Add more batteries to make UPS runtime longer?

[SmileM]

Hi, I have a APC Smart-UPS 1000VA.

I read on the net and some of my friends told me that it is possible to extend the runtime of your ups by adding more batteries to it. You just need to be sure they are both the same type and model.

You just have to connect them in parallel and your runtime will be longer. My friend says he uses this setup and it's safe too. By adding identical batteries in parallel to existing ones you increase the capacity that's all, you won't damage your usp or anything. It will just charge them longer, but hey the runtime will be longer too

It this true?
Any electricians around here?

[bailey]

well, let me say this:
I have expiremented with this same idea.
I have a old apc 500 that I salvaged from a junk pile and tested it , found the batteries were bad.
price of new battieries were a bunch plus had to send old ones back for recycling
so I connected a 12 volt deep cycle marine battery to it and it has been working great for several years now
I don't know what the run time is, but it is a long time.
power always came back on withen a few hrs.