diy solar

diy solar

Bonding multiple Deye 12kW inverters in Off-Grid Mode

houseofancients said:
12k

If you're not pulling more than 4kw per phase, you could consider leaving 1 inverter as a cold backup..
These inverters will pull between 60 and 90 watts per inverter, so leaving 1 off will leave you with a considerable amount of kwh's per 24h not being wasted
Click to expand...
Cold backup? How to do that?

60 watts is better what I have now. Ones I have now pull on idle 120w each and I have 3 of them, so 60 is saving :)
 
liberumyu said:
Hi all.

I hope someone reads this thread still.

I’m getting my two Deye 12kW 3P hybrids soon to run in parallel and I have one question.

Can I connect my entire apartment as backup load? I don’t have a dedicated wiring for backup loads so what I would do is run everything as backup load.
If I do that what will happen while I’m having power from the grid?

My current Inverters don’t have a sell to grid option so everything runs trough them. Is it same with Deye inverters for backup load?
Click to expand...
That's what I am doing with 3 of them in parallel :) . Off grid only, everything is connected to the Load/Backup Port (a big UPS basically).

I had some mishaps yesterday not sure why though ... I was getting lots of F18_AC_over_current_fault_of_hardware, F41_Parallel_system_stop as well as F58_BMS_communication_fault.

I later identified the cause of the F58_BMS_communication_fault (problem sitting between the screen and the chair 🫣 - I was doing a BMS Interface Board Software Update, so of course that triggered the F58 due to BMS_Err-Stop being Enabled on the Inverter, which lost communication with the BMS and stopped correctly).

And I could imagine F41_Parallel_system_stop being caused by the Inverters Stopping not in the right "Sequence" (all the the same time), maybe one stopped before the other 2.

But F18_AC_over_current_fault_of_hardware is something completely new. Some search online might suggest this is due to load shedding or AC undervoltage voltage cutout being set too low, or even a fault in the AC relay (either the grounding one or the Static Transfer Switch, the latter which I do not use).

During one F18_AC_over_current_fault_of_hardware I swear I heard a spark. What the hell ??

The only possible cause I can imagine are:
- The output filter of the Inverter + the EMC filter that I have installed do not discharge sufficiently in the 30-60 seconds changeover that I have with a set of contactors, therefore when Inverter reconnects, effectively it might be having the wrong phase, thus causing an Inrush Current (doubtful for several reasons: the 30-60s and the fact that such Inrush would have VERY low energy (we might be talking about 20-100 uF, not more).
- There is not enough impedance between the 3 Inverters (only approx. 5m of cables from each to the distribution board where they are connected in parallel)

The F18_AC_over_current_fault_of_hardware error never appeared until now.

I am running my 12kW Heatpump and the whole house on these 3 Inverters. The Heatpump being an Inverter type Heatpump, it's particularly smooth at ramping up the Power (although I'd say that the harmonic content of the current it's a whole other story ... Uhm ... Probably a stupid cheap 3ph Diode Bridge Rectifier 🫣).

THD Values of <2.5% of the Voltage (THD_U) are OK-ish.

But THD Values of ~ 60% at around 2kW on the Current (THD_I) is quite hight ...
 
liberumyu said:
I have 4x 200A, so I guess it should work.

I’ll have some time to prepare everything until my “Peter boards” arrive so my batteries can be connected to inverter.

That’s another question, can inverters run without communication to batteries?

Now I’m controlling charge, float and absorbing with HA so wouldn’t mind doing it in future…
Click to expand...
I suggest using BMS Communication.

I also thought that it wasn't needed but:
- You might hit OVP all the time (I had 5 times per day quite regularly unless I monitored constantly on HomeAssistant)
- You might never go High enough for Long enough and therefore you could suffer from an Unbalance

I also thought of doing the same, but given those caveats (which sometimes BOTH occur almost at the same time, i.e. you reduce float/absorbtion to avoid OVP, but then cause unbalance), and I am somewhat skeptical of doing continuous write cycles on the Inverter Flash Memory (I don't want to wear it out and therefore cause the Inverter to Fail), this Project definitively came in handy and it's working quite well: https://diysolarforum.com/threads/jk-bms-can-with-new-cut-off-charging-logic-open-source.79325/. Although I'd caution about lowering a bit the OVP anyway, there is a bit of delay when things can get rought. BMS communication = Inverter goes "Full Voltage & Full Current" for a few seconds (?) until the CANbus heartbeat missing causes it to trip. It was enough to get 1 of my cells to 3.69 V a couple of times yesterday ...
 
silverstone said:
That's what I am doing with 3 of them in parallel :) . Off grid only, everything is connected to the Load/Backup Port (a big UPS basically).

