On 2023/10/29 at 5:12 PM, Rozsda said:

It works!
The battery didn't run down all summer and I couldn't try it.
But recently there have been days when the battery died and the dry contact connected the mains and then the inverter switched to line mode.
Another question. Has anyone disconnected the power supply line between the MAX 2 auxiliary power supply and mppt??? What are the disadvantages of disconnecting it?

Thanks for the info Rozda.

Because my Max ii 8000W does not take track of time correctly, I have decided to no longer rely on the timers of program 99 and 100, but to apply your solution using a dry contact. So I am quite happy with your feedback.

Axpert service will update the Firmware (now 81.02 and 122.12) next week and hopefully that will fix the clock and possible other hick-ups.

Do you happen to know at what voltage to set a pylontech 5000, so as to trigger the dry contact?

PS: I think my model does not have an AUX power supply, nor do I use a seperate mppt. So no info from my part. Sorry.

 

Regards, Kurt

The firmware got fixed, but to no avail. The clock keeps running slow.

Has anybody been able to fix this? (I will start a new topic on this.)

On 2023/11/23 at 8:39 AM, Kurtbe said:

The firmware got fixed, but to no avail. The clock keeps running slow.

Has anybody been able to fix this? (I will start a new topic on this.)

This was actually a mistake on my side. It does now run at the correct time.

On 2023/10/29 at 5:12 PM, Rozsda said:

It works!
The battery didn't run down all summer and I couldn't try it.
But recently there have been days when the battery died and the dry contact connected the mains and then the inverter switched to line mode.
Another question. Has anyone disconnected the power supply line between the MAX 2 auxiliary power supply and mppt??? What are the disadvantages of disconnecting it?

I have done what Rozsda has done: installed a relay and set programme 12 to 47V (and 13 to 51). The battery is now @ 11% with 47.4V. The battery itself (Pylontech US5000) is still showing 2 out of the 6 LED dots, which could indicate that there is more power in the battery than what the Axpert tells me on WatchPower.

But nothing seems to happen. The Axpert is not giving an alarm signal that the battery is low in power (before a recent firmware upgrade it did).

The relay gets it's normal 230V in, but the output is 0. I do not measure anything between A1 & A2 (not even on the Axpert) I connected the dry contact to C - NO. So I assume that as soon as the battery reaches 47V (47,99 to be more precise), the dry contact should switch... but nothing happens. Not even if I set the trigger to 48V.

What could I have done wrong? 

1 hour ago, Kurtbe said:

I do not measure anything between A1 & A2 (not even on the Axpert) I connected the dry contact to C - NO...

I can't follow your diagram. The dry contacts are just contacts; there is no voltage behind them. You have to supply the voltage externally. So if A1 and A2 are the relay coil terminals, then connecting these to the dry contacts on its own won't do anything, and should never have.

Older models had a setting to change the behaviour of the dry contacts, but I don't think that the MAX firmware would still do this.

3 hours ago, Coulomb said:

I can't follow your diagram. The dry contacts are just contacts; there is no voltage behind them. You have to supply the voltage externally. So if A1 and A2 are the relay coil terminals, then connecting these to the dry contacts on its own won't do anything, and should never have.

Older models had a setting to change the behaviour of the dry contacts, but I don't think that the MAX firmware would still do this.

Thank you very much for your (swift) reply!

I was under the assumption that the dry contact was powered and would give a pulse to the relais to switch.

I have re-wired and will have another test tonight (being your day). I will try and run the battery empty during the evening to see if the grid will kick in. Hopefully by tomorrow I will be able to confirm that it does work.

Kind regards, Kurt

 

So far so good. Eventhough a 30mA differential jumped when the change was made from battery mode to line mode. But that is probably the diff itself, since others remained on. Or it could have been my car which was charging at that moment (but only @ 7Amps).

The system switched back to Battery mode in the middle of the night without me noticing. 

I swapped the diff this morning and wil try again tonight. 

