Power Inverter A/C Power Voltage Quality - Oscilloscope Display

[ShadowsPapa]

certainly - Ecoflow River 2 Max power station goes haywire with error codes and needs to be rebooted every time I try powering it from either the cab or bed outlet. Learned not to do that pretty quick

I power my GoalZero from a 12v outlet rather than try to charge it from AC - too much lost converting from the truck's 12v to AC and then back again to charge the power station and the heat from the transformer tells me it's a waste.
So I've never bothered trying to use AC to charge it. I use either solar or DC unless I'm at home then I top it off from the home outlets.

I then wonder - why use the AC instead of charging a DC device via 12v DC? Seems like a loss of energy to heat and the double conversion as you convert from the truck's DC to higher voltage AC and then with your power station, from AC down to a lower voltage DC again to charge the battery in it.

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[emiddio]

Those are fine as well because it's not just a transformer. I've plugged in those "conventional transformers" and been fine - laptop, tablet, and so on)
They are more inside than a transformer. Show me one that puts out AC.
I even ran a cheap "tire inflater" from mine - it's got a motor in it that drives a small, cheap compressor (I use it for the air bags) and my mattress inflater works fine from it.

There's so very little that run on low voltage AC these days - your "wall warts" put out DC.

I go back to my original question - and all I get is speculation, nothing concrete - has anyone actually had any trouble or had anything damaged or not work?
So far it's just "no, but............" and that doesn't count.

Well Yes - I had an issue that motivated me to hook up the Oscilloscope; I was measuring the Voltage, and Hz/Frequency with two different LED measuring devices - photo of them attached, from Amazon - Normally they just work and nothing noticeable, but in the Gladiator when I pick them up to look at their display they were very hot to the touch on their base, almost burn my skin hot - very unusual - now I know why;

Also - what do you mean by "Low Voltage AC" - this is normal AC Voltage like what is in my home, 60 Hz, 120V - nominal, 120V can range from 110V to 130V ?

 

[emiddio]

For 50 bucks, I question how long or how well it would actually handle 500 watts. You truly get what you pay for.
What does your pattern look like with a true load on it- say 400 watts or better?

I have a double-conversion pure sine wave UPS for my wife's quilting and embroidery machines - research into that topic led me straight away from low cost units. (dealing with the power for our network equipment before I retired gave me a head start into that research, and what was quality vs. - yeah, it's fine without a big load types of equipment.
My finding was - a quality inverter isn't cheap and a cheap inverter isn't quality when under load.
So I'd be interested in seeing how that pattern looks, the clean peaks and valleys, under heavy load. That's the tell.

Purpose of picture was to show what Pure Sine Wave Inverter Voltage looks like - not argue for buying a cheap inverter - the inverter serves my needs;

 

[PW45]

I guarantee no one is running anything from their super-capacity 400W jeep gladiator outlet that is sensitive enough to give a shit about that square wave and not a cleaner sine wave. all of the power transfer is still there, calculated by the area under the sine wave.

that eco-flow is a 500-1000W unit, not surprised it didn't work.

OP, thanks for finally answering my old question! I tried a DMM yesterday out of curiosity, but the oscilloscope is the way to go.

https://www.jeepgladiatorforum.com/forum/threads/low-voltage-at-outlet.64249/

 

[fourfa]

I power my GoalZero from a 12v outlet rather than try to charge it from AC - too much lost converting from the truck's 12v to AC and then back again to charge the power station and the heat from the transformer tells me it's a waste.
So I've never bothered trying to use AC to charge it. I use either solar or DC unless I'm at home then I top it off from the home outlets.

I then wonder - why use the AC instead of charging a DC device via 12v DC? Seems like a loss of energy to heat and the double conversion as you convert from the truck's DC to higher voltage AC and then with your power station, from AC down to a lower voltage DC again to charge the battery in it.

You asked if anyone had experienced a problem, I answered. If I could snap my fingers and make a nice, OE quality, fused 12v tap appear at the bed, then I might never have even tried the AC. But I did try it, and it did not work. Asked and answered

I understand you're looking for a fight here as usual, which you're free to do. One might respond with the same attitude and ask, prove to me that the waste heat from DC-AC-DC conversion is meaningful. Hundreds of horsepower engine running hundreds of amps alternator, driving three tons of steel brick down the road, but a slightly warm AC power brick is a problem? One that you'd notice how - worse mileage? Bad vibes? Is the power lost in that brick more or less than what you'd lose in overall thermal efficiency by adding more weight in 6 gauge cabling back to the bed? Or compared to whether the driver took a dump that morning or not?

For what its worth, the Ecoflow has charging rate settings so you can control how much it's drawing at once, which is handy for marginal electrical systems. It barfs even on the lowest settings.

