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Axpert VM II 5KVA Inverter [Programming]


Omarsz

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5 minutes ago, Energy said:

route of Greek gods

Are Roman gods allowed in your pantheon? Because my day job is working on software called venus, which is the Roman goddess of (amongst others, but let's not go there) prosperity :-)

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47 minutes ago, plonkster said:

(Apparently I got the reward for the guy who talks the most at my previous job, at the year-end function... AFTER I've left!)

They did that as they were worried about the length of your acceptance speech - Greer Garson would have paled into insignificance.

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3 minutes ago, Chris Hobson said:

They did that as they were worried about the length of your acceptance speech - Greer Garson would have paled into insignificance.

Rightly too! Do you know how much work this is for an introvert? :-P

(Funny how that works... you may be an introvert... but ask the right question and it opens up doors :-) ).

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  • 1 month later...
On 2018/08/27 at 10:18 AM, Chris Hobson said:

Morning @Omarsz

Attached is your batteries datasheet they are unusual in that they don't specify either a charging current nor an  absorb voltage.

 85.pdf

With that short coming in mind we will use standard values or existing values if they are not excessive.

Bulk charging voltage leave at 56.6V. 

Float charging 54.4 V

Battery Cut off voltage 47V

Back to grid voltage 48V

The charging regime is very high Gel and AGM batteries can accept higher charge but probably 60A is to high. Fortunately their rapid increase in internal resistance restrict current flow. I would try charging at 30A and if that is not problematic raise it to 40A and see.

Ac charging I would make also 30A.

Back to discharge voltage I would make 53 or 54V.. 

 

 

 

On 2018/08/27 at 11:43 AM, plonkster said:

That feels low to me. The documentation is sparse on this info, but looking at the one link, they provide this chart:

Selection_214.png.8bac6d91c46460f0125f540e112a97a1.png

That seems to suggest an absorption voltage of around 14.6V is wanted per 12V increment, so 58.4V for absorption.

On the other hand this image seems to call for something lower... probably float voltage?

Selection_215.png.574b2ae6ab14246e8e32657130ea6700.png

At 25°C. 2.23V times 24 is around 54V, so there I agree with you.

I've switched my Axpert VM2 5kva Inverter to Axpert MKS II 5kva. Batteries are the same.

I've added these values to the new inverter with a technician supervision:

Bulk charging voltage leave at 58.4V. 

Float charging 54.4 V

Battery Cut off voltage 46V (Was recommended by the tectechnician. According to him, It's 50% DOD.)

Back to grid voltage 48V

As I'm a newbie with these things and I'm the one who suggested these values, may I ask if setting the Bulk charging voltage to 58.4V would be dangerous in any sort?

I'm trying to be cautious and avoid anything that would void the battery warranty.

(Currently, Charging and discharging aren't fast as they were with VM II model. Yet, as soon as PVs no longer provide enough light, battery voltage goes down to ~ 49v. I'm not sure if the batteries were fully charged or not as I've tested it for 2 days only while the sky was cloudy.)

Edited by Omarsz
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On 2018/08/28 at 7:21 PM, The Terrible Triplett said:

Adding onto what the others are suggesting you look and and do / change, I'm just looking at more options.

Is there a way that you can load test each battery individually?

Reason being that if the charge drops fast from 100% SOC, there could be a chance that their is a battery or batteries that are faulty.

Another way to try, whilst the batteries are being charged, or under load, feel them for heat. On the sides, poles. Any heat, suggest a faulty battery.

Hello TTT

I've just charged the batteries with Utility. After around 2 and a half hours, one of the 4 batteries is warm. Significantly warmer than the other 3. 

I've also checked their voltages and found that the warm battery has 13.2 V while the other 3 are 12.5 V. 

Is this battery faulty for sure?

My main problem with the system right now is that the storage system doesn't feel like 4 batteries. It discharges faster than another system with 2 * 200ah/12 v with Axpert KS 3kva system.

 

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2 hours ago, Omarsz said:

I've switched my Axpert VM2 5kva Inverter to Axpert MKS II 5kva. Batteries are the same.

