nightbyte

The battery compatibility sheet I sent you suggests that the Sunsynk be set to operate on voltage only. This suggests to me that the Sunsynk and Shoto's are not comms compatible. Dip switch settings are I think correct for the Shoto 4.8 kWh 15S battery, but not for the 5.12 kWh Shoto battery which is a 16S unit. My 2 Shoto 4.8 kWh 15S batteries use the dip settings 1-master, 2-slave and I have not experienced the alarm and tripping issue you mentioned, but then I do not have a Sunsynk inverter and my system is set to use voltage. The battery audible alarm beep (momentary) is normal on boot up or reset of the Shoto. I suggest cut cables as suggested by Jumper, or set to voltage as suggested by Sunsink, or try dip switch settings as used by the Shoto 5.12 kWh 16S battery. Jumper provided the 16S manual with his post.

Oops sorry, Sunsynk

Good day to you Boatmaker, I see Jumper has replied to your question. It is worth trying what he has suggested. Please post the results on this website. I have attached a Sunsink compatibility list from Sunsink, nevertheless I think it is still worth trying out jumper's suggestion. Battery Compatibility .pdf

RSA representative for Shoto batteries is : [email protected] He has answered E-mails from me in English. Give him a try. Regards nightbyte

Suggest you request advise from the SA importers of Shoto batteries: Email address: Shoto Batteries South Africa (importers) [email protected]

Good morning to you gtheophi. Your existing batteries are 15 cell the 5.12kWh battery is a 16 cell, so there are internal differences and the BMS is unlikely to be identical. If you intend to link the batteries with communication cables, as master and slave as indicated in the the Shoto installation guide, there will be issues. The settings for the 5.12kWh battery are quite different to that of the 4.8 kWh battery, and the chance of not being able to fully utilise the full capacity of the 51.2 kWh is most likely. As a BMS is essentially the safety guard for your batteries, it is in my opinion that anything that compromises this would amount to an unsafe system. So in summary: It would be unsafe, in my opinion. You would not be able to fully use the capacity you have paid for. There would be issues in communicating between the two battery types. Your battery warranties would also be placed at risk. The 15 cell SDA10-48100-L5 batteries 48V (4.8KW battery) is still available in the RSA from various sources at competitive prices (for example, West Coast Solar). Perhaps other members of the Forum would also be kind enough to give their views as this issue must affect a number of Forum members. Kind regards Nightbyte

Good day to you Wendl, I need to ask you a few questions to be able to understand your difficulties. I hope you don't mind. Did you receive a Shoto manual with your battery? The Shoto 5.12kW has a specific set of communication requirements and switch settings listed in the 5.12kW manual. That would be the first step to comply with, and may resolve the communication issue. If you did not receive a manual, there were copies on the forum a little while ago. For the moment running on user mode is fine, until the other issues are resolved. Your battery is a 16 cell and has a charging profile of 54.0v to 56.4v The maximum safe setting for voltage is 56/16 = 3.5v per cell. I suggest you check your inverter's existing charge settings and then adjust in the range 54.0v to 56.4v. A lithium battery has a very flat charging curve which becomes very steep towards battery full condition. the difference between 85 and 100% full is less than a fraction of a volt. Most batteries have reached their full potential at around 85% and there is very little to be gain by going higher. Also lithium's can deteriorate if held at 100% capacity, the ideal maximum is just below 90%. holding at higher levels will reduce the battery's life span. When loadshedding kicks in you will notice a sudden and steep drop in capacity as the battery comes down from the steep end of the charging curve. As I mentioned a drop of 1 volt will cause the a rapid initial loss of capacity, thereafter on the flat part of the curve a gradual decline. That is why charging to above 90% has no real benefits. Your error 4 is likely to be resolved by correcting the comms issue, see what the Growatt manual says about that specific error. Kind regards nightbyte

