Hi all

I installed a 50kW Sunsynk inverter with a 60/48 HV Freedom Won battery. From the day of installation the system takes a 1 second dip which in turn switches the clients equipment off. I had FW there and they reckon the batterie is fine, I had the Sunsynk guys out and the reckon all is in order.

Now what in the world can cause that dip? 

10 minutes ago, FrankcF said:

Now what in the world can cause that dip? 

Sunsynk uses high-frequency switching to create a AC sine wave. This design is prone to dipping since it takes time for the control-loop to catch up and tell those mosfets to giddy-up.

Your battery is a tad small for this size installation. You are barely over the 1C battery/inverter ratio. 1.5C is the minimum in my opinion.

Funny enough I have friend with the same problem on a 8kw Sunsynk. Also dips and is undersized (1.275C) on the battery.

@root Is there any way to adjust this or add something to ensure it doesn't switch off the clients equipment?

Edited October 23, 20232 yr by FrankcF
To direct the question

Out of interest do you have both battery ports used ? 50A each port. Maybe you already know this but might be worth the enquiry nonetheless. 

@rootthat 60/48 is more than capable to power that 50kW machine. In fact even a 40/32 FW can comfortably run the Sunsynk 50kW machine.

The amperage rating is way more than 100A. The 40/32 is 100A. So the 60/48 is a larger capable beast. 

@FrankcFhopefully you get this sorted....

 

Why on earth Sunsynk or Deye decided on split battery ports & 2 BMS comms ports. Then further to this separate battery buses when you parallel. Tells me there was some development issues that the hardware could not handle. 

@Steve87, We did it all, tried it all, to no avail. It still drops the clients sensitive equipment with that split second dip. Our last and final option is to add UPS's between the sensitive equipment and the Inverter. 

 

On another note.

Seems like I love getting into issues with 50kW Sunsynk inverters. 

This time, I have two in parallel. Each with their own 200/160 Freedom Won HV Battery. This time all is running like a dream, except the freaking App. It does not allow me to set parameters nor is it reading correctly. I have unbound the loggers and registered them both again to no avail, both inverters online constantly shows faults, but on the inverter itself it runs like a mouse with slippers. .... Words fail me guys  

Edited December 12, 20232 yr by FrankcF

Hit and miss I'm afraid...At least your other 2 are working well. The Sunsynk app is crap use solar assistant. You won't be sorry. 

Edited December 12, 20232 yr by Steve87

Good day 

I have two 50KW sunsynk inverters in parallel with 1 60KW synsynk battery pack on eatch inverter working separately everything works perfect but i cant use the limit to load option. My CT's is correct but now when ever the grid shows then its exporting to the grid and the timer option does not work aswell the system is supposed to use battery to 30% but the batterys does not go lower than 90% if you guys can help that would be awsome

After all was said and done, we got it sorted last night at 23H45. Site is running like a baboon with a stolen banana. 

Thank you all for your assistance and guidance. 

@Steve87 I will give that APP a go. Thank you

@FrankcF how did you manage to get the "dip" issue sorted?

@Moffat, A few comments up, I mentioned that we tried everything to no avail. Even power factor did not help. So we opted on UPS's for all the super sensitive equipment

1 hour ago, FrankcF said:

@Moffat, A few comments up, I mentioned that we tried everything to no avail. Even power factor did not help. So we opted on UPS's for all the super sensitive equipment

That’s a bit sad considering Sunsynk and most inverters tout fast switching in the event of grid outage and also that “Essential Loads”, shouldn’t suffer from this issue. Other less renowned brands have their own gremlins, as no product is perfect but don’t seem to suffer from this particular issue. 

On 2023/12/13 at 2:01 PM, FrankcF said:

@Moffat, A few comments up, I mentioned that we tried everything to no avail. Even power factor did not help. So we opted on UPS's for all the super sensitive equipment

I have a site where there are a few Lathes and Milling machines CNC and all I am running at a load of roughly 22-32kW.

There is continuous dips in power only to be seen on the lights. However if the grid fails then there is a sudden drop out of the system however recovers after a few minutes.
Would the option of adding a PFC to the system help at all?

58 minutes ago, Evan9707 said:

I have a site where there are a few Lathes and Milling machines CNC and all I am running at a load of roughly 22-32kW.

There is continuous dips in power only to be seen on the lights. However if the grid fails then there is a sudden drop out of the system however recovers after a few minutes.
Would the option of adding a PFC to the system help at all?

What size system do you have installed with what batteries?

On 2023/10/20 at 1:38 PM, FrankcF said:

Hi all

I installed a 50kW Sunsynk inverter with a 60/48 HV Freedom Won battery. From the day of installation the system takes a 1 second dip which in turn switches the clients equipment off. I had FW there and they reckon the batterie is fine, I had the Sunsynk guys out and the reckon all is in order.

Now what in the world can cause that dip? 