I had some mishaps yesterday not sure why though ... I was getting lots of F18_AC_over_current_fault_of_hardware, F41_Parallel_system_stop as well as F58_BMS_communication_fault.

I later identified the cause of the F58_BMS_communication_fault (problem sitting between the screen and the chair 🫣 - I was doing a BMS Interface Board Software Update, so of course that triggered the F58 due to BMS_Err-Stop being Enabled on the Inverter, which lost communication with the BMS and stopped correctly).

And I could imagine F41_Parallel_system_stop being caused by the Inverters Stopping not in the right "Sequence" (all the the same time), maybe one stopped before the other 2.

But F18_AC_over_current_fault_of_hardware is something completely new. Some search online might suggest this is due to load shedding or AC undervoltage voltage cutout being set too low, or even a fault in the AC relay (either the grounding one or the Static Transfer Switch, the latter which I do not use).

During one F18_AC_over_current_fault_of_hardware I swear I heard a spark. What the hell ??

The only possible cause I can imagine are:
- The output filter of the Inverter + the EMC filter that I have installed do not discharge sufficiently in the 30-60 seconds changeover that I have with a set of contactors, therefore when Inverter reconnects, effectively it might be having the wrong phase, thus causing an Inrush Current (doubtful for several reasons: the 30-60s and the fact that such Inrush would have VERY low energy (we might be talking about 20-100 uF, not more).
- There is not enough impedance between the 3 Inverters (only approx. 5m of cables from each to the distribution board where they are connected in parallel)

The F18_AC_over_current_fault_of_hardware error never appeared until now.

I am running my 12kW Heatpump and the whole house on these 3 Inverters. The Heatpump being an Inverter type Heatpump, it's particularly smooth at ramping up the Power (although I'd say that the harmonic content of the current it's a whole other story ... Uhm ... Probably a stupid cheap 3ph Diode Bridge Rectifier 🫣).

THD Values of <2.5% of the Voltage (THD_U) are OK-ish.

But THD Values of ~ 60% at around 2kW on the Current (THD_I) is quite hight ...
Click to expand...
Amazing. This really made my day :)

Are you using HA maybe to control inverters? Is that even possible or just you can view data?
 
liberumyu said:
I have 4x 200A, so I guess it should work.

I’ll have some time to prepare everything until my “Peter boards” arrive so my batteries can be connected to inverter.

That’s another question, can inverters run without communication to batteries?

Now I’m controlling charge, float and absorbing with HA so wouldn’t mind doing it in future…
Click to expand...
They can, on voltage, but these class of inverters run best with comms, as it will allow you to use the full feature set
 
timselectric said:
I thought there was. But maybe not, if the manual doesn't specify it.
Click to expand...
I think you are confusing with the AUX/Generator/MicroInverter Port. There I think it's only rated for 50% of Rated Power.

But I think there is definitively a lower Rating in terms of Peak (Inrush) Current on the Load Port, at least from what I could understand by looking at the label, although it's always a bit sketchy what is meant by "nominal", "rated", "maximum".

They could make it much more clearer by simply stating "ARMS" or "Apeak". Then there are no more doubts. Is it a "maximum" peak or a "maximum" short-term RMS ?

1713643423779.png
 
silverstone said:
I suggest using BMS Communication.

I also thought that it wasn't needed but:
- You might hit OVP all the time (I had 5 times per day quite regularly unless I monitored constantly on HomeAssistant)
- You might never go High enough for Long enough and therefore you could suffer from an Unbalance

I also thought of doing the same, but given those caveats (which sometimes BOTH occur almost at the same time, i.e. you reduce float/absorbtion to avoid OVP, but then cause unbalance), and I am somewhat skeptical of doing continuous write cycles on the Inverter Flash Memory (I don't want to wear it out and therefore cause the Inverter to Fail), this Project definitively came in handy and it's working quite well: https://diysolarforum.com/threads/jk-bms-can-with-new-cut-off-charging-logic-open-source.79325/. Although I'd caution about lowering a bit the OVP anyway, there is a bit of delay when things can get rought. BMS communication = Inverter goes "Full Voltage & Full Current" for a few seconds (?) until the CANbus heartbeat missing causes it to trip. It was enough to get 1 of my cells to 3.69 V a couple of times yesterday ...
Click to expand...
That could also be caused by outdated firmware..

Tip to OP, make sure both are running the latest fw ( 1150 main , c042 for lcd) , and both are running the same exact version of it
 
houseofancients said:
They can, on voltage, but these class of inverters run best with comms, as it will allow you to use the full feature set
Click to expand...
Good.

At least I don’t have to wait for boards to arrive to connect system. They will take a good month or more ….
 
silverstone said:
I think you are confusing with the AUX/Generator/MicroInverter Port. There I think it's only rated for 50% of Rated Power.

