Lux ac battery controller

Dave_Fowler

The PV CT clamp is not necessary for the correct operation of the inverter. It allows the app to draw the graphs and give you generation and consumption figures. 
In my system, with two separate PV locations I don't have any point where the outputs can be summed. I obtained a second CT and connected the two in parallel at the inverter. 
Dave F

cm4ever

Hi All

We've got a Lux Hybrid inverter and a paralleled stack of 4x AOBOET Uhome-LFP 2400 batteries.

The combined solar and battery storage system hasn't been long installed and we've only once fully AC charged the battery stack to 100%, so far. 

If I'm right in my understanding : -

A. The hybrid inverter will revert to powering the house from the grid and stop supplying battery generated power to the house when either it's perceived SoC of the battery stack is low and/or the reported battery voltage is low?

B. If the reported battery voltage is low and/or the battery stack hasn't been charged for a while with a perceived low SoC, the inverter will start a forced low power battery charge from the grid to safeguard the batteries to a certain level/battery voltage - it's an inbuilt battery protection/life preservation procedure?

Can someone please comment or confirm if my current understanding above is correct.....

Based on the information above, does anyone have an idea, how long and/or how many full battery stack charges are generally required - so that the hybrid inverter can correctly identify what the real, or a more accurate SoC is - or am I misunderstanding how it's currently working?

One of the reasons for asking is from an inverter reported 50% SoC and a very small solar part recharge during the day - the inverter has powered the house from 5am until 9:20pm - when even though the reported SoC was 22% and battery at 50v it reverted the house to grid power only.....

ianatkin

cm4ever said:

Hi All

We've got a Lux Hybrid inverter and a paralleled stack of 4x AOBOET Uhome-LFP 2400 batteries.

The combined solar and battery storage system hasn't been long installed and we've only once fully AC charged the battery stack to 100%, so far. 

If I'm right in my understanding : -

A. The hybrid inverter will revert to powering the house from the grid and stop supplying battery generated power to the house when either it's perceived SoC of the battery stack is low and/or the reported battery voltage is low?

B. If the reported battery voltage is low and/or the battery stack hasn't been charged for a while with a perceived low SoC, the inverter will start a forced low power battery charge from the grid to safeguard the batteries to a certain level/battery voltage - it's an inbuilt battery protection/life preservation procedure?

Can someone please comment or confirm if my current understanding above is correct.....

Based on the information above, does anyone have an idea, how long and/or how many full battery stack charges are generally required - so that the hybrid inverter can correctly identify what the real, or a more accurate SoC is - or am I misunderstanding how it's currently working?

One of the reasons for asking is from an inverter reported 50% SoC and a very small solar part recharge during the day - the inverter has powered the house from 5am until 9:20pm - when even though the reported SoC was 22% and battery at 50v it reverted the house to grid power only.....

Hi there

I have a similar setup to you except I have 3 batteries rather than 4.

First thing to say is that the SOC reporting is a joke, it bears hardly any resemblance to reality and is nowhere near linear.  I allegedly have 6.6kWh usable and I can go from a full battery at 99% (it never shows 100%) down to showing 20% when I've only used maybe 2-2.5kWh.  From 20%SOC down I can only discharge at a maximum of ~1.7kW from the batteries (compared to 3kW above that).  Once the reported SOC gets down to 11% I normally get at least another 1.5kWh before it actually cuts out.  It doesn't matter how you use the batteries, you will never get a remotely accurate SOC reported I'm afraid.  I don't know if it's any better with the very similar Pylontech batteries.

The default settings on the inverter for "On-Grid Cut-Off SOC(%)" is at 10% so yours should be doing this.  This tends to coincide with a sudden battery voltage drop to <49V in my experience.

By any chance do you have an "AC charge" or "Charge priority" timer set by accident?  If your inverter has intelligent Octopus Agile timing capability is it turned on by mistake?

EVandPV

 I don't know if it's any better with the very similar Pylontech batteries.

Pylontechs report the correct SOC all the way from 100% to 10% when discharging.
Strangely though, mine seem to sit at about 88% for around half an hour then jump to 97%+ when charging.
It's as if the BMS doesn't report any SOC inbetween for some reason, but only when charging.

newbuilder

Any advice grateful:

now have the eps connected but the test shown https://www.wikihow.com/Check-Earthing-at-Home

shows

grid connected 243, 242, 0.22v
eps: LN: 233, L earth, 127, N earth 106.3v

i assume this is because there is no earth rod????

the system has a manual switchover so live and neutral are isolated. 

Do I need to put in an earth rod and is so what part of the circuit does it secure to? The DB that is running with ESP, the house earth in the meter box or the ESP DBoard?

cm4ever

Thanks for the reply and your thoughts ianatkin.

I'd chose to get the 4th battery at install time purely to save the vat on a post install future purchase / potential inevitable cost increase, due to the current high inflation rates and extra capacity availability if I move to an Economy 7 type dual rate electricity account - although for the later, that decision may be delayed until March next year.

Although it's very early days, I do get the impression that the reported SOC can be a bit off, although if it's discharging to cover off a steady load with a relatively small/stable dynamic range, as apposed to a very dynamic load (consisting of very large sparadic peaks) it appears to be fairly linear from what I've seen so far.

I sort of expected the displayed SOC accuracy to be problematic (or a sort of best guess until the system potentially learns some of the real life variables) as it'll only be as good as the coding used to calculate it based probably on perceived variable load, battery stack voltage etc etc, after all battery technology is a bit of a black art, or so it seems.....

Yes I generally have all the defaults set and then to put my observation of approx 22% possibly being misreported/incorrectly calculated due to a very short and low solar charge period during the day. As well as the mid range SOC level at the start of the day.

