A new kid on the block? The new FCHAO 4.2KW AIO Inverter

[meetyg]

Everything started while surfing on Aliexpress for some small components, when I stumbled on this:

https://www.aliexpress.com/item/1005007586473379.html

It's a 230v (single phase) 4.2kw 24v all-in-one.

At first glance, I thought: "OK, another Chinese clone... nothing special here".
But then I realized that this model has built in breakers for AC Input, Output, Battery, PV and an SPD! Just like the "big boys" have (6000XP for example). This is not very common with smaller, cheap AIOs.

It also has top mounted fans, that actually blow upwards, unlike the illogical design of most of these cheap AIOs (Voltronic clones), that have downwards blowing fans.
It also has removable mounting brackets, which I find nice to have.

Then I noticed it's from FCHAO. Some of you may recognize this Chinese brand from thier off-grid/mobile inverters, which are very nice for the price (I have a 1800w/24v model of thiers, pretty impressed with it).

So I was still somewhat skeptical, still was convinced it's a clone like PowMr, Anenji, Anern and others from China.
But I couldn't find anything that resembles it.

So for the price of less than 500$, I thought it's interesting enough to take the plunge...
I ask the seller for a datasheet and user manual. He provided a datasheet, but said that the user manual is included with the inverter.


It arrived today, only a few weeks after ordering.

First impression is that it's larger than I imagined. They actually have two models that are technically the same, but one has all the built-in breakers, in a larger housing. The other doesn't and is more compact.

I currently have a MUST 3K 24V installed, with a subpanel housing all the breakers and SPDs, but I thought that it would be nice to reduce the clutter in that subpanel, with this FCHAO AIO with built-in breakers.

So I took a few quick pictures during unboxing (sorry for the poor quality), just to give you some idea if what it looks like:


I also opened it up, cause I was curious how it looks inside.
So here's a peek:
Battery breaker is 250A:



Battery wires are all 6AWG, silicone insulation.

5 x 40A fuses, which seems to be removable.
I'm not to fond of these automotive type fuses, but at least it has them. Unlike a 4.2kw Powmr I bought previously, which didn't have any fuses.

Cover was easily removable with 8 hex screws, but the display has very delicate pins on the back, which I accidentally bent when removing the cover. I straightened them back before putting the cover back on, as to not cause any shorts.



I temporarily connected the AIO to my power supply, and saw that it draws around 45w when idle.

I also tried to check for N-G bonding when no AC Input connected, and it seems to do bonding, as I only got a few volts AC from Neutral to Earth. It wasn't grounded yet, so this small voltage may be capacitive.
I also tried to measure AC volts on the PV lines, but got some sort of fluctuation. So it goes from like almost 0v to 100v for a split second. I think that's good, because the Powmr 4.2k I previously tested had full AC voltage on the PV lines.

The user manual is nothing special. Resembles alot of the Voltronic clones' manuals. Has some funny typos and mistakes.

But this inverter does have SUB mode, so I think it can blend AC and PV power together to power the loads (just like my hybrid MUST does).

I still need to test this AIO before doing a full install, replacing my good-old MUST 3KW.
I may build a small testing setup, just to get to know this AIO and see if it's worthy replacing my MUST PH18-PLUS 3K.
I might have to rearrange my small PV setup, in order to fulfill the minimum PV voltage this AIO needs, but that's for another post.

I'll keep you updated... If you have any questions, feel free to ask.

 

[Mattb4]

Thanks for the review. Sadly there is many more and better priced alternatives in the 230vAC single phase options (Asia/Euro standard). I keep waiting for one of these companies to produce a decent 7-8kW split phase 24vDC battery model.

 

[meetyg]

Thanks for the review. Sadly there is many more and better priced alternatives in the 230vAC single phase options (Asia/Euro standard). I keep waiting for one of these companies to produce a decent 7-8kW split phase 24vDC battery model.

What are the better alternatives?
Unfortunately, EG4 stuff isn't available globally and AFAIK is only made for split phase (or U.S. 240V).
I would love to get a DEYE/SUNSYNK/SOLIS all in one, but these are expensive for my budget.

