Power supply for efficient battery backup

Communities Science, Engineering, & Security
1

I have been thinking about something for battery backups for a while. Our standard UPS converts ac 120v power to 12v dc to charge a battery. When the power goes out the 12 volt dc is converted to 120 ac then back to dc for our devices.

How much more efficient would it be if we skipped the dc to ac to dc conversion for low power devices like laptops, mobile devices, routers, modems, and other low power devices? Or is the power lost during conversion not that big of a deal? How much would this increase battery uptime?

basically imagine using a direct 12 volt car charger adapter to a battery instead of inverted ac adapter for devices.

I was considering this for a remote wireless bridge series so I could be in the woods and still have internet.

2

This article may interest you.

http://www.csemag.com/single-article/evaluating-ups-system-efficiency/73497ade33f9a66ead63a77f33e94d4e.html

In eco-mode, many UPSs bypass the rectifier and inverter, but this also means there's no real surge protection.

3

I was more wondering about when the battery is in use . Mainly concerned with battery life when no ac power is available..