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Growatt 24v Low DC cut-off at 21v????

solarstuff

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Ontario, Canada
Why is my Growatt 24v SPF 3000 TL using a Low DC cut-off of 21v? And why can't I change the setting!

Shouldn't it be, at lowest, in the 24.5v range to avoid over-discharging?

What can I do?
 
If the lowest "safe" voltage for a lifepo4 is 2.5v (and it is) per cell that's 20 volts on a 24v nominal pack.

21.5v is 2.6875v per cell.

The cutoff isn't supposed to be used for a discharge floor but rather to prevent permanent damage.
 
If the lowest "safe" voltage for a lifepo4 is 2.5v (and it is) per cell that's 20 volts on a 24v nominal pack.

21.5v is 2.6875v per cell.

The cutoff isn't supposed to be used for a discharge floor but rather to prevent permanent damage.
Thanks for replying. I figured that, but the problem is I'm using a AGM and programmed that in.

I'm still getting the 21v figure. Can I still stop worrying?
 
You can go into user mode setting so you can set the parameter for the battery as you wish.
 
20210827_200059.jpg
You'd think so but even on the user custom battery setting whenever I program it for say, 25v, when I click to save the new value it kicks back to 21v. Resetting now with gnashing teeth :)
 
Dragging AGM batteries down to or below 21 volts will make them expensive boat anchors in a hurry...
 
Dragging AGM batteries down to or below 21 volts will make them expensive boat anchors in a hurry...
I cannot change the setting. I followed the '305' reset video but still, the low DC cut off will not switch from 21v.

Has this happened to anyone here?
Do I have a lemon?
 
In use setting you should be able to set 24v as the guide states1630137490782.png
I have the same issue with my 48v system and let Growatt know about it on their FB website.
1630137587084.png
 
In use setting you should be able to set 24v as the guide statesView attachment 62013
I have the same issue with my 48v system and let Growatt know about it on their FB website.
View attachment 62014
So what was your working solution?

After a factory reset I was able to set it to 24v but for AGM that's still 25% charge...way below recommended 'never ever below 50'.
 
So what was your working solution?

After a factory reset I was able to set it to 24v but for AGM that's still 25% charge...way below recommended 'never ever below 50'.
Same here, never been below 57% on my 700ah batteries, they are mainly back up for a power outage to power frig, freezer, tv. 12v powers internet, router and security, wish they would fix this.

Solution is to set back to grid at 51.2, always home ands if not just switch to grid before leaving.
 
I think you need to set it to user if you want to change the LV cut-off. Also, try turning the inverter off so it is in standby mode. Inverter settings require that the inverter is off to change them.
 
Same here, never been below 57% on my 700ah batteries, they are mainly back up for a power outage to power frig, freezer, tv. 12v powers internet, router and security, wish they would fix this.
My 24v bank is sitting at 27.4v (working out Equalization) so I'm not worried now...but I'll switch to mains when I'm going to be away overnight or longer to avoid creating expensive battery-sized doorstops
 
I think you need to set it to user if you want to change the LV cut-off. Also, try turning the inverter off so it is in standby mode. Inverter settings require that the inverter is off to change them.
No joy. Can change setting with inverter on or off but only to the 21v [EDIT: 24V achieved after factory reset] max for LC cutoff. [Still] Madness!
 
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