Hi Mac I don’t know if this is pertinent, but it could be the SOC /fndc getting out of calibration.
I’ve seen this happen if % SOC charge termination is on ( default). Kinda goes into a negative loop. The other thought is that 2 hr absorb is pretty short for that size bank, but maybe that is OB spec? Jay Peltz power. > On Apr 19, 2019, at 10:27 AM, Mac Lewis <maclew...@gmail.com> wrote: > > Hello Wrenches, > > We recently inherited an Outback system that I've been keeping an eye on via > Optics. Its a dual stack 3648 VFXR, with about 4kW of PV with a single > string of EnergyCell 1100RE battery bank (reported to be ~6 months old) ~.46 > kWh at C20. > > I have been observing how the system functions and how the voltage behaves. > We keep getting 2 minute voltage starts on the generator in the middle of the > night that don't seem necessary judging from how much energy has been used > from the battery bank. I am hesitant to tweak anything because these battery > set-points are a bit different than I'm used to. > > As per Outback: > Absorb Voltage is 55.6V for 2 hours > Float Voltage is 54.0V > > I've slowly been dropping the 2 minute start voltage to see if there is a > bottom, but I'm hesitant to take it much lower (maybe I should). > 2 minute start voltage: 44.8 V. > > > The system easily charges the battery bank to 100% (and easily reached the 2 > hr absorb time) every day. The flexnet DC is correctly set up and calibrated. > > The load on the system is pretty consistent. They use between 400 and 600W > throughout the night. > > An average night, they may use about 6 kWh before the voltage sags below the > 2 minute start voltage and it starts the generator. > > Just curious if our 2 minute voltage needs to be dropped or if these > batteries are degraded. What corrective changes can I make to get better > performance? > > I have and will call Outback about this, but I'd like other perspectives as > well. > > Thanks as always for your expertise > > -- > > > > Mac Lewis > > "
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