Float setting a lithium battery? Extensive load shedding and the likelihood that this is the new normal have required a review of my current Axpert inverter and Shoto battery settings. Questions: Should a float voltage be set for my 2 x 4.8kw lithium batteries? Is it correct that float is only used in lead acid and gel type batteries? That a charge voltage of 52.5V = 3.5v per cell for a 15 cell battery, is equal to 95.6% of the battery’s capacity and is the correct setting level for both float and bulk charge voltages in a lithium battery. That you don't need to set a different lower float voltage, as it will reduce the usable capacity of the battery bank. The safe charging voltage (bulk charging) of a lithium battery is 3.5v per cell. While this can be increase it has consequences on cell life and is prevented from exceed a pre-set BMS value. Charge settings (CV): Shoto has a BMS set protection value of 3.65v per cell. At this value the BMS shuts down and will then only allow charging to restart when the 3.5v per cell is level is again reached. Thus 3.5v per cell is the maximum, normal safe charge setting for the 15 cell Shoto battery. While the battery charge may vary around the 3.5v per cell setting momentarily due to cloud, shade and inverter tolerances this will be slight and should never get anywhere near the protection value of 3.65v per cell. In my case I see values of 3.41V to 3.52V. Float settings: I have often wondered why the Shoto lithium battery manual never mentions a float charge, while the Axpert King expects both. Lithium batteries have a totally different chemical composition to the lead acid and gel types. Lead acid and gel types definitely must have a float setting. Consequently, this would seem to have been provided for such batteries, and not necessarily for the lithium’s. A charged lithium, with no draw off maintains its charge state, unlike the lead acid and gel types which lose charge state even with no demand. You can set a float value for your lithium’s without damage to them. However, the consequences are a reduction to the full charge capacity. When preforming a bulk charge from a low charge state, well below that of the float setting value, batteries will be charged to the bulk charge value and then stop charging. Charging of the batteries, after power draw off will then recommence once the charge level has dropped below the float setting value and charge the battery back up to the pre-set float value – not to the bulk charge setting value, reducing the full charge capacity of the battery bank. Measured values based on my system settings: Maximum cell voltage 3.65V per cell 54.75V for 15 cells 100% capacity BMS Shut down Bulk charge voltage 3.50V per cell 52.50V for 15 cells 96.0% capacity Normal operation Float charge setting 3.50V per cell 52.50V for 15 cells 96.0% capacity Normal operation Lower float setting 3.45V per cell 51.80V for 15 cells 94.6% capacity Reduced capacity Change in battery bank capacity for a 2.5hr load shedding period: Float charge setting 3.45V per cell 51.80V for 15 cells Capacity left in battery 27% - DOD 73% after 2.5hrs Float charge setting 3.50V per cell 52.50V for 15 cells Capacity left in battery 33% - DOD 67% after 2.5hrs Figures are based on my system usages, your demand values could differ. Please comment and see if you have a similar outcome. Special acknowledgment and thanks: Based on the excellent work of Andy, on his website on You Tube, “The off-Grid Garage” Andy has done some great work on this topic and others. @OffGridGarageAustralia Website: https://off-grid-garage.com

KGS could you please provide a bit more backround on how and when this occurs. Generally, the built in and factory set Shoto - Battery Monitoring System - (BMS) will do this to protect the battery at a predetermined low voltage over which the user has no direct control. The inverter also has settings, which allows you some control over charging, voltage cut out, and alarm points. Without knowing more about the specific incidents you refer to, it is difficult to be more specific in giving advice. However, that said, I would first study your inverter's manual, which should guide you on the correct settings. I do not have a Growatt inverter so I do not know its cut off, and back to system settings. Also check the Shoto manual which has guidace on the minimum voltages, that if exceeded will see the BMS kick in to protect the battery. Providing the inverter is not defective, it would seem that you have a setting problem. Request a forum member with a Growatt inverter to assist you with their settings, would be the place to start.

Good morning (again) SuperStan, Ok, so it's not the battery 🙂. Check the wiring into and out of the inverter, tightness of lugs and earth-wire battery and inverter connections. Also check inverter programme settings. Has the inverter reported a specific fault on the LCD display? Check the mains supply to the inverter and breaker on distribution board, does the mains supply have an earth leakage and does it trip? Could you explain how you corrected it previously. The fact that you overcame it previously suggests that it could be a programme setting or external supply / demand issue. Finally check the inverter output is not connected to something that is momentarily drawing too much power.

SuperStan what is you location?

Good morning SuperStan, I would like to suggest, as a first step to identifying the cause of the problem that you do the following: Disconnect the battery leads at the battery and measure (with a multi-meter) the battery voltage. It should be above 40 to 43 volts. If not, the system will display symptoms as you describe and you will need to charge the battery. If you do not have a solar input you will need to return the battery to the supplier to charge up or perhaps take it to a friend or a Forum member who stays near you to place on charge from their system. If the battery will not take a charge return it to the supplier as the problem is in the BMS. If however the battery state of charge is above the BMS cut-off voltage then the fault lies within the inverter. Check your connections to the inverter and if correct and system continues to shut down, return the inverter under guarantee to the supplier for repair. I am not an expert on these systems, however this is how I would approach this problem. Please post your results to this Forum topic thread, so that we can all gain from your experience, good luck - Nightbyte.

