Communication between BYD Battery and Kostal Plenticore Inverter

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Having just had a bit of a holly sh** moment... puzzling about 3 byte floats...

I started programming on a Z80 (Sharp MZ80K)... I started in the twilight zone !!
 

Korishan

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Usually takes me longer than 3 bites to eat a float. I try to savoir the flavor, and not get an ice cream headache :p
 

huntworker

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Feb 16, 2021
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@huntworker, what is the final goal of this project? You want to build some monitoring system or connect some other battery to your inverter using this protocol.
I am trying to use a battery from an EV, maybe BMW i3 or even the tesla battery. i3 would be nice since the voltage is in a good range. With a Tesla battery I would need to use the whole pack with 60 to 100 kWh to have a good voltage, which might be a bit oversized. :D
So am trying to simulate the BYD battery for the existing Kostal inverter.
I also thought about using another inverter. I like the Victron pars for its uninterruptible power supply and fast transfer switches. But they are using only single phase concepts. So I would need 3x the MultiPlus || and the SmartSolar RS to have a tree phase system which lead to additional cost for the inverter of around 7 k€. With this system I would have the UPS but thats not worth it.

I am working as electrical engineer for a german company which builds cell management controller, battery management controller and battery junction boxes for different OEMs so I know what I am doing. :)
Only unusual thing for me is to not having a description of the protocols and buses.
 

yasko

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Nov 10, 2017
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OK. I got it. So, we are running on the same track here :) That is pretty similar to what I've done with a Goodwe inverter in my project.
BTW, I'm curious what do you think about this brand of inverters? They are well priced, and for about 1700-1800 euro, you can get a 10kW 3 phase HV hybrid inverter with UPS functionality.
 

huntworker

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OK. I got it. So, we are running on the same track here :) That is pretty similar to what I've done with a Goodwe inverter in my project.
BTW, I'm curious what do you think about this brand of inverters? They are well priced, and for about 1700-1800 euro, you can get a 10kW 3 phase HV hybrid inverter with UPS functionality.
I didn't know Goodwe when I installed my setup.
In the meantime I got in touch with the 48V 3,6kW version GW 3648-EM which has quite interesting data. I like the home consumption measurement with its current transformers. In my case it was "more complicated" with the Kostal smart energy meter which does direct measurement, so all the current need to go though the device.
From technical data and for sure compared to the price, they are pretty good. I do not have any data for durability but expect them to be similar to others.

Your project is very similar to mine, respect for the work you did!
 

hopfi2k

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Jun 21, 2021
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Silent lurker here. Having read the thread with great interest. Wondering if this has materialised into a custom sort of "BYD-BMS-emulator"? Would love to know how this developed!
 

Jagganaut

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Jun 23, 2021
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I am trying to use a battery from an EV, maybe BMW i3 or even the tesla battery. i3 would be nice since the voltage is in a good range. With a Tesla battery I would need to use the whole pack with 60 to 100 kWh to have a good voltage, which might be a bit oversized. :D
So am trying to simulate the BYD battery for the existing Kostal inverter.
I also thought about using another inverter. I like the Victron pars for its uninterruptible power supply and fast transfer switches. But they are using only single phase concepts. So I would need 3x the MultiPlus || and the SmartSolar RS to have a tree phase system which lead to additional cost for the inverter of around 7 k€. With this system I would have the UPS but thats not worth it.

I am working as electrical engineer for a german company which builds cell management controller, battery management controller and battery junction boxes for different OEMs so I know what I am doing. :)
Only unusual thing for me is to not having a description of the protocols and buses.
It is exactly what i intend to install for our home location as well.
Multiple tesla modules are already here due to the fact, that we are reapiring hv-packs.
Before putting them again into real cars, my idea is to use them in our own pv-installation.
The boosttech BMS looks good from easy-installation perspective so i would like to bring these guys
into that thread to assist in that adoption into some piece of usable communication between the plenticores
and the battpack.
After that i would even consider to abandon our PowerWall2 from past referals.
@huntworker If you are located in germany maybe we can combine our efforts ... ;-)
 

huntworker

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Hi all,
my activities stopped during summer because I didn't find any time.
But during summer I got new ideas for the hardware and I will bring it to a PCB design and test it this winter. Plan is to have a running system for Christmas.
@Jagganaut yes, I am in Germany, currently in the south, but soon in the south-west. I am always interested in "damaged" battery modules.
 

xcometz

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Oct 13, 2021
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Hi All,

this topic is very interesting for me. I have old Piko BA without battery und I just connect high voltage DC to battery connection only to make it still stanby on the night to keep the inverter measuring home use.

I did simple deviding your log to some 4 byte floating point and got this result:

Code:
Current: -1.775
SOC: 63.000%
SysTemp: 20.300
MaxCellVolt: 3.264
MinCellVolt: 3.260
MaxCellTemp: 19.600
MinCellTemp: 17.600
MaxVolPos: 3
MinVolPos: 4
MaxTempPos: 1
MinTempPos: 4

0A E2 FF 02 FF 29
CF 77 82 43 -> 0x438277cf = 260.936004639    Cur Voltage
01 0F 8D 43 -> 0x438d0f01 = 282.117218018    Max Allowed Voltage
66 66 A2 41 -> 0x41a26666 = 20.2999992371    SysTemp
66 66 E6 BF -> 0xbfe66666 = -1.79999995232    Current
46 E1 DA BF -> 0xbfdae146 = -1.70999979973    Current
01 03 48 42 -> 0x42480301 = 50.0029335022    Peak discharge current
01 03 C8 41 -> 0x41c80301 = 25.0014667511    Nominal discharge current
01 14 A0 41 -> 0x410a1401 = 8.62988376617
CD CC 9C 41 -> 0x419ccccd = 19.6000003815    MaxCellTemp
CD CC 8C 41 -> 0x418ccccd = 17.6000003815    MinCellTemp
FE D4 50 40 -> 0x4050d4fe = 3.26300001144    MaxCellVolt
75 93 50 40 -> 0x40509375 = 3.25900006294    MinCellVolt
FC        -> 0xFC = 252            Cycle count
02 01 02
3F         -> 0x3f = 63            SoC
01 01 02
B4        ->    checksum

It could be possible that last byte floating point is used to code other thing like max-min voltage position and temperature position.

If I looked your first log, the second byte from each frame have "E2" or "62", it remain me to webasto protocol that use 4bit for sender address and destination address.

@huntworker could you share your log on power on and power off?
 

huntworker

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Hi,
nice to see you interested in the topic. :)

It could be possible that last byte floating point is used to code other thing like max-min voltage position and temperature position.
You mean the last block, in this case 75 93 50 40? I am pretty sure that this is the voltage of the lowest cell since this matches well with the SOC.

If I looked your first log, the second byte from each frame have "E2" or "62", it remain me to webasto protocol that use 4bit for sender address and destination address.
If I have a closer look, the Header of the messages is always the same
E2 FF 02 FF 29 for messages from the battery to the inverter
62 FF 02 FF 29 for messages from the inverter to the battery
So the only change is in the first nibble. But with a even closer look you might see that it is even only changed in the first bit:
0x6 = 0b0110
0xE = 0b1110

@huntworker could you share your log on power on and power off?
Sure, please find the file attached.
Power off is quite easy, the communication just stops.


Edit: attachment was duplicated
 

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