Not so impressed with my new Magnum Energy 4448

[Daddy Tanuki]

This is the problem high frequency split-phase inverters. You can't get full power, unless the two legs are perfectly balanced. Which is nearly impossible to do. Many loads go through cycles of varying draw.
The only way to get full power, is to use a transformer. And then, you might as well just buy a single phase 240v inverter. And save some money.
Which is exactly what I done. Because I didn't want a large heavy low frequency inverter.

not so much a frequency (low vs high) as a split phase issue, one with which I have been wrangling with. prior to order of my current inverter, I could have went either way. I wanted 240 though i did not need it. so then i started ordering items that were 240. split pack etc. now it is either toss all 240 items or continue on with 240 inverters.... we all get sucked up in this one I think.

 

[wmgeorge]

Deleted

 

[Jack Rabbit Off Grid]

not so much a frequency (low vs high) as a split phase issue, one with which I have been wrangling with. prior to order of my current inverter, I could have went either way. I wanted 240 though i did not need it. so then i started ordering items that were 240. split pack etc. now it is either toss all 240 items or continue on with 240 inverters.... we all get sucked up in this one I think.

I went with split phase for two reasons. 1. Ease of wiring to my current split phase panel. 2. I want to power a 240v mini split because the power consumption specs were half of a 120v. The model I purchased claims 33 seer From a 12k unit.

 

[wmgeorge]

I went with split phase for two reasons. 1. Ease of wiring to my current split phase panel. 2. I want to power a 240v mini split because the power consumption specs were half of a 120v. The model I purchased claims 33 seer From a 12k unit.

What brand and model did you go with? I am looking to power a small Mini split.

 

[timselectric]

not so much a frequency (low vs high) as a split phase issue, one with which I have been wrangling with. prior to order of my current inverter, I could have went either way. I wanted 240 though i did not need it. so then i started ordering items that were 240. split pack etc. now it is either toss all 240 items or continue on with 240 inverters.... we all get sucked up in this one I think.

The issue only arises from high frequency split-phase inverters.
High frequency single phase = no problem.
Low frequency split-phase = no problem.
High frequency single phase, with built-in split-phase transformer = no problem.
High frequency single phase, with additional external split-phase transformer = no problem.

 

[Jack Rabbit Off Grid]

What brand and model did you go with? I am looking to power a small Mini split.

I had a credit at Signature Solar that they gave me for a shipping mishap. So I decided to use the credit on their Innovair elite 12k mini split. I was wrong about the seer it’s actually 30.5. I seen it on the box today as I was in my shipping container. I also seen on Signature‘s website today the no long offer mini split’s any longer. YouTuber David Poz has the same one and has posted several videos about it.

 

[Daddy Tanuki]

The issue only arises from high frequency split-phase inverters.
High frequency single phase = no problem.
Low frequency split-phase = no problem.
High frequency single phase, with built-in split-phase transformer = no problem.
High frequency single phase, with additional external split-phase transformer = no problem.

fairly sure the Magnum is a low frequency. (it is, its a fact) and also fairly sure that they recommend keeping the loads balanced. (fact, I got the manual) so either you swapped the particulars between low and high frequency or it applies to all inverters that are split phase. (hint it does).

 

[TomC4306]

Im running split phase hi freq. using parallel 3k inverters. There is no possible way I can think of to keep both legs completely balanced all the time.
Think about it. Freezer and lights and network gear on one leg (and coffee maker). Fridge and lights and tv (and microwave) on the other leg.
Base load on each leg is about 300 watts...but then I make coffee and one leg goes up by 1600 watts. Or wife uses microwave and the imbalance between legs goes up by 2000 watts.
Works fine in my house.

 

[Daddy Tanuki]

Im running split phase hi freq. using parallel 3k inverters. There is no possible way I can think of to keep both legs completely balanced all the time.
Think about it. Freezer and lights and network gear on one leg (and coffee maker). Fridge and lights and tv (and microwave) on the other leg.
Base load on each leg is about 300 watts...but then I make coffee and one leg goes up by 1600 watts. Or wife uses microwave and the imbalance between legs goes up by 2000 watts.
Works fine in my house.

you are using three separate inverters... all of the above comments are in regards to a single inverter that you must keep reasonably balanced for proper performance, or a system of paralleled inverters where each inverter is split phase and L1 and L2 must be kept balanced according to the spec sheets. (exactly how close to balance is never shared in any of the spec sheets.) your system obviously does not fit this scenario. Try to keep on track.

