Inverter Size?

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Ballenxj

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What size inverter do you guys use to run all your electronics? By what size, I mean how many watts?
If you would, please describe a little about your system, and what kind of electronics are you able to run with it?
Will a 1000 watt unit work? 1500 watts? 2000 watts?
Thanks all.
 

Lucky mike

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I run 2000.....a bit more than usual , but I require alot of power when needed..Im also in a Class A.....size will depends on needs and battery supply.

I run
24" tv as needed
900watt Microwave
Coffee
2 laptops & printers
phone chargers
power tools

pretty much what ever I need when I need it......keep in mind I have 8 batteries onboard and a decent solar array...

I would say a 1000 watt unit with a surge capability (1250) for everything needed and I keep a small 650 on hand for lite duty back up...
 

Ballenxj

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Thank you Mike, I'm still trying to figure out what size will be good for me.
I currently have two 100 watt mono crystalline solar panels, and thinking about getting two more. My battery bank will start with two, and maybe end up being four.
I am looking at a small, but very efficient refrigerator that pulls one and a half amps, l.e.d. lighting, and a dual USB charging station for laptop & phone.
I may also get a 12 volt coffee maker, but not sure I want a microwave.
All this might end up being installed in an enclosed trailer much like the one Bob Wells has.
I'm thinking a 1500 to 2000 watt inverter will work?
Any thoughts on this?
 

Willy

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I've got a 1000W pure sine, which has near double that in surge capacity. I've yet to use anywhere near that capacity but, at least, I have the option.. and the price was right. ..Willy.
 

WheelEstate USA

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We have a very low inverter demand, so I've never needed as much as my 400 watt is capable of. There's just not much I need to power with one so far.

I think most seem to go with 1000-1500 W units.
Later, I think I'd like to upgrade to Pure Sine Wave and would increase watts to maybe 1000 at that time. Before I go there, I'll have added more solar/batteries to justify the upgrade.
 
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Donedirtcheap

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I have an Aims 300 that would read 122 volts and a walmart schumacher 400 that would read 95 volts so I I didn't want to use it. I now have a Xantrex 600 watt pure and just run everything off it. Phreds poop sheets says that he has seen inverter voltages that are all over the place but I'm not running my stuff on something that's putting out 95 volts. When I say everything I mean tv's, computers, pads, ps3 and phones.
 

sushidog

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I have a cheapo 400w/800w MSW inverter that runs my TV/DVD player just fine. It will also run a small drill, but not much more. This is all I use it for. I guess it depends on how much a/c power you need. Most of my things run off of 12v, except for my 5,000 BTU ac unit and microwave. Of course you would need a bigger inverter and a huge battery bank to run those. Instead I have a 1,200w/1600w quiet Chinese generator (Triron) that will run the ac just fine at any altitude, but it does not reliably run my 800w Dometic microwave, as it takes a huge surge of power to start. For that I would need a little bigger genny, like a 1,600w/2,000w Honda EU2000 or equiv.

Chip
 

SternWake

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I consider an Inverter a necessary Evil, and try to never use it.

I have an 800 watt MSW coleman and a 400 watt PSW Wagan.

The 800 watt one is now removed from my electrical wall ( needed the room) as the Wagan 400 is much quieter, smaller, and has a lower standby draw. I'd need to reattach the leads to the 800 watter for running my angle grinder or power planer, but it has been a long time since I have needed to do so.

I bought the PSW primarily to recharge my Makita Li-ion batteries as I do not trust the MSW to not kill the charger, and or possible the batteries too. Since new batteries cost nearly as much as a new drill driver kit I decided it was worthy to have the smaller PSW, and after receiving the PSW decided I no longer required my MSW to be mounted. I have the cables ready to go if I do need it, but have not yet needed to do so since receiving the Wagan PSW.

There is no law stating one must have only one big inverter for all possible loads which might ever be used simultaneously. One can get a small PSW for the delicates and get a Beast of a MSW for those less delicate electronics, providing the battery bank is large enought to actually supply 2000 or more watts for any amount of time.
 

