Midnite Solar Rosie HF Inverter 27kW Surge Test

[Midnite Beta Tester]

Disclaimer: I'm not employed by nor compensated by Midnite Solar. I happen to be located near their factories in Arlington, WA and take advantage of the open door policy. I stop in several times a week and try to break stuff! If you stop in and ask if you can attempt to break stuff, they most likely will let you!

I did a 27kW surge test on the Midnite Solar Rosie 6.8kW rated High Frequency Inverter today. COLD START! 12kW of incandescent lights and four portable air compressors. The pumps have a total surge of 15kW and running watts around 7.5kW. Inverter DC input breaker was off. The loads were all switched on, then the Inverter was switched on. The Rosie didn't even flinch! 27kW cold start surge on a High Frequency Inverter! Running watts load was about 16kW. Typical HF Inverters have crappy surge capacity. Not the Rosie! Next week I'll be adding more loads and try to find her upper surge limit. Robin, Midnites President, has told me to try and break their new inverters. I keep trying, but so far not much luck. I did this video, then repeated the surge tests about 10-15 more times.....Stay Tuned!

 

[sunshine_eggo]

Very impressive. What's powering Rosie?

 

[MrM1]

But would it start my 240v well pump? Last I checked the in rush was 42+ amps PER LEG ?

 

[Midnite Beta Tester]

Very impressive. What's powering Rosie?

Yes, very impressive when you consider the limited space in that booth for batteries. At the moment there are four small 12V AGM's in series. Once Midnite has their own LiFeP04 batteries they are developing, those will power the booth with plenty of juice to spare. The test I did was cruel and unusual punishment for those little AGM's! A couple times I just let Rosie keep going. By the time I got to the other side of the booth, left side, to check the battery voltage, it was down to 41.4 with a 16kW running load, from a resting no load voltage of 51.3

Ouch! Poor little batteries! I wanted to see who gave up first? Rosie? or the batteries? At 38.8 volts Rosie's 250 amp DC input breaker tripped. Not unexpected. As battery voltage goes down, current goes up. Next week I plan to do more Beta testing of Rosie in a different area designed for actual stress testing. It has eight L16's and can take a real pounding. There I'll be able to monitor all AC/DC currents/voltages etc. And spank her HARD!

 

[Midnite Beta Tester]

But would it start my 240v well pump? Last I checked the in rush was 42+ amps PER LEG ?

Ohm's law. Your pump is pulling about 10kW at start up, that's a hair over 1/3 of the 27kW Rosie surged in the video. She wouldn't blink! Even with the undersized battery bank I was using....

The final surge limit is unknown for Rosie. I hit her with everything available in the booth. We need to keep hitting her hard until she cries/breaks. Once a known repeatable limit is found that does not cause any problems, that's where software will lock her down. Betting it's at least 30kW...

 

[MrM1]

I can't find any specs or release dates for the rosie? There used to be a PDF floating around here, but it appears Midnite took it down.

(BTW, there's not an ol' used Classic for sale at a discount up under one of those covers at the show is there? I need a standard classic ? )

 

[Midnite Beta Tester]

I can't find any specs or release dates for the rosie? There used to be a PDF floating around here, but it appears Midnite took it down.

(BTW, there's not an ol' used Classic for sale at a discount up under one of those covers at the show is there? I need a standard classic ? )

Here is an updated flyer on all the new upcoming products.

https://www.midnitesolar.com/pdfs/new_products_frontBack.pdf

Midnite does sometimes have used or gently used Classics. Email sales@midnitesolar and ask if anything is available.

 

[MrM1]

Midnite does sometimes have used or gently used Classics. Email sales@midnitesolar and ask if anything is available.

I did. Never hurts to ask

 

[MrM1]

Here is an updated flyer on all the new upcoming products.

https://www.midnitesolar.com/pdfs/new_products_frontBack.pdf

But the rosie is not going to have a built in MPPT correct, just an AC charger? Are there prices being bantered around for that unit yet?

How does the DIY series compare to the Rosie for Inductive Load starting?

 

[SpongeboB Sinewave]

But the rosie is not going to have a built in MPPT correct, just an AC charger? Are there prices being bantered around for that unit yet?

How does the DIY series compare to the Rosie for Inductive Load starting?

Not sure about the DIY surge ? Someone may have tested it ? I bet you hear more about that as time goes on.

The Rosie is not a hybrid inverter unfortunately.

 

[Will Prowse]

What company are you working for instead? Are you on contract with any solar equipment manufacturers? Or distributors? Why are you stress testing this equipment. If for fun, why?

You're coming off as a shill. Stating yourself to be the beta tester of a company you don't work for is very fishy.

 

[Midnite Beta Tester]

What company are you working for instead? Are you on contract with any solar equipment manufacturers? Or distributors? Why are you stress testing this equipment. If for fun, why?

You're coming off as a shill. Stating yourself to be the beta tester of a company you don't work for is very fishy.

