I have Axpert Max 7.2 KW, i set the charging source priority SNU (program number 16) but it is working as i set it on CSO (only solar), the battery will never been charged by AC input until the pv is disconnected. 

any help please.

Edited August 16, 20223 yr by Ali1994
To make the model name clear

5 minutes ago, Ali1994 said:

I have Axpert Max 7.2 KW, i set the charging source priority SNU (program number 16) but it is working as i set it on CSO (only solar), the battery will never been charged by AC input until the pv is disconnected. 

any help please.

As you mentioned on CSO it will only charge from PV. As there is no sun now if in SA it will only charge from the panels later in the day. This to save on grid power used. As your battery is in a charged state now it is fine leaving it in CSO mode as a good 11hrs of sun is available in Gauteng today.

I hope this answers your question.

CNU is for "solar + utility"

CSO is for "solar first"

when i use CNU it means that during the day if the PV generation is less than the max charging current, the utility will provide me with MAX AC charging current, so that i can ensure that my batteries will be full to use it during night  as the utility here is not available during night. But the CNU is working as it is CSO and i cant charge my batteries from utility during the day, just if i disconnect the PV it can be charged by utility.

 

 

 

Seen same behaviour on my clone,do you have a "Utility First" Charging Source Priority available?

From what I can gather from my Axpert MKS IV manual it seems like these settings are only available when in line (SUB)(USB), standby or fault mode.  So your screenshot is showing that you are in line mode - it should be using solar and utility (SNU) to charge. In battery mode (SBU) I assume its always solar first mode CSO.

Edited August 16, 20223 yr by Douw Gerber

34 minutes ago, Douw Gerber said:

From what I can gather from my Axpert MKS IV manual it seems like these settings are only available when in line (SUB)(USB), standby or fault mode.  So your screenshot is showing that you are in line mode - it should be using solar and utility (SNU) to charge. In battery mode (SBU) I assume its always solar first mode CSO.

On the older Axperts as well as this picture there is a solar only. CSO I think on the older ones and OSO in this picture.

Confusing if different letters are used on different models.

Edited August 16, 20223 yr by Scorp007

On 2022/08/16 at 11:20 AM, PsyWulf said:

Seen same behaviour on my clone,do you have a "Utility First" Charging Source Priority available?

I have 3 options
solar first

solar + utility

only solar

i used setting SNU which is Solar and utility .

On 2022/08/16 at 4:54 PM, Douw Gerber said:

From what I can gather from my Axpert MKS IV manual it seems like these settings are only available when in line (SUB)(USB), standby or fault mode.  So your screenshot is showing that you are in line mode - it should be using solar and utility (SNU) to charge. In battery mode (SBU) I assume its always solar first mode CSO.

I am using SUB mode, solar utility battery. And with SNU solar + utility for charging priority

@Ali1994

hi 

I have the same issue with my 7.2max 

it will not use utility to charge while the pv is above 90v. It only charges from utility if set to USB and SNU but then it does not use pv to supply the loads 

seems to be an issue with this inverter 

Hi there, 

I would like to revive this topic. Unfortunately don't have a solution, but having the same issue with an Max2 8KW inverter. But I was wondering whether you have any resolution since this happend 7 months ago?

When I realized what was happening with SNU charge mode not working according to the manual I got the inverter swapped as a warranty claim because it was only two month old when I had to use utilities for charging in line mode. The new inverter behaves in the same way. Its charging with utilities only, if there is no current coming from the panels. As soon as the panels produce current utilities charging stops immediately and only charging with panels happens. 

Thanks for some feedback, Wilfried

Hi,

 

I have literally, this morning changed a setting as I was monitoring the reaction to charge the batteries when on Solar first output, and Solar first charge priority.

 

I changed the Charging priority to be shared between Sol and Uti, seems to be the best setting, as batts are always kept full unless Loadshedding in the evening.

Hi Guys (sorry, only joined the Forum now - waiting for confirmation of registration).

Has there been any resolution on this issue? I had two Axpert Max 7.2kW inverters installed recently and I have the same problem as what some of you have mentioned previously. I choose SNU as the battery charging priority mode (which is supposed to be the most “aggressive” option), but when I want my batteries to receive maximum charge (during daylight hours) I have to switch my PV off, otherwise the charging current will be limited to what the PV can give. So the SNU setting is basically reacting the same as the CSO option (which is surely not right).

Robert

 

 

I think the problem is that the inverter/charger can only run in one way: Either convert DC to AC (inverting, to supply loads or be in standby for surges) or convert AC to DC (charging the battery).

When the AIO is in SUB/SBU modes, the inverter is in "invertering" mode, so it isn't free to run backwards in order to charge the battery.

Some AIOs may have a separate charger or some type of dual conversion.

I noticed the same behavior on my MUST 3KW 24V inverter (Axpert clone I suppose).

From my understanding, the AIO will charge via utility (in utility enabled charging modes, such as SNU or Solar first) , if the battery is low. In this case it will go into bypass/line mode, which will power loads directly from the grid, and then the inverter/charger is free to charge the battery.

