to be honest i feel its not correct .. 
it should not actually do this.. some technicalities .
Target voltage on the inverter is not what is achieved -- battery defines what it needs and inverter should follow but there is a voltage drop on the cable .

battery should stay retained in voltage for internal loads etc ... inverter does not do this correctly .

battery max soc cannot be set meaning it cant charge to 80% or 90% and stop ..it aims to reach 100% not good ..no flexibility 

micro cycling .. should it happen.. no if you have enough pv you solar should drive the loads while the battery is waiting on standby ..

The big questions are 
do you have more then 4 pylontech batteries as the inverters seem to be limited to 30amp charge i stand to be corrected ... in which case you back to using the manual setting ..

I have changed over to using a 5000es with canbus and find it wiling to charge at max rate correctly .. but not on a pylontech battery on my own with our in house bms .

So there are draw backs but if you are using two batteries this would be okay . as a charge rate of 15 amps per battery is normal .. but a max charge rate of 30amp when using rs485 is not .. and seems alot of users face the same issue .

I've been following this discussion with interest.

It seems to me that the fundamental problem is that the Growatt Inverters always deliver Solar power VIA the battery.

I don't know if that is what's going on, but it certainly sounds like it.

The power it needs to keep itself running is also definitely taken from the battery. That's been confirmed by Growatt, so that's a constant draw on the battery, and if you are running without Solar and on Mains bypass you can clearly see your batteries slowly deplete to around 95% SOC over a consistent period of time (6 hours in my case with 2 x US3000) and then get charged backup to 100% in short period (20 mins or so in my case) and then the cycle repeats. And that's purely because of what the inverter itself is drawing from the batteries.

The inverter seems to have no bypass that allows Solar input to get to the load without it first going via the battery?

I don't have Solar hooked up yet, but from what I'm reading the problem there seems to be directly related to the fact that Solar always seems to goes via the battery. In other words, when you are "powering your load from Solar" I don't think you actually ARE powering your load directly from Solar, you are actually powering your load from the battery, which is immediately being replenished by Solar?  And that's why when the battery gets to 100% it cuts the solar off, to prevent overcharging that battery, because effectively you are in a position at that point where the Solar being generated is MORE than you need to compensate for what the load is drawing, and there is nowhere else to put that excess Solar generated energy because the inverter isn't capable of sending it "directly" to the load without the batteries involved.

Is that accurate? Or is it actually splitting the Solar input to:

1. Feed the load directly via a battery bypass circuit.

2. Charge the battery at the same time on the side using any excess?

If I'm right, then the whole issue with Solar really just comes down to:

"The inverter isn't expensive enough to include what it would need to convert the incoming Solar DC to the required clean AC on-the-fly via a bypass circuit, and also divert excess to the batteries to charge them, and to also stop charging them when they are sufficiently charged and simply allow the excess Solar generation that's available to be lost and wasted."

I just get the distinct impression that the Solar implementation on these Growatt's is very basic and simple and will get the job done but is not using any intelligence to be as efficient as possible and protect the batteries as much as possible.

And maybe that's ok if we consider the price point and what you are getting for that price. They really are not very expensive given what they CAN do, in one device, even if what they can do isn't necessarily what we would all like them to be doing.

The Growatt 5000's also can't blend power sources, so that's another limitation that something like a more expensive SunSynk can do effectively (costs about 10 to 12K more than the Growatt).

All very interesting though.

I will probably go Solar fairly soon and right now I'm considering selling this Growatt and buying a SunSynk instead just to avoid the Solar related headaches and also because their UI and software is better.

 

 

 

 

 

 

 

14 minutes ago, SiliconKid said:

I will probably go Solar fairly soon and right now I'm considering selling this Growatt and buying a SunSynk instead just to avoid the Solar related headaches and also because their UI and software is better.

