After almost a year of procrastinating, I thought I'd create a thread for my "new" setup, which I hope to optimize with the help of the very knowledgeable people on the forum.

My previous setup and subsequent change over to this one is detailed in another thread, https://powerforum.co.za/topic/4948-axpert-king-3k-issues-–-inverter-or-battery-fault/.

 

I still use the 3kW Axpert King 3K (SOL-I-AX-3K) 24v, but now with a Pylontech UP2500. I don't currently have solar, so I use it purely as grid backup. Seeing as I've been working from home since lockdown started and Johannesburg's CityPower has decreased loadshedding timeslots from 4 to 2 hours, I have added more load to the system - about half my home's plugs (living area, study/home office, main bedroom, bunch of aquariums and my fridge), as well as all lights. Peak draw is about 1500w, down to about 300/400w, but the average is more around 700/800w. This gets me through loadshedding, and for any non-loadshedding power interruptions, which I don't know how long they will last, I just use power sparingly to increase backup time.

 

The battery was supplied with a RJ45 cable, which I connected between the port labeled Li-Ion on the Axpert to the RS485 port on the Pylon. Considering my Axpert doesn't have the PYL option under the battery type setting, does this do anything? Does the battery and inverter have any meaningful communication?

The guys who supplied the Pylon gave me inverter settings to use, and I have used these settings since May 2020, but am hoping to get confirmation that these are indeed the most optimal settings for my setup and use case, taking into account the Axpert premature float bug and Pylon built in BMS. These are the current settings:
Battery Type: USE
Charge Current: 40A
Bulk Charge: 28V
Float Charge: 27V
Low DC Cut Off: 23V (supplier said 22V)

Edited April 9, 20215 yr by ascheff

My biggest annoyance, which is no fault of the battery, but rather the Axpert, is that I still cannot get a true SOC reading.

I was ready to go the ICC route, but after emailing Diversified Solutions to confirm cable support, found out that the cable only works on the  US2000 and US3000, and not the UP2500. I was apparently only the second person ever to enquire about the UP2500.

So I then installed SolPipLog on a Pi, which feeds data to another Pi with Home Assistant, which I already had running for other stuff around the house. That works great for remotely monitoring everything, except SOC, and I have been unable to get SolPipLog to get data from the Pylon. 

I made my own cable as detailed here, https://powerforum.co.za/topic/2322-youdas-off-grid-lab/page/2/?tab=comments#comment-53641, bought a Sunix USB to RS232 Serial Adapter with Prolific PL2303HxD chip (https://www.sunix.com/en/product_detail.php?cid=1&kid=3&gid=18&pid=1136), and although it can communicate with the BatteryView tool in Youda's post on my Windows PC, I can't get it working with the Pi and older SolPipLog with Pylon support built in, or with the latest SolPipLog and PyLog separated. I can see the PyLog application's communication attempts in its log triggering the led on the serial adapter, but the PyLog application doesn't register any Pylon data. It does however trip up the Pylon, triggering it's protection mode, which is obviously not a good thing. So I'm suspecting that PyLog (and SolPipLog) doesn't support the UP2500 either.

Has anyone been able to get any remote monitoring data from the UP2500? Preferably as MQTT or UDP that I can feed to Home Assistant via Node-Red?

3 hours ago, ascheff said:

The battery was supplied with a RJ45 cable, which I connected between the port labeled Li-Ion on the Axpert to the RS485 port on the Pylon. Considering my Axpert doesn't have the PYL option under the battery type setting, does this do anything? Does the battery and inverter have any meaningful communication?

If you don't have a PYL setting, then no, it does no good.

But you have a removable display on the 24 V King, right? That's what does all the hard work with the BMS protocol. I thought for a while that no 24 V model would offer any sort of BMS interaction at all. But to my surprise, it looks like you get PYL, LIB, and LIC protocols with e.g. removable display version 02.61. Frustratingly, with 02.62, you get none. I have no idea whether the 24 V Pylontech support is finished and working, or if they wanted to do it but decided it was too hard.

So if you're feeling adventurous, try reflashing your removable display to 02.61 and try it out.

What versions are you running now, as a point of interest?

42 minutes ago, Coulomb said:

Frustratingly, with 02.62, you get none.

Upon re-reading, you get one. But that one is PYL (Pylontech protocol).

So if you can get it to work, it appears that Voltronic Power intend to continue to support it in future firmware updates.

Of course, it would be nice if they actually said so somewhere, like on a web page.

Thanks @Coulomb

 

1 hour ago, Coulomb said:

But you have a removable display on the 24 V King, right?

That's correct
 

1 hour ago, Coulomb said:

So if you're feeling adventurous, try reflashing your removable display to 02.61 and try it out.

I would not mind, as long as instructions are clear and the risk of bricking the device is not too big. I've done that type of thing with many types of devices before, but never something of this value. I'm pretty sure I'm out of warranty by now anyway, so not worried about that.

 

1 hour ago, Coulomb said:

What versions are you running now, as a point of interest?

