Axpert Settings

[m00se]

Hello All,

 

So I have had my axpert syste for coming onto a year now. I am a little concerned about my settings and what the right settings are. My configuration is as follows:

2x Axpert 5kva

9x Rene solar 300

4x sonic 250ah running at 48v

Some pics of how I put it all together are attached too:

Could someone please confirm my setting. I'm concerned I'm destroying my damn nice batteries as my bulk charge never seems to get to 57.6v. But rather seems to stay at the float level of 54v. Is this normal?

system set to UPS mode

float 54v

bulk charge 57,6v

charge amps at 50amps and charge from solar only.

 

 

 

 

[Chris Hobson]

AGM batteries can take a higher charge than standard LA batteries but 50A on a paralleled system translates to 100A. Since your batteries do not seem to have a set charging rate on the datasheet, a safe charging rate would be 25A so 12A (or 10A in the case of an Axpert). You are charging at 4 times that rate. The maximum your panels could deliver is 50A but even that is too high.

Give us your settings program1 through to 31 and we can see if we can help.

[m00se]

Hi Chris,

 

Thanks for the assist....Settings are as follows:

00  ESC

01 SBU

02  30

03 UPS

04 SdS

05 Ltd

07 Ltd

09  50

11 30

12  48

13  53

16  050

18  60f

19  tef

20  Lof

22  AON

23 byd

25 fds

26  57.6

57  54

28  PAL

29  42

30  ONE

31  SbE

[m00se]

Hi There,

 

I only have panels on the one inverter, would that make a difference?

 

Marcus

[m00se]

the problem i have is that the bulk charge does not seem to ever get to the 57.6v. It only gets the batteries up as far as float level at 54v. I have seen it at 57.6v in the past but for reason it never gets there now. I have read there is some sort of bug that if the system charges too fast that it does not get to absorb level or something to that effect.

[m00se]

I believe so, my load is generally quite low at between 400w-800w while PV in is over 2Kw+. I have my panels facing NE and they get full sun very quickly in the morning when the sun comes up from behind the mountain. I am going to I believe so, my load is generally quite low at between 400w-800w while PV in is over 2Kw+. I have my panels facing NE and they get full sun very quickly in the morning when the sun comes up from behind the mountain.

[viper_za]

Have a look at this post regarding your settings
 

 

[Coulomb]

It could be the premature floating bug. You say your solar power comes up in a rush when the sun clears the mountains, but that means you could have an extended dawn with little light for half an hour while the sunlight is indirect. During that time, there may be enough light to trigger the bulk charge, but not enough to get over the threshold where it goes from bulk/absorb to float. So it thinks that the battery charge current is tapering down at the end of  the absorb phase, when in reality it is tapering up at the start of the bulk phase. So by the time your blast of direct sunlight comes through, it may often already be in the float phase. Some observations of the charge LEDs around that time should confirm.

The bulk/absorb charge termination threshold does change with paralleled units. Did the change in behaviour from usually getting to bulk to always seeming to be in float  coincide to the second Axpert being installed?

Edit: if the extended dawn theory is correct, my lead acid patched firmware should fix it. Details are on the AEVA PIP-4048 thread.

Edited October 3, 2016 by Coulomb

[Chris Hobson]

9 hours ago, m00se said:

I only have panels on the one inverter, would that make a difference?

9 hours ago, TinkerBoy said:

So then why do you have 2 inverters ?

 

I have to agree with Tinker. Your loads are generally low 400-800w and yet you have 8kW of inverter capability. Your battery bank at 250Ah is marginal for two inverters. So to remedy this one would double your battery bank but your batteries are about a year old now so purchasing an additional 4 batteries would not be recommended, you would need 8 matched batteries. So if you were to buy 8 new batteries you would need to up your panels. The easiest would to mothball one inverter and if you have hassles you at least have a backup plan.

Try allowing  grid to charge (program 16) your batteries and see whether there is some fault with the inverter, but I suspect it is a issue to do with how your system is setup. 