Ballenxj

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So from what I am reading here I could easily run the items I described in post #3 with a 400 watt inverter?
PS, I plan on using propane for heating and cooking. Undecided on a microwave.
Oh, and maybe a real good automotive stereo. Gotta have tunes.
 

highdesertranger

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I use a 1200 watt but hardly ever use it. I will run an angle grinder and recharge my laptop. I also have a 300 and 2000 but never use either one. will sell them later this year. highdesertranger
 

blars

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To accurately read the voltage of a MSW inverter, you need a "true-rms" voltmeter. The MSW will read low on 99% of the voltmeters (and ampmeters) out there. True-RMS will give you the effective power a heater or incandecent light will see, other loads will vary.
 

caseyc

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I have a 2,000 watt inverter installed. But if I had to do it over again, I probably would get something smaller. I originally thought I might want to add a microwave oven, but that never happened. Instead, I use propane stoves for the few times I ever cook, mostly just to boil water. Plus I hardly use my Sony PS3 playstation as I found I don't play games much anymore. I also hardly use my larger Toshiba flatscreen TV as I prefer my smaller 12 volt units. Even my fridge is only used very little. About the only things I must really power are my smartphones, tablets, and small 12 volt powered TVs. Obviously, everyone's mileage will vary. But after doing this van dwelling thing for the past few months, I found that I actually don't need much power for the small devices that I mostly use.
 
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Donedirtcheap

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blars said:
To accurately read the voltage of a MSW inverter, you need a "true-rms" voltmeter. The MSW will read low on 99% of the voltmeters (and ampmeters) out there. True-RMS will give you the effective power a heater or incandecent light will see, other loads will vary.

Ok, thanks. So that's why I see such a difference. I was never completely comfortable using the msw anyway.
 

Ballenxj

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Thanks again for your input guys.
@ Caseyc, how many house batteries do you have for your system, and what are their ratings?
 

caseyc

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I have a single group 27 AGM battery mounted inside a housing underneath the van. Unfortunately, I don't drive enough to keep it charged so the stupid low battery alarm usually rings. If I want to power larger devices, I usually have to run the engine on idle for awhile. Plus I have waaaaay to many items plugged into my inverter 24/7 which cause a drain I'm sure. Fortunately the inverter keeps enough charge to constantly power my small devices though.
 

Ballenxj

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Thanks caseyc, you mentioned that you have a 2000 watt inverter. Do you think you could get away with a 1000 watt or smaller unit? Also, I'm starting to think you might need at least one more house battery.
I'm thinking maybe I could get away with a 600 to 1000 watt unit for my purposes?
I believe I read where SternWake is using a 400 watt unit and wiring all his 12v devices direct? I'm starting to see the logic in that.
 

caseyc

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Having numerous 12 volt outlets is a huge plus. I have 7 different 12 volt adapters plus numerous USB splitters for many devices that require USB powering. Yes I could use more than 1 battery. But the custom shop that installed the battery could only fit a single battery under the van as I don't want any batteries inside the interior. I should also mention that I'm an urban dweller, hence my power needs may be less than someone who is full time in the boonies.
 

Ballenxj

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I see, you have an occasional plug in somewhere? About USB outlets, I have seen inverters for sale that have USB ports as well. I forget where I saw that at, but would be convenient.
 

SternWake

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There is little point in putting a huge inverter on a small battery.

Its kind of like putting a rolls royce merlin engine from WW2 in a 78 Honda civic to run the quarter mile and allowing it a 2 gallon gas tank. It will run out of gas before it makes it to the starting line.

Many people view an Inverter as a solution to powering all stick and brick luxuries crammed into a box on wheels.

The inverter is most effective as a serious battery depleter.

Think about this, a 200 watt load is right around 16 amps, but add for inverter inefficiency and this is closer to 18 amps.

NOt accounting for the Peukert effect, which basically states that at higher loads the battery has less capacity to give(and cannot be ignored), a hundred amp hour group 27 battery, if it was healthy and fully charged when the 200 watt load was initially powered through the inverter, it could power it for less than 3 hours before the battery dropped below 50% state of charge. Account for Peukert at this load, and this is closer to 2 hours. The higher the load the bigger the toll on overall battery capacity.

