MPP Solar + BMS communication/control

mrzed001

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Hi !

I want to build a 48V system with 16 EVE 280Ah cells, and 1(-2) MPP Solar inverter (5048MK aka Axpert King)
But I want this system as an UPS. So no daily charge and discharge.
I think battery to last long I charge it to 60-70%

I know inverter is stupid. It has only the sum V of the cells and the cells discharge curve is very flat. So it does not know the real SoC of the battery.
I know I need a BMS with shunt to really know the SoC.

Is there a solution where the inverter knows the BMS SoC and I can set the real SoC % to charge the battery ?
So the BMS is connected to MPP inverter ?
Or even BMS controls MPP and tells it when it needs to charge battery ?
 

Samsonite801

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Messages
876
I don't know much about MPP inverters (and how they are advancing BMS communication protocols), but Sol-Ark is working with a few battery manufacturers to build systems like this to interact more in synergy:

"Sol-Ark has partnered with many battery companies like SimpliPhi, Fortress, Blue Ion, and Discover to advance inverter and battery control through extensive communications. Most of the time the inverter controls the battery. Now the battery can communicate to control the Sol-Ark inverter to extend the capabilities or life of the battery. They have finished behind the meter Virtual Power Plants for Utilities so they can pay the customer for renting their battery."


As these solutions are not really standardized across the industry and still fairly proprietary, they're likely going to be more expensive, for example, a Sol-Ark 12k, is around $7k, and a Fortress battery is $12.4k...

Sol-Ark:

Fortress:



I did browse through MPP Solar's product catalog and it does show they offer some type of proprietary BMS support (for Pylontech, WECO, and Soltaro brands):

From LV6548 product catalog:
1605541019283.png

From PIP-8048MAX product catalog:
1605542932085.png
 
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mrzed001

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Location
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I know the Sol-ark is a very good inverter ... but it is for US only and does not support EU standards.

I saw this:

It can control the inverter I think.
But ... very little info about it (cant find a decent YT video about it).
I think it uses Victron BMV battery monitor and shunt.
Communication with BMS? Communication with inverter?
What it needs and what it has .... ?
Really I can not find a single plan or diagram or wireing or even what components and cables are needed for this.


Also Pylontech battery's BMS can communicate with MPP inverters ... but others?
Ant, Batrium, Daly, Chargery, Rec, ... ?
Lot of info missing in software side.
 
Last edited:

Samsonite801

Solar Addict
Joined
Oct 15, 2020
Messages
876
I know the Sol-ark is a very good inverter ... but it is for US only and does not support EU standards.

I saw this:

It can control the inverter I think.
But ... very little info about it (cant find a decent YT video about it).
I think it uses Victron BMV battery monitor and shunt.
Communication with BMS? Communication with inverter?
What it needs and what it has .... ?
Really I can not find a single plan or diagram or wireing or even what components and cables are needed for this.


Also Pylontech battery's BMS can communicate with MPP inverters ... but others?
Ant, Batrium, Daly, Chargery, Rec, ... ?
Lot of info missing in software side.

Yeah, BMS and inverter manufacturers are going to have to get more 'on the ball' here in coming up with some kind of open standard, otherwise we will just see these one-off proprietary solutions floating around here and there with no real supported standards outside their own ecosystems.

Here is an example of Pylontech supported inverter list:

WECO:
https://wecobatteries.com/inverter-compatibility/ (they don't even list MPP there, even though MPP lists them as supported on their gear)

Soltaro makes batteries and inverters (they want you to buy both of their solutions in a complete package), so they don't list any other inverters as being compatible with their batteries:

It's like the beta / VHS war or the HDDVD / Blueray war, so basically your choice for now, is to buy a supported, tested hardware, to get full features, or if you are a developer pioneer type, then you can reverse-engineer and figure out CANBUS and write some of your own code and maybe put something together that works. That's what EVTV does, he's got some devs and they reverse engineer, and write new firmware and make custom BMS equipment so inverters can talk to Tesla batteries on CANBUS and whatnot.
 
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mrzed001

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Location
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Yeah, BMS and inverter manufacturers are going to have to get more 'on the ball' here in coming up with some kind of open standard, otherwise we will just see these one-off proprietary solutions floating around here and there with no real supported standards outside their own ecosystems.

Here is an example of Pylontech supported inverter list:

WECO:
https://wecobatteries.com/inverter-compatibility/ (they don't even list MPP there, even though MPP lists them as supported on their gear)
They do ...
Because Voltronic is the original manufacturer that makes the MPP (rebranded) inverter.
Voltronic Axpert King = MPP Solar 5048MK


But I agree. Total chaos. I am just lost.

