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Axpert - strange behaviour (Potential MPPT issue)


PeterDawson

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Anyone yet with a solution to the total PV drop on the Axpert King 5kw?

I experienced another total loss yesterday (first in about 2 weeks). 

Today it was running fine until around 11h30 when there was a sudden drop in the solar watts AND the batteryWatts???  Not sure why . Since then the SolarWatts seems to follow the load, only producing what is needed for the load, stuff the battery!

Any ideas?

System consist of Voltex King 5KVa, 10Kw LifePo4 lithium batteries with built in BMS, 12 x 330w PV

 

image.png

ICC 2602 Dash.JPG

ICC 2602 Graph.JPG

ICC 2602 Settings.JPG

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15 hours ago, KobusC said:

Anyone yet with a solution to the total PV drop on the Axpert King 5kw?

I experienced another total loss yesterday (first in about 2 weeks). 

Today it was running fine until around 11h30 when there was a sudden drop in the solar watts AND the batteryWatts???  Not sure why . Since then the SolarWatts seems to follow the load, only producing what is needed for the load, stuff the battery!

Any ideas?

System consist of Voltex King 5KVa, 10Kw LifePo4 lithium batteries with built in BMS, 12 x 330w PV

 

image.png

ICC 2602 Dash.JPG

ICC 2602 Graph.JPG

ICC 2602 Settings.JPG

Kobus, most I my issues have disappeared. I think the main reason is because I changed my PV panels wiring so that I now have three 330W panels in series. I have the same 12 panels you have, but previously only had 2 panels in a string. This would cause the MPPT voltage to drop below the minimum Volts required.

I also see a big drop in PV Watts, but this is only when the batteries are fully charged. 

image.png.b74934f27c0cf43259a9ccfe524294d7.png

 

My settings are similar to yours, but your bulk charging voltage seems high. You should check with your battery supplier what the recommended values are. Your back to grid voltage and back to discharge voltage are also different.

image.thumb.png.b21b2a7faf94937a7a791360c1a74cd4.png

 

I think the reason the solar doesn't seem to change your battery, is because the battery is actually already fully charged, even though the inverter doesn't know it (SOC 73%).

I have a set of two 3.6kW Pylontech batteries, so with the cable between the Axpert inverter and the batteries, my inverter knows the exact SOC of the batteries. 

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8 hours ago, Pipes said:

Kobus, most I my issues have disappeared. I think the main reason is because I changed my PV panels wiring so that I now have three 330W panels in series. I have the same 12 panels you have, but previously only had 2 panels in a string. This would cause the MPPT voltage to drop below the minimum Volts required.

I also see a big drop in PV Watts, but this is only when the batteries are fully charged. 

image.png.b74934f27c0cf43259a9ccfe524294d7.png

 

My settings are similar to yours, but your bulk charging voltage seems high. You should check with your battery supplier what the recommended values are. Your back to grid voltage and back to discharge voltage are also different.

image.thumb.png.b21b2a7faf94937a7a791360c1a74cd4.png

 

I think the reason the solar doesn't seem to change your battery, is because the battery is actually already fully charged, even though the inverter doesn't know it (SOC 73%).

I have a set of two 3.6kW Pylontech batteries, so with the cable between the Axpert inverter and the batteries, my inverter knows the exact SOC of the batteries. 

 

Pipes

Thanks, will test similar charging settings.

My panels are also wired 3 per series, so I assume my PV voltage is fine.

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5 minutes ago, KobusC said:

 

Pipes

Thanks, will test similar charging settings.

My panels are also wired 3 per series, so I assume my PV voltage is fine.

Yes your PV Voltage looks good. The minimum and maximum MPPT Voltage will depend on your inverter, but I also have a 5kW unit and I think my range is from 70V to 145V.

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  • 2 months later...

I've had a thought on what might be causing the dips. I posted about it here.

Unfortunately, as I was explaining it, I came to realise that the 30 second between dips requirement is not met by many of your data.

Even so, I'd like to know if the charger is in float stage before the dips; it's possible I miscalculated to 30 second requirement.

