Lux ac battery controller

GAJ59

I'm pretty sure Prec is the power rectified by the LUX ie AC from the mains (or AC coupled solar inverter) to DC to the battery.

propnut

GAJ59 said:

I'm pretty sure Prec is the power rectified by the LUX ie AC from the mains (or AC coupled solar inverter) to DC to the battery.

The power drain is battery to Lux. You can see this very clearly by monitoring the voltage drop and battery % over time. It is the DC/AC inverter stage that is consuming the power from the battery. The batteries have some internal losses from their own BMS power requirements and of course internal cell resistance but these are tiny tiny in comparison.

chainreaction

propnut said:

The power drain is battery to Lux. You can see this very clearly by monitoring the voltage drop and battery % over time. It is the DC/AC inverter stage that is consuming the power from the battery. The batteries have some internal losses from their own BMS power requirements and of course internal cell resistance but these are tiny tiny in comparison.

Data I have from the history data sheet using the battery voltage snapshot and battery current (data is shown on the far right of the data sheet) average about 7% loss to convert from DC to AC to meet the inverter output load to the house. At higher discharges from the batteries, % reduces to around 6%. eg at full whack I take 3735w from the batteries to meet a post inverter supply of 3510w. 

propnut

chainreaction said:

Data I have from the history data sheet using the battery voltage snapshot and battery current (data is shown on the far right of the data sheet) average about 7% loss to convert from DC to AC to meet the inverter output load to the house. At higher discharges from the batteries, % reduces to around 6%. eg at full whack I take 3735w from the batteries to meet a post inverter supply of 3510w. 

I think we are talking at cross purposes here. I am talking about losses incurred within the DC/AC inverter stage at idle. In other words when there is no load from the house i.e. self consumption of power from the battery by the DC/AC inverter as opposed to conversion losses.

chainreaction

Ahh ok. I don't see any loss from battery SOC% or battery voltage when I'm on cheap rate before it starts charging IE battery is not charging or discharging. I've gone through the 5 hours with no drop at all.

propnut

chainreaction said:

Ahh ok. I don't see any loss from battery SOC% or battery voltage when I'm on cheap rate before it starts charging IE battery is not charging or discharging. I've gone through the 5 hours with no drop at all.

You won't notice it over 5 hours especially with 4 batteries unless you specifically look for it in the logs. I can guarantee it's there but you are charging from the grid so by the time you wake up the battery is full and assuredly you have never looked and why should you even think to do so. Now for those of us not charging from the grid we notice it during the long winter nights as at a point is loses so much that the inverter decides it must charge the battery to prevent damage. Then when we look in the logs we can see it pulls +-300amps from the grid for a good few hours until the battery reaches 51.7v whereupon it stops. But then you have another dark night ..... wash rinse repeat and all of a sudden your money saving device turns into a cost centre.

chainreaction

Hi propnut, what should I look for away from battery voltages and battery SOC, as these show no change. The header titles on the history data sheet would be good so I can go check. Thanks

philologus

My post of 31.1.23 said;

Just had this reply from Lux:-

There is battery open issue,

1. check whether battery power cable have loose connection. disconnect and connect again.

2. check whether any burn bark at battery input connector of inverter.

3. measure real voltage reading both of battery side and inverter side and check whether voltage reading same.

 I have checked all cables and they are OK. There are no burn marks on any of the cables or where they meet the inverter.

I'm not an electrician so don't want to invalidate the guarantee with the inverter so don't want to mess with the inverter. I have a multi-meter so how do i check point 3?

 I should point out here that I bought the system in May 2019 and paid for  a Pylontech 4.8 battery but they only installed a 2.4. (I was ignorant and thought that the battery that was installed was a 4.8.)

I decided to increase my battery backup to 9.6 and looked for another 4.8 to add. The company I was buying from asked me to send a pic of the battery I had and informed me that it was only a 2.4.

I phoned the installers only to be told that they had gone bust and the new company took over the assets, but not the liabilities of the old company.  I have found the liquidators and made a claim and this is ongoing.

In the meantime, I bought three new 2.4's but couldn't get anyone to install them so I did it myself (It was not difficult). This has worked well for two years - until the present problems started.

 I contacted the new company for advice and they sent an electrician a couple of days ago and he said that it was wired up OK and all the connections were tight, the inverter was working OK and so were the batteries. He said that I needed to contact Lux as it could only be a software problem and they could probably fix it remotely.

