I have brought APC Back-UPS ES 500 for my wireless router (approx 12W load) power supply in case of power failure. Recently I have noticed that UPS is getting shutdown within 6 mins of power failure. I have called APC tech support for resolving this issue. They have told me that I need to connect at least 50W of load so that it will work as per the specs. This minimum load was not mentioned in the manual or "Run Time Chart" (provided at their website). After a long discussion they have accepted that it was not mentioned in the manual... read full review »