My 3KW Hybrid Inverter setup, as a backup for when (not if) the grid goes out.

[keesjanccen]

I'm a Dutch guy living on the island of Koh Samui in Thailand.

This is my 3KW Hybrid setup. Powering my home when the grid goes down.
The grid goes down pretty regularly. At least once per month, sometimes even a few times a week. Usually the power comes back after 1 or 2 hours.

https://imgur.com/zlbMuCV

• Inverter: SunD 3KW - I believe this is a "SAKO Sunon Plus 3K" Clone
• Cells: 8x LifePo4 105Ah EVE
• BMS: Daly 100A 24v 8s
• Solar: None yet.. due to budget constraints..

The main reason for a backup system was the reliability of the grid.
I wanted to build my own hybrid system first; Using an ATS, stand-alone inverter, charger.
But I could not find a reliable source for a 3KW inverter (with more then a week warranty), I'm not used to importing stuff from Alibaba so I had my engineer source it outside the island.
For a simple 3KW 24V inverter the price he came up with was 12.000thb ~ $350. So that opted me to find an all-in-one system instead.
My restriction was online shopping as there is no shop on the island for solar. So I sourced this inverter from Lazada. The specs are pretty good and outperforms anything else I could find in this pricerange.

https://imgur.com/9QEtpNe

I already ordered and tested the batteries and bms before, and had my engineer install it. He also made the nice box for it.

My setup:

I am oke with this setup, its not anything special. Other guys in this forum make their setup look super nice and tight. Mine looks like Mèh
What I am not happy about is the cross-cabling they did with the BMS, first the electrician wired it up incorrectly then had to switch the B- and P- around.
Might mount it sideways instead and have the cable running below it. There is enough space. Let me know what you think and have any ideas on improving anything.




Trying to add additional cooling did not work...


This is the inverter:


Issues with this inverter:
My assumption was just to configure it and be done with it. But there are some issues with it that I did not anticipate.

1. A single fan is running constantly, even though the internal temperature only shows 35C(board) and 37C(cpu).
2. At exactly 00:00h, the inverter switches to Battery mode / SBU priority. Due to the timer setup that cannot be disabled.
3. The battery is being charged (or perhaps trickle-charged) non-stop at 4A. This inverter does not have a LifePo/Lithium profile.
4. Data logging from the SmartESS app is only showing the status NOW, it is not logging any history.
5. Support from the supplier... There is no support.

I have attached the user manual for this system. And also a parts list I used as a guide for my initial setup before I switched to this all-in-one system.
Maybe it will be of some help to someone.

 

[Sojourner1]

It looks like a nice clean setup.

What do you mean by this?

1. The battery is being charged (or perhaps trickle-charged) non-stop at 4A. This inverter does not have a LifePo/Lithium profile.

Looking at the manual it appears that you can set the parameters fairly well to work nicely with LFP.

What is the black thing with the antenna?

 

[Bud Martin]

May be cutout some ventilation ports for the cabinet and put on insect screen to keep the bugs out.

 

[keesjanccen]

It looks like a nice clean setup.

What do you mean by this?

1. The battery is being charged (or perhaps trickle-charged) non-stop at 4A. This inverter does not have a LifePo/Lithium profile.

Looking at the manual it appears that you can set the parameters fairly well to work nicely with LFP.

What is the black thing with the antenna?

Thank you Sojourner1.



The status display constantly displays that the battery is charging, indicated by the icons. The charging current is indicated as 4Amps.
When I turn the inverter off-and-back-on-again; The AC/DC and also the battery charging indicator will disappear. After about 5 minutes, they turn back on.




The app also thinks that the battery is charging at 4A.

However I measured the current with a multimeter; It is ~30mA. When the unit ís charging; The current is off by almost 5Amp. So there may just be an internal calibration issue?

What is the black thing with the antenna?

Its a WiFi antenna The unit has an external Wifi adapter for the serial port / datalogger.
With the app it comes with (SmartESS) it can be set-up to connect to your own WiFi and log the data to an external server on the internet.

The data logging functionality of the app does not work though.. only the realtime information.

 

[keesjanccen]

May be cutout some ventilation ports for the cabinet and put on insect screen to keep the bugs out.

Thank you for the suggestion.
It does have wide gaps in the bottom to allow for airflow, however the fans might just blow the air around in the cabinet.

I did check if the huge fan would do anything to cool down the inverter but even on max it did not change the internal temperature a single degree.

No snakes inside the cabinet yet, but yeah I will put a bugscreen on the bottom. Dont want anything breeding in there

 

[Sojourner1]

Is it possible what you think is charging is actually the idle draw from the unit and being covered by grid power?

 

[keesjanccen]

Is it possible what you think is charging is actually the idle draw from the unit and being covered by grid power?

O, that it is using 100W just to power the AC/DC internal circuit. It might be... but then why power the circuit if the battery is full?
I will open a thread in the Technical support forum to get some exposure to this issue. Maybe there is a pod I can turn or something.

That's what you get when not buying a known brand I guess..