Cheap Inverter - Looking for deeper understanding of operational pitfalls

[OffGridInTheCity]

Background:
My system is off-grid w/grid-assist. I'm in my 5th year of PV (13kw) -> Midnite Classics -> 48v battery (121kwh) -> AIMS Inverters ( 2 x 12,000w) -> House circuits via ATSs (grid assist).

After 4 years (25,000hrs of operation) one of the AIMS started putting out voltage drops or spikes (not sure) above 5% load causing my APC UPSs and ATSs to switch every 10sec over and over. So I pulled it from service. First contacted AIMS support in Dec 2022 and there are no replacement boards available for the foreseeable future.

I need a replacement and I no longer have faith spending $ on brand-name for future support so I'm committed to going cheaper for the 8,000w - 12,000w replacement range such as SUNGOLDPOWER ( https://www.amazon.com/dp/B0B5VS2Y67 ) rather than Victron or Schneider. I also want a single unit instead of parallel setups such as EG4 or MPP Solar.


Question:
There's going cheaper such as SUNGOLDPOWER which makes a reasonably priced ETL 12,000w model but then there's going way cheaper as in this https://www.ebay.com/itm/125394217937 type of approach



I understand that at most it's 8000w continuous and that I'll need to sort of load test it to verify it's not overheating etc...
I understand that it's not likely to run more than a few years compared to 10yrs? for top tier or even 4 years for AIMS....

But assuming I approach this carefully with increasing load tests / monitoring and it will actually sustain 8000w level will it be any riskier than
- my AIMS going haywire causing havoc on my loads?
- hurting home appliances due to noisy sine wave (or something)?
- catching fire compared to AIMS or SUNGOLDPOWER?

I'm asking for comment on risk or warnings to stay away in comparison to a SUNGOLDPOWER 12,000w 240v/120v or AIMS 12,000w 240v/120v baseline.

 

[Bluedog225]

Subscribed. It’s an interesting topic.

Too bad you can’t service the Aims. Good to know. They were on my list.

Be nice to find a cheap option with replacement boards available for later.

I think @upnorthandpersonal took this approach and has access to replacement parts.

I’d be tempted to go with aims again. 4 years isn’t too shabby?

 

[sunshine_eggo]

I would just be absolutely hesitant to believe that there's even a 50% chance of a successful outcome. The free shipping on a massive beast is also questionable.

HOWEVER, if you're a gambling man, and a total loss on the $ is within your risk tolerance, I would say it's tempting.

What about the Sigineer direct version of the AIMS:

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[Mattb4]

The inverter you picture looks like one of those Power Jack low frequency ones. They have a very poor reputation. They are marketed under a few names and a fellow in the US has tried to fix obvious problems and resell them under his brand. Can not think of it at the moment but there is a ongoing thread here at the Forum that is dedicated to it.

 

[OffGridInTheCity]

I would just be absolutely hesitant to believe that there's even a 50% chance of a successful outcome. The free shipping on a massive beast is also questionable.

HOWEVER, if you're a gambling man, and a total loss on the $ is within your risk tolerance, I would say it's tempting.

What about the Sigineer direct version of the AIMS:

Affordable Electric Vehicle Batteries & Components from Electric Car Parts Company

Electric Car Parts Company is your one-stop-shop for affordable electric vehicle parts and components including batteries. Shop our selection and order now!

www.electriccarpartscompany.com

I looked at these but they are similar to AIMS / SUNGOLDPOWER level - I'm wondering about 'way cheap'
Researching DIY Inverters I've discovered that at a basic level there's a core inverter like this:
https://www.aliexpress.com/i/2251832723456167.html?gatewayAdapt=4itemAdapt

and you need a LARGE transformer or a set of large transformers in series to get to 12,000w. There are details such as auto-switching in multiple transformers to help with idle load etc - but fundamentally it's mosfet power unit + controller board + transformer. And the way cheap one will have this and I can afford a couple of them for my own replacement parts and simple enough for me to do maint.

 

[Bluedog225]

That electric car parts company link has some good stuff. Thanks

 

[OffGridInTheCity]

The inverter you picture looks like one of those Power Jack low frequency ones. They have a very poor reputation.

Yes I understand "poor reputation" but what does that mean in technical terms - bad sine wave or short life or both. Spending $ on AIMS and then finding no support is 'poor reputation' as well. Not trying to make this a complaint session on AIMS, but thinking about how to proceed for the future.

 

[Mattb4]

Yes I understand "poor reputation" but what does that mean in technical terms - bad sine wave or short life or both. Spending $ on AIMS and then finding no support is 'poor reputation' as well. Not trying to callout AIMS here, just thinking about how to proceed for the future.

As I understand it what it means in technical terms is they stop functioning just after installation or in some cases before you plug it all in.

Looked it up and the US company that re-markets them is Genetry Solar.

 

[solar8484]

Stay away from the eBay inverter. It's a grossly overrated Power Jack inverter. It's at most 25% of advertised power for continuous usable power quality. Also, prone to failures. The upside for PJ inverters is that repair parts are available and relatively easy to replace.
The Ali inverter board is not bad if you are knowledgeable enough to use it to build/repair your own inverter.

