SauRoN's SomeWatt Solar Install

Paul_S said:
I would convert to single phase because one can maximize the output of the inverter more easily. With 3 phase you need to balance the phases which is less efficient as you always have unused capacity on each phase.

e.g.
12kW three phase is 4kW per phase. Let's say you balance your loads and end up with 1kW spare on each phase. Now you decide you need to add a 1.5kW iron/kettle to the load. You still have 3kW spare on the inverter but you can't use it because it's split across three phases. Good luck finding a 380V three phase iron or kettle. :)

With single phase you can use all the spare capacity up the the maximum limit.
Three phase makes sense where one has high power requirements or longer runs of cheaper (thinner) cable.
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Yep, that's true for most inverters, but not Sunsynk's 12K 3 phase. It can do unbalanced loads, up to 12K per phase on grid. Check it out here:

Edit: a 50K 3 phase is also available for those with mansions (and corporates).
 
SauRoNZA said:
Setting the Zero Export to 10W had the desired effect of zero grid usage today…but had the weird result of sending 0.1 kWh back into the grid according to the Sunsynk.

So set it to 15W now to see what it does tomorrow, but I suspect 20W may be the magic number after all.
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or just turn eskom off altogether if you have enough battery cap
 
AfricanTech said:
I have no idea why it's 3 phase - it's an old house, fairly large but not massive.

How easy is it to convert to single phase?
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I would check what your common peak loads are before going from 3 phase to 1 phase.

We had 3 phase and went down to 1 phase but our peak loads were often too much for 1 8kw inverter to handle. So we added a second inverter, effectively back to 2 phase and so far, so good with the peak loads.
 
RonSwanson said:
Yep, that's true for most inverters, but not Sunsynk's 12K 3 phase. It can do unbalanced loads, up to 12K per phase on grid. Check it out here:

Edit: a 50K 3 phase is also available for those with mansions (and corporates).
Click to expand...
oh, that like was not for the 50K, it was for the ability handle unbalanced loads
 
RonSwanson said:
Yep, that's true for most inverters, but not Sunsynk's 12K 3 phase. It can do unbalanced loads, up to 12K per phase on grid.
Click to expand...

Wow! That is impressive and it's actually cheaper per kW than the 16kW single phase Sunsynk.
 
So I had an F56 (Low Voltage) error yesterday during Load Shedding at around 14% SOC.

Shutdown, Alarm and Restart at 10,11,12 respectively and even then I would imagine not only should it get to 10% but do so gracefully and without an alarm.

Found this video by Keith that suggested from my understanding that if you have AGM values programmed they could trigger based on voltage before the SOC percentage kicks in so tried those and lowered them accordingly, but even so I would imagine no error and just a graceful shutdown.


Didn’t make any real difference and in fact I had an oddity where the moment the grid was lost tonight the power dipped as it switched over which has never happened before.

Battery ran to 14% again and then inverter turned off…but now error this time at least so seemed like there’s at least some change there.

Interestingly looked at the AGM setting screen again while it was off and upon hitting save it all came back online and the moment it switched back to Lithium it turned back off which tells me the BMS is taking control or reporting a value to the inverter which then kills it.

Reported it to the installer as in my mind it should be able to do 10% or even 0% without an issue or complaint if I wanted it to.

He had the online support have a look who firstly said the Time of Use was wrong which has absolutely zero correlation in my opinion to its ability to go below 14% or not, which he agreed with.

Then he forwarded me their statement of “It wont supply 4000w at 14% soc , it tripped because of over discharging. Over current protection” which sounds like complete bullshit to me.

It runs even 8000W happily all day long, why would it suddenly **** the bed at 14%?

Also if it’s a current protection then surely the error would say that instead of Low Voltage?

He wanted to call to explain but I was running around making dinner and putting kids to bed and said we’ll talk tomorrow but it sounds a bit like bullshit to me.

Surely it should be able to run all the way to 0% at its rated outpost of 8kW without any bitching and moaning?

Looking at my history yesterday it was well below 2000W even when it did the same thing at exactly 14% so this seems more like a calibration problem to me where 10% according to the inverter isn’t 10% from the BMS.

****

Also the techie on the other end didn’t seem to understand the difference between kW and kWH from this comment, which is worrying.

“So what is 14% of 14.4kwh, 2kwh, It wont supply 4000w at 14% soc , it tripped because of over discharging”

Or am I the idiot?
 
I would imagine that there is a bit of a dropoff in terms of discharge capacity as the voltage drops, but it should not be as much as you are experiencing. Your 3 batteries should be able to supply 7,2 kW at 50A or 10.8 kW at 75A. That shouldn't drop to 2 kW due to voltage. It is likely that the battery and inverter are not using the same values. Some people had issues with the Hubble batteries as well a while ago and had to set the values manually.
 