Still feeling about with the different predefined 'AC charge' charging options, but non where set that would have interfered at that point in time. I've read/heard that the inverter does indeed have battery protection mechanisms based on SOC and stack voltage levels and can initiate a low level 10% forced charge, but this was a bit different to what I was experiencing, based on the 'reported' SOC....

Just out of interest / curiosity, how is your 3x battery stack connected back to the inverter - are the +ve and -ve inverter connection cables split between the 1st and 3rd battery in the stack i.e +ve to top master battery and -ve to bottom 2nd slave battery in the stack - or do both battery stack connections back to the inverter connect to only the top master stack battery?

Thanks again for you thoughts 

Solarchaser

cm4ever said:

Hi All

We've got a Lux Hybrid inverter and a paralleled stack of 4x AOBOET Uhome-LFP 2400 batteries.

The combined solar and battery storage system hasn't been long installed and we've only once fully AC charged the battery stack to 100%, so far. 

If I'm right in my understanding : -

A. The hybrid inverter will revert to powering the house from the grid and stop supplying battery generated power to the house when either it's perceived SoC of the battery stack is low and/or the reported battery voltage is low?

B. If the reported battery voltage is low and/or the battery stack hasn't been charged for a while with a perceived low SoC, the inverter will start a forced low power battery charge from the grid to safeguard the batteries to a certain level/battery voltage - it's an inbuilt battery protection/life preservation procedure?

Can someone please comment or confirm if my current understanding above is correct.....

Based on the information above, does anyone have an idea, how long and/or how many full battery stack charges are generally required - so that the hybrid inverter can correctly identify what the real, or a more accurate SoC is - or am I misunderstanding how it's currently working?

One of the reasons for asking is from an inverter reported 50% SoC and a very small solar part recharge during the day - the inverter has powered the house from 5am until 9:20pm - when even though the reported SoC was 22% and battery at 50v it reverted the house to grid power only.....

Your understanding is correct.
Pylontech batteries do not have this phenomenon, only uhome it seems.

ianatkin

cm4ever said:

Just out of interest / curiosity, how is your 3x battery stack connected back to the inverter - are the +ve and -ve inverter connection cables split between the 1st and 3rd battery in the stack i.e +ve to top master battery and -ve to bottom 2nd slave battery in the stack - or do both battery stack connections back to the inverter connect to only the top master stack battery?

Thanks again for you thoughts 

When it was installed +ve and -ve to the inverter were both off the master, which is how it's shown in the manual weirdly. I've subsequently swapped them round so one is off the 1st battery and the other is off the 3rd, as that seemed to make far more sense in terms of balancing the wear across the three batteries, if that makes sense?

When I first had the system installed 14 months ago I used to get annoyed about the non linear SOC and the fact that only half the rated capacity is available at 3kW (some mild mis-selling, I was told it would discharge at 3.6kW and wasn't told how soon it would throttle back). I've learned to let it go and just let it get on with it 🙂 

Don't know how accessible your system is (mine is in the loft) but FYI it seems to throw a wobbler every couple of months or so and I have to go up and turn everything off and back on to reset it. If your smart meter IHD is on it's pretty easy to see when the batteries have decided to have a day off 🙂

cm4ever

ianatkin said:

When it was installed +ve and -ve to the inverter were both off the master, which is how it's shown in the manual weirdly. I've subsequently swapped them round so one is off the 1st battery and the other is off the 3rd, as that seemed to make far more sense in terms of balancing the wear across the three batteries, if that makes sense?

When I first had the system installed 14 months ago I used to get annoyed about the non linear SOC and the fact that only half the rated capacity is available at 3kW (some mild mis-selling, I was told it would discharge at 3.6kW and wasn't told how soon it would throttle back). I've learned to let it go and just let it get on with it 🙂 

Don't know how accessible your system is (mine is in the loft) but FYI it seems to throw a wobbler every couple of months or so and I have to go up and turn everything off and back on to reset it. If your smart meter IHD is on it's pretty easy to see when the batteries have decided to have a day off 🙂

Yes similarly ours was wired initially with both leads coming off the master battery, which to me isn't logical for a paralleled stack, as that master battery has the opportunity to skew the stack's combined capability and/or performance. I subsequently checked out the printed inverter manual which appears newer than the pdf online - in the printed version we have, in the 'parallel battery stack' connection guidance, there is now only 1x example battery stack illustration with words to the effect of 'be aware of stack connections' and now clearly shows the +ve coming off master battery and the -ve coming off the bottom battery in the stack.

In my mind it is now using the optimal stack connection back to the inverter and allows for a more equal charging/discharging capability across the entire stack..... as you said it makes more sense.

Yes our system is also loft installed, which if fairly easily accessible thankfully.  Also our IHD is in prime position in the lounge and visible - it and the app/website are what I'm using to keep a check on the system.

QrizB

newbuilder said:

Any advice grateful:
now have the eps connected but the test shown https://www.wikihow.com/Check-Earthing-at-Home
shows

grid connected 243, 242, 0.22v
eps: LN: 233, L earth, 127, N earth 106.3v

i assume this is because there is no earth rod????
the system has a manual switchover so live and neutral are isolated. 

Do I need to put in an earth rod and is so what part of the circuit does it secure to? The DB that is running with ESP, the house earth in the meter box or the ESP DBoard?

I'm not a Lux expert but is your earth terminal connected to anything?

For some types of inverter, that could be normal. (We had a long discussion of inverter earthing a couple of weeks ago, if you can find the thread there's a link to a document on the IET website.)