Just be aware that you have now changed from a model where a firmware update is available (from this forum in fact) to a model where there is presumably* no publicly available firmware update. So you could have had a lightly patched firmware for your old model (not done yet), but your present model will have to wait till a firmware patch file is available. Since you are having battery problems, the lack of availability of a patched firmware could be significant. 

But you seem to have a cooperative supplier, so maybe he will provide a firmware update file if you ask for it. That file could then be patched to fix the premature float bug. 

Can you tell us the main (U1) firmware version please? 

* I say presumably, because I'm not 100% sure if a different firmware main version number is used for the higher voltage MPPT models. There is a chance that the SCC firmware takes care of all the differences somehow. Hence my request for your U1 version numbers. 

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Hello Coulomb

I felt the MKS II is a better replacement for my needs as this can be connected to other (up to 9) inverters. It also could charge the batteries at high Amps from PV (Charging batteries at 23A from PV alone. I couldn't cross the 11A with the VM II inverter)

I've posted about the U1 in another topic where we exchanged some posts (U1= 71.20) 

https://powerforum.co.za/topic/2325-axpert-5kva-firmware/?tab=comments#comment-39029

I do have a cooperative supplier but I have no idea if he has access to a firmware update. I can definitely ask.

Could you please let me know where I can read more about the premature floating bug or how could I notice such a bug? (what problems should I face if I'm not already facing/faced this issue?)

Edited by Omarsz
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17 minutes ago, Omarsz said:

I've posted about the U1 in another topic where we exchanged some posts (U1= 71.20) 

Duh. Sounds familiar. So many versions! I checked my parallel compatibility post, but I failed to update that post with this information. I'll fix it soon.

17 minutes ago, Omarsz said:

I do have a cooperative supplier but I have no idea if he has access to a firmware update. I can definitely ask.

I was also wondering if they'd ever supply a firmware update file when you already have the latest version. 

17 minutes ago, Omarsz said:

Could you please let me know where I can read more about the premature floating bug or how could I notice such a bug?

This post by Weber has a concise summary, and a good way to demonstrate the premature float bug. Voltronic Power please note! You can do this test in your lab, and it conclusively shows that factory firmware is undercharging batteries unless there is no cloud at all!

Quote

(what problems should I face if I'm not already facing/faced this issue?)

Your batteries will be chronically undercharged, which is very bad news for lead acid batteries. A cloud comes by, the battery current goes down, and the firmware says in effect "Oh! The battery current just went low. It must be because the battery is full. I'll switch to float mode." But the reason for the low battery current is the cloud. The battery voltage has to be at or near the absorb/CV voltage for the low battery current to mean that the battery is full. Low battery current is a necessary but not sufficient condition for the battery to be full. Somehow, Voltronic Power have decided that the float voltage setting is the voltage to compare the present battery voltage with, even though they are in absorb / CV stage.

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6 hours ago, Omarsz said:

After around 2 and a half hours, one of the 4 batteries is warm. Significantly warmer than the other 3. 

I've also checked their voltages and found that the warm battery has 13.2 V while the other 3 are 12.5 V. 

Is this battery faulty for sure?

My main problem with the system right now is that the storage system doesn't feel like 4 batteries. It discharges faster than another system with 2 * 200ah/12 v with Axpert KS 3kva system.

Hi Omarsz,

YES, it most probably is the bad apple.

I would take that battery out and have it load tested.

As a matter of fact, check all the batts if you can, see where the others are standing at.

Doing these loads test are not good for the batts, but the only surest way of eliminating a potential brewing disaster ... and to remove any doubt.

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  • 4 months later...
5 hours ago, Getskay said:

I think Axpert manual stated that it support only 3 pannels in series, did you experienced any issue with 6 panels in series ?!

His machines (Axpert VM II then changed to Axpert MKS II) all have the higher voltage MPPT (450 or 500 V). The three panel limit (sometimes two) is for the models that have the 145 V maximum MPPT.

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