I'm not entirely sure which is the display version, I'm assuming U2 (Secondary CPU), which is 01.12. The rest are:
U1 (Main CPU) 51.50
U3 (Bluetooth) 00.21
U4 (SCC) 00.00

 

1 hour ago, Coulomb said:

try reflashing your removable display to 02.61

1 hour ago, Coulomb said:

it appears that Voltronic Power intend to continue to support it in future firmware updates

Where would I get the correct firmware updates? Voltronic's website doesn't have anything other than manuals and monitoring tools that I can find. If you can point me to a legitimate download, either theirs or 3rd party (yours?) I could give it a try

 

1 hour ago, Coulomb said:

Upon re-reading, you get one.

Do you still suggest 02.61, or rather 02.62?
 

11 hours ago, ascheff said:

I'm not entirely sure which is the display version, I'm assuming U2 (Secondary CPU), which is 01.12.

Ah. In that case, I no longer recommend trying later firmware. When reading 02.xx display firmware, I see testing for 48V, (parts of the firmware code behave differently if 48V is not found) so I assumed that 24V models would use the same firmware. If yours is a fairly recent model (what is the manufacturing date on the small sticker?), then it would appear that 24V support is not production ready yet.

It would not be so much of a risk if you could revert to 01.12, or even any other 01.xx display firmware, but this is not possible as far as I know.

Firmware availability has been very low since the appearance of the clones in 2015. (Since the clone wars?) We rely on obscure sites like one in Czechoslovakia and owners that need updates for various reasons (bug fixes, paralleling with older versions) who share the update files. Possibly because they are less popular, 24V firmwares seem much harder to find. 

Edited April 10, 20215 yr by Coulomb
Clarified testing for 48V

11 hours ago, ascheff said:

Do you still suggest 02.61, or rather 02.62?

For you, I now suggest neither. But for general use and for which one to patch, or whether to wait longer, I'm still deciding.

4 hours ago, Coulomb said:

In that case, I no longer recommend trying later firmware.

Just when I thought I saw some glimmer of light at the end of the tunnel

 

 

4 hours ago, Coulomb said:

what is the manufacturing date on the small sticker?

09/2018, so not exactly recent. Which was why I hoped the 01.xx firmware just meant it was way behind on updates

 

4 hours ago, Coulomb said:

Possibly because they are less popular, 24V firmwares seem much harder to find

It seems that way, as well as other support like for the ICC software cable and SolPipLog for the 24v Pylon. The guy from Diversified Solutions (The Cable Guy) said the UP2500 uses a different protocol from that of the US2000 and US3000.

In the interim, while waiting to get the Axpert and Pylon communicating (well, really hoping, as this would be first prize), what would be the recommended settings to use on the Axpert, that will give the Pylon the most freedom to manage itself with the inbuilt BMS?

My priorities in order would be:
1. Protect the battery and it's total lifespan
2. Get the longest possible backup time before cutoff
3. Charge back up to full in the shortest possible time
4. Have the inverter report a more accurate battery capacity

These are the Pylon specifications:
 

My current settings are:
Battery Type: USE
Charge Current: 40A
Bulk Charge: 28V
Float Charge: 27V
Low DC Cut Off: 23V

 

18 minutes ago, ascheff said:

Just when I thought I saw some glimmer of light at the end of the tunnel

If you happen to know someone with a later firmware version removable display, you could perhaps borrow the whole removable display. That way, there is a clear path back to original specifications 😃

Quote

My current settings are:
Charge Current: 40A

Since the recommended charge current is 55 A, I would increase that to 50 A, in line with objective 3.

Quote

Bulk Charge: 28V
Float Charge: 27V

Since your battery will be 8S and mine is 16S, you could do worse than using half my voltage settings. Mine were carefully chosen by my colleague Weber, who teaches electricians about solar batteries. Mine are 55.2 and 53.7, so you should consider 27.6 V and 26.9 V (nearest 0.1V rounded up).

Quote

Low DC Cut Off: 23V

I would not want to go near that voltage (I never let mine go below 51.0 V, equivalent to 25.5 V). But you don't want to go too high, because if the interaction with the back-to-grid voltage (see FAQ #2 if interested in why). So I'd recommend 24.5 V. The latter will mean you can't go below 25.5 V effective for setting 12, back to grid. That's the value that I use. Setting 12 is another important setting, in some ways, the most important. It's what saves the battery from excessive discharge, which is the #1 killer of LFP cells and therefore batteries.

Unfortunately, it means that you need to exercise discipline when there is a long load shed /  utility outage. At least with these settings, you'll get a low battery warning at 25.5 V, and you should use that to immediately reduce loads, and preferably completely shut down the inverter. So leave the alarm beeper on.

2 hours ago, Coulomb said:

If you happen to know someone with a later firmware version removable display, you could perhaps borrow the whole removable display

I don't, unfortunately. So if anyone in my area (Weltevredenpark, Johannesburg) sees this, who has the same model with newer firmware, and is willing to help out, please let me know

2 hours ago, Coulomb said:

I would increase that to 50 A

2 hours ago, Coulomb said:

Mine were carefully chosen by my colleague Weber, who teaches electricians about solar batteries. Mine are 55.2 and 53.7, so you should consider 27.6 V and 26.9 V (nearest 0.1V rounded up).

