DPC3941T battery backup question

I work from home and the power here goes out frequently for 1-2 seconds. I was hoping to prevent loss of internet during those times so yesterday I istalled a backup battery in my Cisco DPC3941T. I thought this would keep my internet working during those brief power interruptions. 24 hours after installing the battery I decided to test it and unplugged the gateway. My phone still had a dial tone, but my internet went down. I plugged it back in and my internet came back up within about a minute which is way beter than the 7-10 minutes it takes when I have no battery installed but still not what I was hoping for. Apart from purchasing a full UPS is there a way to keep the internet working whileon the battery?