What Solar inverter?

[sirquest007]

Hi all,

 

I'm in need of a new inverter.

We live off grid, hybrids will do just fine.
(sorry for the general forum, i could not find electrical forum part)

quite a long post, nice if you read it,
what i'm looking for is advice on what type to buy from the 3 options given.
or, if you have a good 4th option, with real life experience, I'm all ears!
 

 

Our installation is 27 X 325w panels and 16* 200ah batteries.

 

I was a happy puppy, till my current inverters (6kw, GaiaDefender) quit on me.

https://www.aliexpress.com/item/32658016993.html

 

I received really good support from the vendor GaiaDefender , and have been back in China a few times for repairs...

Repair is free but transport and pay tax every time is pricey. (About 300 USD per time)

After having repaired one my self and paid 3 times for transport to repair, I pulled the plug.

Sad for the 3 * 600 USD purchase price, this has to stop.

 

They provide good clean energy, but don't have good thermal management.

With low power draw, the ventilator doesn't start at all... (200-500w) and 500w does heat up... To critical = smoke.
Last one is running now, i've taped 2 x 12v ventilator to keep constant airflow, sadly it only gives 190v at this time.
I'm in need of a new inverter....

 

I have my 3 x POWMR MPPT, 60A, and except for the fact that they make a lot of noise, (small fan) they do a good job)
https://www.aliexpress.com/item/4000021535485.html

 

As I needed to spend money again (cry) I bought a set from easun. 3* 4000w.

https://www.alibaba.com/product-detail/EASUN-POWER-5kva-Solar-Inverter-4000W_62074983113.html
Advise: DON'T!  Really, Really bad.
 

I did not receive the product I purchased, but lighter, cheaper model.
It was supposed to work in parallel, 2 can, the third can't.

MPPT performance is about 50% then what my PowMR converts!!!

 

The device itself doesn't look that bad, but the support... cry.

Last offer was to send the one that can not do parallel to their Thai agent. (for resell)

And buy new one from them (in China). (Not switching units ??)

You can not drive a trike on 2 wheels (for long)

Anyway, it's in Alibaba dispute hands now.

An other 1290..????

But I think/expect/ hope I get to send all 3 to the Thai agent, leaving me with little damage.

 

For the new ones, I've been looking at:

infinisolar 5kw / mpptsolar 5kw
https://www.alibaba.com/product-detail/5000w-Hybrid-Solar-inverter-Grid-tied_60559806917.html   
https://www.alibaba.com/product-detail/Infinisolar-5kW-Hybrid-On-Off-Grid_62086097531.html  

https://www.alibaba.com/product-detail/Factory-inverter-pure-sine-wave-inverter_60837998910.html  
Same product, different sellers, different price and have yes/no stock

The infinisolar have been discussed before on Thaivisa, i don't know if anyone purchased.

it looks like a real powerful unit, massive 29kg for the unit, al and al 35kg.
it can do my 9kw solar and most of my power requirements. 
I do need to do power management, as we have a too powerful submersible pump, 2.5kw.. (at 50m deep)
we can't use all the aircon (Daikin 5 x 9000btu, 530w each) on the same time and the pump ????
lots of other different small things like chargers, and (inverter) refrigerator.
Lucky I have about 30 simple sonoff (https://sonoff.tech/) left over from my mining farm, 
Power management can be automatic.

The last and best offer is 1470 USD include wifi and transport from  Taiwan
(no stock, end of this month)

or

 

https://www.soropower.com/products/Inverter/7/696.html 
Revo II

The Revo II look nice, but after my "light weight" experience...
I'm a bit afraid for its capabilities.
it does have double ventilator, one worry less.
choice would be 2 x 3.2kw (11.75kg )  (as for the solar)

Standard pricing:
The 3.2 = 450usd,
for parallel they need a kit (2x) = 2 x 25
and both need wifi = 2x 35
transport = 130usd.

last best offer for 2 x 3.2kw is 1090 USD for set (parallel and wifi)  and transport.

6.4 KW together is enough to run most equipment at the same time if needed. 

It is purchased via Alibaba, with trade assurance.
(most of the times, this is , when needed, good support)

The Revo II comes with nice phone app to monitor power production and usage. It have touchscreen, (overkill) for easy configuration.
For me they could have saved this gadget, i was not planning on do the installation every day ???? 
all with all, new device build on the "Revo I", for what I can find, most users are happy with.

last option, cheapest, build myself: (6 or 8kw)
https://www.aliexpress.com/item/4000029073794.htm 
https://www.aliexpress.com/item/32948892513.html 
https://www.aliexpress.com/item/32965573930.html 
The heavy coil (=/- 21kg) is about 270 usd include transport   
other parts are small and easy to assemble

The seller gives good pre-sales support on how to connect and output, according to reviews is stable.
It does require a bit soldering and buy / build enclosure.
I have no problems with soldering ????
Total price about 700 usd.


Feedback, please!!!