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Hi Coulomb

Thanks for still thinking about us.

image.thumb.png.e2a0b3a89d9e345a67addac6880c6f3c.png

Zooming in more around the trip:

image.thumb.png.f4ebe3099ecfccdef7af6d5a05f2e0f7.png

Here is a recent trip which occurred while the charger would definitely been in Bulk mode.  This one seems to have been caused by a decent load turning on and off.  My parents are at the house and my guess is that this is the microwave.

As always, I bump the bulk charge voltage setting (prog 26) to kick start the SCC again.  I have been steadily reducing the charge and float voltage which seems to have minimised the trips to maybe once or twice per week.  My parents have been in residence for five weeks now so there is more usage on the system than normal.

Current settings:

Prog 26 - Bullk charge voltage: 51.3V

Prog 27 - Float charge voltage: 50.6V

These are significantly lower than the settings suggested by the battery docs of 53.5V and 52.0V, but they're working for me.  Do you see any issue with running such low voltages?

Thanks as always.

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2 hours ago, PeterDawson said:

These are significantly lower than the settings suggested by the battery docs of 53.5V and 52.0V, but they're working for me.  Do you see any issue with running such low voltages? 

No, I think they are ok, the float voltage is still higher than my own setting (adjusted for 15S). It might take a bit longer to fully charge the battery.

My theory is looking pretty battered at present.

With your lower battery settings reducing the problem, I'm back to thinking it's the BMS panicking over high cell voltages. It may be that if I can find the elusive overshoot and undershoot code, that might finally fix a bunch of problems.

Edited by Coulomb
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On 2020/05/07 at 9:30 AM, Coulomb said:

No, I think they are ok, the float voltage is still higher than my own setting (adjusted for 15S). It might take a bit longer to fully charge the battery.

My theory is looking pretty battered at present.

With your lower battery settings reducing the problem, I'm back to thinking it's the BMS panicking over high cell voltages. It may be that if I can find the elusive overshoot and undershoot code, that might finally fix a bunch of problems.

I lean towards your theory too. 

I have asked one person who is not using bms and he said he is not experiencing any dip. 

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My setup is as follows:
2x 3x400W solar panels an 5KVA 4kW Axpert inverter clone running with 1 Pylontech US3000 battery.
Custom home software scanning inverter and battery at 3 sec intervals. 

With settings of 30A charging and bulk charge Voltage above 53.2V and float 53.2V I get the same PV drop problem if the battery is fully charged and the load is suddenly changed like with an iron switching on or off. 
I have notice under these conditions the inverter float charging have a fast overshoot with 1V to above the 54V triggering the battery protection. This seems like confusing the SCC and seems like it gets into a bad state.

 After dropping the bulk charge Voltage to 52.8V and float to 52.8V the 1V over swing is below the 54V of the battery and there are no problems. These condition is monitored continues in my software and email me if this happens. With theses settings for my setup I don't get this problem any more. 

 

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  • 1 month later...

Hi

I have not been experiencing the total PV loss for a few months now since I dropped my bulk charge and float voltages to similar than Gerhard at 52.4v.

The system has been running very well up to about 2 weeks ago. I noticed on the remote monitoring that the PV input is 0 for the whole day! When I got home I hard reset it and it was working fine again. A few days later the same thing happened. After hard resetting it again starts using PV.

This morning I again noticed the same issue. It appears to be completely random. It was running fine this weekend (see attached) . Today while at work I checked it and saw the same issue.

It appears that the MPPT does not reset sometimes during the night??

Any comments or suggestions would be appreciated.

installed a  Voltex King 5kVa about 6 months ago along with 12x 300w Pv's and 2x 5Kw Lithium batteries.

image.png.98d136da4cb7c8b1e6e625a4c5eaa975.png

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15 hours ago, KobusC said:

Forgot to mention that the PV strings at the inverter do measure their 110v, but inverter does not respond to it.

Ah. I've just responded to ask that on the other topic you posted to.

110 V is fine; there should be no problem. This is sounding like the dreaded dips and freezes problem; with the PV disconnecting all day, that's a freeze.

