skala Posted March 22, 2023 Share Posted March 22, 2023 Good day. I have a 3kW 3024/24 Fivestar inverter/charger connected to a 24v battery setup. New system and running for 4 days now. The inverter settings only seem to cater for a 12v battery and the Manual supplied also only has 12v battery settings. The system is running fine but last night it stopped supplying to the fridge connected. The battery voltage read 23.3v at the time. I am sure it should be able to go much lower, it is a 24v gel setup with 4X12v 100aH. So, 24v 200aH. Being in Cape Town area and being cloudy yesterday, the battery reading on the Inverter showed 23.8v at sun down. I have reset the "battery lockdown voltage" (serial 08) to 9.5v. It was on 10.5v. Would this allow the battery more discharge? Quote Link to comment Share on other sites More sharing options...
Coulomb Posted March 22, 2023 Share Posted March 22, 2023 5 hours ago, skala said: I have reset the "battery lockdown voltage" (serial 08) to 9.5v. It was on 10.5v. Would this allow the battery more discharge? Probably 10-20 minutes more at a wild guess. But lead acid batteries should not be regularly discharged so low. 12.0 V per nominally 12 V module when under load is about the point where the battery should no longer be discharged. In my view, 10.5 V per 12 V module is already far too low. A lead acid battery can be ruined in a matter of months by regularly discharging it below 50% State of Charge (SoC). 10.5 V is essentially dead flat, 0% SoC. I note that 23.3 / 2 = 11.65 V, which is a bit higher than the 10.5 V in the cut-off setting. That's probably because you had a high inrush power load like a fridge that momentarily dropped the battery voltage to below 10.5 x 2 = 21.0 V. It's a pity that factory firmware usually doesn't attempt to compensate for the load dropping the battery voltage. That makes it hard to choose a safe cut-off voltage. Quote Link to comment Share on other sites More sharing options...
skala Posted March 22, 2023 Author Share Posted March 22, 2023 Thanks Coulomb. Using gel batteries, which allows deeper discharge than normal lead acid. Quote Link to comment Share on other sites More sharing options...
Scorp007 Posted March 22, 2023 Share Posted March 22, 2023 5 hours ago, skala said: Thanks Coulomb. Using gel batteries, which allows deeper discharge than normal lead acid. Just because it is Gel does not mean it's not a lead acid. All lead acid should be used at minimum 12V per battery unless you want to buy new batteries after 9 months. Adhere to what @Coulomb indicated. Forget of 9.5V as you are destroying them Coulomb 1 Quote Link to comment Share on other sites More sharing options...
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