Keep the Goodwe and Victron stuff in mind also. Goodwe seems to be performing well for many and Victron obviously offers a lot of flexibility. I cannot be happier that I got rid of my Growatt and got a Victron instead.

so fair is fair ...
I say this because ive done some more testing research and digging .
I have been provided the latest 500.80 firmware that does stages of indicative charge CC CV and FC

Constant current, Constant voltage and float charge if the term has any lack of definition as many say lithium cannot be floated but does have a open Terminal voltage to be maintained..
So using rs485 we charge up to 100% and then solar pv switches off and waits till we reach 94.9% then turns on again ... all the mean while long battery and inverter is carrying the loads .. TOTALLY WRONG .
shouldnt be doing this .

Its purely a firmware issue only way around it is go back to standard USE setting and use the predefined target Bulk voltage and float as a (MARKER) let the voltage drop and the inverter solar knows it should power the loads .

a secret.. the 5000ES can run with no battery connected .. is a high voltage mppt (450VDC) input .

And better yet .. works well on the lithium setting and leaves solar on with the correct settings .. to be confirmed with pylontech .. maybe a user can chime in but it should work with out floating the batteries to high and keeping solar on ready and waiting when loads are being powered .. So far seems to work well on my end solar not turning on and off and batteries are kept charged with minimal current passing either way .

PS to respond to siliconkid .
. Charge the battery at the same time on the side using any excess?

Yes this is the way it should work .. pretty much like victron Mppt waiting to ramp up when commanded to do so to carry the loads and or meet the target voltage using current and maintain it .
The inverters are capable of doing these things .. the problem is with the firmware and getting it made correctly . 

There was another forum member @willietes, who was working with Growatt to resolve the FW issues, but havent heard anything from him since posting that he had the FW and testing it.  

This is also why I am saying that we should be hounding Growatt/Mahone with emails indicating the issues we are seeing. 

i am in talks with them big time . but sadly the language barrier is bad and getting them to understand what is required vs what they feel the system should be doing is two different things ..

still i keep on with it lets see where it takes us .

8 minutes ago, Zimnismoboy34 said:

i am in talks with them big time . but sadly the language barrier is bad and getting them to understand what is required vs what they feel the system should be doing is two different things ..

still i keep on with it lets see where it takes us .

Yip, same here. Its an on off situation. Today they dont understand, but tomorrow we try again and then he gets what I am saying, disappears for a day or 3 and then comes back with a semi answer!

Hi All. So I am still trying to make sense of this 95% 100% SOC charge micro cycling explained here. I stumbled onto this: https://marinehowto.com/lifepo4-batteries-on-boats/ as provided by another thread: 

 

 

In that article (I did not read the whole, long thing so might have missed other info...), if you search for "DURATION AT TARGET VOLTAGE (Over-Absorbing):", you will see that keeping a LFP battery at 100% SOC at the absorption stage (constant voltage) for a long time (like what is done with AGMs or GELs) is very bad and charging needs to be cut, stopped completely at this stage and voltage needs to drop lower. They should not be kept in float. As @SiliconKid mentioned, these inverters cannot power the load from solar without going through the battery (I assume the inverter does not have the ability the sync with the utility and blend power - therefore you need the battery to help the solar panels provide as stable output), therefore we are now in a state where the MPPT cannot give any more current to the battery, cannot bypass the battery, and therefore needs to shut down completely. Everything starts back up as soon as the LFP battery's voltage reduces to safe levels again. 

Anyway, so to me it seems to be ok - if I understand it correctly. I am still curious as to how other (cheap) inverters handles this situation. It looks as if they should do the same, except if they can blend utility and solar to power the load without batteries (like the 5000ES)

 

I can now comfortably give my 5cents of opinion on the 100-95% matter as I have substantially researched this topic.

Research shows that keeping the Li battery at 100% float is the WORST thing one can do to the battery. The cycling is the doing of the BMS and not the inverter. It is the way the battery is intended to be run. Not as the majority do by setting user setting so that the inverter overwrites the BMS.

Simple example of a laptop- if I set my Asus laptop to max battery life on the battery optimiser it charges to 100% then cycles between 90 and 100 while plugged in.

