Another Inverter Selection Question

[86Scotty]

JWA, in case you don't have enough info yet here's another great inverter site:

Power Inverters | DonRowe.com

[1der]

Originally Posted by Glider

I nominate TeleSteve for the inverter award.

I second the nomination!! Great idea! I did not even know those existed.

[JWA]

Originally Posted by TeleSteve

Great information on inverters in this thread.

JWA have you considered just using a vehicle battery charger and not stepping up to 110v with an inverter only to have the charger step back down for the tool battery voltage? I think you mentioned Milwaukee tools but, most of the major tool brands offer battery chargers that are powered from 12v.
]

Well yes that was a short time consideration and its a great idea--------except that the chargers I'll mount permanently inside the truck don't exist with 12 VDC input. This charger: https://www.amazon.com/Milwaukee-48-...B7TFC57YH49BT8 has features the 12 VDC versions don't have, one being a "top off" feature which can lengthen a battery's life.

Mind you this charger is for the old school cordless tool batteries, NiCd to be specific. Tool(s) powered by this system are bullet proof, I've NEVER had one fail in over 12 years of service. I've lost a few but never a failure. I can repair every aspect of the tool, parts readily available. Additionally I own upwards of 14 of these ready to go, at least as many batteries.

I also use Milwaukee's M12 (Li-Ion) tools whose battery life between charges is so ridiculously long an on-board charger isn't even necessary BUT since I'll be adding an inverter for a charger anyway incorporating one more isn't a huge drain on the budget.

Originally Posted by Glider

Geez...I was so entertained by getting into inverter minutiae that I totally missed the simple solution!

I nominate TeleSteve for the inverter award.

Originally Posted by 1der

I second the nomination!! Great idea! I did not even know those existed.

I say the motion is carried; let it be written, let it be so. TeleSteve is forever a holder of an inverter award!

Originally Posted by 86Scotty

JWA, in case you don't have enough info yet here's another great inverter site:

Power Inverters | DonRowe.com

Info is always helpful Scotty---I'll certainly give it a once over!

[Scalf77]

In recent years the choices have moved from Modified Sine Wave vs Pure Sine Wave, to High Frequency vs Low Frequency Pure Sine Wave. While one method is not necessarily better than the other, they have both have their pro's and con's. One key specification that should be looked at with which method is being used is "Surge Power " Many times the surge power for a high frequency is listed much higher than a Low frequency version of the same output. Unfortunately the duration that it can support that surge is usually not listed.


A good explanation of high frequency vs low frequency inversion methods can be found here: Inversion Methods Explained: High Frequency vs Low Frequency


"
Inversion Methods Explained: High Frequency vs Low Frequency
Know your Inverter: High vs Low Frequency Inversion Methods
Download this article as a pdf

IRON CORE TRANSFORMERS AND FIELD EFFECT TRANSISTORS
There are two distinct types of industrial grade power inverters distinguished by the size of their transformers, and the switching speed of their transistors. The ability of an inverter to absorb the electrical surges inherent in certain loads like motors, pumps, and torque-related tools is directly proportional to the physical amount of iron present in the transformer. Size and tolerances of the transistors used in the inversion process, and the speed at which they operate determines the classification of high or low frequency.

INVERSION METHODS EXPLAINED
High Frequency Inverters (HF)
The large majority of inverters available in the retail market are high frequency. They are typically less expensive, have smaller footprints, and have a lower tolerance for industrial loads. HF inverters have over twice the number of components and use multiple, smaller transformers. Their application is appropriate for a wide variety of uses like tool battery chargers, small appliances, A/V and computers, but have a decreased capacity for long term exposure to high surge loads like pumps, motors, and some high-torque tools.

Low Frequency Inverters (LF)
Our UL-listed, low frequency inverters and inverter/chargers are the pinnacle of electrical durability. The massive iron core transformer is aptly capable of absorbing surge loads because of the “Flywheel Effect” inherent in the physical amount of a transformer’s iron. LF inverters have larger and more robust Field Effect Transistors (FET’s) that can operate cooler, in part due to the slower frequency of switching required to produce AC power. These inverters are feature rich to include the optional ability to hardwire additional external GFCI outlets, input of multiple DC voltages, provide regulated dual output voltages (120/240VAC), and integrate chemistry appropriate battery chargers and transfer relays for shore power.

HIGH FREQUENCY
Pros

Smaller footprint
Less expensive
Cons

Doesn’t operate well with high-surge loads like pumps and high-torque tools
LOW FREQUENCY
Pros
Runs well with high-surge loads
Operates cooler
Cons

Heavier
More expensive"



For those interested in Pure Sine vs Modified Sine Wave ("stepped square wave") explanation, it can be found here: Waveforms Explained: Sinewave vs Modified Sinewave

"
Waveforms Explained: Sinewave vs Modified Sinewave
Know your Inverter: Sinewave vs Modified Sinewave Explained
Download a pdf of this article

Waveforms Explained
WHAT DOES YOUR AC VOLTAGE LOOK LIKE?
Every device with a three-pronged plug is engineered to operate from a pure sine wave, utility-grade power source. Industrial users that require AC power in mobile applications utilize power inverters to change the Direct Current (DC) energy from the vehicle batteries to Alternating Current (AC). As with all commercial products, power inverters are available in a wide variety of price and quality levels.