I don't believe I can explain why it's "fun" to stress test something electrical/electronic, and see what it's made of. Quality build, or junk. Can it do warp 12.9? Let's find out! You can do it at Midnites factory or in your own home. Robin Gudgel, Midnites President, most likely would offer to let you, Will, stop in and "stress test" any of his new toys just like I did. Please name any other solar company that does that, here in America, or in any country or any universe?

Will, you can sign up to be a Beta tester just like I did. You don't get any freebies but the cost is reduced and Beta units come with a lifetime warranty. No relationship with any company, distributor or dealer required. You can even be a Midnite Solar competitor and get a Beta unit from them!

For the record: The company I work for and own has nothing to do with Renewable Energy.


Sign up here!

MidNite Solar Inc. Beta testing form

MidNite Solar is the industry leader and manufacture of quality Renewable Energy System electrical components and E-Panels.

www.midnitesolar.com

 

[MrM1]

? I never get to b a beta tester, and I've signed up. And the only thing I do really well is break stuff.

 

[Midnite Beta Tester]

? I never get to b a beta tester, and I've signed up. And the only thing I do really well is break stuff.

It's been awhile since any Beta stuff has been released. You won't be contacted until they have Beta's ready to ship out to testers.

 

[Bud Martin]

So what is surge duration spec at x2, x3 normal rating? 10 seconds? 30 seconds? etc.

 

[Tecnodave]

@willprowse

when Midnight was ready for outside beta testing they posted online and I was the first to offer my services. Beta tester #1 for outside the company testing on the first version of the Marine Kid controllers. I had a few failures and was offered a second kid which I also paid for. I got a serious discount on the product and a lifetime warranty. I was never paid in cash by Midnight for my services. I have not asked the other beta testers but I do not believe anybody was paid for this. Im a retired engineer and have been doing commercial solar since 1967.....hard core communications networks situated on mountain tops...

Companies like Midnight Solar need an “outside view” of what they are doing as users will do things that the designers had not thought of. Its common in industry. I also Beta test for Fluke, but different there, if i field test an item from Fluke I do not pay for the test instrument and it becomes my property to keep and use. Mostly bench meters there but some unusual stuff like a freon leak detector, which i gave to my friend who does auto air conditioning. He wrote his impressions of the device and I handled the report to fluke. My Fluke infrared camera is the chit as is my Fluke 2000 gig-ohm insulation tester

For an incurable tinkerer like myself its a gold mine. Sometimes learning new stuff is the reward....

 

[Hedges]

Beta -
You said,

The pumps have a total surge of 15kW and running watts around 7.5kW.

Did you get a measurement of the AC surge delivered to the compressors and lights?
What kind of motor do they have?

Reason I ask is some types of motors can happily start a bit slower if voltage sags, while others can't.
So I'm asking if 6.8kW rated Rosie did in fact deliver 27kW, or that's just what surge would have been if powered from grid.

 

[SpongeboB Sinewave]

Yeah, Midnite BT is just one our biggest fans and does well with his own business, selling generator parts.

Six years ago he helped me BIG time when my wife of 30 years passed away suddenly. He had not even met Penny, my wife. Just a super nice guy with an interest in this stuff and a big heart.

We tried to help him too recently since his gal of 35 years passed away. MBT also has a couple of OutBack Radians he plays with. He definitely needed a distraction and I'm sure that this stressing inverters and such helps him muchly as well as helping us a MidNite with his emotional support volunteering.

Yeah, this may seem like a weird thing but MBT is not your normal every day kind of guy. Very rare to find a friend like him these days.
I'll let him respond more if he wants to.

boB

 

[SpongeboB Sinewave]

Beta -
You said,

Did you get a measurement of the AC surge delivered to the compressors and lights?
What kind of motor do they have?

Reason I ask is some types of motors can happily start a bit slower if voltage sags, while others can't.
So I'm asking if 6.8kW rated Rosie did in fact deliver 27kW, or that's just what surge would have been if powered from grid.

I wasn't there at the time he came up with those values but the surge can be huge. The way to really measure that surge is to connect a current probe and voltage probe into an oscilloscope to get instantaneous values. The surge may only last a couple or few AC cycles.

And the incandescent light bulbs (1500 W each I think) have an extremely low resistance when they are cold compared to when they are lit up after a few seconds. 10 times or so higher surge I think depending on their temperature after resting a moment.

 

[Hedges]

I wasn't there at the time he came up with those values but the surge can be huge. The way to really measure that surge is to connect a current probe and voltage probe into an oscilloscope to get instantaneous values. The surge may only last a couple or few AC cycles.

That's what I do!
I have since bought the Harbor Freight 1000A DC clamp ammeter (because it measures down to 0.01A DC, good for checking PV strings.) It does surge, which I haven't tried but a coworker did.

Power Factor and Startup Amps

Because I have suitable equipment I'm going to put up measurements I've taken, might help someone with planning a system or general education. Motors draw a startup surge of considerably more amps than they draw while running. With grid power you may see the lights dim briefly, but if you have...

diysolarforum.com