Lux said (today):

Hi,

If you think battery power cable firmly connected then check whether any burn mark at battery input connector of inverter.

measure real voltage reading from both of inverter and battery side and check whether same reading voltage as inverter reading.

firmware does not control input voltage reading.

Input voltage of battery going up and down,

There are no burn marks.

So, again, they want me to check voltages.

Any thoughts please?

I am considering asking an electrician with lots of solar experience to come and have a look and to write a report to stop this passing the buck routine if I can. I am not getting full use from my system and as the days get longer this will get worse.

When the sun shines the panels produce. The inverter sends it to the house needs first. Any excess is sent to the grid - which is not what I want.  Sometimes it sends  a small amount (less than 20v) to the batteries. When the sun went down today  and I had 62% SOC no power is being taken from the batteries to feed the house. It is all taken from the grid.

I bought the "Battery View" version B3.0.3 some time ago and it is telling me that Bat 1 is 18%, Bat 2 is 16% Bat 3 is 19% and bat 4 is at 29%.

When I watch the inverter panel it often flashes up " No A/C power flow", but otherwise all is well. Temps normal. Voltage state normal. Current state normal

What am I missing?

George.

1961Nick

philologus said:

My post of 31.1.23 said;

Just had this reply from Lux:-

There is battery open issue,

1. check whether battery power cable have loose connection. disconnect and connect again.

2. check whether any burn bark at battery input connector of inverter.

3. measure real voltage reading both of battery side and inverter side and check whether voltage reading same.

 I have checked all cables and they are OK. There are no burn marks on any of the cables or where they meet the inverter.

I'm not an electrician so don't want to invalidate the guarantee with the inverter so don't want to mess with the inverter. I have a multi-meter so how do i check point 3?

 I should point out here that I bought the system in May 2019 and paid for  a Pylontech 4.8 battery but they only installed a 2.4. (I was ignorant and thought that the battery that was installed was a 4.8.)

I decided to increase my battery backup to 9.6 and looked for another 4.8 to add. The company I was buying from asked me to send a pic of the battery I had and informed me that it was only a 2.4.

I phoned the installers only to be told that they had gone bust and the new company took over the assets, but not the liabilities of the old company.  I have found the liquidators and made a claim and this is ongoing.

In the meantime, I bought three new 2.4's but couldn't get anyone to install them so I did it myself (It was not difficult). This has worked well for two years - until the present problems started.

 I contacted the new company for advice and they sent an electrician a couple of days ago and he said that it was wired up OK and all the connections were tight, the inverter was working OK and so were the batteries. He said that I needed to contact Lux as it could only be a software problem and they could probably fix it remotely.

Lux said (today):

Hi,

If you think battery power cable firmly connected then check whether any burn mark at battery input connector of inverter.

measure real voltage reading from both of inverter and battery side and check whether same reading voltage as inverter reading.

firmware does not control input voltage reading.

Input voltage of battery going up and down,

There are no burn marks.

So, again, they want me to check voltages.

Any thoughts please?

I am considering asking an electrician with lots of solar experience to come and have a look and to write a report to stop this passing the buck routine if I can. I am not getting full use from my system and as the days get longer this will get worse.

When the sun shines the panels produce. The inverter sends it to the house needs first. Any excess is sent to the grid - which is not what I want.  Sometimes it sends  a small amount (less than 20v) to the batteries. When the sun went down today  and I had 62% SOC no power is being taken from the batteries to feed the house. It is all taken from the grid.

I bought the "Battery View" version B3.0.3 some time ago and it is telling me that Bat 1 is 18%, Bat 2 is 16% Bat 3 is 19% and bat 4 is at 29%.

When I watch the inverter panel it often flashes up " No A/C power flow", but otherwise all is well. Temps normal. Voltage state normal. Current state normal

What am I missing?

George.

Check the contacts & the terminals on the AC & DC breakers.

propnut

If you are not confident using a test meter or are not comfortable with electricity then it is always safer to get a sparky in. Testing voltage may still not help solve the problem. Voltage is just a potential difference between two points in a circuit. Current is the actual flow of electrons through a circuit. You can have voltage without current. You say the sparky checked that the wires were tight BUT did he actually disconnect them and reconnect them ??? You may have what is called a dry joint. This is where (sometimes due to arcing) a connection exists but it is not sound and as a result presents itself has high or even infinite resistance. I would disconnect all and visually check for signs of arcing on both sides of each connection as well as those on the inverter. As 1961Nick says, the breakers should be checked as they too are connections in the circuit.

EVERYTHING MUST BE SWITCHED OFF FIRST !!!!!