@Steve87 @Moffat @MikSA @root Guys, I had a lengthy debate with the director of technical at Sunsynk and it turned out well. They had one of their top techs log into the system and do a thorough check into the backends, which us plebs can't access. Here is their feedback

Findings on the practice.

• The battery profile is not setup correctly , the nominal voltage for this battery is 411Vdc , yet the battery is only charging up to 331Vdc @99SOC , Please contact freedom won to log into the battery and check as well as update profile and adjust the battery profile.

Now I have to contact FW AGAIN, and ensure they go out to site and let me know what they can do to resolve the issue. (Note, FW has logged into this battery multiple times and have always assured me they find no fault) 

@FrankcFtypical explanation from Sunsynk....

FW have 2 battery profiles for their HV series of batteries. One is Atess HV and Sunsynk HV. Atess has 2 options for HPS and PCS. HPS uses High Voltage but lower VOlatge than the PCS. The PCS uses the HV+ battery which supports higher voltage range. 

My point is that FW only has a single Battery profile for Sunsynk. The voltage range is constant not as the Atess which has 2.

@Evan9707 You needed a Transformer based Low frequency inverter because you have High inductive loads. Typical of the Sunsynk is that is it High Frequency and this is not well matched for these loads. 

The magic is in the large transformer on the Atess Equipment...It makes the load not drop, the load stays Uninteruppted.

Inductive loads have inrush(surge) currents typically 4-10X the run current. Best to measure inrush current with a meter that has the INRUSH function. Size inverter accordingly.

HF inverters have no meaningful surge capabilities in most cases. They don't have the large transformers present in LF units, and can't do it. Their surge ratings are often for an AC cycle or two (1/50th of a second).

If you don't want to live with regret, you size an HF inverter to accommodate the entire inrush surge within it's continuous rating.

10 minutes ago, TaliaB said:

 Their surge ratings are often for an AC cycle or two (1/50th of a second).

If indeed only for 1 cycle would you feel if they quote the maximum as 2 x for 10 sec that they would not be able to deliver it for this time? 

Here I refer to specs for a high frequency inverter. 

@Steve87 @Evan9707

Completely agree with Steve on the Inverter Spec. 

Another option could be to install VSD's to all the high inductive equipment. 

32 minutes ago, FrankcF said:

Another option could be to install VSD's to all the high inductive equipment. 

I think this is the only way to go for now. The VSD will provide a lot of relief...

@FrankcF thanks for the feedback. I think a lot of the end users who are not "technical" tend to then have issues because:

1. When manufacturers (battery or inverter) say, "all is well", they tend to be people who are just passing on the message;
2. Sometimes if it's "over the phone", there's no documented evidence that the person ever said such a thing;
3. Finally the sad part, which is the greater, is the amount of time spent, trying to get someone knowledgeable on the manufacturers side, to look into the issues that may be raised, which is frustrating to both the installer, reseller and end-user.

Now talking of inductive loads, a 50kW system is quite large, relative to the average domestic household, but how then would this issue be addressed in the domestic scenario where a household has 5kW Inverter and likely a FW small battery but having an induction cooktop running of the system?

Edited February 6, 20242 yr by Moffat

@Moffatthe small inverter will likely suffer the same type of issues. However, from what I have observed its mainly 3 phase motors that cause these issues. How an inductive cooker compares unfortunately, I have no relevant experience. 

From what we have observed this is becoming quite a talking point & what's more is that The Sunsynk Containerised solution also comes with a disclaimer of no heavy 3 phase motors for it's use. They specify its mainly to be used for office parks as office parks don't deal with industrial 3 phase heavy equipment. 

A dead give away that the design is transformerless in architecture. Would be great to see what that 50kW Sunsynk looks like inside. They unfortunately do not expose anything & it's a sealed unit. 

 

 

9 hours ago, Steve87 said:

@Moffatthe small inverter will likely suffer the same type of issues. However, from what I have observed its mainly 3 phase motors that cause these issues. How an inductive cooker compares unfortunately, I have no relevant experience. 

From what we have observed this is becoming quite a talking point & what's more is that The Sunsynk Containerised solution also comes with a disclaimer of no heavy 3 phase motors for it's use. They specify its mainly to be used for office parks as office parks don't deal with industrial 3 phase heavy equipment. 

A dead give away that the design is transformerless in architecture. Would be great to see what that 50kW Sunsynk looks like inside. They unfortunately do not expose anything & it's a sealed unit. 

 

 

@Steve87 so on top of all the other issues with transformerless designs, the next question would be to see how many of these units actually make, in longevity to or past the warranty stage. Off the top of my rocker, am just imagining switching on an Induction Cooktop to make a cup of tea, the fridge motor then kicks in and also maybe a 0.5hp water pump. If one has LED lights, they're likely to possibly flicker but long term what then happens to sensitive equipment like laptops or desktops. Makes sense now why on the warranty form they say: "The product is not suitable for supplying or running life-sustaining medical devices..."