I have reduced my setting 02 to provide a maximum charging current of 20 Amps. The Axpert inverter programme (setting 02) states: max charging current = Utility charging (programme 11) current + solar charging current. So set 11 to 10Ah, then 10Ah + ? Ah = 20Ah (set in 02). Thus 10Ah + 10Ah = 20Ah maximum charging current. Did this to reduce charging load and inrush current on inverter capacitators. Should also prolong battery life (I hope). Have not experienced any negative results and system still recharges in about 3 to 4 hours after load shedding with batteries at 70% DOD and a draw off load of about 400watts. Comments please ?

Good day to you Vanfam. Thankyou for contributing to this Shoto thread. Firstly 52.5v is a conservatives setting well within Shoto's recommended charging values and is extremely unlikely to harm your LI battery. The battery LED lights are an accurate gauge of what is happening, as they are directly part of the BMS inside the battery. My experience is that the inverter's indictor bar graph display is not nearly as accurate and just give a general indication. For example when your battery is fully charged and in float mode battery LEDs will be off, except for 1 (far right) which should just flash, about once a minute indicating that the battery is in float charging. Here what I suggest you try. Use a hand held multimeter set to about 75v or more on the DC range and measure the battery voltage directly at the battery terminals, red to positive, black to negative. Do this for the different battery led light displays and record the voltage at 4,3, and 2 LEDS also when only 1 LED is flashing in float mode. These are the real voltages in your battery (SOC). Now compare these to the inverter bar graph display. The inverter charge state bar display has been reported by other users and has a reputation for inaccuracy when in user mode for Lithium iron batteries. I believe that Axpert inverter software was originally configured for non lithium batteries, and while the inverter works perfectly with Lithium batteries in the user mode this inaccuracy of the indicator battery indicator bar may be a hang over from the sealed battery period. I too was originally confused by this conflict of display conditions. I performed the multimeter testing at different conditions as suggested above until I was satisfied with what was the real voltages in the battery compared to the bar graph on inverter. Incidently the inverters load measurement bar graph appears to be accurate and believable. Charging current: I have 2 batteries and used 40Amp and have not experienced any alarms. Yes, 20 amp is probably fine. The Shoto battery manual says charging current setting +/- 1C3, which I take to mean 33.3 Ah. The Axpert inverter programme (setting 02) states: max charging current = Utility charging (programme 011) current + solar charging current. If you set 011 to 10ah, then 10Ah + 30Ah = 40Ah (as in setting 02). In your case 10Ah + 20 = 30Ah. Tired of having to multimeter the battery terminals I have installed an inexpensive digital voltmeter (fused) adjacent to the battery bank which allows me read directly the battery voltages at the flick of a switch. The inexpensive digital voltmeter was obtained from Communica, Cape Town and works well. Further, I strongly suggest that you install the Axpert PC monitoring software that you should have received with your inverter. if you experience issues with this software as I did approach Mecer Cape Town Technical Support. They were excellent and provided me with working updated software (ask for Craig). Please provide feed back on your experiences. Regards.

Thankyou for contributing to this group. This is a rather unusual question and one that I have only limited knowledge and experience with. I have experienced a defective BMS programming issue which caused the battery to go to a very low voltage and then shutdown completely. It then refused to accept a charge and had to be returned under warranty to the supplier. They reportedly re-programmed the BMS and reset the battery. Since then it has operated as specified in the manual. The manual that came with my battery stated that the BMS is provided with the following low voltage protections: Alarm recovery value 43.2v, Alarm value 42v, and Protection value 40v. My understanding is that the BMS shuts down the battery at 40v and places it in a standby mode. To re-activate the battery it must be placed on charge by the inverter and the voltage raised above 43.2v The battery can remain in the standby mode for sometime (the manual suggests 6 months and then needs to be re-charged). My inverter's low cut off voltage is: Setting 029 Low DC Cut-Off - 46.7v (gives DOD maximum of 80% on a 48V battery bank). This is well above the BMS values, but that is because I do not want the batteries to drop below 80% depth of discharge and potentially damage the batteries. With my average load of around 450W the normal 2.5 hour load shedding period sees a DOD of 68 to 70%. I am conservative by nature and would suggest a settings below 46V (around 90% DOD on a 48v battery bank) should be avoided as battery life could be negatively impacted. Hope this assists you. Please provide feedback on your experience.