 

[OffGridInTheCity]

As I understand it what it means in technical terms is they stop functioning just after installation or in some cases before you plug it all in.

I read a post about 'fixing up' a cheap inverter unit like this - https://www.aliexpress.com/i/2251832723456167.html?gatewayAdapt=4itemAdapt
Before using it, they inspected it and found bad soldering on mosfet legs (for example). Maybe the Power Jack is similar in that an inspection / 'fix-up' might lead to better results. Since I'm somewhat DIY - I'm willing to do this if the fundamental unit is 'safe enough' while operating.

 

[OffGridInTheCity]

Stay away from the eBay inverter. It's a grossly overrated Power Jack inverter. It's at most 25% of advertised power for continuous usable power quality.
The Ali inverter board is not bad if you are knowledgeable enough to use it to build/repair your own inverter.

Yes - it's listed at 16,000w but that's flat out 'mis-info'. It's 8000w 120v or 8000w 240v but not 16,000w all together - is misleading advertising ploy. The output is fundamentally limited by the size of the transformer and a 16,000w transformer would weigh 300lbs or it would need multiple transformers - which it does not have per pics. It's also a function of the number of mosfets - you need at least 24 'kind of thing' for 8,000w to keep amps / mosfet low enough to cool.

I'm guessing the unit I linked which is listed at 16,000w actually has an 8,000w transformer but 6,000w continuous would be more likely due to heat etc. I'm OK with all that for the price as long as I don't damage my home appliances.

 

[sunshine_eggo]

I think this is the guy that used to "fix" PowerJack units and re-sell them:

Genetry Solar – Satisfaction Guaranteed ….or your power bill back! ™

www.genetrysolar.com

"As of Jan 11 2023, Genetry Solar will no longer be offering support for Power Jack / Upower Inverters. This includes Email and Phone Support."

 

[Shimmy]

FWIW, the APC issue might not be a sign of a bad inverter. I would get it sometimes with noise on the line with one of my units. I think it took a few hard reset cycles to get it back to normal. It was on grid power when it happened to me; it appeared to be triggered by a filter capacitor in another UPS. No repeat in about a year for me.

As for the ultra-cheap inverter-- looks like "modified" sine wave (aka square wave), which will not support most loads. Anything with a motor will see excess heat and bearing wear, dimmers won't work reliably, and some other equipment is likely to not be reliable.

Life of the AIMS is disappointing. I guess you have to pick your battles...

 

[solar8484]

Yes - it's listed at 16,000w but that's flat out 'mis-info'. It's 8000w 120v or 8000w 240v but not 16,000w all together - is misleading advertising ploy. The output is fundamentally limited by the size of the transformer and a 16,000w transformer would weigh 300lbs or it would need multiple transformers - which it does not have per pics. It's also a function of the number of mosfets - you need at least 24 'kind of thing' for 8,000w to keep amps / mosfet low enough to cool.

I'm guessing the unit I linked which is listed at 16,000w actually has an 8,000w transformer but 6,000w continuous would be more likely due to heat etc. I'm OK with all that for the price as long as I don't damage my home appliances.

It has enough FET's but the driver is poorly designed and prone to blow up. You may get 6kW out of it if you add bigger better cooling fans but the power quality will be bad and that will likely degrade your appliances over time.

 

[Mattb4]

Here's the Thread I was thinking about: https://diysolarforum.com/threads/genetry-solar-6kw-inverter-review.25057/

 

[OffGridInTheCity]

FWIW, the APC issue might not be a sign of a bad inverter. I would get it sometimes with noise on the line with one of my units. I think it took a few hard reset cycles to get it back to normal. It was on grid power when it happened to me; it appeared to be triggered by a filter capacitor in another UPS. No repeat in about a year for me.

Thanks for this sharing. I have 2 x AIMS. I'm pretty sure it's not the APC UPS 3000 because the other AIMS it works. I also set sensitively as low as possible and it switched to grid every 10sec anyway.

As for the ultra-cheap inverter-- looks like "modified" sine wave (aka square wave), which will not support most loads. Anything with a motor will see excess heat and bearing wear, dimmers won't work reliably, and some other equipment is likely to not be reliable.

Life of the AIMS is disappointing. I guess you have to pick your battles...

It's a good question. What is the expected life of a $4,000 (today) 12,000w inverter? If replacement parts are available - they wanted $717 for the main control board before they found they don't have any and won't be getting any - and one is willing to DIY replace parts ever 4 years, then a $200/year operational cost is not so horrible.

I think it's the utter lack of replacement boards that is putting me in a tizzy. I tried to buy a Sigineer control board as they look identical (picture wise) and I could at least try to unsolder / use the parts and transfer them to my AIMS board - but they wouldn't sell me one. I wonder if they are out of stock as well.

