Hi guys,

We have a series of Axpert 5000VA inverters. On a hot day, we have a situation where sometimes something switches on and then the inverters throw up a 03 (high battery voltage) error and the system switches off for about 30 seconds and then back on. Battery importer has been in and checked BMS parameters, et cetera. Problem persists. I suspect possible voltage bounce on the batteries but am not certain.

Anyone got any ideas?

Thanks in advance.

18 hours ago, CDL said:

sometimes something switches on and then the inverters throw up a 03 (high battery voltage) error

I would expect that more when a large load switches off, and something (utility or solar) is charging the battery.

It's possible that the battery has high internal resistance. This could be the result of chronic undercharging of the battery, especially if it is a lead acid type.

All Axpert inverters suffer from the premature float bug, unless they are running patched firmware. Can you check through logs to find out if the battery voltage stays near the absorb voltage setting for something like an hour? If no logs, you could monitor the battery voltage manually, preferably on a cloudy day.

Thank you so very much Coulomb. These are LifePo4 batteries - but I see on the link you posted that this can occur with both battery types. This is a friend's installation. I see on my own Victron installation, they battery voltage will sometimes throw up a very brief spike on a hot day when something switches on. It looks like a kind of "voltage bounce". And sometimes will go as high as 59.87 V. I think the same batteries combined with the Axpert may also be "bouncing" and causing the inverters to throw up an error.

Edited November 20, 20205 yr by CDL

6 hours ago, CDL said:

This is a friend's installation. I see on my own Victron installation, they battery voltage will sometimes throw up a very brief spike on a hot day when something switches on. It looks like a kind of "voltage bounce".

it could also be the solar charge controller overshooting as a reaction to the increased load.

It's possible that your friend has absorb/bulk and/or float voltage settings too high. Perhaps the BMS is switching off the battery due to the excessive voltage, and that allows the solar charge controller to push the battery terminal voltage too high, because there is now no battery to absorb the excess energy from the solar charge controller.

If your friend has a 15S battery, check that the absorb/bulk voltage setting (setting 27) is no higher than 52.5 V.

H Coulomb, thank you so much for this. I will relay the info. 

Okay, so I had a look at some of the data again. It seems to happen when the batteries are full. A large load is switched on (let us say for example a draw of -70 A) and you see a sudden drop in the battery voltage at the same time. Say from 54.49 V down to 52.88 V. Then there's a sudden reversal in battery current. Goes from -70 A up to +14 A. Voltage then simultaneously bounces up to say 56.8 V (sometimes as high as 58 V) and then there's a sudden drop almost immediately after that down to 55.5. So it seems to be something along the lines of the charge controller overshooting. This is on my Victron system with the same battery array as my friend is using with his Axpert. So I guess something similar may be happening in that context as well.

Edited November 25, 20205 yr by CDL

On 2020/11/20 at 3:20 PM, Coulomb said:

it could also be the solar charge controller overshooting as a reaction to the increased load.

It's possible that your friend has absorb/bulk and/or float voltage settings too high. Perhaps the BMS is switching off the battery due to the excessive voltage, and that allows the solar charge controller to push the battery terminal voltage too high, because there is now no battery to absorb the excess energy from the solar charge controller.

If your friend has a 15S battery, check that the absorb/bulk voltage setting (setting 27) is no higher than 52.5 V.

I'm wondering if you can help me,

I've go a Axpert 5kva connected to a 2.4kva Shoto battery(50ah, 48v), no solar connected yet. I also got the 03 overvoltage error on my system. So I shutdown the system and did the following.

• I powered off everything, including the battery(all wires still connected).
• I powered on the battery, the inverter screen light up and shows the battery symbol, indicating the battery is connected.
• I then switched on the main breaker that supplies the inverter with AC, the screen then indicated that the AC was connected and within 5 seconds the battery started to charge.
• Then I switched on the invertor with the little black switch at the bottom, for 10 seconds nothing happened(while the system initializes).
• The screen then showed the bypass symbols for n split second it disappeared and the alarm buzzer started sounding off and the screen showed the error 03.
• The battery then shutdown and proceeds to enter into a protection mode.
   

To my understanding and what you have describe, a 03 indicates overvoltage on the battery terminals, so while it was showing this error I used the up/down arrows on the Axpert to navigate to the batt voltage display and the reading showed 120v(I did this whole sequence 4 times, every time it shows exactly 120v).

The battery has been tested properly and works as expected indicating there is nothing wrong with the battery, I'm 100% sure of this.

This system has been running for 2 to 3 years in this configuration and this problem occurred 3 weeks ago.

Any suggestions to what could cause the. This problem occurred randomly, meaning when everything was fine with the mains. The mains did not cut out.

23 hours ago, willem12345 said:

I used the up/down arrows on the Axpert to navigate to the batt voltage display and the reading showed 120v(I did this whole sequence 4 times, every time it shows exactly 120v).

That sounds like there is a problem with the hardware that measures the battery voltage. I've heard of 90 V being displayed; perhaps if the measurement comes to more than 120 V it clips the result to 120 V. Hence the steady reading (when it's playing up; presumably it has a reasonable measurement when not playing up).

If you're handy with electronics, the culprits are likely eight resistors worth about R0.5 each, they might be affected my moisture, or they get cracked, shorted by solder bridges, etc.

Otherwise, if I'm right, you will need to get it repaired. Since the parts cost is so low, it would be good to find someone who can do board level repair, rather than replace the main board at some 500x the cost (excluding labour).

