Rosen 48 volt 200amp/hr loosing Amp/hrs and SOC dropping each day

[Baja John]

I have installed my Growatt 6kw, 12 500W moncrystalline panels and 2 Rosen 200amp hour batteries in January 2022. The system is running fine and no issues at all with the amount of amps/volts supplied to the inverter. My problem is since January when the batteries were installed they charged from SOC 49% to 96% no problem in approx. 5 hrs. As each day pass's the SOC drops 2% and my Amp/hrs drop 2amp hrs. It is now March 17th and my SOC 66.66% and amp/hrs 133.16 after a full day of charging. Actually they stop charging around 11 am as the Y warning comes on both batteries. The warning is OV-warning which is over voltage according to the manual.
I have contacted Rosen and they were able to reprogram Bat 2 and it showed 196 amp/hrs after doing this update through my computer. However since then last week the same problem is happening, it is loosing 2 amp/hrs a day and SOC dropping. Bat 1 they could not update through my computer and waiting for them to figure that out. My concern and question is why are these loosing SOC and amp/hrs since new.
Bat one is only at SOC 33% at 7am and at this rate it will shut down at 20% which isn't going to be long from now. I am not using AC units at the moment but summer is coming. My peak amp draw per day is 28.6 amps and average 18.3 amps. Thanks if someone can help, I live in Mexico and am totally off grid and totally isolated from major centers.

 

[TorC]

Can you get at measuring actual cell voltage with a good meter? That would be useful in determining which piece of equipment is incorrect.

This looks like a thread with a very similar issue that might have some additional insight: https://diysolarforum.com/threads/soc-drops-by-2-every-day.35687/

 

[Baja John]

Can you get at measuring actual cell voltage with a good meter? That would be useful in determining which piece of equipment is incorrect.

This looks like a thread with a very similar issue that might have some additional insight: https://diysolarforum.com/threads/soc-drops-by-2-every-day.35687/

. Not sure if I can open it up to measure the voltage on the cells. It does give me the voltage at the cells on the screen. Hoping that will work for some help.



At 7am on Bat 1 cell #1 voltage is 3311 mV and at 4pm cell #1 voltage is 3580 mV



At 7am on Bat 2 cell #1 voltage is 3313 mV and at 4pm cell #1 voltage is 3579 mV



One thing I have noticed that around 10:30 am Bat 1 and 2 both show a OV warning. This is when they no longer charge. Then the warning will go away after a bit as power is being taken from the batteries instead of the solar. Once that happens the warning goes away and they charge till the warning returns. By mid afternoon the warning stays on till sun goes down and the batteries kick in.



I have 12 500watt panels on the roof and they do have enough to run the house all day. But when the battery warning OV goes on inverter switch’s to batteries and amps from panels goes from 79 amps to 9 amps. Sorry the pictures are mixed up.



I did contact Rosen and the Technician through my laptop managed to set Bat 2 to higher SOC and ah but he couldn’t set Bat 1 they are working on a solution for that. My concern is even though they set Bat 2 it still loosing SOC and ah each day as is Bat 1.



Thanks for you time and open to any suggestions. I am still waiting for the tech to get back to me.

 

[MisterSandals]

as the Y warning comes on both batteries.

So where exactly is the OV warning displayed? On the batteries? On the charge controller? On the inverter?

But when the battery warning OV goes on inverter switch’s to batteries

I cannot figure out what you have.

What charge controller and inverter do you have?
What are your charge settings?
Have a pic of the whole setup?

