[RE-wrenches] Operating Voltages Outback RE High Capacity Battery

[Jay]

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 <maclewis1 at 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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