[m00se]

I got the 2 inverters so that i was ready to wire up the NW facing roof and for the times to over come the high loads when wife goes nuts with all the appliances. limiting her options there is a no go. let me aslo correct the 400-800w load. This is the idle time and what i was trying to get at was there was plenty capacity to do both load and charge. Naturally when the pool pumps turn on there is a little more coming off.

So las night i tried the settings as suggested by Viper_za. let the batteries grid charge at 2Amp. This has not take the the batteries past 54v either. I unfortunately dont have a BVM battery monitor. I will have to get one but would like to fix this without it for now.

The Float bug was what i was alluding to earlier and the system started with the two inverters. Im not quire sure i understand what triggers the absorb to kick off. Am i correct in assuming that that the batteries should always hit the 57.6v and taper down to float?

[cvzyl]

m00se, you are correct. The charging is initially at constant (max) amps e.g. on my inverter it is set at 25A. So if there is 25A available from solar it will charge at 25A constantly, once it reaches bulk voltage (58V in my case) it maintains that voltage and the current starts dropping off. If the current drops off below a certain level while in bulk charge for longer than 4 mins I think it will switch to float which is 54V in my case. Charging is then only at about 1A for my bank.

Something that can trigger a false switch to float for me is when the batteries are already at bulk/absorb voltage (58V) but still taking quite a bit of current, lets say 20A. If a large load starts in the house there will be very little excess solar available so charging current will drop. The inverter then sees this as the trigger to switch to float.

In your test I think 2A grid charging is too little, set it at 20A to test. You should see voltage increase steadily until it reaches 57.6 and maintain that while charging current slowly drops off.

[cvzyl]

Here is an example of my battery volts and charging current. The dips you see in charging current was short periods where load consumed more solar and less was available for charging.

[viper_za]

34 minutes ago, m00se said:

So las night i tried the settings as suggested by Viper_za. let the batteries grid charge at 2Amp. This has not take the the batteries past 54v either. I unfortunately dont have a BVM battery monitor. I will have to get one but would like to fix this without it for now.

Hi m00se I was more looking at you having the max charge current and the max utility current the same.
That leaves you with 0 current for solar to charge at.

Option 2 works like this.
Maximum charging current = utility charging current (option 11) + solar charging current (this has no setting = Option 2 - option 11).

 

The 2A grid suggested is only to keep the bank on float when you have the inverter on bypass mode

[ebrsa]

Like m00se I also installed 2 x 4Kw Axperts with solar panels connected to the master. The reason was to cope with loads in excess of 4Kw capacity of one inverter. Tinkerboy and Chris you have both questioned m00se's dual inverters. My concern was what would happen to one inverter if fed by the grid and I should increase the load much higher than 4Kw. Hence the installation of 2 Axperts to ensure that smoke will not materialize at high demand when grid fed. I just wanted to connect the whole house via the inverters. Now at least I can safely load up to 8 Kw, or did I just waste money?

[ebrsa]

Thanks for your reply TinkerBoy. I guess I did not phrase my question clearly. I only have 9 x 250W panels on my flat roof and not space for more. So the question should really be, how does one overcome a possible load of more than 4Kw other than installing 2 inverters with the inverters driven by the grid and not batteries at a high demand load. My understanding of the Axpert literature is that it is capable of a sustained output load of 4Kw, irrespective of whether the input is solar, batteries or grid. In my case I am really just trying to feed the sustained load from solar or some battery power and leave the high demand loads to the grid. Also I set up AICC to switch to grid if battery SOC goes below 80% as fed from a BMV700. I have noticed that you have a 4Kw Infini if I am correct. How do you manage higher loads. Any advice and explanations will be much appreciated

[SilverNodashi]

14 hours ago, ebrsa said:

Thanks for your reply TinkerBoy. I guess I did not phrase my question clearly. I only have 9 x 250W panels on my flat roof and not space for more. So the question should really be, how does one overcome a possible load of more than 4Kw other than installing 2 inverters with the inverters driven by the grid and not batteries at a high demand load. My understanding of the Axpert literature is that it is capable of a sustained output load of 4Kw, irrespective of whether the input is solar, batteries or grid. In my case I am really just trying to feed the sustained load from solar or some battery power and leave the high demand loads to the grid. Also I set up AICC to switch to grid if battery SOC goes below 80% as fed from a BMV700. I have noticed that you have a 4Kw Infini if I am correct. How do you manage higher loads. Any advice and explanations will be much appreciated

What happens if you power-off the 2nd inverter, just for a day? Does the charge increase at all?