Thank you


 

 

On Fri, 15 Nov 2019 at 09:14, Frank Van der Horst <[email protected]> wrote:

https://www.alibaba.com/product-detail/EASUN-POWER-5kva-Solar-Inverter-4000W_62074983113.html  

 

Edited November 15, 2019 by sirquest007

[tjo o tjim]

No direct experience, but have you thought about separating the charge controllers and inverters, and breaking the batteries into 48V strings?  That should get you into a more commodity/modular type of arrangement. 
 

Also, your battery bank seems small compared to your PV for off-grid; how deep of a discharge are you doing on it each day?  I wonder if that is part of your reliability problem when you talk about low voltage. 

[sirquest007]

@ tjo o tjim

Battery bank seems small ??
16 x 200ah... 16 x 10.000THB.. 160.000THB

Probably the largest private battery array in Thailand ???? It's about 35KWh,
That is 35 hour 1000 watt discharge before the batteries go beyond a point of no return
Not many other crazy farang will spend 160k only on batteries.. 
(powerwall would be about 2.5x this price)

DOD at night about +80% (= +80% full) in a rainy week about +50%
Normally it is charged back to full before noon.

Many things you run during day time, and that is the time most energy is produced.
many sun  = many energy

many sun = hot

hot = many air conditioner usage ???? (and refrigerator uses more power)

keeps it in balance.

Rainy days have often more wind, 
There are 4 x 800w wind turbine to help power production on that time.

I have 48 volt system, as you can see, all of the products in the links are 48V ????
 

At this moment, I have separate mppt = charging and separate inverters.

This worked OK, except that the inverters are not capable of running 24/7 (as you can read)
My first idea was indeed to have split system for failure safety... 

The inverters bought are really good quality, except no 6kw inverter will work long without cooling.

As they need replacement, I have the option to choose inverter with MPPT, or without.

Having with, have many benefits, especially for monitoring (power production / usage) 
Also, the MPPT get +/- 115 volt from the panels , (or higher, depending on system)
Convert 115 DC to 220 AC is more efficient then 48 to 220.
about 10 to 13.5% more efficient. (!)
(+/- 80% for normal 48v DC to 220AC inverter/ 93% (!!) for combination MPPT / Inverter)

Question for the readers:
- 5kw Inverter with MPPT (29kg)
- 2 x 3.2 inverter with MPPT (2x11.75kg) (and handy app for monitoring)
- stay separate, maybe build own inverter, as you can see, it's not that difficult. And if it breaks, its the "cheap" PCB part.

The 5kw/29kg seems to be best quality build, no fail-back
The 6.2kw/23/5kg is newest technologies, highest efficiency (if it works) and have fail-back to 1 unit if it dies.
The inverter separate is least efficient, no fail-back

the 'fail-back I now use, 180v ????

About this low voltage.... (180v) is simple => defective inverter. (again)
an inverter converts (if working OK) DC (in my situation 48v) to AC (normally 220v)
My inverter uses 22 transformers to do this, each 10v, , apparently 4 are not working as it should.
(yes, I've checked the fuses, each transformer have own 20A fuse, they are OK)


 

[sirquest007]

I've repaired an other 6kw , and placed 2 additional ventilator.
that will work for a while. (220 volt)

After long thinking and discussions with the sellers i've chosen 3 times the Revo II
https://www.soropower.com/products/Inverter/7/696.html
Price 480 usd include parallel kit and Wifi + 170 transport makes 1610 usd.

while the "InfiniSolar Plus 5kW" looks like military grade equipment, it ain't low frequency inverter.
the 29kg would ma a person think so, it can have a big copper coil 
Nada.
while probably not a bad product, its internals look like "normal" 5kw  inverter and normal MPPT.
it does have many ferrite clamps on the cables, but that does not make it 29kg.
apparently the robust looks have a lot to do with it ????

Showstopper was that the 10.000 watt solar is split into 2 x 5000 watt.
my 18 panels make 5500 watt.
and I can do 3 x 9, or 18+9.
at the high price, buying a second was not inside budget.
also the 5kw was on the low side.

I'll close the deal next week and let you guys know how the Revo II works out for me!

[Metropolitian]

How did everything went?

[sirquest007]

The Revo II was shipped on 21 December, sadly by DHL.

 

I don't like DHL, they have always long process time and crazy price.

 

The previous 3 inverters costs about 95 USD tax via UPS.

Now DHL 235.

 

Lucky the seller will pay this additional costs. (We agreed on UPS)

 

DHL staff claimed to process the parcel, and went on holiday...

Not to return for 6 January.

 

It took some time to find out what the holdup was.

Once I knew, a polite phone call to the manager was enough to get it assigned to different staff member.

 

I guess they felt bad about it as the processing was done during friday- Saturday night.

(Normally a route for high priority parcels)

 

If we are lucky we receive them on Monday!

 

[Thaifish]

Sirquest, Any updates? I am costing/looking at installing a 15 panel system in both series and parallel. Each panel 310W 8.36A 37.09V. The resulting feed into the Inverter (3 strings x 5 panels in series and then put the 3 strings in parallel) would be 4651W 25.08A 185V. How does the WIFI display work. Is it tied to the internet? Where is the data stored? I really like the idea of having a record to look at so you can see the performance.