 

[TomC4306]

Single inverter split phase has two inverters inside one box

 

[timselectric]

fairly sure the Magnum is a low frequency. (it is, its a fact) and also fairly sure that they recommend keeping the loads balanced. (fact, I got the manual) so either you swapped the particulars between low and high frequency or it applies to all inverters that are split phase. (hint it does).

My original statement, only applies to high frequency split-phase inverters. And the almost impossible ability to get the full rated power from them. If the magnum is low frequency, then you will see that I said that they don't suffer from this problem.
While my statements are correct, I never mentioned the Magnum. As I have no experience with the Magnum brand. After rereading the thread. I'm not sure what I was replying to. It's possible that I replied to someone else, in the wrong thread.

 

[wmgeorge]

So is everyone defining 50 vs 60 Hz as low and high frequency or what?

 

[Daddy Tanuki]

So is everyone defining 50 vs 60 Hz as low and high frequency or what?

no high frequency vs low frequency is in regards to the actual design of the inverter, one runs with a very large transformer coil uses less devices and puts less stress on the devices as they are run at a lower frequency. the other design uses a very small transformer and runs with more switching devices at a higher frequency.

End result is high frequency designs are cheaper to produce, not as durable with less surge capability.
Low frequency = durable, large surge capacity, physically heavy, and higher cost.

a few other things that we are discussing are inverters that put out split phase 240, two 120 lines that are 180 degrees out of phase form one another, and the difficulty in drawing full power from a 240 split phase unit when you you use it for 120, and 240.

 

[timselectric]

So is everyone defining 50 vs 60 Hz as low and high frequency or what?

No
Low frequency inverters, use an internal transformer, to provide the higher AC voltage.
High frequency inverters, produce the higher AC voltage electronically.

 

[wmgeorge]

No
Low frequency inverters, use an internal transformer, to provide the higher AC voltage.
High frequency inverters, produce the higher AC voltage electronically.

So how do you know which is which, brand names? As a electrician I would want the transformer for reliability. BTW thanks for you and the others who answered!!

 

[timselectric]

So how do you know which is which, brand names? As a electrician I would want the transformer for reliability. BTW thanks for you and the others who answered!!

Usually stated in the product description.

 

[Daddy Tanuki]

So how do you know which is which, brand names? As a electrician I would want the transformer for reliability. BTW thanks for you and the others who answered!!

generally speaking they list it as a low frequency inverter in their literature. if in doubt ask here on the forum somebody has used the inverter you are looking at before trust me. and will be able to give you info.

the biggest tell is the weight. a 4kw low frequency inverter is going to weigh at least 50-70 lbs due to the size of the transformer. a high frequency unit will be about 1/3 ~1/2 of that.

next biggest tell is surge current, surge capability, overload ability etc. names change but a low frequency can normally surge to about 3 times its power for short durations. such as when starting a motor... I have a 2kw HF xantrex that will not start my drill press even if nothing else is hooked up. My magnum MS2012 on the other hand is also a 2kw inverter and it starts the drill press while running the lights, without any sign that it is working hard. its surge power is high enough that it just does what it is supposed to do.

lastly cost: tier one LF inverters are never cheap. even the chineese made LF inverters are expensive these days. it has to do with the amount of copper used in the transformer.

 

[timselectric]

The extra weight, also increases shipping costs.

 

[Old_Skewler]

I went with split phase for two reasons. 1. Ease of wiring to my current split phase panel. 2. I want to power a 240v mini split because the power consumption specs were half of a 120v. The model I purchased claims 33 seer From a 12k unit.

I am in a very similar situation with an existing split-phase genset wired to a split-phase electrical panel. Because of that I had decided to keep the existing wiring and purchase a split-phase inverter to facilitate the integration of the inverter.

After some delicate and tedious research, the same Magnum 4448 inverter was at the top of my list.

Now imagine how not happy I am to read about your issues with the same inverter I am about to purchase...

 

[MichaelK]

The extra weight, also increases shipping costs.

I think that anyone that bases their purchasing decision on shipping weight has no clue what they are doing.