Batteries need to work,not stay at float. This is the normal practise.

 

I think the problem is rather that the inverter can’t blend power sources. Hooking a battery up to an inverter will always cause the battery to work, it is (in most instances) the power supply of the inverter.

However, it seems the Growatts are using the battery to actually provide solar to the loads, indirectly. It should be perfectly fine for the inverter to draw its self consumption (once it is charged) from the battery and invert the excess PV to the loads. It is still using the battery. Otherwise I am sure Victron would put lots of warnings on its “keep batteries charged” option.

My personal opinion is that inverters, which can’t blend power sources, should only be used in off-grid situations. It makes no sense to have an inverter, connected to the grid and PV, that needs to power all its loads at any given time from one of the two. It will always underutilise the PV.

14 hours ago, Johan-Henry said:

So I am still trying to make sense of this 95% 100% SOC charge micro cycling explained here

 

2 hours ago, jykenmynie said:

I think the problem is rather that the inverter can’t blend power sources.

I think some of it has to do with the canbus communications with the battery. In later discussions, it seems these Growatt inverters work fine with the same  battery, as long as you set the settings in some way, or if there is no comms.

Now this is a field I know a little something about. Some of these managed batteries do current control. They instruct the inverter to charge or disharge by a certain amount. Quite often these batteries will send a zero when they want the inverter to stop completely (eg when the battery is completely full or completely empty), in Victron speak we call that the DCL (discharge current limit) and the CCL (charge current limit).

The DCL=0 case is mostly uncontroversial. Pylontech batteries, for example, send this before the battery is completely empty, and that way it protects itself from very deep discharges and so prolongs the life of the battery.

The more problematic case is when the battery sends CCL=0. Then the kind of toplogy of your inverter, and how your PV is coupled, comes into play.

As one example, imagine an SMA system. All your PV is tied on the AC side, using SunnyBoy grid-tie inverters. Then you have a SunnyIsland inverter connected to the battery. This inverter charges the battery and listens to the CAN-bus BMS on the battery. If the battery says CCL=0, the inverter can do that. It does not affect the delivery of PV at all. That's tied on the other side, flows normally to the loads, and out onto the grid if not limited.

Or consider a Goodwe. The PV connects directly to the high voltage DC bus, in other words even though it is a hybrid, the PV ties onto the grid in a very similar manner to the SMA example above, on the high voltage side. It can take the battery current right down to zero and just leave it there, without affecting PV delivery at all.

But now consider the cases where the PV is DC-tied, which is the case with this Growatt and also with many Victron systems. This is what you could call a "push pull" system. The DC chargers push current into the DC bus (and the batteries), and the inverter takes current from the same. If the load and the PV does not quite match, the remainder naturally comes from the battery.

Now imagine trying to do current control in a setup like this. With a hybrid inverter, some of that is possible. You can mix in some grid power in order to comply with a lower DCL, and you can limit solar chargers to comply with a lower CCL, but the basic problem remains: That in a DC-coupled setup, the battery is an integral part of the power delivery mechanism, and a complete zero situation is never going to happen.

Now I get to my point: I think these troubles start when batteries designed for one kind of ecosystem (the current-control world) is used in the other ecosystem. The battery says CCL=0, and so the inverter stops all charging (throttles the MPPTs to zero), and then the inverter has no choice but to discharge the battery rather than use the PV. After a while, the battery raises the CCL again (since it is now down to 95%) and suddenly the world returns to normal, for a while.

This gives you that little bit of micro-cycling at the top. And of course you don't want that.

The solution is to not do current control, but to adjust the charge voltage of the battery. If you don't want the battery to charge, lowering the charge voltage will stop that. It's as sure as the fact that water cannot run uphill. But that would be the "other" kind of ecosystem I referred to.

Now some inverter makers have workarounds implemented to bridge these little issues. And I assume, Growatt hasn't got there yet.

