12v 1A power supply, I am sure they don't need 1A current to function. Planning to use sealed lead acid 12v 7Ah battery.

Think I have two options..

Option 1: Will the attached battery charger circuit suffice my need?  http://www.myra-simon.com/bike/charger.html
Option 2: Or can I use any battery charger available in the market, and draw power directly from the battery with the charger connected? will it provide uninterrupted supply in case of power failure?

Thanks in advance!
Girish

[fubar.gr]

There are 13.7 Volt plug packs available, specifically for float charging lead acid batteries.

You can simply connect that in parallel with the 12V 7Ah battery and then to the router.

When the AC power is on, the plug pack charges the battery and powers the router. When AC power is off the battery powers the router.

Don't worry about the extra 1.7 Volts, routers use DC to DC converters and can handle a wide range of input voltages.

[girishso]

Thanks @fubar.gr!

That's much simpler!!

I happened to have ordered a Lithium charger from Aliexpress, it allows setting charge current/voltage, also the float charging current.  I hope there is no harm in using this charger for charging the sealed lead acid battery. (http://www.aliexpress.com/item/5A-Lithium-Charger-CV-CC-buck-Step-down-Power-Supply-Module-LED-Driver-New/32580191958.html)

Thanks again!