[BritManToo]

13 minutes ago, Thaifish said:

The resulting feed into the Inverter (3 strings x 5 panels in series and then put the 3 strings in parallel) would be 4651W 25.08A 185V.

I once got 250w out of my 330w panel, that was for 1 hour in the monsoon.

The last 6 months, I've been lucky to break 200w, normally it hovers around 150-175w at mid-day.

Crossy claims much the same from his panels.

At this moment (11:30am sunny day) my panel (hardwired) output is ........

 

 

Lower your expectations to less than 200w/panel ........ 3,000W peak is more realistic.

15 x 330w panels will generate 15 units of electricity/day.

Edited February 10, 2020 by BritManToo

[Thaifish]

Are any of you guys feeding excess power back into the grid? If so what is the process with Provincial Electricity Authority (PEA)? How do they work credits out with excess power you may supply back to them?

[sometimewoodworker]

6 hours ago, Thaifish said:

Are any of you guys feeding excess power back into the grid? If so what is the process with Provincial Electricity Authority (PEA)? How do they work credits out with excess power you may supply back to them?

The majority of people are running the meters backwards or just very slowly forwards. It is difficult and expensive to install a system where you get officially paid

[Thaifish]

17 hours ago, sometimewoodworker said:

The majority of people are running the meters backwards or just very slowly forwards. It is difficult and expensive to install a system where you get officially paid

Thank you sometimewoodworker for comment. It is a positive reply to what I wish to hear. I have done heaps of calculations on paper with Sun angles expected efficiency and return on investment etc. I am at a stage where I think I can purchase materials and do it for a lot less than have Somchai do the same job. I might be looking at a 6 year return on investment. Maybe 180,000Bht -- compared to 240,000Bht++ Somchai wants. Electricity in Thailand is relatively cheap compared to Western Countries but I am happy to look up at the sun in the comfort of my A/C room knowing soon it will be free. Our house consumes most power 10am till 2pm water Irrigation pumps and A/C. Hopefully a 4.5Kw system will drop my power bill around 1800/2000Bht P/M to get the return.

 

[zzSleepyJohn]

On 2/10/2020 at 10:03 PM, sometimewoodworker said:

The majority of people are running the meters backwards or just very slowly forwards. It is difficult and expensive to install a system where you get officially paid

Not only is that process difficult and expensive,  it might be hardly worth it considering the official feedback rate per Kwh is less than half your ordinary domestic forward rate.

 

I used to think a grid-tie system feeding unofficially into an old style mechanical meter at the forward rate with the idea of turning it backwards might be a good idea,  but I'm not so sure now.

 

I'm reading that although some old meters' discs can turn backwards under reverse power,  their dials may be ratcheted to prevent them following.  Not clear because since unapproved unofficial attempts to feed power back to the grid are illegal,  it's hard to find anyone admitting on-line that they've got it working.  

 

Not only that,  new digital smart meters which are set to replace old mechanical ones will only register reverse power when you've paid the money for them to do so, and then only at the abysmal official backward rate. 

 

So I'd caution anyone budgetting for a new grid-tied solar system to check carefully and not to necessarily assume ordinary domestic forward Kwh consumption rates in their calculations.

 

On the other hand,  I can't see there's anything to prevent an unofficial grid-tied solar system from simply reducing ordinary forward consumption bills due to aircon and fridge and freezer etc.  during the day when the sun is shining.   - Or even at night too if you add a big battery.

[BritManToo]

20 hours ago, Thaifish said:

I have done heaps of calculations on paper with Sun angles expected efficiency and return on investment etc.

No need, a 330w panel produces just under 1KWhr/day all year round in Thailand.

In the summer you get hotter sun, but less of it because of the rain, which evens out with the winter where the sun isn't as strong but it's there all day.

 

1 panel generates 1 unit every day.

The reality is around half the calculated. 

Edited February 12, 2020 by BritManToo

[Thaifish]

Thank you gentleman for your effort replying. I am a novice trying to build up a better knowledge.

I need to do more research especially with the local TEA. I do not think there would be many days or hours that my planned 4.5Kw system will push power back into the grid. But in saying that I would like to get a return from them for doing so if it happens. Interesting to hear the disks can be ratcheted slowing the return supply down. 

 

Being a retired Ship's Captain doing calculations keeps me occupied. The internet makes it so easy nowadays. In Burriram there is a difference of 46Deg in the Suns angle throughout the year.  In my planning I want to change the angle of the solar panels each 6 months to capture the most power from the Sun. March 21st and September 21st.  

[WalterVandervort]

I've Solinba to hook it to my bench top power supply and see if it would get warm, at 18v and 5 amps, it never got more than a few degrees warmer than ambient, and it's efficiency was 90+% percent according to my fluke mulimeter and kill-a-watt. Truly surprising for such a cheap unit.

[Thorgal]

What is your well pump set-up? With or without booster pump?

You should operate the 2,5kW well pump(s) 1 or 2 hours at night to fill your storage tank.