Jump to content

How to force Axpert out of bypass mode


gertc
 Share

Recommended Posts

Hi all

I have 3 Axpert 5 kva inverters in parallel with a BMV702 battery monitor.  I use AICC software to monitor and control them.  On the odd occasion the SoC dips below 50% and AICC switches the inverters to grid.  But for some reason I cannot them switch them back to Battery mode.  I have tried to change the settings in AICC, click on the manual battery mode button but all without luck.  Is there a way to force the axpert (on the inverter itself) to go back to battery mode?

Thanks!

Link to comment
Share on other sites

As a quick and dirty, you could disconnect the mains.

This will force the inverters back to battery mode.

Once the switch happens, and providing the SOC is above 50%, you can reconnect the mains and the inverters should stay on battery mode.

The other solution is to go into the inverter settings and change to SOL (solar only)

Link to comment
Share on other sites

gert when do you want the inverters to switch back ? What is your SOC ?

If your bank is in such a state that it is not safe to swich back even if AICC gives the command it will not respond. I have seen in testing that it can take up to 15min for the inverters to swich if you do it a lot. I send the command and they anser with a ACK stating they received the request, but will only act when it is happy to do so.

 

Regards.

Link to comment
Share on other sites

Jaco, In this case the inverters went to grid when the SoC dropped to below 50% juts after sunrise (07:00).  The PV output was not big enough yet at that moment, but shortly afterwards it was more than enough to power the house and recharge the batteries.  I saw this and tried to manually change the inverters to go back to battery and also tried to change the setting in AICC to go back to battery mode at 60%.  Eventually it went back to battery mode around 11:00 when the batteries were almost full again.  Battery settings are at 44v (setting 12) and 54v (setting 13). I attach the AICC graph to illustrate the situation.

2016-03-11_06-24-07.png

Link to comment
Share on other sites

Hi gertc

 

This is suppose to work like that, because you have your back to solar/battery voltage set to 54v then only will AICC accept your command.

Your batt voltage probably only reached 54v again at 11:00

This is why all of us are adding the BMV to the axpert so we have better control over it, then we can set that back to solar voltage a lot lower because we now have a more accurate way of measuring what is going on with the batts.

A bit worrying is that you are pushing around 5000+ watts (+-90A) into your batts, How big are they?

Link to comment
Share on other sites

To be honest I have not tested if your battery volts are below the back to grid volts and you want to go back to solar if the inverters will switch. I dropped my back to grid voltage to 46 volts so it would not get in the way of the SOC

Link to comment
Share on other sites

11 minutes ago, jdp said:

To be honest I have not tested if your battery volts are below the back to grid volts and you want to go back to solar if the inverters will switch. I dropped my back to grid voltage to 46 volts so it would not get in the way of the SOC

I don't think you will have to test it, the inverter should just ignore your command if it does not meet the back to solar volts if it's part of the firmware.

Gertc best is to keep an eye on what your battery volts are and when you would like to swap back to solar and determine it like that, it's a learning curve.

I will have to check on mine for you tonight

Link to comment
Share on other sites

  • 1 year later...

 i also have a problem in the inverters, I have 3 Axpert 5 kva inverters  which connected together to make 3 phase when I connect the grid system is working stable ,when I seperate the grid and working in battery and connect daynamic load like motor the system be unstable , the three inverters can't work in three phase mode at battery ( the output voltage is 230 v between line and neutral at every inverter , but 450 v between l1 & l2 and 150 v between l2& l3 ) ,  but when i connect the grid the output voltage of inverters is same as input voltage (grid) ( 220 v between line & neutral and 380  between the two lines ) and it work stable.

Link to comment
Share on other sites

Hi Mohamed 

Welcome to the forum.

I have no experience running Axpert in three phase. The only thing I can think of is a small inconsistency in the setup.

The power side of the inverters connection should be as the diagram below

5966229f3b226_Screenshot(126).png.a0cec9b6b7cd1b576a4fbf823dac69b2.png

There should be no current sharing cables connected between inverters only communication cables connect according to the diagram below.

