1.) Judging from their cost graph [0] it seems to be about 3-4 (definitely less than 5). I&#x27;m guessing that the points where the costs increase is due to batteries wearing out and having to be replaced.<p>2.) Probably? The cost bumps in 1 don&#x27;t make much sense otherwise.<p>3.) Hard to tell, in a home system there isn&#x27;t such a huge cost savings to be had with a battery. As for usefulness it&#x27;s a really short term battery but it&#x27;d be good enough to let the system power-down&#x2F;suspend gracefully instead of losing power immediately. That niche is pretty well served by UPSs for people who care though and everyone else doesn&#x27;t care already. It might find a small niche for consumers but it won&#x27;t be ubiquitous.<p>[0] <a href="http:&#x2F;&#x2F;www.theplatform.net&#x2F;wp-content&#x2F;uploads&#x2F;2015&#x2F;03&#x2F;open-compute-microsoft-les-benefits.jpg" rel="nofollow">http:&#x2F;&#x2F;www.theplatform.net&#x2F;wp-content&#x2F;uploads&#x2F;2015&#x2F;03&#x2F;open-c...</a>