Anyone used or got a 2000w pure sine wave inverter? As im looking for a decent one

[oBladeo]

I'm looking for a 2000w pure sine wave inverter (4000w peak) but i can't find any reviews for them on the standard sites with the products.
e.g.
http://www.amazon.co.uk/inverter-convert-battery-output-electricity/dp/B00BY9A6ZK/ref=sr_1_1?ie=UTF8&qid=1377721231

I'm looking to spend between £200-£300max so can anyone point me in the right direction as i don't want a crap chinese one that will set on fire.

(it has to be a sine wave)

Thanks

 

[RogerL]

Is this for a canal boat with a bank of 12v batteries - or a single caravan battery ?
At the 90% quoted efficiency, that 2000w Inverter will draw 185 amps continuous or 370 amps at peak power, either of which is waaaaay above a single leisure battery's capability.

 

[oBladeo]

Not bothered about the draw chap just bothered about the inverter as i won't be running it at peak or at the continuous level. By using a larger inverter it means that it will not be under stress at anytime. Also by using a pure sine means that the power efficiency (less draw) is better at a lower output (also games consoles have to have pure which i use to play blurays while the kids are asleep).

 

[ProfJohnL]

I'm sorry to disagree but your assumption that a pure sine wave inverter is more efficient is I am afraid is fundamentally wrong.

The most efficient inverter has output devices that are fully on or fully off. Essentially a square wave output. Quasi Sine wave outputs are a stepped square wave, which means at some times during the cycle the output devices are operating in their transfer range which means they are wasting some energy'

For each step you add to the transfer function to more closely follow the sine wave, the output devices become more lossy.

Ultimately a 'pure' sinewave output requires the output devices to operate continuously in their transfer region, which means they are continually being lossy.

Larger inverters use more output devices to provide the desired current, which also means their quiescent power usage will be bigger than inverters designed for fewer output devises and lower currents. Using an over sized inverter for a small load will almost certainly use more power than an inverter closer to the required load.

However If you are determined to proceed on this course of action, I seriously doubt you will find a western sourced new product, of the capacity you are looking for at the price you have suggested. Also for better reliability you might be better to look for a 24Vdc or even 48Vdc inverters, and use multiple batteries in series. Such devices are used in canal boats, or some maintenance lorries used by the utility companies.

Some of the marine versions also include the circuitry to provide proper maintenance charging of the connected batteries when mains is available.

You might also consider some of the larger uninterruptable power supplies made for computer systems - though you might need to find some way of disabling the warning buzzer that plays when the mains is cut.

 

[oBladeo]

Demo of the isses with modified
http://www.youtube.com/watch?v=CzmfsU06qN8

Plus games consoles will not work with modified sine. I know i have tested this.

Still have the issue of brand. Anyone know?

 

[RogerL]

The reality today is that most quality electronics are made in China, as well as the undesirable stuff - so country of origin won't work to give you what you want.

 

[ProfJohnL]

Hi again,

I'm sorry but the demo you point has a number of ill informed comments and incorrect assumptions.

The first and major one is the presenter points to the box for the pure sine wave device and implies that the difference between a modified sine and a pure sine is as shown on the box. I think that was cheap marketing ploy by the manufacture to exaggerate the point.

In most cases that is not accurate. What is shown is a single stage square wave, which is not a modified sine in the context of power supplies. The vast majority of modified sine wave will be constructed from two or more stacked square waves and will more closely match a sine wave but will still have eight or more distinct steps visible on each full cycle.

Virtually every appliance that uses either wire wound transformer or motor will react to a modified sine wave. The noise is undeniable, but will diminish as the number of steps increases in the modified sine wave output.

The demonstration using the 'power' meter is highly unreliable as these meters expect to see a sinusoidal mains power supply. They are not capable of resolving the RMS equivalent of non-sinusoidal wave form, thus any measurement of a square wave will be inaccurate and cannot be used for direct comparisons.

Meters for accurately measuring power transfer of non-sinusoidal waves tend to be very expensive, and not likely to be used for domestic plug in power measurement devices.

 

[oBladeo]

A modified sine still does not work for my purpose. So i'm not sure why you keep talking about it?

Allot of devices require a pure sine wave and will not work on anything else. Modified is fine for microwaves and the such but not for the purpose i need.

I think i'll buy this one. I don't need a chargerinverter as i'd like to keep that seperate.

http://www.ebay.co.uk/itm/2000W-4000W-Peak-DC12V-PURE-SINE-WAVE-POWER-INVERTER-DIGITAL-DISPLAY-SOFT-START-/190884445311

 

[RogerL]

A lot of devices require a pure sine wave and will not work on anything else.

In umpteen years, you're the first caravanner I've heard who needs a pure sine wave inverter - I guess most are using different equipment to you.