In this way I use the grid like a generator to pervent the batteries running dry in the morning, typically around 5-6 o'clock. Just a little top up will do, because soon the sun will start charging again (typically 7-8 o'clock). This is a workaround to prevent the Axpert to take its own 70W per hour from the grid, and only use the grid in cheap nighttime. This setup also allows me to test the system for an extended period. If I do not have to rely on the grid for more than a year or so, then I will disconnect completely from the mains and run the house 100% off-grid. 

Two questions:

1. Program 3 (input Volt range) is set to UPS (Which I assume switches quicker than APL: 15ms as opposed to 20ms). Is that correct?
2. Is there a way to finetune program 12 and 13? Because the difference of % in the battery between 47 or 48 V is huge. Ideally I would like to switch to grid @ 15% and quit the grid again @ 30%. (My Victron sets actually allow to set the % rather than the Voltage.)

Regards, Kurt

Out again with a big bang... Same diff. jumped. But again: the car was charging.

Getting back to battery mode was marked by a flicker of the lights, but all circuits remained on. 

I will now try and drain the battery without charging the car.

Most probably it is the car that makers the diff jump. Tried to drain the battery with an electric heater, and the system switched to line mode with only a flicker of the lights. 

So now, all I am hoping for is that I can finetune the the battery percentage...

@ Coulomb: AEVA: would this be 'Australian Electric Vehicle Association' ? (Because there is a lot of AEVA about in Google.🙂

On 2023/11/27 at 3:53 AM, Kurtbe said:

Most probably it is the car that makes the diff jump.

It's not a good idea to try to switch from utility to or from battery when an electric car is charging. The on-board chargers all have a PFC (Power Factor Correction) stage, which has a big inductor at the input. Interrupting current through an inductor causes a big spike of voltage, in the kilovolt range. There are circuits to absorb this, but they may have part of that current go through ground conductors briefly. This could cause protection devices (we call them RCDs, residual current devices or similar) to trip. Also the protection devices (often MOVs or Metal Oxide Varistors) wear out, they degrade slightly with each protection, and you don't want to blow up your expensive on-board charger.

I realise that regular load shedding will make that hard to avoid, but maybe a smallish UPS for the car? The Axpert King models would not need this as they have double conversion, but you probably don't want to change your inverter model now. 

Edited November 28, 20232 yr by Coulomb

On 2023/11/27 at 4:09 AM, Kurtbe said:

AEVA: would this be 'Australian Electric Vehicle Association' ? (Because there is a lot of AEVA about in Google.

Yes, indeed it is. We try to be helpful. 

Edited November 28, 20232 yr by Coulomb

5 hours ago, Coulomb said:

It's not a good idea to try to switch from utility to or from battery when an electric car is charging.

Hi Coulomb, Charging the car was done on purpose to drain the batteries and see if the relais would switch. I will not do that again! I normally only slow charge here (5 to 7A) when there is an exces of solar power and as soon as the car draws from the batteries I stop charging. 

And that basically leaves me with the following questions. 

On 2023/11/26 at 2:18 PM, Kurtbe said:

1. Program 3 (input Volt range) is set to UPS (Which I assume switches quicker than APL: 15ms as opposed to 20ms). Is that correct?
2. Is there a way to finetune program 12 and 13? Because the difference of % in the battery between 47 or 48 V is huge. Ideally I would like to switch to grid @ 15% and quit the grid again @ 30%. (My Victron sets actually allow to set the % rather than the Voltage.)

If anybody knows how to activate the dry contact based on SOC%, rather than Voltage, please let me know...

Greetings, Kurt

On 2023/11/26 at 11:18 PM, Kurtbe said:

Program 3 (input Volt range) is set to UPS (Which I assume switches quicker than APL: 15ms as opposed to 20ms). Is that correct?

Yes. Except I believe that it's 10 ms claimed for UPS.

On 2023/11/26 at 11:18 PM, Kurtbe said:

Is there a way to finetune program 12 and 13? Because the difference of % in the battery between 47 or 48 V is huge.

