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Hello, I recently got an Infosec E4 LCD LT UPS, unfortunately the two batteries that came with it were dead, so I replaced them with new ones same capacity and voltage (12v & 7Ah), then I downloaded the software to tweak and monitor the UPS, the temperature is normal 18°C, the output power is 220v 0.5A at 50Hz, which only 12% of the load capability of the UPS. The batteries take a very long time to get to 100% but when I remove the plug from the outlet to test the UPS then it can only supply power for a maximum of 5mins . If I’m not mistaken, the batteries voltage is 24v and their capacity should be 3.5Ah since they are in serie, which means 84Wh and I’m consuming 110W (assuming the load as DC current), so it should last at least 45mins. I didn’t find any approximations in the internet to have an idea on how much time a UPS should take so I hope I don’t have bad batteries, but if so then the fault alarm must be triggered, like when I test it the first time with the dead batteries.
Hi @vertinhol I think your calculations are a bit incorrect. If the batteries are in series the voltage is 24V but the current is still 7A. It doesn’t halve, it is the same. It doubles if you connect the batteries in parallel i.e. 14A but then the voltage stays at 12V. If the load is 110W @ 24V this equals 4.58A so theoretically it should last for about 1.5 hours. But in real life the voltage starts to drop as the batteries are being used and it may get to a point where there is insufficient voltage not current. It may be that you have 1 faulty battery that is failing under load or is faulty but usually most UPS run for only about 5-10 minutes so yours is probably OK They’re primarily designed to give enough time to save any work that is open and to shut down safely or to cover unstable mains power supplies not to keep working for hours on end. Cheers