5966237f8581a_Screenshot(127).png.ca6374540b54f561677c33a3862b54d5.png

 The programs pertinent to multiple Axperts are Program 28 where you identify inverter(s) connected to L1 (3P1), L2 (3P2) and L3 (3P3).

The other program for multiple inverters is program 30 which is for interpreting when Solar first (program 1) will be applied.

596626b6df316_Screenshot(128).png.92bf0587c4f0147f64eeb059437b708d.png

I fear there is a phase mismatch in your system but cannot figure out how it would occur. I see Plonky has just replied so I am sure he has a solution.

 

 

Link to comment
Share on other sites

12 minutes ago, Chris Hobson said:

Plonky has just replied so I am sure he has a solution.

Not a chance! I just linked to the Giant Power manual for the same inverter that shows the same picture you linked, plus the settings you need to set to tell each inverter what phase it is in. If that's done, then unfortunately I just don't know.

Link to comment
Share on other sites

@Mohamed Arafa, is it always a steady 150 Vac between two phases? Might it slowly drift with time? 

This would tell if the comms cables are working but the firmware gets the phases wrong, or if the inverters are not talking to each other. 

I figure 38° between two phases, and 161° between the other two pairs. I can't think of any reason for this, or anything special about those phase angles. 

It might also be interesting to know what voltages you measure soon after going to battery mode when the mains is present. 220 V line to neutral implies line (bypass) mode. I think you should see close to 398 V line to line (sqrt(3) x 230 V) because the inverters should stay synchronised to the mains in battery mode when mains is present. Then keep measuring phase to phase while you open the AC input breaker (remove utility mains). Does it spring to 150/450 or slowly drift towards these figures or stay at 398 or something else?

Link to comment
Share on other sites

6 hours ago, Coulomb said:

Does it spring to 150/450 or slowly drift towards these figures or stay at 398 or something else?

Yup, I agree with Sir Charge here. If it drifts towards these figures, then your phase-syncing isn't working (you essentially have three single phases each running at their own pace). If it jumps to it immediately, something else is wrong.

Link to comment
Share on other sites

On 13/07/2017 at 8:37 AM, plonkster said:

Yup, I agree with Sir Charge here. If it drifts towards these figures, then your phase-syncing isn't working (you essentially have three single phases each running at their own pace). If it jumps to it immediately, something else is wrong.

@Mohamed Arafa

Check if the neutrals of all three units are combined at inverter side and on the load side and there is no break. Also the neutral should be earthed separately in some cases by using a grounding relay or direct neutral to earth ( i don't know the code of South Africa) 

Also important to note that this happens only when Axpert are first switched on at commissioning. After once seeing grid connection as long the battery remains connected they remain in sync.

In short 

After making all settings one by one switch them off 

1, first switch on Battery 

2. Switch on Inverters one at a time 

2 Switch AC inputs  ( grid should be available)

3. Check if there no errors displayed  - flashing AC symbol or error codes 

4 Switch on output breakers - preferably balanced loads first 

 

Another possibility of this happening on cold start ( no Grid)  if the load impedances seen by the inverter are not same. also,  The output cables and input battery cables have to be of the same length the  Axperts are finicky about this 

I have also seen this problem on Axpert when I experimented with 3 phase setup  in my case you could easily see the voltages drifting apart and coming closer if measured long enough ( i had loaded only R Phase with lots of LED bulbs and TV etc. while other phases did not have loads at the time of measuring )

The drifting stops the moment AC input is connected though and remains in sync even after removing grid. I noticed this particular problem when trying to use a small 3phase 6.5 KVA DG to feed Axperts . The DG sinewave was distorted and the Axperts could not find reference signal ( evident by constantly switching between grid and inverter mode when set to UPS

 

Axpert manual specially mentions this in commissioning direction ( switch Input breaker  first then output breakers first for all inverters followed by output breakers)- 

 

Also important to note that this happens only when Axpert are first switched on at commissioning. After once seeing grid connection as long the battery remains connected they remain in sync.