I need a :
  • inverter charger (MPP 5048MK)
  • BMS 16s 48V ( ??? )
    • Chargery: good 1,2A balance, needs extra relay to disconnect battery, communication maybe with @BarkingSpider solution​
    • ANT: low 0,2A balance​
    • Tiny​
    • Heltec: active balance 2A​
    • Daly: 0,2A, has canbus maybe compatible with something​
    • Rec:​
    • Batrium: expensive, balance 1,2A, has canbus possible compatible with something​
  • an inverter control
  • a battery monitor
    • only Victron BMW 702 is compatible with ICC ?​
    • do not even know which is compatible to which inverter control ... and to connect it with what ...​
  • a pre charge resistor (when battery is switched back no inrush current)
  • 48V relay (magnetic, controlled) or better manual switch with control (if error then break circuit)
    • which can be used with which BMS and pre charger and inverter control and ....​
Did I forgot something ?

So I feel a bit lost. Like playing with Lego where the pieces fit, do not fit, or maybe fit together ... but then another pieces do not fit :D

:alien: o_O
 

Samsonite801

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Joined
Oct 15, 2020
Messages
876
They do ...
Because Voltronic is the original manufacturer that makes the MPP (rebranded) inverter.
Voltronic Axpert King = MPP Solar 5048MK


But I agree. Total chaos. I am just lost.

I need a :
  • inverter charger (MPP 5048MK)
  • BMS 16s 48V ( ??? )
    • Chargery: good 1,2A balance, needs extra relay to disconnect battery, communication maybe with @BarkingSpider solution​
    • ANT: low 0,2A balance​
    • Tiny​
    • Heltec: active balance 2A​
    • Daly: 0,2A, has canbus maybe compatible with something​
    • Rec:​
    • Batrium: expensive, balance 1,2A, has canbus possible compatible with something​
  • an inverter control
  • a battery monitor
    • only Victron BMW 702 is compatible with ICC ?​
    • do not even know which is compatible to which inverter control ... and to connect it with what ...​
  • a pre charge resistor (when battery is switched back no inrush current)
  • 48V relay (magnetic, controlled) or better manual switch with control (if error then break circuit)
    • which can be used with which BMS and pre charger and inverter control and ....​
Did I forgot something ?

So I feel a bit lost. Like playing with Lego where the pieces fit, do not fit, or maybe fit together ... but then another pieces do not fit :D

:alien: o_O

Yeah, on my 2 upcoming battery bank builds, I'm not gonna worry about calculating exact SOC values that much, I'll just set my charge cycles and inverter shutoff voltages to cycle for a long-life curve like this (in the green), and not really worry too much about it, I'm thinking it will last long enough until the next battery technology comes out like Lithium Air or something... The inverter/charger cycle will be narrow enough that it will never step on the feet of the BMS's (last line of defense) thresholds...

1605561656348.png
 
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mrzed001

Voice of reason
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Messages
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Location
Hungary - EU
Yeah, on my 2 upcoming battery bank builds, I'm not gonna worry about calculating exact SOC values that much, I'll just set my charge cycles and inverter shutoff voltages to cycle for a long-life curve like this (in the green), and not really worry too much about it, I'm thinking it will last long enough until the next battery technology comes out like Lithium Air or something... The inverter/charger cycle will be narrow enough that it will never step on the feet of the BMS's (last line of defense) thresholds...

View attachment 27707

I think I saw a video where
- inverter thinks SoC 80%
- big load
- inverter thinks SoC gone down 30-40%
- inverter starts to charge
And that is bad.
I think the video was to demonstrate the pylontech BMS communication.
So after setting it to PYL the inverter knows the real SoC and do not start to charge the battery.
 

dRdoS7

Solar Enthusiast
Joined
Aug 2, 2020
Messages
95
Hi,


Yeah, on my 2 upcoming battery bank builds, I'm not gonna worry about calculating exact SOC values that much, I'll just set my charge cycles and inverter shutoff voltages to cycle for a long-life curve like this (in the green), and not really worry too much about it, I'm thinking it will last long enough until the next battery technology comes out like Lithium Air or something... The inverter/charger cycle will be narrow enough that it will never step on the feet of the BMS's (last line of defense) thresholds...

View attachment 27707

I have 18 cells, so I did a table for my settings:

18 Cells.jpg

Yesterday I charged the bank to 65.7V, and reached 280Ah. Last night we took out 89Ah, and have 189Ah remaining. Bank dropped to 59.2V, so that matches the table.

This morning the bank is around 60.6V, which doesn't match the table WRT Ah.

18 Cells-BMS.jpg

18 Cells-Classic.jpg

I have my SCC & Inverter set both set to Absorb to 64V.

I'll post later what Ah the bank gets to once it goes back to Float.

dRdoS7
 

dRdoS7

Solar Enthusiast
Joined
Aug 2, 2020
Messages
95
When I got home from shopping at 11am, the SCC was in Float, and I had my readings on SCC & BMS @ 280Ah remaining.