I don't expect to see 7-8kw 24v options. That's alot of current for 24v (~300A), which would require very thick wires and PCB traces, which is not cost effective for these manufacturers.
I think 4.2kw is probably the feasible limit.

 

[Mattb4]

...

I don't expect to see 7-8kw 24v options. That's alot of current for 24v (~300A), which would require very thick wires and PCB traces, which is not cost effective for these manufacturers.
I think 4.2kw is probably the feasible limit.

Double 4.2kW or for that matter 2 of the 3.6kW models stacked in one box out there would do it. Sungold does offer a 10kW 24vDC split phase model but at a hefty price point. (~$3,000).

ETA: WZRELB makes 24vDC split phase inverters that go up to 12,000W just no combination AIO style.

 

[meetyg]

Just an interesting note:
They put 1000v SPDs in this inverter, which has a 500v maximum PV input.
Is this OK ? Should I replace them with lower rated ones, to actually protect the PV side?

 

[Rednecktek]

And I thought the PowMr 3.2kw was the largest thing you could find in 24v 120v US power. I wonder if there will be a 120v US version in the forseeable future.

 

[Mattb4]

And I thought the PowMr 3.2kw was the largest thing you could find in 24v 120v US power. I wonder if there will be a 120v US version in the forseeable future.

PowMr is now carrying the 3.6kW for 24vDC same as my Sumry that I reviewed in the Hybrid and grid tie inverter Forum. PowMr has quite a few relabeled 24vDC AIO's including some LF models. What they don't have is any parallel capable or split phase models in 24vDC.

 

[Rednecktek]

Huh. I just bought the 3.2kw off their site last week, it was the largest 120v unit they offered in 24v.

 

[Mattb4]

It is likely not up on their site yet but you can order it off Ebay.

 

[Rednecktek]

Double the MPPT cappacity...

Sold on Ebay before it's on the manufacturers site...

Cheaper than the smaller unit...

Raises a lot of red flags for me.

 

[Brucey]

Just an interesting note:
They put 1000v SPDs in this inverter, which has a 500v maximum PV input.
Is this OK ? Should I replace them with lower rated ones, to actually protect the PV side?

SPDs would be to protect from lightning and not for protection against accidental over voltage due to poor system design (taking into account colder temps increasing V beyond rated Voc). The aio charger may well die, but protect your downstream equipment.

 

[Mattb4]

Double the MPPT cappacity...

Sold on Ebay before it's on the manufacturers site...

Cheaper than the smaller unit...

Raises a lot of red flags for me.

As I mentioned I am running the Sumry version of it. Over the last couple of years PowMr has been quick to rebadged a new AIO offering as one of their own. It frequently does not show in their website for sometime. I will say mine is not a SRNE and it has a few shortcomings. https://diysolarforum.com/threads/s...d-with-operational-review.88331/#post-1213326

 

[meetyg]

I previously bought a Powmr 4.2k 24v Single phase (230v) AIO. Same as Sumry (I think Sumry is the manufacturer).
After brief testing, I ended up selling it.
Wasn't too impressed with the build quality. Also no fuse on the battery input, no N-G bonding and full AC voltage on the PV lines.
I know that alot of these AIOs with high PV voltage (450-500v) have this problem, including some EG4s. But that's why I stayed with lower voltage MUST inverter that doesn't have this issue.

It's not that I don't have some critism on the FCHAO but I'm hoping it will perform well.

My main criticism is:
1. The use of 6 AWG Silicone wires internally, with crimped copper terminal rings that have "100A" written on them. For a 4.2kw machine, I think this is a bit undersized. I would rather see at least 4AWG with bulkier tinned-copper terminal rings.

2. The use of 1000v PV SPDs. I would rather see 500v SPDs on it, as to protect the PV input capacitors and components.

Both issues are resolvable, it choose to change them, I can.

BTW, I contacted the seller about the COM port. I asked whether it's for monitoring or BMS communications and what software can I use with it. He answered that's its for RS232 communications only. But didn't answer my question about software.