In short 

After making all settings one by one switch them off 

1, first switch on Battery 

2. Switch on Inverters one at a time 

2 Switch AC inputs  ( grid should be available)

3. Check if there no errors displayed  - flashing AC symbol or error codes 

4 Switch on output breakers - preferably balanced loads first 

 

 

 

 

Link to comment
Share on other sites

28 minutes ago, ghatikar said:

Also the neutral should be earthed separately in some cases by using a grounding relay or direct neutral to earth ( i don't know the code of South Africa)

You're not allowed to bond it a second time, so normally you'd have to use a grounding relay that is only closed when disconnected from the grid, in other words when running on grid you rely on the neutral/earth bond provided by the supplier (usually at the transformer, if you have a TN-S cable), and when running off-grid you create your own bond.

Link to comment
Share on other sites

  • 1 month later...

Hi Chris,

Program 1 = SOL, 12= 46 , 13 was on 54.0v when it got stuck on btpass having red the forum thread I followed gertc solution and I set  13= 48. 

Now it stays on SOL/Battery  mode without tripping by to Util 

I hope have done the right thing lol ..

 

Thanks for swift response Chris :):) 

 

 

 

Link to comment
Share on other sites

6 hours ago, Newbie said:

Hi Chris,

Program 1 = SOL, 12= 46 , 13 was on 54.0v when it got stuck on btpass having red the forum thread I followed gertc solution and I set  13= 48. 

Now it stays on SOL/Battery  mode without tripping by to Util 

I hope have done the right thing lol ..

Thanks for swift response Chris :):) 

Program 1 = SOL  In this mode the inverter will use solar and battery if solar is available and switch to grid at night. Bearing in mind that grid kWh are cheaper than kWh stored in the battery so you probably want to be on grid at night.

Setting Program 12  to 46V is low . 46V is roughly equivalent to a state of charge (SOC) of 20% - you are working you batteries hard. This not an absolute as you may find that if you have a small bank a large load something like a kettle will draw your batteries down to 46V and as soon as the load is removed the battery voltage recovers. If your battery bank is larger (400 Ah+) then you are busy murdering your batteries and you actually want to go to grid.

I suspect what is happening is that you are discharging your batteries till they nearly flat. The inverter switches to grid but Program 11 is set too low or Program 16 does not allow grid charging and so it takes a long time to switch back to solar appearing to be "stuck" in grid mode. Program 13 is way too low and your batteries are not getting the chance to get a restorative charge.

What is Program 11 and Program 16?

How many panels and what size are they?

Link to comment
Share on other sites

Hi Chris,

 

Sorry for late response, please do find my response in green :) 

Program 1 = SOL  In this mode the inverter will use solar and battery if solar is available and switch to grid at night. Bearing in mind that grid kWh are cheaper than kWh stored in the battery so you probably want to be on grid at night.

  I shall reset my timer to grid mode from 19:00 PM since you've enlighting me about the point made above.  :) 

Setting Program 12  to 46V is low . 46V is roughly equivalent to a state of charge (SOC) of 20% - you are working you batteries hard. This not an absolute as you may find that if you have a small bank a large load something like a kettle will draw your batteries down to 46V and as soon as the load is removed the battery voltage recovers. If your battery bank is larger (400 Ah+) then you are busy murdering your batteries and you actually want to go to grid.

What is the save volt I can set program 12 ?   Am currently running on  4x 12v 250ah AGM (BSB) battery bank.

I suspect what is happening is that you are discharging your batteries till they nearly flat. The inverter switches to grid but Program 11 is set too low or Program 16 does not allow grid charging and so it takes a long time to switch back to solar appearing to be "stuck" in grid mode. Program 13 is way too low and your batteries are not getting the chance to get a restorative charge.

What is Program 11 and Program 16?

Program 11 = 30A (default) , Program 16 =  050( only solar)

 

 

How many panels and what size are they?

 

 

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...