Unfortunately, we (this forum) don't seem to have a solution for that, or even a convincing mechanism.

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  • 4 weeks later...

Will it damage you inverter or pv panels if you connect a DOL starter switch with a timer to reset you pv voltage on a hourly basis - between pv panels and inverter? It works if I do it manual with my disconnect switch when pv freeze happens.

Im just conserned about damaging my equipment when reset happens under load. Can someone give advise please.

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  • 2 months later...

Hi guys

Stumbled across this informative thread, after experiencing the exact sane thing: newly installed PV array and PV Watts dropping to zero randomly during sunny midday. Stays that way for until next day and then seems to reset.

Very insightful reading here, but seems the issue still persists? Does anybody know if there has been feedback on this on perhaps new firmware planned? Or perhaps some acknowledgement/response from the original manufacturer (Voltronic?).

I read about @Coulomb's Axpert firmware patch and was going to investigate that for improved use of my Axpert, but now I am wondering if I should first focus on resolving this annoying Axpert glitch 🤔

My system consists of:

- Easypower branded Axpert (sticker model 5KVA-48VDC - see pic)

- 12x Easypower Deep cycle VRLA batteries (HXG12-100 (12V100Ah)). 3x 48v Strings = 300ah capacity

- 12x 305w Canadian Solar panels (4 strings of 3 panels each)

- Victron BMV-702

- Running ICC on RPi

By the way, I realise the SOC graph from the BMV looks odd. It’s very newly installed and I only set the calibration settings after taking these screenshots. Hopefully will correct my SOC readings going forward!

Thanks!

Jaco

 

 

A74C90BB-4BAB-46FC-8015-9C5ED373E740.jpeg

49A3FB97-67A1-48A4-9375-7185724140F1.jpeg

42BF3D66-7D85-471B-A1B0-2ECCF45DC2D9.jpeg

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2 hours ago, JAvandermerwe said:

305w Canadian Solar panels (4 strings of 3 panels each)

Are they 60 cell? The ones I looked up are, but Canadian make a lot of different panels. If 72-cell, then that's your problem.

What peak PV voltage are you seeing?

2 hours ago, JAvandermerwe said:

I read about @Coulomb's Axpert firmware patch and was going to investigate that

You have a clone, so it may not be advisable or even possible to update the firmware.

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11 hours ago, Coulomb said:

Are they 60 cell? The ones I looked up are, but Canadian make a lot of different panels. If 72-cell, then that's your problem.

What peak PV voltage are you seeing?

You have a clone, so it may not be advisable or even possible to update the firmware.

Thanks @Coulomb, appreciate your reply. The panels are 60 cell (half cell panels - the suppliers also advised to get them for this reason 👍)

Max PV voltage reading to date was 114v, and although I've only had the panels in for a few days, seems to peak daily at around 100-110v. 

Pity about the Axpert clone. I'm secretly hoping it will die, so I can replace it with a "true" hybrid like the Sunsynk 8kw that I see is also available through Powerforum-store. Wish I had been aware of this forum before I started my solar journey!

 

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1 minute ago, JAvandermerwe said:

Thanks @Coulomb, appreciate your reply. The panels are 60 cell (half cell panels - the suppliers also advised to get them for this reason 👍)

Max PV voltage reading to date was 114v, and although I've only had the panels in for a few days, seems to peak daily at around 100-110v. 

Pity about the Axpert clone. I'm secretly hoping it will die, so I can replace it with a "true" hybrid like the Sunsynk 8kw that I see is also available through Powerforum-store. Wish I had been aware of this forum before I started my solar journey!

 

Graph of PV experience to date...

 

A50FBC2B-C0FB-4C7F-BF28-6B30E940E1DB.jpeg

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On 2020/10/02 at 9:27 PM, JAvandermerwe said:

Max PV voltage reading to date was 114v, and although I've only had the panels in for a few days, seems to peak daily at around 100-110v. 

Ok, so that should be under the over-voltage limit, even at 0°C (barely, and at those times the sun intensity is likely lower than now). 