 

[Baja John]

I have a Growatt 6000 inverter, 12- 500watt perc monocrystalline RS-96 Series panels and 2 Rosen 200 amp/hr 48 volt batteries. Totally off grid. Installed January 2022. The warning comes on the each battery. It is the OV warning. I am pretty new to this and installed this system myself as in Mexico where very little help is available. However not tech challenged somewhat. I am not sure of the charge settings as going from the Growatt manual set up, once I choose Lithium L05 in step 5 of the set up the charge rates and such are pre determined by this setting.
It is so weird to me that I do have ample power to run the house during the day from the panels I have like 79 amps coming in from the panels at 10am and the batteries are charging just fine, about 26 amps each. Then around 10:30-11:00am the OV on the batteries goes on and then the charging stops from the inverter. Inverter goes from a 79amp charge to 9amps. The batteries will then start running the house till they discharge to + or - 50 volts and then the OV warning goes off and the solar will take over once again till the batteries go into OV.
When I installed the system in January both batteries had SOC 96 and ah 196. Since then they have dropped 2% a day. The Rosen Tech over Teamviewer was able to reset Bat 2 but not Bat 1 as no communication. Saying this if Bat 2 was reset why is it still dropping 2% each day?
I am trying to work with Rosen but am hoping maybe I can get a clearer idea of what is going on. Gonna get hot in Mexico soon and would like to start running my AC units.

 

[Baja John]

 

[TorC]

I didn't readily find any default settings list. If you can go through the menus and find what voltages your growatt is set to we may be able to help. Right now my top guess is that the GW is set to charge to a voltage that is probably within reasonable for LFP, but above the Rosen cutoff. As the voltage rises and approaches CV mode it exceeds the battery limit, which shuts down. Doesn't fully explain the 2% per day loss, however, as you'd expect it would more likely charge every day to the same 9x%. Getting towards wild speculation here, but I suppose maybe it could be never resetting the SoC because it cuts off on OVP before the battery itself reaches full charge and it resets the counter.

Hmmm... maybe it's possible some batteries use a 15S config for a 48V± to be more drop-in compatible with lead acid settings, rather than the more common for lithium 16S for 48V+, and the Rosen is one of the former, and thus needs either the growatt lead acid setting or better a custom LFP config? You could try asking Rosen tech when you next talk to them. Anyone with more experience want to chime in on this possibility?

 

[AKvalleyguy]

Hmmm... maybe it's possible some batteries use a 15S config for a 48V± to be more drop-in compatible with lead acid settings, rather than the more common for lithium 16S for 48V+,

Rosen was recently selling a 15S 48v 200AH so your suspicion is right on. I don't have a Growatt inverter, I'm still running Outback equipment, so I have nothing even remotely intelligent to add.

 

[Baja John]

I will see if I can figure out the charge settings and fire them off in the next post. Not sure if this helps but been going through this forum and finding out all kinds of good stuff. For example the screen on the Rosen batteries I can bring up the voltage for the cells. They are all pretty much the same voltage in each cell. At 7am the cell voltage is 3311 mV and bat voltage is 49.70 for bat 1 and bat 2. At 4pm cell voltage is 3580 mv and bat voltage is 53.72 for bat 1 and bat 2.
If I am understanding what one member posted in a chart if the mV is 3311 then bat is at 40% and if mV is 3580 then bat is at 100%. This this sounds correct and the battery is not showing the correct SOC or ah? Yes my concern is if the inverter see's a SOC of less than 20% it will shut everything down. Totally solar and that would not be good.

 

[Baja John]

Yes the Rosen Battery has 15 cells that I can read on the battery display voltages and temps. Reading you post TorC does this mean that using the preprogrammed lithium setting for charge/cutoff which is not settable when choosing lithium on the Growatt. If I choose an option US2 05 on the Growatt 6000 then I can set charging and cut off's. This would mean no BMS communication however. This help any? The x's are in 11 to 13 can not be set when in L01 51

 

[TorC]

I don't have any experience with programming a Growatt. Maybe someone who does knows in detail. Looking at those pics, if you don't get someone who knows more, I'd look at finding out the voltage setpoints recommended for the Rosen battery and try setting them with the US2 lithium program. Probably not an ideal long-term solution, but there's a decent chance it'll let you get to a full SoC recorded while you figure out the communications.

 

[MisterSandals]

I think @FilterGuy is working with a Growatt. Let’s see if he can help.

 

[FilterGuy]

OK..... I have not studied the whole thread but I did skim through it and identified at least 2 things to address.

