big problems with Growatt 6k

[Schnickasky]

Hello,



I purchased a 6000 watt growatt solar charge inverter for an offgrid application with a 48V (13s) lithium battery bank. The device does not work properly.



I am using the User2 settings because I have no BMS. I set all settings correctly (allthough I have no idea what the difference between float and bulk is) and the minimum voltage cutoff is fine.



What I expect is the following behavior:

1) The device charges the batteries at full amperage until it hits the max voltage I set and then keeps this voltage.Every other charger does this (constant current and then constant voltage) What I get instead is this: It charges but a volt or more below my max voltage inexplicably it stops charging. Then my batteries have to drop by a volt or 2 until it charges again, (but again stays well below the charging voltage I set). The problem is clear: what that means is that I never get full batteries and I might get into the night with only 70% capacity charged.



2) When I use AC power, the inverter USES THE BATTERIES, not the solar panels to power my load. At some point, solar kicks in but for the first minutes, no power is drawn from the panels. I of course wan t the power to always be supplied by the panels (if there is sun)



3) Once there is low voltage shutoff (I set the voltage), THE AC POWER DOES NOT COME BACK on until the batteries are about 4-5V (about 50-60% charge) above the minimum cut off voltage. So on a cloudy day, that mean it could be the better part of the day where I have no AC power although my batteries have been charged back to a level above low cut off in the early morning soon after sunrise.



So is this a lemon and should I have it replaced or are there some mysterious settings I don’t know about (I feel like I tried all).



Thank you for your help

 

[Darren67-72]

I don't want you to go unanswered here so...
You said; it's not your settings. But, it is.
I guess nobody wants to spend great amounts of time with someone that has their mind "set".
How ironic. Just a little fun there.
Check out Wills videos, he covers a lot of this.
Then explain how you want your system to work. And, then, someone will help you get there.
I don't think your inverter is bad.

 

[Schnickasky]

Thank you for your reply. Well I went through the settings over and I just found nothing I could possibly have changed. If it is my setting I would be very happy because it means I don't have to send the unit back. Who is Will and how can I see his videos? Thanks again.

 

[Brainwater]

What type of batteries do you have, and what settings have you used?

 

[Darren67-72]

Will Prowse is the guy that started this forum.
More important is.... Is your inverter a hybrid grid tied (to sell power) , or off grid, with grid tie?
With growatt, maybe others too, if a single setting is off by .2v it can cause things to happen, you would not expect.

 

[TomC4306]

If you don't even know what the difference between bulk and float is, how can you say all your settings are correct?

 

[TomC4306]

BTW.. one is constant current and the other is constant voltage I'll let you guess which is which.
This is really pretty elementary stuff that you should understand before deploying a system like this.

 

[shot428]

I own a T6000 DVM and had a similar issue

It really does matter what battery you are using in order to get help

What I saw was that things did not work as expected until I got the float setting right

 

[BenFromSignatureSolar]

Hello,



I purchased a 6000 watt growatt solar charge inverter for an offgrid application with a 48V (13s) lithium battery bank. The device does not work properly.



I am using the User2 settings because I have no BMS. I set all settings correctly (allthough I have no idea what the difference between float and bulk is) and the minimum voltage cutoff is fine.



What I expect is the following behavior:

1) The device charges the batteries at full amperage until it hits the max voltage I set and then keeps this voltage.Every other charger does this (constant current and then constant voltage) What I get instead is this: It charges but a volt or more below my max voltage inexplicably it stops charging. Then my batteries have to drop by a volt or 2 until it charges again, (but again stays well below the charging voltage I set). The problem is clear: what that means is that I never get full batteries and I might get into the night with only 70% capacity charged.



2) When I use AC power, the inverter USES THE BATTERIES, not the solar panels to power my load. At some point, solar kicks in but for the first minutes, no power is drawn from the panels. I of course wan t the power to always be supplied by the panels (if there is sun)



3) Once there is low voltage shutoff (I set the voltage), THE AC POWER DOES NOT COME BACK on until the batteries are about 4-5V (about 50-60% charge) above the minimum cut off voltage. So on a cloudy day, that mean it could be the better part of the day where I have no AC power although my batteries have been charged back to a level above low cut off in the early morning soon after sunrise.



So is this a lemon and should I have it replaced or are there some mysterious settings I don’t know about (I feel like I tried all).



Thank you for your help

If you would post the settings you have programmed you will get the help you need here. There are several people on this forum that have a strong grasp on how these systems work. All of the issues you have listed are settings related so sharing those rather than just stating they are all correct would probably help you get your system working like it is supposed to.

 

[Schnickasky]

Hi. Well, I do understand what float and bulk charge means but only in reference to lead batteries. In lithium I only know constant current and constant voltage charging which is exactly what I described in my original post. I am using Lipo batteries, 13s without BMS. Sorry I am not as educated as some of the repliers want me to be, I understand I will not get the answers I seek here (Growat has not replied) but can I please get an answer for just 1 question: Do I need to send the unit back because it's defective or is it the settings? Thank you

 

[BenFromSignatureSolar]

It is the settings. Where did you buy the unit? Going to growatt directly isn't going to be much help.

 

[Mattb4]

Perhaps I am misunderstanding but when you say you are running a 13S LiFePO4 battery without any BMS installed does that mean you have only 13 cells wired in series rather than the normal 16 for a 48v system?