Thanks @plonkster for the insightful reply. So for the scenario where you would want to use the Growatt SPF5000TL with a Pylontech stack (max charge current limit issues aside) connected to solar and utility, would it then be better for the health of your Pylontechs to:

• Leave BMS disconnected, set appropriate voltage levels so that everything is voltage controlled - thereby giving up on an accurate SOC reading but avoiding micro cycling
• Connect BMS and endure some micro cycling on the top end 
• Avoid the Growatt SPF5000TL - LFP combo until they have sorted all of this with some firmware workarounds

7 minutes ago, Johan-Henry said:

would it then be better

I can't say. What I can say is battery makers provide a shorter warranty when not used with a Hybrid inverter. Drop the Growatt, install a Multiplus. Problem solved 🙂

33 minutes ago, Johan-Henry said:

Leave BMS disconnected, set appropriate voltage levels so that everything is voltage controlled - thereby giving up on an accurate SOC reading but avoiding micro cycling

I am fairly sure that even on US2 mode this dropping of PV also occurs once you reach the float voltage. I have seen it happen once since running on US2 mode, but sure I will be able to confirm it soon once the sunnier days return in CPT. 

I have not had much time lately ..Hence the silence .
However Float and the term float is used very loosely 
Many a lithium battery producer do state a charge CV or constant voltage .
You have  a scenario here that i need to get really deep into .
First factor you have batteries that have components in them that require power .
Second You have a growatt inverter that takes its power from the battery when not charging and in Lithium Float charge stated on the screen as FC. (40w -55w)
With these two you have a parasitic load on the battery that needs retention .

Inverter/Solar tied systems rely mostly on Voltage set points to calculate what to do .
float is used to maintain voltage and match this using the Solar charge controller .
You charge the battery to x and float at Z creating a minimal potential voltage difference where (lead acid needs some current to maintain it in Float ) And lithium doesnt need current going into the battery but does need to be matched with open cell voltage to retain the charge .

So with out drifting to far into detail .
GRowatt Axpert Votlronic all use voltage set points till now and then essentially charge up to .. and drop down to float once charge is reached correctly .

The Voltage set point means that once solar has charged up when a load is applied on the ac side the inverter tries to match this firstly with solar .. why because the voltage set point is lowered due to the load created on the ac side the dc falls . So having a Set float marker voltage is ideal .. the inverter knows when solar needs to jump in as this is a primative and basic function of the Axpert growatt inverters etc .
Victron is a communication network eco system with all talking to each other vebus and ve direct to mppt and bms to battery and can essentially control all using this well co ordinated network .

Back to Voltronic/Axpert/Growatt ..

So float is a target voltage and believe it or not alot of the SA lithium batteries use floats that are close to 3.5v per cell ..... think about that .. comment if you wish .

So moving back to the aim . Float to cater for parasitic loads is not a bad thing if its close to 100% soc and the voltage is close to Open cell voltage when full .

So whats the next step if this means a voltage of 3.3v per cell then so be it accordingly to your research etc .
With no potential Voltage difference and even with a CCL of 3 amps you will get no current flow at this voltage .

so floating lithium cells with the correct settings is not a BAD thing .

Next we move onto why in heavens name GRowatt does what it does ..
So the firmware charges up to 100% . Turns off solar on the 5000TL but on the 5000es doesnt ..
meaning you can actually run off solar if the load is not too great or more then the solar production . IF it is indeed more then solar it will use battery and then at 94.9% soc charges the battery back up again .
Wrong on all accounts .. why ? because if the battery was maintained correctly using the correct CVL charge voltage limit and the inverter followed this like it was supposed to we wouldnt have this mess.. 

 

I have a Growatt SPF 5000 ES inverter  with a US3000 pylontech battery and its giving me BMS error, please assist with Firmware updates. [email protected]

On 2020/08/25 at 2:12 PM, Zimnismoboy34 said:

so fair is fair ...
I say this because ive done some more testing research and digging .
I have been provided the latest 500.80 firmware that does stages of indicative charge CC CV and FC

Constant current, Constant voltage and float charge if the term has any lack of definition as many say lithium cannot be floated but does have a open Terminal voltage to be maintained..
So using rs485 we charge up to 100% and then solar pv switches off and waits till we reach 94.9% then turns on again ... all the mean while long battery and inverter is carrying the loads .. TOTALLY WRONG .
shouldnt be doing this .