1) The lithium setting on the Growatt is intended for use with a battery that can communicate with the Growatt. I am not familiar with Rosen so do not know if it is capable of communicating or not.
* Is there any coms cable between the Growatt and the batteries? If not, then there is no communication. If so.... there may or may not be proper communication.

Even if the battery can communicate with the inverter, I am not convinced of the need to do so. Furthermore, with the unique 15 cell battery, I would lean toward not letting it communicate even if it could (See point 2). Growatt is too sparse with their info to figure out if it would work well and how to debug it if it isn't working properly)

2) If you have a 15 cell battery communicating with an inverter that is defaulting to 16 cell settings, it would completely explain the over-voltage warnings. The charge voltage needs to be dropped.
I have never run 15 cell systems, but I like to run the cells between 3V on the low end and ~3.5 or 3.55 on the top end. For 15 cells, that translates to 45V for the Low voltage disconnect and 53.25 for max charge.

You mention Mexico, to it is in North America. Do you have the SPF 6000T DVM-MPV? That has 240V in and 240V-Split phase out.

For now, I will assume it is the SPF 6000T DVM-MPV. If it is not the following instructions may not apply.

NOTE: The critical settings for this problem are highlighted in purple
EDIT: The settings recommended below are for a 15Cell battery. These are not appropriate for a more typical 16Cell battery.
Program 1: Output source priority:
I usually set this to SBU Priority. (Solar-Batery-Utility). Please read the manual to see if you want something different.

Program 2: Maximum charging current:
Set this to the combined max charge for the to big Rosen batteries. (It the rosen can take 50A charge, you would set this to 100A for the two of them.


Program 3: AC input voltage range
Set this to APL (If there is no AC input, this does not matter)

<There is no program 4>

Program 5: Battery type
Set this to USE (User defined)

Program 6: Auto restart when overload occurs
I would set this to restart disabled. If an overload occurs you want to investigate before things get turned back on

<There is no program 7>

Program 8: Output voltage
Measure the voltage you get from the utility and pick the closest setting. (If there is no AC input, set it to 230V)

Program 9: Output frequency
Set this to 60hz

<There is no program 10>

Program 11: Maximum utility charging current.
For now, leave this at the default 30A. However, this depends on how large the circuit feeding the inverter is and how much power your appliances will take when in pass-through mode.
30A of charging will draw ~7A from the AC. If the inverter is being powered by a 30A breaker, that only leaves 23A for the appliances. (If there is no AC input, this does not matter)

Program 12: Setting voltage point back to utility source when selecting “SBU priority” or “Solar first” in program 01
For a 15 cell system, this should probably be around 45V, but it only goes down to 46V, so set it to 46V (If there is no AC input, this does not matter)

Program 13: Setting voltage point back to battery mode when selecting “SBU priority” or “Solar first” in program 01
For a 15 cell system, I would put this at 49V (If there is no AC input, this does not matter)


More in the next post

 

[Baja John]

Yes my Growatt is a SPF 6000T DVM-MPV model. Split Phase. I am totally off grid no utility power available. In program 1 it seems like Solar First and SBU priority are worded the same. I am presently on Solar First should I change it to SBU then? Program 5 there are two user defined. USE and US2. US2 it says suitable for lithium batteries when not using BMS cables. I am assuming then this is the program to use? Program 12 and 13 don't apply as no utility correct? I am attaching the spec sheet for the LPH48V200AH batteries.
On program 19 and 20 now that these can be set cause I am changing to User Defined what program 19 CV charging voltage be set at and also program 20 floating charging voltage and 21 low cut off voltage?

 

[FilterGuy]

EDIT: The settings recommended below are for a 15Cell battery. These are not appropriate for a more typical 16Cell battery.Program

14: Charger source priority:
I would set this to SNU.

Program 15: Alarm control
I would set this to BON (Alarm on or Buzzer ON)

Program 16: Backlight control
Your choice. LOF (Light off will save a tiny bit of power)

Program 17: Beeps while primary source is interrupted
Your choice

Program 19: C.V. charging voltage If self-defined is selected in program 5,
Set this to the charge voltage the battery instructions tell you to use. If they don't tell you, set it to 53.25V. If you still get OV errors on the battery, drop it down to 52.5V.