You might be able to make the problem come and go with heat or cold. That would at least confirm that it's a hardware fault.

Thanks so much for your response, @Coulomb.

I'm an electronic/software engineer, so I can probably fix it on a hardware level. So like most software engineers, I hoped that I could fix it with a firmware update. 

But the device is still in its warranty so it's going back for them to fix it. 

Your cracked resistor theory is probably spot on considering that it happened the first time on a very cold morning. 

Edited June 23, 20223 yr by willem12345

On 2022/06/21 at 3:54 PM, Coulomb said:

That sounds like there is a problem with the hardware that measures the battery voltage. I've heard of 90 V being displayed; perhaps if the measurement comes to more than 120 V it clips the result to 120 V. Hence the steady reading (when it's playing up; presumably it has a reasonable measurement when not playing up).

If you're handy with electronics, the culprits are likely eight resistors worth about R0.5 each, they might be affected my moisture, or they get cracked, shorted by solder bridges, etc.

Otherwise, if I'm right, you will need to get it repaired. Since the parts cost is so low, it would be good to find someone who can do board level repair, rather than replace the main board at some 500x the cost (excluding labour).

You might be able to make the problem come and go with heat or cold. That would at least confirm that it's a hardware fault.

Do you perhaps have any diagrams or pointers on where to locate the resistors to test? I have a "Synapse" / Axpert 3.0V 3KVa which I left running with no load while away. It triggered the 03 voltage error and since I have an independent voltage display on the battery (Mastervolt 24V Lithium) it also showed that the battery was sitting at 30V (usually around 27V) I got my house sitter to pull the battery fuse and bypass it. Now that I am home and testing it is working under load but the voltage values on the inverter is definitely not aligned to the battery voltage. ( 29V on inverter, 26.7V on battery) and it's fluctuating on the inverter display. Now I have another all day power outage and cannot go without it but so far under load it's running and hasn't triggered the voltage alarm. It's also not charging from the PV since the inverter voltage is still showing high and it thinks that the battery is still at 100%. I changed the fans recently and I do have coastal conditions so it's likely that salt or moisture has been a factor. (warranty expired)

Sorry to hijack this thread, does anybody know of somebody close to centurion that would be able to repair this on inverter. My parents have exact same issue on Solarwize ( clone of axpert) 5kw inverter with Gel Batteries. 

28 minutes ago, JPNiemand said:

Sorry to hijack this thread, does anybody know of somebody close to centurion that would be able to repair this on inverter. My parents have exact same issue on Solarwize ( clone of axpert) 5kw inverter with Gel Batteries. 

Contact @BritishRacingGreen on the forum. 

@Scorp007 thank you so much have done so. Really hope somebody can help, and not be cost of a new one 

36 minutes ago, JPNiemand said:

@Scorp007 thank you so much have done so. Really hope somebody can help, and not be cost of a new one 

https://forums.aeva.asn.au/viewtopic.php?p=96186#p96186 - there is more detail in this thread, however this may not be applicable to the version you have.

Sorry for hijacking this thread but I am also having a similar problem with a 3KVA hybrid MUST inverter. What's interesting is that whenever I load the inverter to the main house consumer unit, with all the breakers off except for the lighting and all the lights On, the inverter is working just fine. But as soon as I switch On the sockets breaker the inverter throws up error #3 (Battery voltage too high) and shuts down for few seconds and then On again. This results in On/Off of the inverter until I switch off the sockets breaker. After installation the system was working just fine for close to five months after which it started malfunctioning. But when I load the inverter directly, e.g. by connecting a heavy load like 1800w heater directly to the output terminals, the inverter works just fine. This leaves me confused if its the inverter faulty or if there is something wrong with the socket wiring. Anyone with an idea of what could be wrong I will really appreciate.

2 hours ago, Samuel said:

Sorry for hijacking this thread but I am also having a similar problem with a 3KVA hybrid MUST inverter. What's interesting is that whenever I load the inverter to the main house consumer unit, with all the breakers off except for the lighting and all the lights On, the inverter is working just fine. But as soon as I switch On the sockets breaker the inverter throws up error #3 (Battery voltage too high) and shuts down for few seconds and then On again. This results in On/Off of the inverter until I switch off the sockets breaker. After installation the system was working just fine for close to five months after which it started malfunctioning. But when I load the inverter directly, e.g. by connecting a heavy load like 1800w heater directly to the output terminals, the inverter works just fine. This leaves me confused if its the inverter faulty or if there is something wrong with the socket wiring. Anyone with an idea of what could be wrong I will really appreciate.

I'm not an expert, but if you are getting an error with a breaker circuit it sounds like the inverter doesn't like the common neutral / earth, especially if it kicks out with only the plug breaker (lights often aren't earth protected but plug circuits are). From testing mine was using the neutral relative to each input, ie AC, Solar and Battery and when it was misbehaving I noticed that the neutral difference had drifted between each by a voltage approximately equal to the incorrect battery voltage it was displaying on the inverter. In other words, it was measuring 20V when the battery was really at 27V and the voltage delta between the neutral / earth was around 6-7 volts. In my case the voltage divider resistors needed replacing (this is the part of the circuit which measures these DC voltages. Again I am NOT an expert and an electrician who is experienced in this can check your neutral and earth connections to rule that out at least. If nothing is obvious, maybe test the inverter on another circuit if you can. (same battery and setup, but another form of load via a circuit breaker) In other words a potential faulty breaker, earth leakage breaker or a "floating earth"  somewhere on that circuit.