SW+5548 Inverters

[stratford4528]

Totally not intended as a sales pitch. Samlex inverters are American.
I was only trying to help and advise
As I said I am off grid and use wind solar and lister 6-1 with heat exchanger that produces all my hot water

[ChrisOlson]

It might say "SamlexAmerica" but they're made in China.  I don't see anything they build that has generator support or dual AC inputs.  It looks like their "flagship" model is 3,000 watts and only weighs 22 lbs?  How's that supposed to hold up under overload?  Cripes, my Outback PSX-240 transformer alone weighs 50 lbs and our SW Plus inverter is 150 lbs.  The weight of the unit tells you how heavy duty it is.  If it's light there's nothing in there that will hold up delivering 60 amps in overload for 30 minutes.

Nor do they have adjustable high/low voltage cutout, four-stage battery charging, automatic generator start or any of the stuff that makes an off-grid inverter an off-grid inverter.

I look at the specs for their 48 volt model and it says it shuts down at 61.0 VDC for over voltage?  How's that supposed to work?  Cripes, I absorb my bank at 62.0.
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Chris

[Mary B]

My 24 volt Samlex has been fine at my 29 volt equalize voltage. Closer to 30 actually according to the monitor software.

[ChrisOlson]

I absorb at 62.0, equalize at 64.0.  In really cold weather and the batteries cool down to 40-45 degrees in the utility room, the absorb voltage goes to 64.0 due to the temp compensation.  An inverter that shuts down at 61.0 ain't gonna cut it for off-grid unless you want to deficit charge the bank to keep the lights on.
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Chris

[ChrisOlson]

That 5548 is one hell of an inverter.

Sort of an old thread now. But I think folks like to hear about stuff that works too. We had an early Thanksgiving dinner today because our daughter was here from Illinois. Our new SW Plus 5548 passed what I will call the "Thanksgiving Dinner Test" with flying colors. In our totally electric home the Thanksgiving Dinner Test is big.

You can test stuff in a lab, or try to simulate real world conditions for testing. But there is nothing that can put the test to equipment like a woman.

My wife cooked turkey in the oven at 350 degrees for two hours, and while that was happening she's preparing the rest of the food. At T minus 30 minutes there's all this other food she has ready to cook, including a big dish of corn in the microwave, dressing, vegetables and a 2 gallon stainless steel container full of potatoes on the induction cooktop, plus the coffee maker all primed up and ready to throw the switch.

Then she makes the "loop" around the kitchen.
All four "burners" on the induction cooktop to Full Burn. Check.
Microwave on Full Radiation. Check.
Coffee maker on Max Brew. Check.

Now the inverter had been handling the convection oven very nicely for two hours. But in the 30 seconds it took my wife to enable Maximum Energy Consumption Mode it made that 5548 get right up out of its easy chair and go to work. I saw 77 amps load on the ICM on the kitchen wall. The status light was on and the generator had started within the first six seconds of Maximum Energy Consumption Mode. But it took it 30-40 seconds to get the gen to full load to help out with all this. But the inverter and 4 kVA generator handled it all over the next 30 minutes with not even a single flicker in the lights in the house.

When everything in that range would cycle "on" the total system load approached 100 amps with the generator supplying 30 amps of it and the inverter supplying from 45 amps (5.4 kVA) to 69 amps (8.3 kVA) intermittent during the final countdown to Dinner Time.

I swear - they do not build inverters like that anymore.
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Chris

[DamonHD]

Sounds like you've built yourself a really nice mini-grid in effect, with a decent pool of well-matched generation/conversion/storage.

Which just goes again to prove that renewables, with a little helping hand from fossils at interesting moments, really can do the job.

Rgds

Damon

[ChrisOlson]

The whole reason I wanted to change our system was because dual inverters for 240 volt was pretty inefficient.  My concern was that a single 5548 wouldn't be able to handle the peak loads.  But it proved that it can.  And the single inverter with the big PSX-240 transformer to supply the other leg of split phase power is more efficient, by almost double, than running dual inverters with a balancing transformer.

I knew The Test would come when my wife fired up her Nuclear Load Bank in the kitchen and put everything to Max.  I was monitoring all this VERY closely and was damn nervous that the power was going to go out when I saw 77 amps on that inverter and the generator was still warming up and not sync'd yet.  But the cooling fan in the inverter had not even come on yet when the generator came online to help reduce the load back to rated continuous capacity on the inverter.

There's a reason these big inverters weigh 150 lbs.  And it's not because they bolted some lead bars inside just to add weight.  It's got copper in it, and three big freaking transformers that allow it to do that.  It's kind of like you can buy a truck with 450 hp.  Some trucks with 450 hp got 18 wheels and pull trailers that weigh 80,000 lbs.  Other trucks with 450 hp just got a little box on the back that can haul two bales of hay.  They're both technically trucks and got the same hp.  But using the one with the little box on the back to pull the 80,000 trailer probably won't work.
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Chris