Program 20: Floating charging voltage. If self-defined is selected in program 5
Set this to 49V

Program 21: Low DC cut-off voltage. If self-defined is selected in program 5,
Set this to 45V. This is the lowest the inverter will let the battery get before it shuts off power.

Program 22: RS485 Communication Address
Leave this at the default. It does not matter.

Program 23: Battery equalization
This must be set to diS (Disabled)

Program 24: Battery equalization voltage
Leave at default (Equalization is off so it does not matter)

Program 25: Battery equalized time
Leave at default (Equalization is off so it does not matter)

Program 26: Battery equalized timeout
Leave at default (Equalization is off so it does not matter)

Program 27: Equalization interval
Leave at default (Equalization is off so it does not matter)

Program 28: Equalization activated immediately
Leave at default (Equalization is off so it does not matter)

 

[FilterGuy]

In program 1 it seems like Solar First and SBU priority are worded the same. I am presently on Solar First should I change it to SBU then?

No If there is no utility SOL is fine.

Program 5 there are two user defined. USE and US2. US2 it says suitable for lithium batteries when not using BMS cables. I am assuming then this is the program to use?

Yes I guess US2 is the better option. (I wish Growatt would explain this better).

Program 12 and 13 don't apply as no utility correct?

Correct.



This is the key set of specs we need to know:



Since the max charge voltage is 54.75V, we should set the inverter to something slightly less than that.
In my previous post I said 53.25.... but lets bump that up to 53.75.

Program 19: C.V. charging voltage If self-defined is selected in program 5,
Set this to the charge voltage the battery instructions tell you to use. If they don't tell you, set it to 53.75V. If you still get OV errors on the battery, drop it down to 53V.

The cut-off discharge voltage is 40.5 volts. we should set the inverter to something greater than that. In my previous post I said 53.25V. Lets take that down to 42 volts.

Program 21: Low DC cut-off voltage. If self-defined is selected in program 5,
Set this to 42V. This is the lowest the inverter will let the battery get before it shuts off power.

Float voltage is not really a thing for LiFePO4 so the ideal situation would be to turn it off. However, since we don't have that option, we need to set it to something well below the charge voltage. My previous post said 45V and that is fine.


BTW: You might find that when you go to set some of the parameters, it won't let you. The best I can figure out is that when there are dependencies between settings you have to set the 'dependent' parameter and then turn the inverter off and back on.... then you can set the dependee parameter. As an example, after you set program 5 to US2, you might not be able to change 19, 20, or 21 till you power cycle.

What I do is go through and set everything it lets me set, power cycle, and try the parameters that still need to be changed. If need be, I'll power cycle and go through it a 3rd time to get the last parameters.

 

[Baja John]

Thanks let me wrap my head around all this. Yes I have no AC back up or utility power available. So 12 and 13 will not apply. Can all this programing be done while the inverter is running on solar and battery or do I need to turn solar off? Just want to make sure don't make a bad mistake.

 

[FilterGuy]

Thanks let me wrap my head around all this. Yes I have no AC back up or utility power available. So 12 and 13 will not apply. Can all this programing be done while the inverter is running on solar and battery or do I need to turn solar off? Just want to make sure don't make a bad mistake.

I am not aware of any requirement to turn solar off...... but it would not hurt if you do.

 

[Baja John]

I am not aware of any requirement to turn solar off...... but it would not hurt if you do.

Ok thanks, think what I will do is get all ready for tomorrow morning. The batteries are on OV warning now. In the morning they will not be and discharged down. Will keep you posted.

 

[TorC]

Doesn't really matter on timing, other than being as convenient for you to shut down for a few minutes as reasonably possible. All you're doing is changing the setpoints of what the inverter does. Change that when you like, and the new settings will take effect as soon as the inverter sees the battery within the range of the new settings.