Ultimately it's irrelevant for me, I power it straight from solar with no connection to the truck electrical at all. Meanwhile my fridge, which has its own battery and BMS, runs very happily from the AC inverter if I need it to (which I don't, usually) and its power brick barely gets warm if I do. Hard to see the harm in that. I might get around to running proper 12V power to the bed one of these days, might even add a big battery, DC/DC power system, proper solar conditioning, big proper inverter, lots of thick cables and dead weight, and suffer yet more payload and mileage loss. I keep not getting around to it. I wonder if anyone will try to pick a fight about the inefficiency of carrying those extra 50 lbs of hardware when I do

 

[ShadowsPapa]

Also - what do you mean by "Low Voltage AC" - this is normal AC Voltage like what is in my home, 60 Hz, 120V - nominal, 120V can range from 110V to 130V ?

It was mentioned in another post - that the "wall wart" was just a transformer. They are more than that. They don't just put out low voltage AC (such as 12 volts AC - and there have been those that do just that!). They put out DC these days.
I bet most would have a lot of trouble finding one that was just a transformer and put out low voltage AC (meaning something like 24 or 12 volts, etc.)
They put out DC.
I have a couple that do indeed put out low voltage AC - meaning there is no + and - polarity on the output end - they put out low voltage AC and are indeed pretty much "just transformers" I believe they were for early Cisco equipment or even old style network adapters for laptops.

Our home voltage runs about 124 volts according to our Liebert double-conversion UPS. I'd have to check that again since the power company moved us to a different set of lines coming from the east instead of west like we were on.
It gives a nice readout on frequency, voltage and so on of the incoming line power.

 

[MrBones]

Those are fine as well because it's not just a transformer. I've plugged in those "conventional transformers" and been fine - laptop, tablet, and so on)
They are more inside than a transformer. Show me one that puts out AC.
I even ran a cheap "tire inflater" from mine - it's got a motor in it that drives a small, cheap compressor (I use it for the air bags) and my mattress inflater works fine from it.

There's so very little that run on low voltage AC these days - your "wall warts" put out DC.

I go back to my original question - and all I get is speculation, nothing concrete - has anyone actually had any trouble or had anything damaged or not work?
So far it's just "no, but............" and that doesn't count.

I was only thinking of the transformer heating. But I agree, that inverter isn’t going to harm anything that’s plugged into it.

 

[ShadowsPapa]

I understand you're looking for a fight here as usual, which you're free to do.

No, I was just wondering why power it that way. That's all. Simple question based on my experience with things electric.

You answered about having a problem with your power supply - it obviously doesn't like that wave form. I find it interesting, but it is what it is.

so you can control how much it's drawing at once, which is handy for marginal electrical systems. It barfs even on the lowest settings.

showing it's not lack of power capacity - but the wave form itself it's choking on.
Yes, you answered that.
I then asked - why power it that way?
I ordered the accessory 12v charging cord for mine to avoid the double conversion losses, heat losses and so on - and that's been discussed here before in other threads.
I asked what others have asked more than once - why go through the losses of that sort of charging. That's all I did. It's been brought up in other places long before I asked it here.

One might respond with the same attitude and ask, prove to me that the waste heat from DC-AC-DC conversion is meaningful.

Go back and ask the other members why THEY asked why charge from AC instead of 12v.
Go ahead and search - you'll find it's been brought up more than once. But because I was like the 3rd or 4th to ask, and because it was me - now it's a problem to ask?
Sorry, I just asked exactly what people like Hootbro and others have asked in the past - but I get blasted for it.

 

[ShadowsPapa]

I was only thinking of the transformer heating. But I agree, that inverter isn’t going to harm anything that’s plugged into it.

Yeah, with almost everything that's sold these days having the ability to be powered by your vehicle's 12v system, it seems odd that we bother much with inverters. Granted, there are still some things that won't work that way, but seems a waste of energy and heat.
I'd expect heat to be greater with that wave form than pure sine wave. I'm not an EE, I only worked in an EE company and tried to pay attention while there. I let the others be engineers while I kept their equipment operating and networks up.
My last 3 scopes wore out, power supplies fried and so on so I got a mini hand-held scope for my work. Would still like to find something of decent size like the HP I used to have.

Funny thing - others in several other threads on this same topic - using a transformer in the inverter outlet - "why" instead of powering directly, but I get blasted for asking. Not you - but read on......

it's why I had decided to just LEAVE - but thought, naw, I'll try to step back in a bit - and for asking the same questions I've seen asked here over the years, I'm trying to start something.

 

[emiddio]

I am not sure what the 12V fuses are for folks that use 12V, but 400 watts at 12V is 33.33 Amps;

All the engineering, etc, that goes into providing, a 60 Hz 115 V power inverter to the vehicle - my view is why not provide a high quality pure sine wave inverter - considering they are not that expensive ?

