Modified sine wave vs pure sine wave inverters - Page 2

creeky · 02-15-13, 08:30 PM

What I hear Xringer saying is that I can plug my wall wart into my 12 volt battery bank and it will run my laptop without problems.

Xantrex says
"many models of electric blankets, coffee makers, laser printers and
other devices that regulate heat using a microprocessor that may not operate correctly"
I use all of these devices.
They go on to say "The more complex or state-of-the-art your demand is, the more likely you will want and need to consider a TSW (true sine wave) inverter."

Another site (DanRowe) states:
the following devices that will normally not work with modified sine wave inverters:
Laser printers, photocopiers, magneto-optical hard drives
Certain laptop computers (you should check with your manufacturer)
Some fluorescent lights with electronic ballasts
Power tools employing "solid state" power or variable speed control
Some battery chargers for cordless tools
Some new furnaces and pellet stoves with microprocessor control
Digital clocks with radios
Sewing machines with speed/microprocessor control
X-10 home automation system
Medical equipment such as oxygen concentrators

Another site (civicsolar.) states:
"Some appliances, such as microwaves, drills, clocks or speed motors will not produce full output if they don't use sine wave current, moreover they may damage the equipment. Some loads, such as light dimmers will not work without sine wave at all."

I'm not sure of Verdigo's need, but I live offgrid. I need to be able to plug it in and have it work. So, to those who actually plan to rely on their "solar" systems:

Non mppt solar controllers, square wave or modified square wave inverters ... they're the model t of the solar industry. they were useful at one point, but now we have better tech. ya, it's a bit more expensive. but do you want to get up to your cabin and find out x y or z doesn't work properly because you dragged decades old tech up when you could have spent a few extra bucks and be microwaving a quick lunch for the kids and then going for a hike?
A modern car is 30k average now. I don't see anyone opting for a Model T on their commute.

Xringer · 02-15-13, 10:00 PM

Quote:

Originally Posted by creeky

What I hear Xringer saying is that I can plug my wall wart into my 12 volt battery bank and it will run my laptop without problems.

Nope, what I said was:
"some small 1Amp wallwarts will even run okay on 50+ DC (from my 48v battery bank)."

A new Dell laptop switching power supply takes 100 to 240v 50-60Hz @ 1.5A
The DC out is 19.5vdc @ 4.62A (90 watts peak).
That's a lot more power than a wall-wart. It might run on 50 volts DC,
I would have to try it to be sure..

There is no way it will run on 12vdc..

Acuario · 03-12-13, 07:35 AM

MSW inverters are ok for some things BUT almost instantly destroy others - so beware!

The problem is due to the transient voltages on the switching edges of the 'square wave'. They can easily exceed the peak working voltage of some of the components used in modern transformerless power supplies.

These psu's (generally used as they are low cost and can deliver small amounts of power that is required for micro processor circuits) use capacitors that have to be rated above the peak voltage delivered by the supply. These are normally rated at 250VAC (in Europe). The transient voltages on the edges of the square wave from the inverter can be extremely high both in voltage and power and far exceed the working voltage of these capacitors - result - BANG.

I've personally experienced this on a number of occasions where customers of minehave plugged in brand new devices to their power systems and they have gone bang.

Typically any microprocessor controlled device (fridge, freezer, washing machine, water pump pressure control system, etc...) is potentially proneto this failure.

The solution is either a pure sinewave inverter or replace the power supply with a transformer.

stevehull · 03-12-13, 08:19 AM

Modified sine wave (MSW) will screw up a lot of things. My TV can't tolerate MSW and the radio make a terrible noise

.

I quickly changed out to pure sine wave (SW) and regretted getting a MSW as I lost money when I switched out.

In my opinion, SW is the ONLY way to go.

Steve

Xringer · 03-12-13, 11:40 AM

Maybe I've never seen any problems here is because I'm using 120vac models..?.
No visible voltage spikes on the MSW inverters I've been using.

I wonder if the use of surge protectors (or surge suppressors) would be useful?

I only use my main MSW inverter (2.5kW & 5kW peak) for backup during grid failures.
The inverter cost was a factor. Since it's cost (under $200) was about 1/4 the cost of a 2.5kW 48vdc sinewave inverter (back when it was installed).

Today, sinewave inverters from China are not as costly.
2000W DC AC Pure Sine Wave Inverter Off Grid for Wind Solar System DC12 24 48V | eBay
If I every zap mine, I'll go for a sine wave model..