2 hours ago, Coulomb said:

So I'd recommend 24.5 V

Thank you, I'll apply these changes.

2 hours ago, Coulomb said:

Unfortunately, it means that you need to exercise discipline when there is a long load shed /  utility outage. At least with these settings, you'll get a low battery warning at 25.5 V, and you should use that to immediately reduce loads, and preferably completely shut down the inverter. So leave the alarm beeper on.

I have a lot of my electrical equipment on Sonoffs connected to Home Assistant, so I will use that to switch stuff off accordingly, whether I'm home or not

 

Thanks for all the advice @Coulomb, much appreciated

4 hours ago, ascheff said:

if anyone in my area (Weltevredenpark, Johannesburg) sees this, who has the same model with newer firmware, and is willing to help out,

In fact they don't have to have the same model; that's the point of the removable display firmware. It can be used on 3 kW and 5 kW models, 48 V and 24 V, Kings and VM IIIs. Maybe also Axpert MKS IIIs. The MAXs seem to have their own display firmware, or maybe the others will catch up with the 12.xx MAX display firmware.

1 hour ago, Coulomb said:

It can be used on 3 kW and 5 kW models, 48 V and 24 V, Kings and VM IIIs.

Oh great, I have a friend with a 5kW King. I will find out what version his display has

On 2021/04/10 at 7:34 AM, Coulomb said:

If you happen to know someone with a later firmware version removable display, you could perhaps borrow the whole removable display. That way, there is a clear path back to original specifications 😃

I have finally been able to have a look at the display on my friend's 48V 5kw King. Display firmware is 01.21, and I also confirmed that he has the PYL option on setting 5.

Is it possible to download/extract the firmware from his display to update mine? Or what would the next step be once I have access to it? Just trying to determine how long and for what I would need it, as he runs his house on his, so would not be able to remove it for long.

5 hours ago, ascheff said:

I have finally been able to have a look at the display on my friend's 48V 5kw King. Display firmware is 01.21,

Ah. Unfortunately, this is very old firmware, for a 48 V model. So I don't think you'd learn much by using that firmware.

5 hours ago, ascheff said:

Is it possible to download/extract the firmware from his display to update mine?

No.

I just don't know what to recommend for 24 V models. Taking another quick look at the firmwares I have here (all 02.XX), I suspect that they'd work fine, but can't be sure.

There may even be a hardware change from 01.XX to 02.XX; Voltronic just don't give these sorts of details. So the safest thing might be to get the latest 01.XX that you can find. I'm not aware of any firmware update files for removable display firmware 01.XX.

Your best bet would be to request a firmware update from your supplier. They (or their contacts in Taiwan) will know whether you can get Pylontech support for your model or not. There was talk early on about requiring a hardware update to support direct communications with the Pylontech BMS. But maybe you could purchase a new removable display (if that's all that is needed) for a reasonable sum of money.

7 minutes ago, Coulomb said:

Your best bet would be to request a firmware update from your supplier. They (or their contacts in Taiwan) will know whether you can get Pylontech support for your model or not. There was talk early on about requiring a hardware update to support direct communications with the Pylontech BMS. But maybe you could purchase a new removable display (if that's all that is needed) for a reasonable sum of money.

Thank you. I'm going to do this, will feed back if I have any luck

On a slightly related note, since the SOC the Axpert displayed isn't really worth anything, how reliable is the battery voltage? Can I use that to roughly calculate remaining percentage? I was thinking to take whatever the voltage is at as a percentage inbetween my cut off voltage and the voltage the battery settles at after the initial drop when charge is removed, with a load. Would this give me a rough idea, better than the Axpert reported percentage, of where I am backup wise?

26 minutes ago, ascheff said:

since the SOC the Axpert displayed isn't really worth anything, how reliable is the battery voltage?

It's actually surprisingly good, most of the time. Occasionally they need a little calibrating. One of my two needed this.

Quote

Can I use that to roughly calculate remaining percentage? 

Really roughly, yes. The trouble is, LFP cells have two quite flat plateaus in their voltage versus SOC graph. Plus, the internal resistance of the battery means that the voltage is affected by loads and charging current as well.

So you're actually better off adding an external battery monitor, such as a Victron BMV. When set up correctly, these can count coulombs (amp·seconds) in and out of the battery, and give a decent estimate of SOC.

8 minutes ago, Coulomb said:

Plus, the internal resistance of the battery means that the voltage is affected by loads and charging current as well.

 

I've actually noticed this. With a biggish load when the voltage reaches 25V, I cut some of the non-essential equipment using my home automation. That immediately raises the voltage again to 25.6V or more

 

11 minutes ago, Coulomb said:

So you're actually better off adding an external battery monitor, such as a Victron BMV

 

Thanks, I'll look into this

I've run into an issue with my inverter, for which I created a separate thread