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Advice on Axpert 5KVA System.


Johan v d W
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Good morning guys,

We have an Axpert 5Kva Inverter, connected to 12 x 270Watt panels, connected in 4 x 3 panel strings and with 16 x 200Ah batteries connected as 4 x 4 banks of batteries. The system was opperating without any problems for about 5 weeks until the batteries were used without full daily recharge by pv. Since then we cant seem to get batteries fully charged and the system wil stop charging the batteries halfway through the day even with alot of daylight left. It only stop charging the batteries but still supply the load untill sun down. Need some advice on settings please.

 

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Morning Johan

Here is some questions :

  1. How to you measure your batteries? The Axpert it self or a BMV
  2. How far do you discharge your batts per day?
  3. Do you monitor your system?
  4. How did you determine that your batts are not charging anymore?

This should get things started.

 

Regards

Paul

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Hi there Paul. The Voltage is as per Axpert and i have used a multimeter to test it. After about midday each day I am told thatthe Axpert LCD Screen show that the Batteries are not Charging but the line run straight past to the Load. Very Confusing

Regards

Johan.

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10 minutes ago, Johan v d W said:

Hi there Paul. The Voltage is as per Axpert and i have used a multimeter to test it. After about midday each day I am told thatthe Axpert LCD Screen show that the Batteries are not Charging but the line run straight past to the Load. Very Confusing

Regards

Johan.

Sorry Paul im not there every day but it is monitored by a friend who live in the house.

The machine is set to discharge to 50%.

The Voltage when discharged is 46V and when the charge stop at halfway through the day it is at 52V.

When we Installed it it used to charge to 56.6 V.

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Ok , to be honest I dont know to much about the LCD but @Chris Hobson knows a fair amount about what all the images tells you. 

Regarding the monitoring of the batts.  
You have spent a fair amount on your system and if you are going to draw it down to 50% ( most of us here prefer to draw to 20% soc) I would say you must get a proper battery monitor. Again most of us here use a BMV 702 or 700. They are a bit expensive  +  R 3k but if you would like your batts to last you will need one. Here is quite a few discussions as to why it is a bad idea to use Volts to determine your SOC , the short answer is , you need to let the batts "rest" for a day before you will be able to get a fairly reliable reading. 

Second I would suggest you get some software to log your data from the Axpert and the BMV if you get one.  Manie's monitor software is quite popular and he has spend quite a bit of time to develop it so have a look at it as it is well rounded by now. There are other options also available but it will require quite a bit of time to get going. 

Just another note as well I think you should also post all your settings on the inverter. Chris posted a "manual" here that explains all of them and what should be ideal but some times the setup is not done correctly so it might also help.

 

P

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Hi @Johan v d W

I believe that there are a number of issues that you need to address;

  1. The Axpert is no good at determining State of Charge and you will damage a very expensive battery bank unless you make some changes fast - install a BMV-702 battery monitor and ICC software to monitor the equipment and control switching behavior using info provided by the BMV - this will cost a small fraction of replacing a damaged 800Ah battery bank. 
  2. Download the Coulomb/Weber firmware and flash your system, the primary advantage is that it addresses a bug where the Axpert goes to float too early resulting in battery under-charge.
  3. If you dont already have buy and install 4x HA-02 battery balancers to make sure that your batteries stay "in synch". Series connected batteries can very easily go out of synch resulting in failure of the entire battery bank - look in the downloads section for more info.

Lastly I have to say that your system is way out of balance. You have 12 x270W panels which will produce 16kWh on a good day. Your battery bank is 800x48 = 38.4kWh, even at 50% discharge you will need 19kWh x 1.25 (inefficiency) = about 24kWh to recharge, and that is before you have supplied any direct consumption loads.

You will need a 2nd Axpert in parallel and another 12 panels to balance your system (both inverters would share your existing battery bank).

Coulomb - Patch Instructions.docx

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  • 2 months later...

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