 

[Ampster]

Hi. Well, I do understand what float and bulk charge means but only in reference to lead batteries

As someone said earlier Bulk is the same as constant current, it's voltage setting is where the transition to Constant Voltage takes place.

 

[Ampster]

. I am using Lipo batteries, 13s without BMS.

Do you mean LiFePO or Lipo (Lithium Polymer)?
That will affect what voltage settings you use.

 

[shavermcspud]

This has got danger written all over it, LiPo cells + no BMS

 

[Darren67-72]

This is why I stepped out. I came to this site for help, when I started and people here helped he emencly!!! I'm here, on this site to return the favor 5 fold. I am glad to do, anything I can and answer any questions I can.... for those who are willing to listen. They make the final decisions, it's their system!!! We are just here to offer ideas and experiences.
I appreciate all you guys willing to help a guy out!!!

 

[Darren67-72]

Hi. Well, I do understand what float and bulk charge means but only in reference to lead batteries. In lithium I only know constant current and constant voltage charging which is exactly what I described in my original post. I am using Lipo batteries, 13s without BMS. Sorry I am not as educated as some of the repliers want me to be, I understand I will not get the answers I seek here (Growat has not replied) but can I please get an answer for just 1 question: Do I need to send the unit back because it's defective or is it the settings? Thank you

2 people now, have stated; it's the settings. Not the inverter!

 

[Ampster]

I will state that it is the settings also, but I would like to have confirmation on the chemistry so we know what the settings should be for 13 cells in series?
No matter the chemistry, that is a number of series cells that could require voltage settings outside the range of your inverter and in that case it could be the wrong inverter or the wrong battery for that inverter.

If LFP the nominal voltage per cell is 3.2 volts
If LIPO the nominal voltage is 3.7 volts. This would be a nominal pack voltage of 48 volts and a max voltage of about 53 volts. This is the most likely but please confirm it is LIPO that you are using. ?

 

[Quattrohead]

Do you mean LiFePO or Lipo (Lithium Polymer)?
That will affect what voltage settings you use.

13 x 4.2v has to be Lipo to get the 48+ volts the inverter want's.
But yeah, the lack of understanding what he has and the inherent dangers in Lipo batteries, then no BMS...yikes ?‍?

 

[BenFromSignatureSolar]

I was kind of hoping for a typo there. the 3 and 6 are pretty close on the keypad ?‍

 

[42OhmsPA]

I have no BMS.

You have a bomb making system without a BMS

 

[Ampster]

You have a bomb making system without a BMS

The good news, I think I remember him saying he has a fireproof bag to charge them in. Some of those RC packs can be charged with a balancing charger.

 

[Schnickasky]

Thank you for the reply. I have a cobalt chemistry Li-Ion, 13s, 20Ah = 1kwh each, and I have 6 of them. To increase the life I want to only charge them to 53.3V max (=4.1V/cell) and discharge them to 43V min. I actually had a short breakthrough: Against the manual I tried the USE instead of the US2 settings and for the first time it worked! It charged to my desired 53.2 volts (the device refuses to accept odd decimal numbers) and then tapered off the amps and kept it at that voltage. Loads were power by solar, just as I wanted. However - the next morning all was lost. The batteries were at 45.3 volts, the panels had full sun (102V) but the unit did not charge at all. The display said 0V for the solar panels. I waited a few hours. Nothing. Then I arbitrarily changed the user profile to AGM and, lo and behold, charging started. I immediately changed back to USE setting. Naturally I do not want to have to do this every morning, so what could be wrong in my settings now? Thank you
PS: Unless the unit is unpredictable, I never charge or discharge my batteries at high rates and I do have a temperature alarm on the battery. I figured this is my BMS. Is this still dangerous?

 

[Schnickasky]

sorry for the duplicate posting

 

[Zwy]

Thank you for the reply. I have a cobalt chemistry Li-Ion, 13s, 20Ah = 1kwh each, and I have 6 of them. To increase the life I want to only charge them to 53.3V max (=4.1V/cell) and discharge them to 43V min. I actually had a short breakthrough: Against the manual I tried the USE instead of the US2 settings and for the first time it worked! It charged to my desired 53.2 volts (the device refuses to accept odd decimal numbers) and then tapered off the amps and kept it at that voltage. Loads were power by solar, just as I wanted. However - the next morning all was lost. The batteries were at 45.3 volts, the panels had full sun (102V) but the unit did not charge at all. The display said 0V for the solar panels. I waited a few hours. Nothing. Then I arbitrarily changed the user profile to AGM and, lo and behold, charging started. I immediately changed back to USE setting. Naturally I do not want to have to do this every morning, so what could be wrong in my settings now?

Float should be set 0.5V under bulk setting under the USE menu, however if you do not have a BMS, then this becomes dangerous.

This is how GW works regarding bulk and float. The GW will charge the battery to the bulk max voltage setting and stop charging. When the battery voltage drops to the float setting, the GW will begin charging again to maintain that float setting.

Thank you
PS: Unless the unit is unpredictable,

I think the unit may be just fine. At this point, user error is more apparent.

I never charge or discharge my batteries at high rates and I do have a temperature alarm on the battery. I figured this is my BMS. Is this still dangerous?

Without a BMS, you do not have individual cell monitoring in place. This is important as bulk and float settings need to be configured for any cells that are runners to keep the individual cells from overcharging. Overcharging a cell can lead to a runaway situation with your pack. Very dangerous and considering you are using Li-Ion and not LFP chemistry makes it much more important.