Small or large Inverter or both? ;)

[C-Cat]

I'm getting ready to downsize from our huge older Class A to a Class C with better maneuverability and to give me more boondocking options. I have spec'd out my new solar system, but I'm not sure about the Inverter. Our Class A had an older but well working 2000 Watt Inverter, which almost met all our needs (it was not a pure sine, which gave us a few problems, but overall it worked), so we didn't have to worry about it. Most Class C's (particularly the older model years) don't come with an Inverter, so I will need one.

Right now I plan to invest in 320 watts of panels (2*160w and upgrade option for another 2) with a 700 watt capable MPPT controller and likely feeding 2 deep cycle batteries at first (or 4 if the price is right).

My loads are 2-3 Laptop computers and a few small devices (I work from the road), a bigger external monitor (this one is a power hog and sometimes I leave it off) and maybe the microwave from time to time (and I would like to not have to worry about tripping the Inverter with all these loads at the same time). Some day in the future I may want to run a small window ac or something like that, but that will need to wait until I can upgrade the battery bank and solar system later.

Now the actual question: right now I'm thinking one 3k pure sine serving the whole coach, or should I rather splurge on a bigger boy (4k+) to have some more reserve capability (and so that once I upgrade the battery bank I don't have to worry about having to upgrade the Inverter again).

Or should I go with something smaller (and upgrade it later), or even 2 Inverters (a small one for the computers and a bigger one for the other loads)?

Sorry for the long story...

Chris (C-Cat)

 

[SternWake]

Limited battery capacity, will only be able to power so much inverter.

So one could have a 3000 HP drag racing car, but only have enough fuel tank to get 1/16 of a mile.

powering a 4Kw inverter at 4Kw is going to require a lot more than 4 deep cycle golf cart batteries.

Your proposed battery and solar system is never going to be able to power a 4Kw inverter at full tilt, so no reason to get one.

I have a wagan 400 watt PSW inverter, i have an 800 watt MSW inverter, and I rarely turn on either, but put me in the one small PSW and one big MSW camp.

 

[tx2sturgis]

or even 2 Inverters (a small one for the computers and a bigger one for the other loads)?

This is my preference. One large inverter powering everything has a larger 'phantom' load even when powering smaller devices.

In my large truck I have a 1500 watt modified for the microwave, its only turned on when I need to cook or warm something, then I have a 400 watt pure for the more sensitive loads like chargers and the laptop.

 

[SternWake]

It seems that inverters are widely seen as the solution to powering all stick and brick devices/appliances.

But, my 12v to 19.5v 90 watt DC to DC converter uses significantly less battery power(12 TO 20% less) than does my 400 watt PSW inverter powering the AC to DC transformer which came with my laptop.

My PSW inverter was mainly bought for my power tool battery charger as I had issues with older powertool battery chargers self smoking on MSW.

I do use my PSW inverter for powering my canon Pixma printer, which requires 16vDC, but if I had to keep my printer powered all day long, I would certainly be using a voltage boost converter dialed to 16vDC instead of running the inverter to power the electrically noisy 115vac to 19vdc power brick.

INverters themselves are electrically noisy. i can turn mine on powering nothing and some strong TV stations disappear.

Some poeple think they need an inverter to recharge USB charged devices. A quality 12v USB power source can be had for mere peanuts, and use a fraction of the battery power required compared to a large inverter turned on just to power a USB power supply.


I view inverters as a necessary evil, but I will never use it when the other DC to DC options are available and so much more efficient.

My 90 watt laptop DC to DC power supply was/ is 22$. Their ciggy plugs are an issue but that rant is a separate thread.

Many DC devices that require voltages above 12 can use a boost converter device like this:

https://www.amazon.com/DROK-Converter-Transformer-Regulator-Controller/dp/B00E8D7XYG

devices requiring voltages less than 12vDC can use a Buck converter like this:
https://www.amazon.com/dp/B06XRXPJ67?psc=1

Both these devices will be much more efficient than using an inverter to power the original power bricks/ wall warts which came with the appliance.

Avoid the inverter, when possible, is my recommendation. Unless one has gobs of battery capacity and solar wattage and does not need to worry about being wasteful.

Its usually much easier and cheaper to use less electricity than plan on having enough to not worry about electrical consumption.

A 4 Kw inverter would be nice when one needs to bake a potato in a microwave, boil a kettle of water, run a tablesaw and a dust collection system, all at the same time on a thousand+ pound battery bank with several thousand watts of solar in addition to other charging methods.

For 2 or 4 normalish size batteries i do not see much point in getting more than a 2KW inverter, unless one is going to rev the engine and let the alternator attempt to power 1400 to 1800 watts of extra load, that the batteries could not power by themselves.

 

[wagoneer]

I use 2 a 400 for charging and small screen TV and a 1000 for tools and blender no micro. Most of my "stuff" running 12 volts right off battery. 2 Crown 6 volt.

 

[John61CT]

Explore all options for going DC direct, get an inverter as a last resort only.

A small one that is switched on only to run that one exceptional device for a short time IMO is best.

Charging and TV screen can (IMO should) be done without an inverter.

