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Off-grid advise needed. Axpert VMIII + Pylontech + Generator


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Hi,

After only reading on this forum for a couple of months now I've registered because I've been having some problems that I can't find the answer to.

We have an off-grid house and a holiday house that we rent out, that we run of the following system:

1. We have a off-grid system that consists of 10 x 300wp panels connected to the new Voltronic Axpert VMIII, we had this running with 8, 4 year old, Trojan L16's but recently updated to 4 Pylontechs US2000b+ batteries. To be able to better monitor the state of charge the batteries are hooked up to a Victron BMV 712 as well. I've connected the data cable that came with the pylontech cable set to the dedicated Li-Ion port on the inverter. The problem that I keep running in to is that the inverter doesn't read the battery soc and keeps giving an low battery error. Since the specs of the inverter state that this port can be used for CAN as wel as RS485 I've tried both ports on the battery with no result. Am I doing something wrong or is there another way to get the inverter to communicate with the batteries?

2. Besides that we are experiencing problems with our generator. The generator has no problem running the house and the inverter. Tried this with out the batteries connected. Problems start when the inverter tries to charge the batteries. There is a spike in voltage, from to 230 up to 280-290 and then the voltage on the generator drops to 0 fro 30 seconds and comes back on again, inverter picks up the AC, goes into line mode and as soon as it tried switching to charging the same thing happens again. What can be the cause of this? The generator is rated at 5kw and I've set the inverter to only draw 10A so to my knowledge this should work. The generator has no problems running a 2300w saw. We where hoping to be able to run the generator and charge the batteries on dark days.

I've set up the inverter as follows:

1. SUB 

2. Max. Charge 80A

3. APL (Apliances 90v-280VAC)

11. 10A (Max. Utility charging current)

12. 48v (back to utility)

13. 51v (back to battery)

16. SNU (Solar + Utility can charge battery)

26. 53.2v (bulk charge)

27. 53v (float charge)

29. 47,5v (low DC cut of)

The Generator is an ITC GG7000FE (5kw continuous and 5,5 max)

 

 

 

 

 

 

 

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8 hours ago, Cefas said:

The problem that I keep running in to is that the inverter doesn't read the battery soc and keeps giving an low battery error. Since the specs of the inverter state that this port can be used for CAN as wel as RS485 I've tried both ports on the battery with no result. Am I doing something wrong or is there another way to get the inverter to communicate with the batteries?

Welcome Cefas. To my knowledge, the Axperts is approved for connection with the Pylontechs, but through 3rd party software as well as a specific cable that gets manufactured in South Africa. The Axpert itself does not have the build in functions to communicate with the Pylontehc.. 

The guys who use Pylontech with Axpert, uses ICC and the custom build cable can also be found on that page. 

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8 hours ago, Cefas said:

We have a off-grid system that consists of 10 x 300wp panels connected to the new Voltronic Axpert VMIII

From what I've heard (and note this what I've heard) the VMIII have the capability to communicate with the Pylons.

I must admit, that there are not that many of them here in SA, and personally have only seen one in action so far.

So I would suspect you might have a bit of research ahead of you to get the SOC going the way it should be.

R

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6 minutes ago, Jaco de Jongh said:

Thanks Riaan, I wasnt aware of this. Sorry Cefas, seems like i was wrong. Hope you find out how to run them together.

No problem Jaco, although it is claimed to operate like that, we all miss some small print somewhere that might prove you were correct ;-)

" BMS Communication port: CAN and RS232 or RS485"

This "indirectly" implies that the VMIII can communicate via CAN or RS232 or RS485 with the Pylon BMS.

What this entails in a nutshell needs to be seen.

As we all have experienced with the myriad of terminology, is that manufacturer and user understanding of term or function sometimes are worlds apart.

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Riaanh, Jaco, Thank you for your replies, I forgot to mention that the inverter is the 5Kw 48v model. It is the one with the detachable screen and has indeed a designated port for a cable from the BMS to the inverter. But for some reason the inverter doesn't read the right state of charge. I've set it up according to specifications in this document: http://www.mppsolar.com/manual/Pylontech Lithium/Pylontech inverter setup SOP.pdf the last 5 pages are about the inverter we are using. I even tried connecting the cable backwards because it has labels on what side you should connect to the batterie and inverter. I will try a bit more and if I get it to work will post it here.