Modified Sine Wave Inverters
Modified sine wave inverters are a cost effective choice to run appliances and equipment that is less sensitive to power fluctuations, such as lights and some tools. Modified sine wave inverters simulate AC power inverted from DC batteries. In most cases, applications like motors, pumps, and heaters are only mildly inefficient using this type of power. Other loads that charge batteries, produce audio and video, or operate computers or processors will not operate properly, or may be damaged on this waveform as the power supply cannot adequately filter the improper AC voltage. Check UL listings when purchasing a modified sine wave inverter as they often do not have UL listings because the output is altered by wave shape distortion called Total Harmonic Distortion (THD).

Pure Sine Wave Inverters
Pure sine wave inverters produce the equivalent to utility-grade power. This power source will help your tools and computers run more efficiently, preventing failures due to excessive heat. Components that power audio and video devices, such as TVs, stereos, and other sensitive electronics will produce clean sound and clear images. Cordless tool chargers will not damage expensive batteries. Many devices like variable speed motors, communications equipment, and certain cordless tools require pure sine power to operate. And appliances that may run on modified sinewave power, such as refrigerators and large appliances, will run better and with fewer issues using sine wave power. The best way to ensure serviceable longevity of your loads is to use UL listed, pure sine wave power inverters and inverter/chargers.

Pure Sinewave Pros and Cons
Pros

Utility-grade power
Will run any device
Cons

More expensive
Modified Sinewave Pros and Cons
Pros

Less expensive
Cons

Won’t run sensitive power electronics like computers or variable-speed motors
"


-greg

[Glider]

Really useful information, Scalf77. More bedtime reading for me!

[JWA]

Originally Posted by Glider

Really useful information, Scalf77. More bedtime reading for me!

Agreed, not the bedtime reading though...............

[arctictraveller]

Interesting information I was not aware of. My experience contradicts some of the info though. I have been running a 3000w square wave inverter on my boat for nearly 15years. In that time it has powered pretty much everything I have plugged into it including tv's, battery chargers, computers, monitors, coffee pots, stereos etc, with zero problems. There were a few exceptions though, the first being an electric blanket controller which self destructed the first day. After figuring it out, I added a second true sinewave inverter to power it and other waveform critical items such as the Toyo direct vent heater which has a variable speed fan. If I had to do it all over again, there would be no reason to put in a square wave inverter, and unless low cost is a critical factor, I see no reason to use a square wave in any application. As for high frequency vs low frequency, fortunately few of us have a need to run pumps, A/C compressors, big motors or other high surge loads so that part of the decision can be mostly ignored.

[Scalf77]

Jeff,
I would tend to agree with part of your assessment. I ran a a Tripp-lite Modified Square Wave in my van for about 12 years. I did come upon a few things that did not run at all, but not a lot. I believe that power brick technology has changed how many items actually can run on a modified square wave than the older days.

There can be a price to pay for running things on Dirty Power. While the cost (in power) of converting DC to a Modified Square wave is less than a similar sized pure sine wave. The problem is you generally loose that on the operational side, the device using the dirty power needs more of it, works harder and puts more stress on the device than clean power of a pure sine wave

I always use microwave popcorn as a good gauge. Since most microwave now have a popcorn button, try popping a bag on shore power and then on a Modified Sine Wave., generally the results are not a fully popped bag of popcorn.

Moving to the low frequency vs high frequency debate I would generally differ. I think smaller high frequency inverters have their place, I would tend to draw the line around 1000 watts. For a large 2000 or more unit I would stick with low frequency. The high frequency units have a high part count, run hotter and generate more heat.On paper and in use the high frequency units will have a higher failure rate.

The large iron core transformers of low frequency units tend to cause a need for robust chassis design and thus tend to handle the rigors of being in one of our rigs. With the High Frequency units, they tend to to cram as many parts as possible into the smallest footprint. This invariably leads to shock and vibration induced errors.

greg

[ShuttlePilot]

^^^ Greg, that is a much more articulate answer to my "no extruded aluminum cases" rule. although I respectfully disagree with high frequency has it's uses under 1k watts. At least with the current offerings of inverters.

-Eric

[Scalf77]

Originally Posted by ShuttlePilot

^^^ Greg, that is a much more articulate answer to my "no extruded aluminum cases" rule. although I respectfully disagree with high frequency has it's uses under 1k watts. At least with the current offerings of inverters.

-Eric

point taken, I should have also said that I would only run a high frequency inverter at half it's rated power. I don't own one ( that may say something) , so I can't really give any real life feed back.


-greg