[ebrsa]

Thanks a lot for the explanation TinkerBoy. At last the penny dropped and at last I understand how your system works. Would be a bit tricky in Swartland Municipality where I live. I was told by a resident with a grid tied inverter that the municipality pays him R0.685 and charges R1.18 per Kwh. Also no roll over or credit balance is allowed. So he has to feed in 72% more than his consumption just to break even. I guess we still have a long way to go in our country before renewable energy usage becomes as attractive as it should be. 

I just switch AICC to grid when I know consumption is going to draw more than about 20A from the batteries. Not an ideal situation and that is why I suggested that a feature that would switch AICC (PPi) to grid and back to solar between to values that can be set would be desirable, at least for me. I live in hope that it may be added at some future date.

[ebrsa]

SilverNodashi I have not tried switching off the slave inverter yet. The solar panels are connected to the master. Also the weather is all over the place, cloudy one moment and bright sunshine next. Typical Cape winter weather so I will have to wait for summer and sunny days to see what happens.

[m00se]

Hi Guys, So i though i would share an update.

So to re-cap. I just could get the inverters to go past the 54v float in charging my batteries. I tried various thing from this forum and had no real luck. On resetting it back to the original setting with slight changes to the max bulk charge level and float point (0.2kw) added to each setting. The darn things just started working right. No idea what actually made it work buy hey Im happy its back to normal.

Now Im off to installing the AICC Pi which i have eagerly been waiting for.

[Coulomb]

7 hours ago, m00se said:

On resetting it back to the original setting with slight changes to the max bulk charge level and float point (0.2kw) added to each setting. The darn things just started working right. No idea what actually made it work ...

Maybe the gradual dawn is still your problem, and by resetting in the middle of the day, you start bulk charging with good sunlight and it gets past the termination condition and you get a full charge. But perhaps tomorrow or the next day you'll have the same problem at dawn.

[MarinusG]

I've included my settings for the 3 Axpert cluster that I have installed along with some of the thinking behind each option (based on my understanding). The system has been pretty solid in this configuration using AICC to monitor and control.
Firmware 72 40 and 01 24 respectively 

Pretty happy with the charging that I'm getting:

going to float just after 12:30 (BMV is triggered to 100% a bit earlier...)

01 SBU 
This mode is for on-grid use where you want to minimise grid usage. It will use the battery whenever solar is not available. It will only use the grid when the battery gets low. Link

02 70
This is within the limits of my battery bank - i.e. I can safely charge at a total of 210 Amps for the 3 Axperts combined. Solar can provide roughly 60 Amps maximum per Axpert (3kW). This will set the upper limit for solar charging and should we within the limits of connected batteries.

03 UPS
Conservative setting for grid voltage range i.e. if grid falls below 170V or rises above 280V it will be deemed to be unavailable

04 SdS
Inverters should remain on regardless of load

05 USE
User defined battery settings

06 LrE
Personal preference - I have protection breakers installed on all circuits supplied, so comfortable to restart in the event of overload

07 trd
More worried about temperature - so disable restart for overheat

09 50
50hz for SA

11 10
Small charge current from grid if the batteries dropped below SOC specified in AICC

12 45
Lowish voltage for back to utility - this is a fail-safe in the event that AICC doesn't switch for some reason and the batteries are being drained. This is an anti-nuisance setting to avoid accidental switching in the event of high load walk-ins. 