I'll set Absorb to 62V, and see what happens tomorrow.

dRdoS7
 

Csimmer

Solar Enthusiast
Joined
Sep 8, 2020
Messages
42
I have just used the bmv700 SOC relay to turn a contactor on and off to control the PV power into the charger, works a treat. I can charge to 80% without it going to float or having to use a low charging voltage.
 

solardad

Solar Addict
Joined
Apr 13, 2020
Messages
305
I have just used the bmv700 SOC relay to turn a contactor on and off to control the PV power into the charger, works a treat. I can charge to 80% without it going to float or having to use a low charging voltage.
What contactor are you using? Thinking of doing something similar. Thanks
 

denarius

Solar Enthusiast
Joined
Apr 8, 2021
Messages
29
an inverter control
  • ICC software ... needs a RPy 3 ... needs some cable to inverter .... needs some cable to BMS ?
  • or @BarkingSpider here makes one https://github.com/BarkinSpider/SolarShed/ needs some things to?
  • or 4-5 different github progz
Hi mrzed001

I previously used ICC and converted to solar assistant. It's overall significantly better including the power management:

The cable to the inverter is typically a USB to USB B (printer cable) or for the newer models it's USB to micro USB. A BMS cable is optional.

Overall the reason for using solutions like these is to have a good monitoring interface that stores history and that you can access remotely. Some inverter vendors build their own monitoring units such as the Victron Venus:

Other vendors rely on 3rd parties, Voltronic is such a vendor. Example 3rd party device:

Out of all the monitoring solutions I tried, solar assistant is the best. I run 2x Voltronic 5KW inverters in parallel, currently with low loads at night:

1617927371572.png
 

mrzed001

Voice of reason
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Messages
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Hungary - EU
Hi mrzed001

I previously used ICC and converted to solar assistant. It's overall significantly better including the power management:

Thanks I will check it out.
But the main problem with both system I think is that they can only communicate with Pylontech BMS.
Self build packs do not have it.
I bought a Heltec JK 2A active balance BMS. It has RS485 port too.
So I am afraid I have to write a Heltec to Pylontech communication conversion.
And I have only the detailed tech spec for the Heltec comm part.
 

dRdoS7

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Joined
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Messages
95
Hi,

Self build packs do not have it.
I bought a Heltec JK 2A active balance BMS. It has RS485 port too.

I have an MPP inverter & a JK BMS, no communication between them. Works OK for me. Inverter limits are set inside the BMS limits. If there's a cell/battery problem, the end result is still no battery power, whether they communicate or not. It's either: "I'm empty, bye!" Or: "I'm nearly empty, cut me off".

Am I missing something?

Would be nice to have better monitoring of the BMS on the PC though, the JK app sometimes loses the BMS, or the window which I have the remote phone running in, loses communication (using scrcpy or Teamviewer).

I should add that I have a Midnite Classic, with a WbJr, so that gives me a good SOC. More for information than any form of control. Even if I wanted to use it for anything, I can't as the AUX1 stopped working, and the AUX2 is used by the WBJr.

dRdoS7
 

TheSmartGerman

New Member
Joined
Feb 10, 2021
Messages
32
Hi,
I'll just like to go back of the title of this thread, it was about BMS communication.

in the manual of the 5048 MGX in setting 5 you have a big list:

Is any of this protocols know e.g. Lib-protocol? Would be great to build a "translator" from DalyBMS to "Lib-Protocol"



1627035955631.png
 

Roqm

Solar Enthusiast
Joined
Jun 17, 2020
Messages
174
I know the Sol-ark is a very good inverter ... but it is for US only and does not support EU standards.

I saw this:

It can control the inverter I think.
But ... very little info about it (cant find a decent YT video about it).
I think it uses Victron BMV battery monitor and shunt.
Communication with BMS? Communication with inverter?
What it needs and what it has .... ?
Really I can not find a single plan or diagram or wireing or even what components and cables are needed for this.


Also Pylontech battery's BMS can communicate with MPP inverters ... but others?
Ant, Batrium, Daly, Chargery, Rec, ... ?
Lot of info missing in software side.
If you want e.u version search for "sunsynk"
 

mrzed001

Voice of reason
Joined
Apr 10, 2020
Messages
721
Location
Hungary - EU
I got some informations:


And we already have JK Heltec RS485 BMS protocol documentation. Also more working interpretation for it (with RasPi) on Github.
With this can write a Heltec to Lib BMS communication conversation. A RasPi, 2 RS485 port and some Python code.
I scrolled down in the MPP doc and did not find any unusual item on it.

The big question is that this lib protocol will be available on other MPP Solar inverters ?
In the 5048MK user manual I still only see the Pylontech option.
Maybe a someone got a similar doc from MPP Solar for Pylontech ?
 
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