Mac,

Only removing 6kWh from 46kWh of storage should not be able to produce the 
voltage sag to trigger AGS. That’s only about 13% at a 100Hr rate. Voltage 
should be no where near that point. Have you verified actual voltage when the 
AGS is triggered? Loose wiring or terminal corrosion can cause voltage drop but 
I would think that an easy find/repair you would have checked.

Saying the battery easily charges to 100% worries me as sulfated batteries do 
that. Healthy LA batteries take many hours to reach full saturation. Has cell 
voltage been compared for non-uniformity? Has the equalization charge been 
performed? 

I am not a fan of the unusual low voltages that Outback prescribes for 
EnergyCells and seriously wonder how these voltages can properly maintain these 
cells. CV is below the point where balanced O2 and H2 evolution takes place. 
But, thats off point.


Larry Crutcher
Starlight Solar Power Systems




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

"Yo solo sé que no sé nada." -Sócrates

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