03-12-13, 08:19 AM	#14
stevehull Steve Hull Join Date: Dec 2012 Location: hilly, tree covered Arcadia, OK USA Posts: 826 Thanks: 241 Thanked 165 Times in 123 Posts	sine wave vs. modified sine wave Modified sine wave (MSW) will screw up a lot of things. My TV can't tolerate MSW and the radio make a terrible noise . I quickly changed out to pure sine wave (SW) and regretted getting a MSW as I lost money when I switched out. In my opinion, SW is the ONLY way to go. Steve __________________ consulting on geothermal heating/cooling & rational energy use since 1990

03-12-13, 11:40 AM	#15
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	Spike protection? Maybe I've never seen any problems here is because I'm using 120vac models..?. No visible voltage spikes on the MSW inverters I've been using. I wonder if the use of surge protectors (or surge suppressors) would be useful? I only use my main MSW inverter (2.5kW & 5kW peak) for backup during grid failures. The inverter cost was a factor. Since it's cost (under $200) was about 1/4 the cost of a 2.5kW 48vdc sinewave inverter (back when it was installed). Today, sinewave inverters from China are not as costly. 2000W DC AC Pure Sine Wave Inverter Off Grid for Wind Solar System DC12 24 48V \| eBay If I every zap mine, I'll go for a sine wave model.. __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less..

02-15-13, 08:30 PM	#11
creeky Journeyman EcoRenovator Join Date: Jun 2011 Location: a field somewhere Posts: 304 Thanks: 64 Thanked 44 Times in 31 Posts	What I hear Xringer saying is that I can plug my wall wart into my 12 volt battery bank and it will run my laptop without problems. Xantrex says "many models of electric blankets, coffee makers, laser printers and other devices that regulate heat using a microprocessor that may not operate correctly" I use all of these devices. They go on to say "The more complex or state-of-the-art your demand is, the more likely you will want and need to consider a TSW (true sine wave) inverter." Another site (DanRowe) states: the following devices that will normally not work with modified sine wave inverters: Laser printers, photocopiers, magneto-optical hard drives Certain laptop computers (you should check with your manufacturer) Some fluorescent lights with electronic ballasts Power tools employing "solid state" power or variable speed control Some battery chargers for cordless tools Some new furnaces and pellet stoves with microprocessor control Digital clocks with radios Sewing machines with speed/microprocessor control X-10 home automation system Medical equipment such as oxygen concentrators Another site (civicsolar.) states: "Some appliances, such as microwaves, drills, clocks or speed motors will not produce full output if they don't use sine wave current, moreover they may damage the equipment. Some loads, such as light dimmers will not work without sine wave at all." I'm not sure of Verdigo's need, but I live offgrid. I need to be able to plug it in and have it work. So, to those who actually plan to rely on their "solar" systems: Non mppt solar controllers, square wave or modified square wave inverters ... they're the model t of the solar industry. they were useful at one point, but now we have better tech. ya, it's a bit more expensive. but do you want to get up to your cabin and find out x y or z doesn't work properly because you dragged decades old tech up when you could have spent a few extra bucks and be microwaving a quick lunch for the kids and then going for a hike? A modern car is 30k average now. I don't see anyone opting for a Model T on their commute.

03-12-13, 07:35 AM	#13
Acuario Apprentice EcoRenovator Join Date: May 2011 Location: Tortosa, Spain Posts: 221 Thanks: 2 Thanked 81 Times in 46 Posts	MSW inverters are ok for some things BUT almost instantly destroy others - so beware! The problem is due to the transient voltages on the switching edges of the 'square wave'. They can easily exceed the peak working voltage of some of the components used in modern transformerless power supplies. These psu's (generally used as they are low cost and can deliver small amounts of power that is required for micro processor circuits) use capacitors that have to be rated above the peak voltage delivered by the supply. These are normally rated at 250VAC (in Europe). The transient voltages on the edges of the square wave from the inverter can be extremely high both in voltage and power and far exceed the working voltage of these capacitors - result - BANG. I've personally experienced this on a number of occasions where customers of minehave plugged in brand new devices to their power systems and they have gone bang. Typically any microprocessor controlled device (fridge, freezer, washing machine, water pump pressure control system, etc...) is potentially proneto this failure. The solution is either a pure sinewave inverter or replace the power supply with a transformer.