 

[OffGridInTheCity]

It has enough FET's but the driver is poorly designed and prone to blow up. You may get 6kW out of it if you add bigger better cooling fans but the power quality will be bad and that will likely degrade your appliances over time.

This is what I was wondering about when I started the thread.

However, comments above about 'just not working at delivery' and 'ebay scams' are helpful to me to bring me back in focus. You're right that $700 ebay listing for a 100lb unit (at least $200 shipping) is too good to be true.

I was thinking more about technical issues but I've experience ebay scams buying batteries in years past. And at 100lbs it's not easy to just try to return it. This highlights that one of the things you get with Sigineer or Growatt or SUNGOLDPOWER or AIMS etc - is you can likely get a replacement if it flat out doesn't work.

I might well be better off buying DIY parts myself if I want to go waaaaay cheap - and then I'll be able to fix it because of hands-on experience building it .

 

[automatikdonn]

Background:
My system is off-grid w/grid-assist. I'm in my 5th year of PV (13kw) -> Midnite Classics -> 48v battery (121kwh) -> AIMS Inverters ( 2 x 12,000w) -> House circuits via ATSs (grid assist).

After 4 years (25,000hrs of operation) one of the AIMS started putting out voltage drops or spikes (not sure) above 5% load causing my APC UPSs and ATSs to switch every 10sec over and over. So I pulled it from service. First contacted AIMS support in Dec 2022 and there are no replacement boards available for the foreseeable future.

I need a replacement and I no longer have faith spending $ on brand-name for future support so I'm committed to going cheaper for the 8,000w - 12,000w replacement range such as SUNGOLDPOWER ( https://www.amazon.com/dp/B0B5VS2Y67 ) rather than Victron or Schneider. I also want a single unit instead of parallel setups such as EG4 or MPP Solar.


Question:
There's going cheaper such as SUNGOLDPOWER which makes a reasonably priced ETL 12,000w model but then there's going way cheaper as in this https://www.ebay.com/itm/125394217937 type of approach
View attachment 137561


I understand that at most it's 8000w continuous and that I'll need to sort of load test it to verify it's not overheating etc...
I understand that it's not likely to run more than a few years compared to 10yrs? for top tier or even 4 years for AIMS....

But assuming I approach this carefully with increasing load tests / monitoring and it will actually sustain 8000w level will it be any riskier than
- my AIMS going haywire causing havoc on my loads?
- hurting home appliances due to noisy sine wave (or something)?
- catching fire compared to AIMS or SUNGOLDPOWER?

I'm asking for comment on risk or warnings to stay away in comparison to a SUNGOLDPOWER 12,000w 240v/120v or AIMS 12,000w 240v/120v baseline.

I have the SGP 8kW and two SGP 12kW units. I think they are very nice. I did some videos on them..

 

[Bluedog225]

I would just be absolutely hesitant to believe that there's even a 50% chance of a successful outcome. The free shipping on a massive beast is also questionable.

HOWEVER, if you're a gambling man, and a total loss on the $ is within your risk tolerance, I would say it's tempting.

What about the Sigineer direct version of the AIMS:

Affordable Electric Vehicle Batteries & Components from Electric Car Parts Company

Electric Car Parts Company is your one-stop-shop for affordable electric vehicle parts and components including batteries. Shop our selection and order now!

www.electriccarpartscompany.com

I emailed them asking about buying replacement boards at the time of purchasing the inverter. No response.

 

[OffGridInTheCity]

I emailed them asking about buying replacement boards at the time of purchasing the inverter. No response.

AIMS - I first started asking for an AIMS 12,000w inverter control board replacement at the end of Dec 2023 - and after a couple of months, AIMS support flat out said - no boards....
From: AIMS Support [mailto:techsupport@aimscorp.net]
Sent: Tuesday, February 28, 2023 11:25 AM
To:
Cc: AIMS Support <techsupport@aimscorp.net>
Subject: RE: Replacement Parts? - AIMS 12,000w @ 48v ETL Inverter

Dear ,

This request you have seen has already been cancelled. Please disregard that request.
No we still do not have any boards available at this time.
I wish we had better news sir.

Regards,
Sky McDermott
---------------------------------------------------

SUNGOLDPOWER - I went with 12,000w SGP because of the above but I accidentally burned up a control board. Initially SGP support took my PayPal $ and said 5-7 days to ship and 7 days to arrive... but now it's been over a month and it's still in 'test at the factory'.
From: sales02@sungoldpower.com [mailto:sales02@sungoldpower.com]
Sent: Monday, March 20, 2023 2:16 AM
To:
Subject: Re: RE: Need a Control Board (PN: 53562-03PM2210082034) for a Brand New SUNGOLDPOWER UL 1741 12000W 48 - It's my fault

Good day,

I am sorry keep you waiting. But the replacement parts is still in our factory and being tested. Could you wait one more week?
Sorry for the delay again. I push our factory every day. But the process can not speed up as expected. Thank you for your understanding and patience.

Regards,
Sunny
-----------------------------------------------------

Not sure what's going on - but replacement boards are not looking good!