Not really. It's lead acid thinking.

There is a way to use the low DC cutoff voltage, which has 0.1 V precision, to fine tune one of them, I forget the details. It's a fixed voltage between this setting and the lower of the two "back to" settings.

1 hour ago, Kurtbe said:

If anybody knows how to activate the dry contact based on SOC%, rather than Voltage, please let me know...

I have a non-standard BMS and a very old model, but my understanding is that the more recent models and firmwares will give you some activity that is based on percent SOC instead of battery voltage, including settings 12 and 13, IF you are using "the cable" (connect to a battery BMS via a suitable cable, and have the battery type set to one of PYL, WEC, etc).

It might even work that way if you are using Solar Assistant or similar to "talk to the BMS on the inverter's behalf".

1 hour ago, Coulomb said:

IF you are using "the cable" (connect to a battery BMS via a suitable cable, and have the battery type set to one of PYL, WEC, etc).

It might even work that way if you are using Solar Assistant or similar to "talk to the BMS on the inverter's behalf".

That would be a big jump for me to make. 

Anywhere where I can learn the basics how to employ "the cable"?

On first glance Solar Assistance would only let one use SOC when constantly connected to the grid, and not to operate the dry contact...

But I am eager and willing to learn...

😉 Kurt

Also, does anybody know how to start WatchPower for PC? The first thing the manual says is to enter a a proxy IP number and a port... I have no idea...

Or, do I have to be on "the cable" already?

(manuals should be made for dummies like me...)

Thanks for any info...

Kurt

7 hours ago, Kurtbe said:

The first thing the manual says is to enter a a proxy IP number and a port... I have no idea...

I believe that's only needed in unusual circumstances, like a PC in a large network that has a special configuration. 

The main trick with Watchpower is to know what Comms port (e.g. COM5) that your USB to serial adapter is connected to. The AEVA upload instructions cover this, because you need the same thing when reflashing via a Windows PC. Though finding the comm port is described in detail in the first part of this post, linked near the end of the upload post. But you probably know this already. 

On 2023/11/29 at 12:59 AM, Coulomb said:

The main trick with Watchpower is to know what Comms port (e.g. COM5) that your USB to serial adapter is connected to. 

Which probably means that WatchPower from PC will not function without "the cable". I assumed it would connect via WiFi like the App...

Apparently I am assuming a lot. (But I'm getting to understand why Axpert is so much cheaper than Victron...)

On 2023/11/28 at 3:10 PM, Coulomb said:

It might even work that way if you are using Solar Assistant or similar to "talk to the BMS on the inverter's behalf".

Solar assistant allows the setting of hours to prioritise Utility or solar. (Probably based on program 99 and 100). But so far I do not find anything to set 12 &13 by SOC%. 

I will post a new thread about this and see if anybody has an idea.

Meantime: what goes on in this scenario: I have tested night charging @2Amps-230V (=460Wx8hrs=3680W input) but that only delivered 5% battery gain (480W in 8 hours), 460W input, consumption in house was 90W, + Axpert @70W, leaves 300Wx8hrs=2400W available to put into battery. Yet only 480 were put in. What happended to the other nearly 2000W?

Greetings, Kurt

1 hour ago, Kurtbe said:

I have tested night charging @2Amps-230V (=460Wx8hrs=3680Wh

No, the two amps is at the battery end of the "battery charger". So it's about 2 A x 50 V (assuming a 48 V model) x 8 h = 800Wh. For a 24 V model halve that.

But the self consumption is about an amp, so halve that again. This setting is basically designed to cover the self consumption and leave a tiny bit spare for leeway.

 

4 minutes ago, Coulomb said:

No, the two amps is at the battery end of the "battery charger". So it's about 2 A x 50 V (assuming a 48 V model) x 8 h = 800Wh.

 

OMG... I have a lot to learn yet.

Thanks again!!!

