AGS Generator Configuration Tweak Advice.

Fizbin

I need some help with maybe configuring my Kohler Generator to kick on automatically prior to a system shutdown due to low voltage.

My AGS I think needs tweaking.  In the config it says “State of Charge Level to Start Generator” 20%. So the Gen will automatically kick on with the SOC is <20%.  But, the SOC never drops below about 90% per the graphs and data.  Yet the voltage this morning dropped below 50v which triggers a system shutdown.

 

Whereas I’m sure there is nothing malfunctioning, I think one of two things.  Either the AGS needs to potentially be re-synched with the actual voltage, (49.5 V should also reflect a SOC of maybe 40%-50%) or the generator should be set some how to kick on based on a voltage reading rather than an arbitrary SOC.

 

Thoughts?

BB.

What kind of battery bank (FLA, AGM, etc.)? What temperature (roughly) is the bank.

For example, as a very rough estimate, around 46 VDC and moderate discharge, an FLA battery is something like 50% discharged.

You probably want the genset to "run"/bulk charge the battery bank (FLA) from 50% to ~80% SoC (typically in the morning) and let the solar charger take over absorb and float. Running the genset at 50%-80% or so of rated load is relatively fuel efficient. Running genset much below 50% rated output typically much less efficient (for gasoline and propane type gensets.

Diesel genset generally "like" to be loaded at 40% or greater loading. Running at low output loading, they can glaze cylinders, "wet stack", carbon buildup.

Here is a nice write up with charts of battery voltage vs state of charge vs various charging/discharging currents:

http://www.scubaengineer.com/documents/lead_acid_battery_charging_graphs.pdf

Guessing at State of Charge for FLA batteries is pretty hit or miss...

There are Battery Monitors that measure the current vs time of charging/discharging current (i.e., pull 20 amps for 3 hours = 60 AH drawn from battery bank). For the most part, Lead Acid batteries are fairly "efficient" based on Amps * Time (i.e., pull 10 AH out, put 10 AH back in). FLA batteries are not that energy efficient (i.e. draw 10 amps * 12 volts = 120 Watt*Hours; vs charge 10 amps * 14.8 volts = 148 WH charging).

Some Victron and Xantrex (and others may be out there) battery monitors have programmable output (i.e., program "on" at 50% or less SoC, and "off" at 80% SoC). Actively cycling FLA batteries from 50-80% is very efficient and does not harm battery life (storing/resting batteries at 75% or less SoC, they will sulfate and eventually die if left in that "low charge" state fo days/weeks/months at a time).

https://www.solar-electric.com/search/?q=battery+monitor

You have to be careful about this whole AGS setup... Don't want to waste fuel, don't want to crank genset with no fuel, run engine to overheat/no oil failure, etc.

Easy to run genset with very little load (batteries charge, genset will not shut off). Or genset will not start (various mechanical issues, AGS not triggering, dead starting battery, etc.) and your main battery bank is taken dead and probably ruined.

Things to make sure--Your DMM battery(ies) is good (weak battery=goofy readings). make sure connections are good (reading 46.0 volts at battery bus terminals, and near 46.0 volts at AGS sense input terminals).

Have seen other "issues too"... One that has bitten more than a few folks... The "genset" charges it's starting battery from its AC output (i.e., genset running, possibly from AC utility power). Genset does not run 9 months of the year, the genset starting battery goes dead... More than a few folks have added a small solar panel+solar charge controller to the genset battery so that it stays charged year round.

-Bill

Fizbin

I have 16 Simplifi Phi LFP.
When you ask what temperature, there is no temperature sensing equipment attached to them.  

Your 46v and 50 discharge figure seem about what I was thinking to be accurate.

Under somewhat normal circumstances, this is the first time the gen has needed to turn on.  Usually there is plenty of power.
What led to this lack of power it was super cloudy the entire day on Thursday. There were high winds and the outside temperature only got up to 30 degrees.  We used the booster pump and the well pump on and off for 24 hours as we were dripping many hose bibs around the place.  By comparison, we're doing the same thing now but yesterday was pure sun.  At 0530 as I type this we're at 53v so we'll be fine.  The sun will be up and we'll be generating power in 4 hours.

The Kohler is a 20kw propane unit.

The generator battery stays powered when not in use from the whole system.  The gen runs a 20 minute self test every Wednesday morning.  It's all running real well. except for SOC reporting. 

ELYNN4

How are you determining the SOC.  If you are using voltage with your LFP batteries this could be the issue.  It’s much more accurate to use a Battery Monitor that measures the amp hours removed from the batteries and triggers the AGS accordingly.

Fizbin

I'm using the 

Schneider Electric Conext Battery Monitor 24/48V

SKU 

865-1080-01

I finally found a pdf online, I'm going to try and dig in to this a bit today as it's cold and cloudy.
Last night at 2000 I had to go out and flip the gen on manually as we ran out of power an hour later I went back out to flip it to Auto, even though it won't turn on by itself.

The original installer disappeared.  It was all way way way beyond their skill set to install the system.  My consultant that I hired is pretty good but a bit overwhelmed.  I have a call into him and he is researching it but I bet won't do much beyond what I can do with the manual and you folks here.