It might still be interesting to disable all but one string, and temporarily rewire that string as 2S, to see if it dramatically improves the dropouts. These 145 V absolute max solar charge controllers do seem to prefer 2S. But I wonder if 2S would be enough with 60-cells, when conditions aren't ideal (cloudy or early/late in the day).

It could be temperature. Are the fans working hard? Do they push air downwards or pull it up? The latter is the way Voltronic do it, so the clones likely copy that "feature". Older firmware was either too quick to ramp up to maximum fan speed, or too slow. Around 2015, it was probably the latter. In which case, a lot of the time, the fans are mostly countering the natural rise of hot air. IF you can update to patched firmware version 73.00e, it will work the fans much harder (but mostly during the day when the SCC needs it). Don't update to factory firmware version 73.00, as you will run into fault code 90 (which seems designed to embarrass clone manufacturers, and frustrate their customers).

Just reversing the fans (if needed) provides a worthwhile increase in cooling. It can be done without taking off the main cover; just take out the serial comms board (assuming it's the same with a clone, of course).

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On 2020/10/03 at 2:50 PM, Coulomb said:

Ok, so that should be under the over-voltage limit, even at 0°C (barely, and at those times the sun intensity is likely lower than now). 

It might still be interesting to disable all but one string, and temporarily rewire that string as 2S, to see if it dramatically improves the dropouts. These 145 V absolute max solar charge controllers do seem to prefer 2S. But I wonder if 2S would be enough with 60-cells, when conditions aren't ideal (cloudy or early/late in the day).

It could be temperature. Are the fans working hard? Do they push air downwards or pull it up? The latter is the way Voltronic do it, so the clones likely copy that "feature". Older firmware was either too quick to ramp up to maximum fan speed, or too slow. Around 2015, it was probably the latter. In which case, a lot of the time, the fans are mostly countering the natural rise of hot air. IF you can update to patched firmware version 73.00e, it will work the fans much harder (but mostly during the day when the SCC needs it). Don't update to factory firmware version 73.00, as you will run into fault code 90 (which seems designed to embarrass clone manufacturers, and frustrate their customers).

Just reversing the fans (if needed) provides a worthwhile increase in cooling. It can be done without taking off the main cover; just take out the serial comms board (assuming it's the same with a clone, of course).

Super, thanks for the helpful suggestions @Coulomb. Probably going to pass on testing the 2S theory, simply because its a very awkward, high location for the panels, with no easy way for me to access the wiring. I will however look into the fans & cooling. It was fairly hot on the day I experienced the dip, but been quite cool and overcast since then, and the issue has not yet reoccurred.

In the meantime, I'm also learning how to fine tune my BMV's settings and SOC readings. Quite a fun journey so far, and so much to learn! 😄

Jaco

 

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  • 1 month later...

Morning

I have read through this forum and am having a similar challenge with my PV

I have a 5kw Must Hybrid Inverter with built in MPPT. 9 x 365w panels (connected 3 in series x 3 rows). And 4 x 200ah gel batteries.

My system works on a load matching basis for the solar during the day and at night draws from the batteries but keeps the batteries at 50.0V in case of load shedding.

Normally the PV voltage ramps up to around 120V and charge power ranges anywhere from 500w to 3,500w depending on the load needs.

It’s been working well since i installed (a month ago) however from 2 days ago i noticed on the monitoring system that (while the sun is out and sky clear) the PV voltage spikes to higher levels ie around 125V or above and the charge power drops to around 150w and the charger current drops to 2.9-3.1a - this happens for a period ranging from 15mins to 1.5hrs - the first day was 1.5hrs at one go (from 7.15-8.45am) and then 10-15min periods three times after and then day 2 15mins and yesterday 15mins both around 2pm

Any ideas?

should i change my bulk and float rates for my battery

it only started behaving like this after the heavy rain and storms on the weekend but i cant imagine thats changed anything as it works like normal for most of the day except for these short periods when i see the dips

 

PV table1.bmp PV graph1.bmp

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