Kurt

I got lost in the settings of the inverter! Help me figure it out!
I use SBU mode! If the battery runs out, it switches to line mode. I think that in this case the PV only charges the battery and does not help the grid.
In reality, the PV helps the grid and only charges the battery when the PV production is more than the output load.
Is this a correct operation???

17 hours ago, Rozsda said:

I use SBU mode! If the battery runs out, it switches to line mode. I think that in this case the PV only charges the battery and does not help the grid.
In reality, the PV helps the grid and only charges the battery when the PV production is more than the output load.
Is this a correct operation???

Yes, I believe so, even though I don't own a Max. From the manual, re setting 01, SBU output source priority:

"Solar energy provides
power to
the loads as first priority.
If solar energy is not sufficient
to power all connected loads,
battery energy will supply
power to the loads at the same
time.
Utility provides power to the
loads only when battery
voltage drops to either low
level warning voltage or the
setting point in program 12."

If you want to blend PV and utility power, you want the SUB output source priority:

"Solar energy provides power to
the loads as first priority.
If solar energy is not sufficient
to power all connected loads,
Utility energy will supply power
to the loads at the same time."

On 2023/11/30 at 8:18 PM, Rozsda said:

I got lost in the settings of the inverter! Help me figure it out!
I use SBU mode! If the battery runs out, it switches to line mode. I think that in this case the PV only charges the battery and does not help the grid.
In reality, the PV helps the grid and only charges the battery when the PV production is more than the output load.
Is this a correct operation???

Hi Rozsda,

SBU: Utility only starts working when battery and solar are 'out'. It will then charge the batteries at the speed set in program program 11. It will also provide power to the house. When solar power is generated, this power will be sent to whatever demands power: this can be the batteries or the house. Only when batteries have sufficiënt power, you will return to battery mode.

Two remarks however:

• EVEN in battery mode The Axpert will continuously take 70W from the grid. That is why I (and you) use the dry contact and a relay to avoid that.
• But then (in SBU mode) it is ONLY the settings from program 12 and 13 that make the Axpert switch to and from the grid. (Unless you cut off manually)

On 2023/11/28 at 3:10 PM, Coulomb said:

I have a non-standard BMS and a very old model, but my understanding is that the more recent models and firmwares will give you some activity that is based on percent SOC instead of battery voltage, including settings 12 and 13,

Hi Coulomb,

I have been roaming the net for days to find a solution. Unfortunately I got nowhere.

Somebody has an EG4-6500EX, which seems to be an Axpert Max/ He has this option in his firmware. If I had that option it would solve all problems...

Do you think there is any chance of acquiring this for my Axpert max ii?

So far I have solved the problem by adding a timer to the relay, which only allows the red to connect between midnight and 08 in the morning. On top of that, setiing program 05 to USE (user-defined) allows for program 13 to be set lower than 51V (apparently that was dictated by Pylontech). So I have now put 49V as the return to battery point.
This might sort of work, but of course it is still not comparable to SOC% setting. 

So if somebody knows about some firmware that would allow it... please let me know.

Greetings, Kurt

On 2023/12/11 at 8:11 PM, Kurtbe said:

Do you think there is any chance of acquiring this for my Axpert max ii?

Yes. This facility appeared between display firmware version (1)22.16 and 22.20. So just update to display firmware version 22.20 and get your BMS cable working. 22.20 is in this post; don't use the main firmware there as it's for a 10 kW Max II model. 22.20 is a "unified" firmware, it should work on either display chipset, so don't worry about the lack of leading 1 in the firmware number.

[ Edit: However, the DSP firmware also has to support a new set of commands. As of 81.07, it does not. So if you have 81.07 or less, until a newer 81.xx comes out, this won't help. Sorry for the incomplete information; I didn't realise at the time I posted. ]

It's possible you may have to update your main (U1) firmware as well. It has to respond to an undocumented QDOP command from the display for the SOC functionality to work.

 

Edited February 8, 20251 yr by Coulomb
" send an undocumented QDOP command to the display" → " respond to an undocumented QDOP command from the display