About 175 to 200 watts of solar and all day would be required in a sunny environment in late spring summer or early fall for the solar to return the amount of electricity that was removed by that 200 watt load in under 3 hours. Doesn't seem fair does it?

But even an AGM battery needs 105 to 115% of the amount of energy taken from it to return to full charge.

Aged flooded batteries might require up to 150%.

So, just as it is important to match solar wattage or other charging sources to battery capacity, it is also important to match inverter size to battery capacity.

One can always have a huge inverter capacity, but in general a 200 watt inverter powering a 100 watt load is going to be much more efficient than a 1000 watt inverter powering a 100 watt load.

Bypassing the need for an inverter is wise, whenever possible.

I last used mine to power my 60 watt soldering iron, and to also power this laptop, when I was fixing my DC to DC laptop car adapter whose cord was compromised. I was going to just get a small 150 watt PSW inverter to power my Makita Li-ion battery charger for my drill driver but then I looked and saw it required 250 watts. So I got a 400 watt PSW Wagan. It does indeed pull close to 250 watts, cycling between 6 and 20 amps when charging a Li-ion battery pack.

Using an inverter to power USB charged devices might very well be the definition of vandweller wastefullness.

The inverter will likely use more battery power just turned on and powering nothing than the following product would use to charge the device.

http://www.amazon.com/TopG-Apple-Ce...d=1403062695&sr=8-16&keywords=USB+car+charger

A cleaner install is a product like this:
http://www.amazon.com/Blue-Sea-Syst...8&qid=1403065060&sr=8-1&keywords=blueseas+USB

For powering laptops:
http://www.amazon.com/Charger-Latit...=8-3&keywords=dell+latitude+e5500+car+adapter

Just replace 'dell latitude e5500' with your make and model.

Mine uses 15 to 50% less battery power than using my inverter to power the provided power brick. Been going for 3 years now, the only issues are that a Ciggy plug cannot really pass 90 watts for long before getting too hot, but that is another issue.

Some 120 volt TV's actually run on 12v DC and come with the power bricks to convert 120Vac to 12vdc. In such cases one could wire it directly to the 12v fuse block and bypass the inverter and power brick. Many DC to DC converters exist that will take 12v and step them up or down to the voltage required by a device, whether it be 14v or 19vdc or 24vdc. Using an inverter to power the appliance provided power brick which converts 120Vac to 19vdc is just plain wasteful.

Also note that inverters can cause lots of electrical interference when listening to radio, or watching OTA TV. I've heard they can also affect Wifi and bluetooth but cannot confirm or deny this. In Some devices and inverter can cause a 60 HZ buzz in amplified speakers.

Anyone wanting to power a microwave via an inverter needs a Big honking inverter, and a big battery bank, and a serious recharging source. In my opinion this a stick and brick luxury that should be avoided by those living on battery power.

It is possible to negate some of the huge battery bank and recharging sources required by running the engine while running the microwave, but lets do a little more math.

Lets say that at Idle speeds when the engine and alternator is hot, the Alternator can make no more than 50 amps( mine can only do ~32)

50 amp x 14.4v is 720 watts. Even a "700 watt microwave" will actually consume 1000 to 1200 watts, so the battery will still be having to provide ~300 to 500 watts just to feed the inverter to feed the microwave or you can place a brick on the gas pedal and hold the rpms up in the 1500 to 2000 range to bake that potato without depleting the battery. Notice that this math also ignores the additional 15% efficiency penalty caused by the inverter, and also assumes the alternator to battery and battery to inverter cabling is suffering zero voltage drop, which cannot be ignored either.

There are also a lot of reports of Microwaves having very short lifespans when powered by MSW inverters.
I think there are a few 12v microwaves out there, but their performance is not well regarded iirc.

Caseyc, I've said this before, but your chest fridge is designed to work on 12v DC and 120vac. If you are using your inverter to power it, your are simply wasting electricity and battery power. It will not get any colder on 120Vac. It will just use more electricity, about 20% more for no benefit whatsoever.


The Inverter is perhaps a Necessary evil, for some things, but employing it for everything is unwise.

Remember these is no rule that says one Inverter has to be big enough to power every single thing which might be turned on at once.