But does somebody have an idea what is going wrong between the inverter and the generator? I've setup the inverter to only take 10A from the generator, even when I setup program 11 to 2A the voltage spikes, the voltage meter on the generator falls to 0, the generator keeps running and after 30sec the voltage comes back up again and the same thing happens again. I've got it to work by hooking up a 600w jigsaw and have the running while the inverter starts up the charging. As soon as I let go of the saw the voltage spikes again and the voltage is cut.

 

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Hi Cefas,

At this time, there is no comunication Pylon-Axpert available. What your paper says is there is a way to configure Pylon-Axpert, whitout comunication port, changing some parameters of the Axpert. 

It´s possible in a few months new firmware will be available for 48 V Axperts an Infiny.

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Javi thanks for the info, will be patient until then 😉 Still can't get the generator to work though, we found out that the generator was running a bit slow. The generator is working good now, but the inverter doesn't want to accept it, it will see the AC from the generator, put it in by-pass and then drops it. I've seen some threads talking about the same problem and that it was solved by updating the firmware. Our inverter is on U1 20 57 U2 01 08 U3 00 20, could this be the problem?  @Coulomb or @Chris Hobson Would one of you maybe have an answer for this?

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11 hours ago, Cefas said:

The generator is working good now, but the inverter doesn't want to accept it, it will see the AC from the generator, put it in by-pass and then drops it. I've seen some threads talking about the same problem and that it was solved by updating the firmware. Our inverter is on U1 20 57 U2 01 08 U3 00 20, could this be the problem?

 @Coulomb@Chris Hobson

That firmware update to fix generator over-sensitivity was years ago. Your machine and firmware are quite recent compared to that problem. 

Axperts have always been picky about the AC input, especially generators. It seems best to use generators with electronic inverter regulators. Most of the cheaper models won't have this.

Others have reported problems similar to yours. I can't imagine what would cause the generator voltage to spike and go to zero. I guess because the load comes on suddenly, but then why does adding a load help?

Sorry I don't have a generator so I can't see the problem first hand. 

Edited by Coulomb
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15 hours ago, Cefas said:

Javi thanks for the info, will be patient until then 😉 Still can't get the generator to work though, we found out that the generator was running a bit slow. The generator is working good now, but the inverter doesn't want to accept it, it will see the AC from the generator, put it in by-pass and then drops it. I've seen some threads talking about the same problem and that it was solved by updating the firmware. Our inverter is on U1 20 57 U2 01 08 U3 00 20, could this be the problem?  @Coulomb or @Chris Hobson Would one of you maybe have an answer for this?

MPP Solar, shows a paper in which you can see the gennie requirements:

https://www.mppsolar.com/v3/catalogs/PIP-HS_MS genset requirement.pdf

It seems the most restrictive parameter is the slew rate, which is the change of frecuency per second.

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@DeepBass9 they don't make 'm like that anymore😁 wish we would have one of those! Nowadays its all high tech short life span...

But great news, we managed to get it working. After a bit of fiddling with the motor speed we managed to get it stable enough to accept it when the batteries where full. The inverter still kicks the generator off when it the batteries need charging but if we put a load on of 500w it works! So when needed I can top the batteries up to get me through some grey weather periods.

One question about the batteries and inverter combination, because they don't seem to communicate well together am I in risk of damaging the batteries or inverter with the settings I'm using: Max. Charge: 80A, Bulk Charge: 53,2V , Float: 53V, Low DC cut off: 47,5V. Or is it safer to set the bulk charge a little lower?

Thank you all for contributing so far!!

 

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1 hour ago, DeepBass9 said:

Adendorff

Last engine I was involved with that came from Adendorff: Had a complete set of spares to overhaul the engine (piston rings and some bolts). Which makes you wonder... they are that worried about it? :-) It was clearly a knock-off of an older design Yanmarr engine, even had an old headlamp attached to the side, which I can only assume was because it was used in a small tractor of some kind. Worked well enough in the application...

Edited by plonkster
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On 2018/11/29 at 7:44 AM, Cefas said:

am I in risk of damaging the batteries or inverter with the settings I'm using: Max. Charge: 80A, Bulk Charge: 53,2V , Float: 53V,... 

I would change the float setting lower, to 50.3 V. It's not good for lithium batteries to spend too much time at higher cell voltages. 

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