Most opinions I have read seem to advocate no need for the inverter since most devices are DC - but if one needs 400 watts the inverter seem to be the only outlet that can power 400 watts, as 33.33 Amps is more than the 12V outlets fuses ?

There are devices that only have a 120V plug that run on AC to DC conversion and the arguments here are that the quality of the AC V is OK - but again - why not provide pure sine wave output since it is not that much more expensive - compared to all the engineering costs to provide an inverter to begin with ?

 

[Radio Guy]

I am not sure what the 12V fuses are for folks that use 12V, but 400 watts at 12V is 33.33 Amps;

All the engineering, etc, that goes into providing, a 60 Hz 115 V power inverter to the vehicle - my view is why not provide a high quality pure sine wave inverter - considering they are not that expensive ?

Most opinions I have read seem to advocate no need for the inverter since most devices are DC - but if one needs 400 watts the inverter seem to be the only outlet that can power 400 watts, as 33.33 Amps is more than the 12V outlets fuses ?

There are devices that only have a 120V plug that run on AC to DC conversion and the arguments here are that the quality of the AC V is OK - but again - why not provide pure sine wave output since it is not that much more expensive - compared to all the engineering costs to provide an inverter to begin with ?

The 120V inverter (actually about 90V) is not 100% efficient and will use more than 400w @ 12V to make 400w @ 90v. If it’s around 80% efficient that would up its input current to about 40A and could be more.

The square wave output of the inverter is not good for some electronics which are designed for 50/60Hz operation. The super square and fast rise and fall times will have a huge amount of harmonics that will be dissipated as heat in some RF EMI filters and I’ve used other square wave inverters on equipment with internal transformer power supplies and have heard the metal transformer laminations singing and complaining about the dirty power it’s being fed.

 

[Jcsii]

I power my GoalZero from a 12v outlet rather than try to charge it from AC - too much lost converting from the truck's 12v to AC and then back again to charge the power station and the heat from the transformer tells me it's a waste.
So I've never bothered trying to use AC to charge it. I use either solar or DC unless I'm at home then I top it off from the home outlets.

I then wonder - why use the AC instead of charging a DC device via 12v DC? Seems like a loss of energy to heat and the double conversion as you convert from the truck's DC to higher voltage AC and then with your power station, from AC down to a lower voltage DC again to charge the battery in it.

I always charge my Jackory using the AC Since the charging input is current limited. The ac brick puts out 19v vrs the 12v from the cigarette lighter so more charging watts from the ac plug

 

[emiddio]

The 120V inverter (actually about 90V) is not 100% efficient and will use more than 400w @ 12V to make 400w @ 90v. If it’s around 80% efficient that would up its input current to about 40A and could be more.

The square wave output of the inverter is not good for some electronics which are designed for 50/60Hz operation. The super square and fast rise and fall times will have a huge amount of harmonics that will be dissipated as heat in some RF EMI filters and I’ve used other square wave inverters on equipment with internal transformer power supplies and have heard the metal transformer laminations singing and complaining about the dirty power it’s being fed.

My original post with the 2 Oscilloscope pics show the oscilloscope's digital calculations of various parameters with no-load and a 200W light bulb;

no-load was +162V, -164V Square Wave; RMS calculated as 118.37V;

200W load was +120V, - 122V Square Wave, RMS calculated as 107.13V;

Many other parameters shown in the display pics;

BTW - I use a UPS for my home desktop computer - it can consume 75W to ? 300W depending upon CPU load; The UPS would completely reject the square wave output from the vehicle inverter;

 

[Mr._Bill]

I am not sure what the 12V fuses are for folks that use 12V, but 400 watts at 12V is 33.33 Amps;

All the engineering, etc, that goes into providing, a 60 Hz 115 V power inverter to the vehicle - my view is why not provide a high quality pure sine wave inverter - considering they are not that expensive ?

Most opinions I have read seem to advocate no need for the inverter since most devices are DC - but if one needs 400 watts the inverter seem to be the only outlet that can power 400 watts, as 33.33 Amps is more than the 12V outlets fuses ?

There are devices that only have a 120V plug that run on AC to DC conversion and the arguments here are that the quality of the AC V is OK - but again - why not provide pure sine wave output since it is not that much more expensive - compared to all the engineering costs to provide an inverter to begin with ?

The cost for one person is not much to use better equipment. When dealing with thousands of vehicles, the cost grows and the effect on the bottom line usually becomes the deciding factor. These are not standard devices, they are customized to fit under the dash and be remotely controlled. The quality is not the best, but it is adequate for the majority that are going to actually be using it.

 

[nanook12]

I use the truck 12V to charge the goal zero, the AC 400W to run the refer/freezer when driving. When I’m done driving, I plug the refer into the goal zero. Never had any problems running the refer/freezer from the backseat 400W. Two different refer/freezer units - Igloo and Dometic.

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