Reiniervd Posted April 14, 2022 Posted April 14, 2022 I have a Power Star Pure Sine inverter 2000w 24v. I have 4 x 100ah agm batteries connected. I mainly use it as a back-up in the office with 3-4 people working on it. Load is not too hectic ,about 500-600w an hour measured with a max of 1400-1500w (laser printer) The issue I have is that the current setup is not lasting the 2 hours of load shedding. I monitored it today thinking it might be the batteries that are shot. So loadshedding was ongoing this morning , load was 300w more or less, after about 40mins the Inverter stated the Batteries were at 70% and voltage shown as 25.8v .Literally like 5-10 mins after I checked the system shutdown and the inverter showing the batteries are at 25% on the little LCD panel. Voltage is still reflected as 25.8v more or less on the lcd panel. restarting the inverter still yields the 25% option. I then measured each battery and voltage was at 13.0v. * Could this be the batteries that are totally done? Should they not show lower voltage when shutting down the inverter? * Could this be an issue with the Inverter somehow? as the settings for the inverter to shutdown is set at 11v or something close to that (std settings not configurable). * best way I should test this ? try another inverter with the current batteries? * how do we test AGM batteries? Can I take them somewhere to do a test? like a batterycentre of sorts? Thanks! Quote
Scorp007 Posted April 14, 2022 Posted April 14, 2022 You need to 1st charge the batteries full before taking to any battery place to check. It is funny that the voltage did not drop below 25.8V when the inverter showed 25% left. You also need to check what you setting for shutting down is set at. Place your setting here and members might be able to pinpoint the problem. 25.8V is still nearly full. Quote
Reiniervd Posted April 14, 2022 Author Posted April 14, 2022 I have attached the settings, the inverter does not have options to configure, it is all preset. Low voltage cutoff is set at 20v, so it should have been fine according to me, however the Inverter for some reason thinks the battery % is at 25%, so not sure if that is maybe an issue with the Inverter. Quote
Reiniervd Posted April 20, 2022 Author Posted April 20, 2022 did a quick test again , so think it might be batteries. below is how the measurements went : 0 minutes battery 78% and 25v 27 minutes battery 70% and 24.6v 49 minutes battery 50% and 23.4V 73 minutes battery 50% and 22.4V 83 minutes shutdown measured consumption over the more or less hour : 350-400watt. (0.35kwh) So it seems the batteries went to basically flat (22.4V) with 400watt consumed , which is not a lot to be honest. So I am going to try and disconnect the batteries and test them individually and see if there is maybe a bad battery * any tips how to test them ? Are these battery testers you can buy worth the while ? * if the batteries are dead, can I sell them for scrap/recycling ? who can I contact for this ? Quote
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