13 50
Lowish voltage for back to Solar - shouldn't need this since AICC is in control, but will avoid unnecessary use of grid if the Axperts switched. 

16 CSO
In the event that the batteries drop below SOC specified on AICC, use grid to trickle them up to avoid standing discharged (limited by setting 11). Useful for a 'full charge day'

18 BOF
No beeping

19 KEP
Stay on the selected screen

20 LOn
Keep the back-light on

22 AOF
No beeping

23 bYE
Enable bypass in the event of overload

25 FEn
Not really getting any faults, but keep them when they happen.

26 56
Specific bulk charge voltage for my bank

27 54.8
Specific float charge voltage for my bank

28 PAL
Parallel mode

29 44.5
Last resort cut-off voltage in the event of no grid. 

30 ONE
As long as one Axpert has PV available, honour setting in register 1

31 SbE
Solar balance enabled for maximum utilisation of solar energy.

[MarinusG]

On 10/3/2016 at 8:29 PM, m00se said:

I only have panels on the one inverter, would that make a difference?

While this seems to be OK, I would be tempted to move a string across to the second inverter. This keeps the two inverters in a consistent mode. I'm not sure exactly how the current sharing is done, but having PV on both at least lets them agree that it's day time, when it is...

[SilverNodashi]

On 10/29/2016 at 9:19 AM, MarinusG said:

While this seems to be OK, I would be tempted to move a string across to the second inverter. This keeps the two inverters in a consistent mode. I'm not sure exactly how the current sharing is done, but having PV on both at least lets them agree that it's day time, when it is...

You don't ^need^ todo this. 9 panels on a single axpert will work fine. The 2ns Axpert will be used to give more KW energy to the house.From experiments I didn't see any difference between running 6 panels per inverter, in a dual inverter setup VS running all 12 panels on a single inverter in the same setup. The inverter doesn't need to know when it's day or night 

[ebrsa]

@SilverNodashi you asked if I have turned off one of my 2 Axperts for a day and the answer is no. I turned it off to see what happens and it beeped and for a short time a red led came on with error 8 displayed on the LCD display. According to the manual that is internal component failure so I turned it on very quickly. I turned off the switch on the inverter itself. Does anyone know whether it is safe to turn off one of the Axperts in a cluster, with the switch on the inverter, for any length of time.

I am still looking for an answer as to the maximum load one can draw from one inverter when in grid mode. If that is limited to 4Kw then why the bypass setting on overload (parameter 23), of I suppose, 4Kw on batteries. That is why I have 2 inverters as nowhere can I find information to indicate what the maximum load may be when the inverter switches to bypass to grid or if one switches it to grid mode with AICC. Does anyone have this information perhaps. If I could draw say 8Kw in grid mode, there is no need for 2 inverters.

[SilverNodashi]

5 hours ago, ebrsa said:

@SilverNodashi you asked if I have turned off one of my 2 Axperts for a day and the answer is no. I turned it off to see what happens and it beeped and for a short time a red led came on with error 8 displayed on the LCD display. According to the manual that is internal component failure so I turned it on very quickly. I turned off the switch on the inverter itself. Does anyone know whether it is safe to turn off one of the Axperts in a cluster, with the switch on the inverter, for any length of time.

I am still looking for an answer as to the maximum load one can draw from one inverter when in grid mode. If that is limited to 4Kw then why the bypass setting on overload (parameter 23), of I suppose, 4Kw on batteries. That is why I have 2 inverters as nowhere can I find information to indicate what the maximum load may be when the inverter switches to bypass to grid or if one switches it to grid mode with AICC. Does anyone have this information perhaps. If I could draw say 8Kw in grid mode, there is no need for 2 inverters.

ok so it sounds like you have a problem. And, yes, it's safe to shutdown one or two inverters in a cluster. 

BUT, now I need to ask, are there panels connected to both the inverters, and if so, what is the value of setting 30?

 

EDIT: To answer your second question: The inverter will switch over to Eskom when the batteries are too low, i.e. cannot deliver 4KW.