 

[highdesertranger]

yeah a 12v TV that doubles as a monitor will save you some, compared to your power hog monitor. then run your lap tops directly off of 12v. I don't know what your misc. stuff is, but can you get it in 12v? I bet you don't even need an inverter. highdesertranger

 

[tx2sturgis]

Inverters themselves are electrically noisy.  i can turn mine on powering nothing and some  strong TV stations disappear.

This aint no lie! :exclamation:

You should see what they do to the reception on the HF and VHF/UHF ham bands..

For most users the noise is not all that noticeable, until they try to use the nearby AM or FM radio or FM modulator with XM/Sirius radio.

But I do want to add that all of the little switching power supplies used to directly power and charge the laptops and other DC-DC devices also put out a lot of noise....they are almost never shielded for RF. Plus the operation of computing equipment like laptops, smart TVs internet devices, and some LED lighting all add to the local noise on RF.

Still, the 12v bricks do tend to be more efficient, overall, than running one large inverter, with its phantom losses, and all the plugged in devices, with phantom loads whether the connected unit is on or off.

C-Cat, I agree with these guys that finding the specific 12v power brick for each item (or buying the 12v version) is the best answer, but my previous answer is also valid, for the thread title question posed, ie: Small or large inverter, or both.

I say....BOTH!

{thumbs-up}  <<< Missing emoji...  ;-)

 

[SternWake]

The DC to DC and AC DC transformers are electrically noisy too, and mine can knock out actual channel 8, which comes in at full strength otherwise. I have achieved a lot of mitigation of the RFI with snap on ferrites, and some shielding, but will at some point enclose the power supply in a faraday cage of a material yet to be decided upon. My reflectix window panels placed inbetween the power brick and the TV prove remarkably effective, but sometimes the wire to the laptop needs to be shielded too to keep channel 8 from getting pixellated.

 

[tx2sturgis]

Is your TV antenna inside the vehicle?

If it is, then moving it outside the vehicle should help.

 

[SternWake]

Is outside. Inside i get no stations. Outside 30+. Usually, depends on weather with hot and dry bad. Cool and foggy best

 

[tx2sturgis]

Is outside. Inside i get no stations. 

Ok that helps.

You had previously said that you were able to block some of the interference by placing a shielding between the power brick and the TV.

This means that the interference is getting to the TV either directly thru the cabinet of the TV, or possibly, its being conducted via the TV coaxial cable along the shield, out to the antenna, then of course, back into the TV tuner.

I don't know specifics about your vehicle...is it a fiberglass top of some kind or a metal roof like a van?

It's possible that a few snap-on chokes, or preferably a toroid with several turns of cable thru it, placed on the TV coaxial cable itself might eliminate the interference.

You could try a few if you are really wanting to solve the issue. Maybe its tolerable as is.

The operative word in the world of ferrite beads and torroids is the word "mix" which simply means what frequencies the material will filter and what it will pass.

Here is some information if you want to get kinda 'sternwakian' with it....love that term.



http://palomar-engineers.com/ferrite-products/ferrite-cores/ferrite-mix-selection

 

[C-Cat]

Fantastic info guys!

I will rethink my approach and probably start with a smaller inverter for my work loads (pun intended! ) until I can afford a larger battery bank and more solar. I will also look into 12v power supplies for the laptops, however, these are pretty power hungry 170w PSUs (workstation Laptops) and most 12 volt universal adaptors only do 90w...
And my bigger screen is actually a 4k 40inch... as far as I know there's no 12 volt option for something like that "yet"...

But a 1k pure sine inverter might do the trick powering my work setup for now... and save me money intially. what would be your favorite affordable brand?

If I need to run the microwave or the ac, my future class C will likely have a generator on board!

-Chris

 

[C-Cat]

Yep, just looked and there is no off-the-shelf 12 volt adaptor that can output the 20volt / 170w peak that the Thinkpad W520 is calling for... small inverter it is for me...

 

[C-Cat]

How about this one (anybody using this brand)? https://www.amazon.com/dp/B072JJTWJT/ref=twister_B0739JXJV7?_encoding=UTF8&psc=1

 

[John61CT]

Samlex and Tripplite as second​ tier if you don't want to invest in Vanner or Magnum.

But the 90W adapter would likely be fine long the laptop isn't cranking top power usage hours at a time, just needs to keep the internal battery charged.

Try it and see anyway.

With any electronics using a power brock, just look at the specs and match them, really isn't rocket science.

 

[C-Cat]

And how about these if I could afford 4 right off the bat: https://www.amazon.com/dp/B01ACKDGPS?psc=1

 

[tx2sturgis]

There are better brands but not at that price...

With all those high dollar items you plan to run, I'd spend a little more and get a good, reliable, well-known brand.

Your not running a $25 coffeepot.

Xantex and Samlex are good brands...there are others. Be sure to also order an inverter wiring kit if one is not included.

I've gotten in trouble here for recommending someone spend more...so if you are on a tight budget, then disregard.

 

[John61CT]

Xantrex (note spelling) makes decent products, but not an inexpensive brand, and has **zero** repair support for its consumer line of inverters once past the warranty.

Victron and Outback are better value in the top tier. MasterVolt is quality but overpriced.

At the low end some say Bestek can last a while?

 

[tx2sturgis]

Oops....forgot the 'r'...thanks for catching that, I cant go back and fix it...