I hope it supports one of the protocols support by SolarAssistant, but I guess I will have to investigate myself.

 

[meetyg]

My main problem now is getting it temporarily setup, with a high enough PV voltage (150v starting, 120v MPPT minimum).
While I could connect my two dissimilar arrays in series (currently connected in parallel), I prefer not to, because I don't want to disturb my existing system.
I need it for backup of critical loads, so I don't want to do any changes or disconnect PV from it.

I do have some used panels I could throw in my driveway and connect in series, but my wife isn't too happy with that idea, giving up on our parking space.
So I have to do some rethinking.
My current setup is on my Pergola, but there is no room for adding panels, let alone 6 used and bulky panels I have.

I was thinking that maybe for testing purposes, I could get some sort of DC-DC boost converter (connected to a small array), but most of them available are only with 120v max, which would not fulfill the 150v starting voltage needed by the FCHAO.

 

[RSahan]

Inside looks like every other cheap AIO's. Maybe the did the value add by installing those breakers.

I honestly have no idea why you guys go through multiples of these cheap AIO's when you can simply buy a superior, IP65, proper hybrid like Deye 5kW for $950 with 5 years of warranty

 

[Rednecktek]

Somebody's gotta test out the cheap krap for us poors. Saying "Just spend more money" is a lousy option when you're on a budget. Given the option of a cheap unit that works okay AND the panels AND the batteries AND so on OR drop the same cash for a name brand inverter that gets to sit in a box while you're scraping up money for the rest of the system while you're sitting in the dark... well... I'll take the whole system.

 

[meetyg]

Inside looks like every other cheap AIO's. Maybe the did the value add by installing those breakers.

I honestly have no idea why you guys go through multiples of these cheap AIO's when you can simply buy a superior, IP65, proper hybrid like Deye 5kW for $950 with 5 years of warranty

Not that simple.
You see maybe in the U.S. a Deye or other respectable brand AIO costs 950$, but for us living in other places in the world, the price is far from that.
After shipping, import fees and taxes and local dealer/reseller profit, these units can cost 2-3 times more than MSRP in the U.S.

So we don't have much choice but to buy cheap.

Now because of this, I actually made a small profit, locally selling the Powmr 4.2k that I didn’t like.
I don't have multiple AIOs either.
Just one MUST 3k which has been performing pretty well for now (not without some quirks, but OK). But I'm looking to improve/upgrade.
Since my current system is 24v, I'd like to stick with that for now.

 

[Brucey]

Inside looks like every other cheap AIO's. Maybe the did the value add by installing those breakers.

I honestly have no idea why you guys go through multiples of these cheap AIO's when you can simply buy a superior, IP65, proper hybrid like Deye 5kW for $950 with 5 years of warranty

Solark has exclusive distribution in North America for 120/240 split phase Deyes, so that $1k Deye ends up costing $3k here

 

[RSahan]

Not that simple.
You see maybe in the U.S. a Deye or other respectable brand AIO costs 950$, but for us living in other places in the world, the price is far from that.
After shipping, import fees and taxes and local dealer/reseller profit, these units can cost 2-3 times more than MSRP in the U.S.

So we don't have much choice but to buy cheap.

Now because of this, I actually made a small profit, locally selling the Powmr 4.2k that I didn’t like.
I don't have multiple AIOs either.
Just one MUST 3k which has been performing pretty well for now (not without some quirks, but OK). But I'm looking to improve/upgrade.
Since my current system is 24v, I'd like to stick with that for now.

Deye got 24v 3 or 3.6kw which is probably in the $700-800 range. No need to make local dealers rich. Just buy from Alibaba. Plenty of cargo forwarders are on Alibaba as well so you can get it shipped by boat for much cheaper

If you are looking for something even cheaper then MPP or SRNE are the way to go.

 

[RSahan]

Solark has exclusive distribution in North America for 120/240 split phase Deyes, so that $1k Deye ends up costing $3k here

Yep but OP is in a 230v country

 

[Mattb4]

Somebody's gotta test out the cheap krap for us poors. ...