But I think there is definitively a lower Rating in terms of Peak (Inrush) Current on the Load Port, at least from what I could understand by looking at the label, although it's always a bit sketchy what is meant by "nominal", "rated", "maximum".

They could make it much more clearer by simply stating "ARMS" or "Apeak". Then there are no more doubts. Is it a "maximum" peak or a "maximum" short-term RMS ?

View attachment 210505
Click to expand...
There is no difference in output between load and grid port, other than grid can have power coming in and out, and load only can have power going out
 
houseofancients said:
Simply, keep one off, and don't parallel till you need it
Click to expand...
If he's in Off-Grid mode he cannot do the "trick" of dynamically switching the Battery Off. That would be the biggest Power saving.

Similarly, you cannot turn them off via Modbus, without causing a Trip. And for Off-grid that's also not an option.

I saw some Posts on GitHub where I forked my Deye ESPHome Repo where they talked about these things. But for me (for the two reasons mentioned above) that cannot be done without Service Interruption (in my case I have a set of Contactor performing the Function of "Automatic Transfer Switch" with 30s Transfer Time - I wanted something simple and robust no Software etc, just Contactors and Voltage Monitoring Relay, 30s Transfer Time to avoiding switching the Contactors ON/OFF/ON/OFF all the time in case something Funky [like yesterday] occurs).
 
liberumyu said:
Good.

At least I don’t have to wait for boards to arrive to connect system. They will take a good month or more ….
Click to expand...
Btw.. no familiar with "peter boards" other than what I saw on a yt channel..
This looks very much like a hobby project, so please do be careful as it may lead to unexpected results
 
silverstone said:
I think you are confusing with the AUX/Generator/MicroInverter Port. There I think it's only rated for 50% of Rated Power.
Click to expand...
Yes
That's what I considered "backup". I was guessing from context of the question.
It wouldn't be the first time that I was wrong. lol
 
silverstone said:
If he's in Off-Grid mode he cannot do the "trick" of dynamically switching the Battery Off. That would be the biggest Power saving.

Similarly, you cannot turn them off via Modbus, without causing a Trip. And for Off-grid that's also not an option.

I saw some Posts on GitHub where I forked my Deye ESPHome Repo where they talked about these things. But for me (for the two reasons mentioned above) that cannot be done without Service Interruption (in my case I have a set of Contactor performing the Function of "Automatic Transfer Switch" with 30s Transfer Time - I wanted something simple and robust no Software etc, just Contactors and Voltage Monitoring Relay, 30s Transfer Time to avoiding switching the Contactors ON/OFF/ON/OFF all the time in case something Funky [like yesterday] occurs).
Click to expand...
There is no "trick" and no automation for cold backup
And yes there will be a service interruption when paralleling again, but it will save 3 kWh / day or more, and if you're not needing 24kwh ( or 8 kWh per phase) on demand available, this may be worth considering
 
houseofancients said:
That could also be caused by outdated firmware..

Tip to OP, make sure both are running the latest fw ( 1150 main , c042 for lcd) , and both are running the same exact version of it
Click to expand...
To be honest I'm running a VERY old version of the Firmware (unsure now ... I think I got it at the Beginning of 2023 but it's still running 2022 or even 2021).

BUT you know what they tell you ... You know the Devil you have, you don't know the Devil you get.

And then I don't know if I can downgrade ...
 
houseofancients said:
Btw.. no familiar with "peter boards" other than what I saw on a yt channel..
This looks very much like a hobby project, so please do be careful as it may lead to unexpected results
Click to expand...
I’m curious as well. Nothing more than what Andy from OFF GRID GARAGE posted.

I guess it’s just a translator between JK BMS and Deye. If not it’s going to be a bit expensive game replacing 4 JK BMS with some that can talk to Deye… My battery banks are DIY and I’m really proud of them :)
 
liberumyu said:
I’m curious as well. Nothing more than what Andy from OFF GRID GARAGE posted.

I guess it’s just a translator between JK BMS and Deye. If not it’s going to be a bit expensive game replacing 4 JK BMS with some that can talk to Deye… My battery banks are DIY and I’m really proud of them :)
Click to expand...
Please do let us know your experience..
Although for that money I would probably bought the jk server rack comm bms'es , if I was feeling adventurous ;)
 
houseofancients said:
There is no "trick" and no automation for cold backup
And yes there will be a service interruption when paralleling again, but it will save 3 kWh / day or more, and if you're not needing 24kwh ( or 8 kWh per phase) on demand available, this may be worth considering
Click to expand...
Well pros and cons.

One Inverter less means also:
- MPPT number of Channels is reduced -> Less Solar Power/Energy Production (unless you have lots of MPPT Channels to spare so you can transfer them to the other Inverter)
- Less ability to cope with "High" Load Steps
 
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