Hey everyone! I've got a 200A 12ah 12v AGM battery connected to a 1000W inverter via a 90A breaker. Just to give you a bit of background, I've previously used this inverter with a resistive heater that pulled around 900-1000W, and it ran fine, albeit at reduced power. Right now, my battery is in float mode, and whenever I plug in my fridge (which pulls about 200W), the inverter display shows a voltage drop from 13.5V to 11.5V in just a few seconds before it shuts down. After a moment, it turns back on and repeats this cycle. I'm checking with an outlet device showing 220V at 0.9 amp max. What am I doing wrong? Why is my battery voltage dropping so much with such a small load when it handled the larger one before? For reference, I've set Absorption at 14.7V and Float at 13.8V, and all my wiring is 2AWG from the battery to the inverter via a bus bar.
1 Answer
Make sure to check that voltage drop using a multimeter. If the voltage is genuinely going from 13.5V down to 11.5V, your battery could be faulty or past its prime. You want to confirm whether that’s purely a display issue or if it’s actually happening at the terminals.
So I should check the battery terminals, right? Even though the battery is less than two months old, could the inverter be the problem instead?