I try. However there is a fair amount of snobbery in the PV world. Personally I like finding inexpensive things that do a task and have a reasonable lifetime. Sure occasionally you run into stuff that is not worth having even if it was cheap. Luckily we have places like the Forum here where people give their experience.

 

[meetyg]

I try. However there is a fair amount of snobbery in the PV world. Personally I like finding inexpensive things that do a task and have a reasonable lifetime. Sure occasionally you run into stuff that is not worth having even if it was cheap. Luckily we have places like the Forum here where people give their experience.

You took the words out of my mouth

To add to this, it's not like the more expensive brands are trouble free...
So yes, maybe those issues can be fixed due to good support by a large company.
But that support also comes at a premium (price).

 

[meetyg]

Just a little update, after doing some more testing on this unit:

I finally got around to DIYing another 24v 50ah battery, so now I had the chance to test this AIO a bit.
I previously connected it to a PSU, just for powering it on, as I didn't want to disconnect one of my 2 24v 105Ah batteries from my main system.

Now connected to the small 24v 50Ah battery, I tested charging from grid and a bit of loads. Still can't test solar, as my PV array currently doesn't meet the minimum PV voltage of this AIO, but I plan on getting new panels next month.

Anyways, some interesting things I learned about this AIO:

1. It doesn't do N-G like I previously thought. Previously, I measured voltage between N and G and didn't get any significant AC voltage. I suspect this maybe due to having it powered via the PSU. Does this make sense?
Maybe it was because previously it was set to SBU, and now I had it on SUB (but with grid input disconnected, only ground attached)?
I'll have to check this again...

2. It works with SolarAssistant!


I had an RJ-45 to USB adapter cable laying around, intended for MPP inverters RS232 communications. This cable worked fine, connected to Pi3 with MPP/VOLTRONIC inverter type selected in SA.
SA reported that "NXP" was detected and that I should try with the SUMRY type, but that gave less data and no settings could be changed. So I went back to VOLTRONIC and SA is working fine. Interestingly, SA shows that the model number is VMII-NXPW5KW.
I tried looking that up on Google, but it seems like a different model. Maybe FCHAO copied the firmware from some Axpert model or something, IDK...
Also mentions it's a 3800K/VA model, which I don't know if it's true (should be 4200w).


3. The AIO has an LIB battery type not documented in the user manual. When choosing this, in SA it still reports the battery type as FLOODED. SA also shows battery types with various BMS protocols. I don't know if this is really supported by the FCHAO AIO, or if this is hard-coded in SA for VOLTRONIC inverters.

4. Something weird is going on with grid charging: It seems to start fine, but then ramps down the current. I think it was trying to target float voltage, not bulk/absorption.
Did the same with battery as USE and as LIB.
I think I will have to check this again and see how it charges with solar.

5. Tried some loads: a small room heater.
At low setting the heater pulled 1kw, and the AIOs fans didn't even power on. I ran that for about a minute. Maybe if I ran it for more time, the fans would kick in. But then at high setting, pulling around 2.2kw, the fans kicked in immediately. That's a bit too much load for my little 24v 50Ah test battery, so the naturally the inverter started to complain about low voltage, so I turned the load off after a few seconds.

That's all for now. I was happy that it works with SA, otherwise that would be a deal-breaker for me.

It was also very convenient having all the AC and DC breakers in place in the unit itself. Hookup for testing took me 5 minutes.

 

[Rednecktek]

LIB? Are you sure that isn't Li8 as in Lithium 8s? As opposed to Li7 which would be a 7s 18650 type battery?

Too bad there isn't a 120v version.

 

[meetyg]

LIB? Are you sure that isn't Li8 as in Lithium 8s? As opposed to Li7 which would be a 7s 18650 type battery?

Too bad there isn't a 120v version.

Could be LI8, but as opposed to SRNE AIOs, there are no other options for lithium (no LI7 etc...). Other options are AGM and FLA