timselectric
If I can do it, you can do it.
- Joined
- Feb 5, 2022
- Messages
- 18,717
Not alone, but everything adds to the budget.
Not so impressed with my new Magnum Energy 4448
- Thread starter Jack Rabbit Off Grid
- Start date
MichaelK
Solar Wizard
I think as a retired electrician, you have an understanding of what's referred to as "inrush current"? And also that you can not measure inrush with a standard clamp meter because the reading is not fast enough? You have to buy a special clamp meter designed to read "inrush" (that means expensive).
As a general rule, transformer based low-frequency inverters have far higher "inrush" capability then high-frequency models. As a general rule, HF can surge 200% for 8-16 milliseconds. LF models however might have the capacity to surge 200% for 5-60 seconds, literally 1000X longer. You need this very long surge timing for the starting of electrical motors that run under load, like power tools, compressors, and pumps.
MichaelK
Solar Wizard
Actually, there is one very important factor where weight is critical. If you are buying a MPPT charge controller that weights 8 pounds, it is likely a real MPPT controller. If however the shipping weight is 8 oz, then most likely it is a fake PWM controller. So, with some solar electronics making the heaviest purchase might be the best choice!
Daddy Tanuki
Solar Wizard
don't worry it is as solid of one as you can get in its class. I have two of the 4448 and to be honest if I had understood the difference between it and the 4048 (120 non split) for my use the 4048 would have probably been better. Other than a lightening strike that took out my charging board on one of mine, I have had no real issues with them.
that same lightening strike took out a neighbors fridge and hot water heater so it was in good company.
I have since went the gonzo route for lightening strike protection with every line protected both AC and DC with the Midnite solar surge protectors and have had no issues since then with lightening even though we have had several close strikes since that time.
YMMV.
Daddy Tanuki
Solar Wizard
what about when you can only ship via USPS and they have a weight limit.... not everyone's circumstances are the same. the heaviest thing I can ship to my bases post office is 70 lbs and a 4448 boxed up is right at the limit for shipping to me. anything bigger and I would have to ship commercial, pay Japanese import taxes and basically take it in the shorts.
Hedges
I See Electromagnetic Fields!
- Joined
- Mar 28, 2020
- Messages
- 20,780
No, but basing one's (inverter) design decision on weight is another story.
Also, high frequency inverters could reach 99%, vs. low-frequency a mere 98% (bragging rights, you know.)
You're thinking of the inrush transformers can supply, and I'm studying the inrush they can draw. Fun stuff!
I hooked a CV/CC supply to a power transformer and caught the waveform with a scope. 15 milliseconds of low current, then it shot up to CC limit.
Turned supply off, then back on. This time 2 milliseconds until it shot up. With core left magnetized, it saturated quickly (in about 25% of one half line cycle.)
If I alternated polarity before each time I applied voltage, it always held off the current for 15 milliseconds. Almost two (60 Hz) half cycles, or one and a half (50 Hz) cycles.
When you turn a transformer off, then back on again, it is a coin toss whether it will get hit with the same polarity twice in a row. If you do, Inrush! Current is limited by winding resistance, not inductance. (I wonder if similar effect occurs in motors, or if inrush is always repeatable.)
I need to determine max surge for the transformers, also for SMPS, and and ensure simultaneous vs. sequencing of supplies doesn't trip breakers.
But I don't see anything inherent in low-frequency transformers that let them deliver higher surge current. I think some high-frequency inverters do have multiple second surge ratings. Is Sigineer high frequency? 20 seconds at 3x nominal current. "General Rules" were made to be broken.
3000 Watt 12 Volt to 120 / 240Vac Split Phase Pure Sine Inverter Charger
3000W Pure Sine Power Converter, converts 12V to 120VAC 240Vac. Built with smart battery charger of 70 amps. LF transformer inverter, 50Hz 60Hz output.
www.sigineer.com
Has DC supply to OP's inverter been ruled out? Wiring resistance and condition of battery.
Daddy Tanuki
Solar Wizard
Signeer is a good example of a Chinese inverter maker that is rapidly approaching tier one status... as long as they do not let their standards slip. They have several different models which is what has kept me from buying one to date. they change models so rapidly I am wary of buying one and not be able to repair it a year later. but i really like the specs on their 12kw and 18 kw units... not to mention the fact they are offering 3 phase models...No, but basing one's (inverter) design decision on weight is another story.
Also, high frequency inverters could reach 99%, vs. low-frequency a mere 98% (bragging rights, you know.)
You're thinking of the inrush transformers can supply, and I'm studying the inrush they can draw. Fun stuff!
I hooked a CV/CC supply to a power transformer and caught the waveform with a scope. 15 milliseconds of low current, then it shot up to CC limit.
Turned supply off, then back on. This time 2 milliseconds until it shot up. With core left magnetized, it saturated quickly (in about 25% of one half line cycle.)
If I alternated polarity before each time I applied voltage, it always held off the current for 15 milliseconds. Almost two (60 Hz) half cycles, or one and a half (50 Hz) cycles.
When you turn a transformer off, then back on again, it is a coin toss whether it will get hit with the same polarity twice in a row. If you do, Inrush! Current is limited by winding resistance, not inductance. (I wonder if similar effect occurs in motors, or if inrush is always repeatable.)
I need to determine max surge for the transformers, also for SMPS, and and ensure simultaneous vs. sequencing of supplies doesn't trip breakers.
But I don't see anything inherent in low-frequency transformers that let them deliver higher surge current. I think some high-frequency inverters do have multiple second surge ratings. Is Sigineer high frequency? 20 seconds at 3x nominal current. "General Rules" were made to be broken.
3000 Watt 12 Volt to 120 / 240Vac Split Phase Pure Sine Inverter Charger
3000W Pure Sine Power Converter, converts 12V to 120VAC 240Vac. Built with smart battery charger of 70 amps. LF transformer inverter, 50Hz 60Hz output.
Has DC supply to OP's inverter been ruled out? Wiring resistance and condition of battery.
Full disclosure, I work for MidNite Solar, I think the HF design gets a bad rap on surge mostly based on current product, not a nature of the design itself, I have seen a HF design by one of the current top charge controller manufacturers surge greater and longer than a Magnum or Schneider, And our engineering dept tells me the same with our new Rosie. Time will tell for sure but I wonder if its just that most of the current HF designs are not as robust in design?
Old_Skewler
Solar Enthusiast
Thanks for the feedback Ken, it is reassuring!
This is my first off-grid setup and I have limited experience with electrical systems, so I need something reliable.
MichaelK
Solar Wizard
Actually, when I ordered my XW+, the deliverer refused to drive to my front door because his truck was too big. I had to meet him at a K-Mart parking lot, and backed my pickup truck against the back of his delivery truck. Then we slid the XW's pallet from one bed to the other. Just an example of the hoops I have to jump through to get what I want.