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diy solar

What is the Best way to reduce your grid consumption ?

EPicTony

EPicTony

Solar Enthusiast
Joined
May 29, 2022
Messages
225
Location
NE Ohio
So I have my EG4-6500 running split phase and it's working great. I have it set up for SBU (solar, battery, utility).
It's getting dark and I'm on battery now. Tomorrow when there is solar power will the unit charge the battery AND produce 120vac or does the battery charge happen first and then the inverter produces 120 vac ? The manual is not clear on this. I have the charging mode set to utility AND solar ( I did wire up the AC input). I'm just trying to fully understand how this unit functions. I want to reduce my grid consumption to a minimum. Thanks for any help.
 
Is there no data log to show what is coming and going? My utility shows me hourly usage and generation pushed back.
 
time2roll said:
Is there no data log to show what is coming and going? My utility shows me hourly usage and generation pushed back.
Click to expand...
I use solar assistant. I have control of inverters while im away and can see everything on my phone
 
Watchpower is the program that comes with the inverters, but to be honest, it's not worth the time to set it up. Like @Dyotat100, I use Solar Assistant for monitoring my environment.


EPicTony said:
OK but when does the utility charge the battery ? This is unclear.
Click to expand...
In regards to the grid charging, the inverters will only use the grid to charge the batteries when you're in grid-bypass mode. That could be "USB", "SUB" or your inverters might drop below the settings in option 12 and switch to the "U" in "SBU". When in Utility mode, then options 11 and 16 come into affect to determine what your utility charge rate is going to be as well as your charging priority.
 
SBU as stated above will only charge with utility if your battery voltage dips below your setting.

Setting 11 is how many amps (DC) are allowed for charging. I have mine set to 60A.

Setting 12 is the battery voltage low limit where the inverter switches from solar/battery over to grid bypass/grid charge. I have mine set to 48V. If you battery never Dips below this voltage, the grid will never charge the battery (this is a good thing).

Setting 13 is the battery voltage at which the system moves from Grid back to Solar/Battery. I have mine set to 52V.

You can force the grid on while in SBU if desired simply by turning off the solar input. For instance last week I knew an ice stormmwas coming here in NH. The night before when my solar production was over, I flipped my PV breaker off, then raised setting 11 to 90A on each inverter and raised setting 13 to 57V. When I hit 57V, I flipped the solar breaker back on and the system went back to battery mode as soon as it "sees" the solar (even though it's dark and the solar isn't producing).
 
PreppenWolf said:
SBU as stated above will only charge with utility if your battery voltage dips below your setting.

Setting 11 is how many amps (DC) are allowed for charging. I have mine set to 60A.

Setting 12 is the battery voltage low limit where the inverter switches from solar/battery over to grid bypass/grid charge. I have mine set to 48V. If you battery never Dips below this voltage, the grid will never charge the battery (this is a good thing).

Setting 13 is the battery voltage at which the system moves from Grid back to Solar/Battery. I have mine set to 52V.

You can force the grid on while in SBU if desired simply by turning off the solar input. For instance last week I knew an ice stormmwas coming here in NH. The night before when my solar production was over, I flipped my PV breaker off, then raised setting 11 to 90A on each inverter and raised setting 13 to 57V. When I hit 57V, I flipped the solar breaker back on and the system went back to battery mode as soon as it "sees" the solar (even though it's dark and the solar isn't producing).
Click to expand...
"You can force the grid on while in SBU if desired simply by turning off the solar input. For instance last week I knew an ice storm was coming here in NH. The night before when my solar production was over, I flipped my PV breaker off, then raised setting 11 to 90A on each inverter and raised setting 13 to 57V. When I hit 57V, I flipped the solar breaker back on and the system went back to battery mode as soon as it "sees" the solar (even though it's dark and the solar isn't producing)." Curious, in solar assistant is 57 volts on 48 volt batteries equal to 100%SOC?. Otherwords charging to 57 volts is ok for 48v batteries?.
 
bones1 said:
Curious, in solar assistant is 57 volts on 48 volt batteries equal to 100%SOC?. Otherwords charging to 57 volts is ok for 48v batteries?.
Click to expand...
To answer your question, yes. 48 volts is the nominal voltage. I'm gonna try and not be confusing...

The allowable voltage depends on the battery chemistry. I believe the EG4 batteries are Lithium Iron Phosphate (LifePo4). With LifePo4 batteries, there's no direct correlation between voltage and state of charge because the cells have a very flat charge/discharge curve (if you would like to know more, search for "Off Grid Garage" on Youtube. Andy does a great job explaining it).

LifePo4 (48v packs) should have a max voltage of 58.4 (there are 16 cells in series to make a "48v" battery. the max voltage per cell is 3.65v. 3.65x16=58.4).

In these server rack batteries, the manufacturers tend to dial down the max charging voltage to try and prolong the life of the pack. I'm not sure what the EG4 batteries have set in their BMS and correct me if I'm wrong, but I don't think there's any way to change those values is there?
 
I have several li ebike batteries nominally rated at 48v.
These charge to 53 to 54v when new, a little less after a few years.
 
w8dev said:
To answer your question, yes. 48 volts is the nominal voltage. I'm gonna try and not be confusing...

The allowable voltage depends on the battery chemistry. I believe the EG4 batteries are Lithium Iron Phosphate (LifePo4). With LifePo4 batteries, there's no direct correlation between voltage and state of charge because the cells have a very flat charge/discharge curve (if you would like to know more, search for "Off Grid Garage" on Youtube. Andy does a great job explaining it).

LifePo4 (48v packs) should have a max voltage of 58.4 (there are 16 cells in series to make a "48v" battery. the max voltage per cell is 3.65v. 3.65x16=58.4).

In these server rack batteries, the manufacturers tend to dial down the max charging voltage to try and prolong the life of the pack. I'm not sure what the EG4 batteries have set in their BMS and correct me if I'm wrong, but I don't think there's any way to change those values is there?
Click to expand...
Thanks. So settings made in solar assistant under battery settings edit will overide and replace what the inverters are set to on 12,13 etc I believe..
 
bones1 said:
Thanks. So settings made in solar assistant under battery settings edit will overide and replace what the inverters are set to on 12,13 etc I believe..
Click to expand...
Yeah, they will actually make the changes in the inverter. Just a better interface to make changes. Very rarely do I actually change values on the inverter anymore. I just open SA and make my change. So much easier than scrolling through a menu to try and find “option 22” or whatever needs changing.
 
w8dev said:
Yeah, they will actually make the changes in the inverter. Just a better interface to make changes. Very rarely do I actually change values on the inverter anymore. I just open SA and make my change. So much easier than scrolling through a menu to try and find “option 22” or whatever needs changing.
Click to expand...
Thanks, Adam. Obviously, I am new to Solar Assistant programming and you guys are a great resource as is your youtube channel. I just saw this graph under power settings, oh boy
 
Do you use this
 

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At the moment I'm not because I'm testing some other things out.

When I was though, I just used it to switch my units to grid-bypass if my inverters dropped below 10%. I didn't care about what the time was. Then once the power got up to 40%, it switched back. Obviously if you wanted to make sure you had more power in the event of a power outage, you could set the 10% value higher for those, "just in case" moments.
 

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