If you already own the 120vac devices you want to power then look at their power specs listed on back, or on the power brick. This is the Maximum load the device can draw, not necessarily the load the device will always draw.

Powering any device for any length of time, and you better hope it is not much more than 100 watts, unless you also have a fairly large battery bank and significant recharging resources.


Darn the 5 minute editing rule!!

One can use more than one inverter, having a smaller quieter more efficient one to power the low wattage devices, and a Big bragging rights inverter to have, just in case one cannot possibly live without a microwave or Hair dryer.
 

caseyc

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Bellenxj, I would follow what Sternwake suggests regarding power needs. Bottom line is there's no need for overkill when it comes to power needs. It's more important to determine what your projected power needs will be. Even then, you don't REALLY know until you've been doing it full time for a few months or so, and then you'll get a better idea of your true power needs. In my case, it turns out my power needs are not as much as I had thought. Mostly this is because I don't use my larger appliances hardly at all.

I should clarify something. 4 of my 12 volt outlets are connected to the auxiliary battery. The other 3 12 volt outlets are connected to the main vehicle battery. I have numerous small devices plugged into the 4 different 12 volt outlets connected to my auxillary battery. However, the inverter connected to the auxillary battery does NOT, repeat NOT require the inverter to be turned on to power the 12 volt devices (such as tablets, 12 volt TV, etc). That's the reason why I simply have a bunch of 12 volt devices connected 24/7 to the 4 different 12 volt outlets connected to the inverter/auxillary battery, because the inverter doesn't need to be on to power the 12 volt devices. I realize this writing might sound convoluted, but hopefully this makes sense. On the other hand, I do need to turn on the inverter (connected to aux battery) if I intentionally want to turn on my larger appliances, such as the fridge and larger flatscreen TV, Sony PS3, etc. These devices require larger power consumption, hence turning on the inverter.

Sternwake, to answer your question regarding my fridge, yes it's true my Dometic fridge can run on either inverter household electricity power OR by 12 volts since it came with a 12 volt adapter. However, the reason I choose not to run the fridge by 12 volts is because I'm afraid of burning a fuse from any one of the four 12 volt outlets connected to the inverter/aux battery. I've already blown the fuse a couple times and it's a hassle for me to replace the fuse. The custom van shop provided me with a supply of extra fuses of different colors and amps, and I was proud of myself the last time when I was able to figure out how to replace a blown fuse. In doing so, I have to remove various things to clear a path going to the inverter box and work in very tight space to replace a fuse. It's really a pain in the butt for me. However, I don't have the problem when plugging the Dometic fridge to the inverter. That's because if the aux battery is low in charge, it will simply beep with an annoying alarm. But at least nothing is blown and no fuse needs replacement. If I want to run the fridge, I usually turn on the inverter while driving to wherever I'm going for a half hour or so. I could also turn on the fridge while the car is parked (engine off), but I would only do so for a short time.

If you think blowing a fuse to one of my 4 12 volt outlets connected to the inverter/aux battery is a pain to replace, it's even worse if I blow a 12 volt fuse connected to the van's primary battery. I've done that a couple times, and I simply cannot figure out how to replace such fuses. In such case, I need to go to the Ford repair shop, or my mechanic, to figure out how to replace a blown fuse connected to the main battery which is an entirely different process.

I don't know if any of the above makes sense. What I do know is that I've learned some hard lessons about power usage in the past couple years that I've had my van. Plus I'm very sure the way I'm doing things is not efficient in the least. The one major thing I had done in the past several months was to switch to small 12 volt devices to meet my needs, as opposed to having to turn on the inverter connected to the auxillary battery. I really hate having to turn on the inverter. I hate even more the loud beeping alarm sound telling me the battery is low. So annoying. I could go on and on about various annoyances related to battery usage, but you get the point.

You might find this ironic, but I even have a brand new 2,000 watt Yamaha generator/inverter that I got from a Yamaha shop. For only 1 gallon of gas, the sucker is suppose to provide power for at least several hours. Guess how many times I've used my brand new Yamaha generator in the past year? Answer, none! Hah! That's because I have no room to store my generator in the van. Instead, I currently have my generator stored at a friend's garage. It's a shame, I know. By the way, no I'm not going to sell it, haha!
 
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