Edited April 26, 20242 yr by meetyg

22 hours ago, meetyg said:

When the AIO is in SUB/SBU modes, the inverter is in "inverting" mode, so it isn't free to run backwards in order to charge the battery.

...

I noticed the same behaviour on my MUST 3KW 24V inverter (Axpert clone I suppose).

That's not my understanding.

I think your MUST 3 kW24 V inverter doesn't have SUB output source priority. Models like that can only perform utility charging when in bypass mode, where the load is supplied solely from the AC-in port.

But in models operating in SUB output source priority, they connect AC-in to AC-out and to the DC<->AC converter's AC side, and the power flow changes dynamically to and from the battery. The magnitude and sign of the power flow should reflect the various settings, present load, estimated available solar power, and so on.

It's pretty clever, but also easy to get wrong.

Actually, my MUST (PH-18 PLUS) does have SUB mode. 

At least from what I have played with the settings, I didn't see it charging from grid when in these modes. 

Also, in SUB and SBU, I noticed that there is no relay switching (as apposed to SOL mode, where it will physically switch after sunset). So I think you are correct that the inverter is connected, but I was convinced that it can only run one-way. I remember reading this somewhere too, but then again there are so many models around...

 

10 minutes ago, meetyg said:

At least from what I have played with the settings, I didn't see it charging from grid when in these modes. 

@Coulomb

OK, so after reading your answer again, it made me re-think my previous statements. 

So let me just summarize, to make sure I understand:

1. AIOs (were talking about Voltronic and probably most clones) that have SUB mode, are capable of utility charging while not in bypass mode.

2. I guess the reason that I didn't see utility charging in modes other than UTI (bypass) is probably due to the fact that in UTI mode, it doesn't care about "back to grid" or "back to battery" settings.

But in SUB/SBU, it will only charge via grid if battery is lower than a threshold in the settings. From my observation it's the lower of the two.

 

15 hours ago, meetyg said:

Actually, my MUST (PH-18 PLUS) does have SUB mode. 

Ah. That MUST is not an Axpert clone; it does its own thing, including exporting power the the grid if enabled (if my memory serves).

15 hours ago, meetyg said:

1. AIOs (were talking about Voltronic and probably most clones) that have SUB mode, are capable of utility charging while not in bypass mode.

SUB is not a "mode", it's an output source priority. Which mode it ends up in depends on availability and strength of the various power sources (AC-in, PV, battery). SUB usually means blending AC-in and PV, UTI/USB usually means line mode (not bypass mode), and SBU usually means battery mode. Many people and I suspect some monitoring software make this mistake.

When output source priority is in SUB mode and the inverter is in line mode (blending AC-in and PV), then yes I believe that it can utility charge the battery. All it has to do is to reverse the power flow of the DC<->AC converter.

I'm not familiar with the term "AIO"; I assume it means "inverter" or perhaps "inverter-charger". Oh, or All In One, duh. Meaning it also has a transfer switch incorporated.

15 hours ago, meetyg said:

2. I guess the reason that I didn't see utility charging in modes other than UTI (bypass) is probably due to the fact that in UTI mode, it doesn't care about "back to grid" or "back to battery" settings.

Depending on the model, UTI (often called USB in later Axpert models) output source priority often means that the inverter is in bypass mode. In bypass mode and UTI/USB output source priority, yes, I don't believe that it cares about those settings. But bypass mode and SBU output source priority does heed these settings, which may or may not cause the inverter to change to battery mode when the battery is believed to be strong enough.

16 hours ago, meetyg said:

Also, in SUB and SBU, I noticed that there is no relay switching (as apposed to SOL mode, where it will physically switch after sunset).

SOL output source priority will switch between battery mode during the day and line mode at night. In models with this output priority option, line mode means in effect bypass mode, since these models don't allow the "blending" connection (all 3 of AC-in, AC-out, and the DC<->AC converter all connected together, and the DC<->AC converter allowed to operate in the DC->AC power flow direction. Switching between battery and bypass modes does indeed require switching two relays (the two AC-n relays, one for live and one for neutral).

It is all very confusing, I'll readily admit.

On 2024/04/28 at 1:43 PM, Coulomb said:

That MUST is not an Axpert clone; it does its own thing, including exporting power the the grid if enabled

Yes, it's an odd little creature 😺. 

While in some ways it's very similar to Voltronic/MPP all-in-ones, they certainly have diverted quite a bit from them. I think early models of the MUST inverters were clones. But I guess once they've got so different, you can't really call them clones anymore.

It does seem however to inherit some of the Voltronic quirks, like the premature float bug.

It's actually feature rich, with some setting not seen much in other devices (LBU/SBU solar output priority) and of course the grid feedback.

Anyways, thanks for the deep explanation! I certainly have learned alot. First I now understand the difference between LINE mode and BYPASS. I used the terms alternatively, but as per your explanation there is a big difference.