Its purely a firmware issue only way around it is go back to standard USE setting and use the predefined target Bulk voltage and float as a (MARKER) let the voltage drop and the inverter solar knows it should power the loads .

a secret.. the 5000ES can run with no battery connected .. is a high voltage mppt (450VDC) input .

And better yet .. works well on the lithium setting and leaves solar on with the correct settings .. to be confirmed with pylontech .. maybe a user can chime in but it should work with out floating the batteries to high and keeping solar on ready and waiting when loads are being powered .. So far seems to work well on my end solar not turning on and off and batteries are kept charged with minimal current passing either way .

Hi Zimnismoboy34, please share the latest 500.80 firmware for Growatt inverter, having a BMS error. [email protected]

Hi there .. this firmware wont work with your model i got the digits slightly wrong its 500.08. 
The firmware will only work with the 5000TL HVM

21 hours ago, Zimnismoboy34 said:

this firmware wont work with your model

I'm a noob 👶 when it comes to Growatts; could you briefly summarise the difference between the ES and the TL-HVM, please?

May I ask, previously a few pages back there were some settings that meant you didn’t get the micro cycling issue but didn’t have as much info soc etc.

would those settings be better for the health of the battery? I know the growatts have drawbacks but if you could keep the batteries functioning well then it should be such a big issue?

I can't get my Axpert King to hook up with the Pylontech properly yet.

so it reads I need a cross-over cable and put it into the CAN port then set function 05 battery type to PYL.

Done. but not working. I get an Error Fault 32 after a few minutes. "Communication Interrupted".

Hi All, this thread has been really helpful, I was one of those with a USE config instead of the BMS doing its thing. My setup is just to alleviate the cuts in my area - we get a lot of faults as the municipality is growing really fast and nothing being done about the infrastructure. No Solar at this stage as I am renting but when I buy again will add solar. 

Anyway my install was done in June this year. Growatt SFP5000TL HVM-P and 2 x Dyness 3.6KW LI Batteries. I don't have the new firmware yet as I was only added to the forum yesterday but I went home to try the suggestions. My Dip Switches were incorrect so I fixed that and restarted the whole system, then I selected Lithium and 1 and the little LI icon has come up and is solid and I now have a battery SOC percentage. The firmware on the unit is 500.07/002.00/null as per the shine phone app. 

Some questions please:

1) Do I still need to do the FW update? If so please would someone share the files with me.

2) My Shinephone app is no longer consistent, I find the device showing as offline a lot of the time. Is this a firmware issue linked with the change to using the BMS?

3) Is it possible to change the config of the unit using the shinephone app? I tried the control tab on the app and it asks for a password to make changes, I cant find any record of this password in any of the documentation I was provided.

Appreciate any advice.

6 hours ago, ThomasSage said:

3) Is it possible to change the config of the unit using the shinephone app? I tried the control tab on the app and it asks for a password to make changes, I cant find any record of this password in any of the documentation I was provided.

Yes, the password is growatt + the current date i.e. growatt20200902 - got that info off here: https://gathering.tweakers.net/forum/list_messages/1984968

 

19 hours ago, capkasa said:

so it reads I need a cross-over cable and put it into the CAN port then set function 05 battery type to PYL.

I believe you need to connect to the RS-485 port of the Pylontech, NOT the CAN port.

Also, the cable is non-standard, not even cross over. See other replies for the correct pinout of the cable. You may also need to update your firmware, unless you are already running at least 71.92 (main U1) and 02.40 (removable display / BMS, U2).

[ Edit: this topic is for Growatts; not the same as Axperts, though there are many similarities. ]

Edited September 2, 20205 yr by Coulomb