SauRoNZA said:
So I had an F56 (Low Voltage) error yesterday during Load Shedding at around 14% SOC.

Shutdown, Alarm and Restart at 10,11,12 respectively and even then I would imagine not only should it get to 10% but do so gracefully and without an alarm.

Found this video by Keith that suggested from my understanding that if you have AGM values programmed they could trigger based on voltage before the SOC percentage kicks in so tried those and lowered them accordingly, but even so I would imagine no error and just a graceful shutdown.


Didn’t make any real difference and in fact I had an oddity where the moment the grid was lost tonight the power dipped as it switched over which has never happened before.

Battery ran to 14% again and then inverter turned off…but now error this time at least so seemed like there’s at least some change there.

Interestingly looked at the AGM setting screen again while it was off and upon hitting save it all came back online and the moment it switched back to Lithium it turned back off which tells me the BMS is taking control or reporting a value to the inverter which then kills it.

Reported it to the installer as in my mind it should be able to do 10% or even 0% without an issue or complaint if I wanted it to.

He had the online support have a look who firstly said the Time of Use was wrong which has absolutely zero correlation in my opinion to its ability to go below 14% or not, which he agreed with.

Then he forwarded me their statement of “It wont supply 4000w at 14% soc , it tripped because of over discharging. Over current protection” which sounds like complete bullshit to me.

It runs even 8000W happily all day long, why would it suddenly **** the bed at 14%?

Also if it’s a current protection then surely the error would say that instead of Low Voltage?

He wanted to call to explain but I was running around making dinner and putting kids to bed and said we’ll talk tomorrow but it sounds a bit like bullshit to me.

Surely it should be able to run all the way to 0% at its rated outpost of 8kW without any bitching and moaning?

Looking at my history yesterday it was well below 2000W even when it did the same thing at exactly 14% so this seems more like a calibration problem to me where 10% according to the inverter isn’t 10% from the BMS.

****

Also the techie on the other end didn’t seem to understand the difference between kW and kWH from this comment, which is worrying.

“So what is 14% of 14.4kwh, 2kwh, It wont supply 4000w at 14% soc , it tripped because of over discharging”

Or am I the idiot?
Click to expand...
Can you ask them to see the cell voltages?
 
furpile said:
I would imagine that there is a bit of a dropoff in terms of discharge capacity as the voltage drops, but it should not be as much as you are experiencing. Your 3 batteries should be able to supply 7,2 kW at 50A or 10.8 kW at 75A. That shouldn't drop to 2 kW due to voltage. It is likely that the battery and inverter are not using the same values. Some people had issues with the Hubble batteries as well a while ago and had to set the values manually.
Click to expand...

My opinion as well.

The BMS is reporting 47.44V at 12%.
 
I would guess that one of the cells reaches it's low voltage cutoff under load and then raises an error which leads to the shutdown.
 
P924 said:
I would guess that one of the cells reaches it's low voltage cutoff under load and then raises an error which leads to the shutdown.
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Further testing with the Voltages from the manual entered under the AGM setting definitely corresponds with the Voltage settings kicking in before the BMS settings as per Keith's video.

Basically the moment it touched 47V it turned off as per the value below. In reality this is about 16% on the BMS.

Shut Down(cut off) Voltage: 47V Shut Down(cut off) SOC: 20% Restart Voltage: 49V

So how on earth does one work out that Shutdown value in Voltage to correlate to 10% instead of 20%?


Also just for my sanity what does Restart actually mean? What's meant to happen at that value?
 
SauRoNZA said:
Further testing with the Voltages from the manual entered under the AGM setting definitely corresponds with the Voltage settings kicking in before the BMS settings as per Keith's video.

Basically the moment it touched 47V it turned off as per the value below. In reality this is about 16% on the BMS.

Shut Down(cut off) Voltage: 47V Shut Down(cut off) SOC: 20% Restart Voltage: 49V

So how on earth does one work out that Shutdown value in Voltage to correlate to 10% instead of 20%?


Also just for my sanity what does Restart actually mean? What's meant to happen at that value?
Click to expand...
Very hard with LFP's flat curve. What are the battery specs again? Cut-off bulk etc?
 
I have the same issue as @SauRoNZA, same battery except I have 2 in my bank. Also shuts down at 14%. Going to try and set the voltages manually when the clouds clear up here, and see what % it corresponds to. Guess it's a process of trial and error.

With that said, this will only be for exceptional circumstances. Under normal conditions I don't go below 20%, mostly because I don't want any issues should I need to put in a warranty claim...
 
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