How do I set my Growatt SPF 3000TL LVM to not drain my battery to zero?

rykelo

New Member
Hello everyone, I have a Growatt Off Grid Solar Inverter SPF 3000TL LVM 24v receiving PV from 3 panels 440w each, in series, able to charge my LiFePo4 battery (a custom built 4000w without BMS communication supplied by a local solar company) and power the loads in my trailer. The main appliance is a 548 kWh/year refrigerator, and there's a little reducer running at all times converting 120v into 12v for the lights (LED) and carbon monoxide detector. My challenge is the battery keeps dying overnight, and then I'm unable to power up the Growatt in the morning (even if it's sunny). I have no connection to the grid, and no generator (yet). My efforts to configure the Growatt to prevent the battery from draining to zero haven't worked. Any help would be greatly appreciated!

Settings:

01 Output source Priority: SOL
04 Power Saving Mode : SdS (disabled, when I enable it, it immediately turns off the 120v to the trailer, even though there are loads)
05 Battery type: US2 (lithium battery without bms communication)
06 Auto Restart when overload occurs: enabled
07 auto restart over temp: enabled
12 setting voltage point back to utility source when selecting sbu priority or solar first in program 1: 24v
13 setting voltage point back to battery mode when selecting SBU priority or solar first in
program 1: (26v? I can't remember)
19 and 20: charging voltage and floating charging voltage: 28.2v
21: low DC cut off voltage: 24v

Thanks guys!
 

Tbj35j

New Member
I tried the 04, saving mode and had the same problem, but when I plugged in a heat gun it came on and stayed on until I turned the heat gun off. I'm not sure where the fine line is.

If someone knows more please post or direct me to the info.
Thanks
 

Wildman13

New Member
I tried the 04, saving mode and had the same problem, but when I plugged in a heat gun it came on and stayed on until I turned the heat gun off. I'm not sure where the fine line is.

If someone knows more please post or direct me to the info.
Thanks


I had same issue but even when I plugged in a heat gun it wouldn't kick on. Had to switch it back to full on vs savings mode
 

Rednecktek

Solar Addict
What is your battery voltage in the morning when the AIO doesn't turn on? If it's less than 23.9v then your Setting 21 isn't doing its job. Conversely you can try bringing that setting up a bit. The manual should say what the minimum voltage to operate is, make sure #21 is at least half a volt above that.
 

rykelo

New Member
What is your battery voltage in the morning when the AIO doesn't turn on? If it's less than 23.9v then your Setting 21 isn't doing its job. Conversely you can try bringing that setting up a bit. The manual should say what the minimum voltage to operate is, make sure #21 is at least half a volt above that.
Thanks for the info! The guy who built my battery says low voltage is 24V. So you're thinking I should try putting setting #21 to 24.5V?
 

Rednecktek

Solar Addict
Yes, you can try that and then (hopefully) check it with a meter once it shuts itself off to make sure it's doing it at the right voltage.
 

rykelo

New Member
Thanks @Rednecktek good idea to check with the meter. I'll do that next time I'm up there. Hey do you know whether the Growatt has some kind of cold protection built in to prevent it from charging the LiFePo4 battery below freezing? I've been worrying about that now that it's getting colder. Thanks.
 

Belzo

New Member
If I'm not mistaken you are going to want to make sure your low cut voltage is lower than your back to grid voltage as well. Hope you get your problem solved. Update if you did 👍
 
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