 

[colin-yorkshire1]

A modified sine still does not work for my purpose. So i'm not sure why you keep talking about it?

Allot of devices require a pure sine wave and will not work on anything else. Modified is fine for microwaves and the such but not for the purpose i need.

I think i'll buy this one. I don't need a chargerinverter as i'd like to keep that seperate.

hi, in theory I see where you are comming from, and indeed had similar thoughts while rewiring and rebuilding the m/home, I went to extraordinary lengths to get it right and balance the systems between 12v 230vEHU and inverter.
however in practice the the whole issue was a bit more pragmatic, and in reality only used the 1kw PS inverter for about a dozen times in the 10years we used the van, as it was far simpler to use the vans 12v, gas, or just plug it into a EHU,
despite the hype on current drain, noise and interference, I can tell you they hammer the battery are only really usefull for short term uses, and the fuses blow very often,
now I used 2 batteries and made sure the inverter could not drain the vehicle battery, and had the charge circuit designed so as soon as the van was started it boost charged the (internal aux one) first via a extra alternator.
even so it killed the first battery in 2 years, to this end I am now very scepitcal that apart from emergency short term use, using a inverter as a perminant power source, was such a good idea,

 

[ProfJohnL]

...................So i'm not sure why you keep talking about it? ........................

Hello oBladeo
The reason I have given the answers I have, is you have made or included statements in your postings that I know to be wrong, and to leave them unchallenegd unexplained may give other readers who are considering using inverters of both types the wrong steer on which way to go. You used a Youtube clip as the justification for your approach, and I felt it was appropriate to explain how the clip was not giving an accurate picture of what it was showing.
I do not deny using a full sine wave inverter will provide the best possible power, but for many appliances such purity is not always necessary, but the choice is of course yours, though your descision may be based on questionable data and opinions.
I wish you well with your project, but I do belive you may find your unusual approach may present a number of unforseen challenges.

 

[colin-yorkshire1]

I wish you well with your project, but I do belive you may find your unusual approach may present a number of unforseen challenges.

you have got that spot on Prof. good luck.

 

[ChrisUK]

I have a modified sine wave inverter and found that the TV and laptop PSUs both buzz alarmingly so I don't ude it. It also wrecked two electric tooth bruch chargers, my stupidity for doing it twice.
However 2kva is bl!***y big!

 

[oBladeo]

Well after much searching and allot of reviews and info i've just paid £507 delivered for this 3000w

http://www.ebay.co.uk/itm/140903489178

I'll have the main feed for the van feeding directly into this and also have the battries attached at the sametime to charge and switch to allow constant power. Great unit and does everything i need. I'll give you a review once fitted.

 

[ProfJohnL]

I note its both bigger and considerably more expensive than you were looking to spend. You should take note of what the manufacturer reccomends for the type of batteries it requires - They are likely to be marine approved batteries, and as a consequence much more expensive - But their charge capacity and sustaind current take off capacities are important, otherwise the inverter will rapidly damage normal caravan leisure type batteries.

 

[ProfJohnL]

Duplicate post.

 

[oBladeo]

I just couldn't trust one of thos dodge looking cheap ones for the equpiment that was going to be plugged into this.

The inverter allows you to select the type of battery so it shouldn't damage anything. I also like the 10ms switch so works like a UPS. With the sleep function and remote it should be really good on power. Just need got pick up a 230ah battery now and some 0 awg cable with connectors to go with the 2 x 75ah batteries i already have (just a pitty i didn't save all my car audio equipment from when i use to build high powered system).

 

[ProfJohnL]

Your last comment about different sizies and ages of batteries conserns me .
On high powered dc systems where multiple batteries are used, the best practice is always to use multiple batteries of the same make, model size and AGE. All batteries are not equal. and whilst the device may have managmant for different types of batteries it will be same, not mixed stock.
Bearing in mind the specification of the device is 3000W continous with a peak of 6000W that equates to 500A at 12V dc!
As a battery ages its capacity to deliver current changes . This would mean that it will not play a balanced part in the pack and imbalances will mean that some cells are more likely to over heat under moderate to heavy loads.and of course batteries of different makes or size will also perform differently. Particularly where batteries are connected in parallel any mismatches can cause massive currents to flow between batteries or cells. Overheating will lead to some cells outgassing hydrogen with the very real risk of explosion.

 

[Parksy]

I just couldn't trust one of thos dodge looking cheap ones for the equpiment that was going to be plugged into this.

The inverter allows you to select the type of battery so it shouldn't damage anything. I also like the 10ms switch so works like a UPS. With the sleep function and remote it should be really good on power. Just need got pick up a 230ah battery now and some 0 awg cable with connectors to go with the 2 x 75ah batteries i already have (just a pitty i didn't save all my car audio equipment from when i use to build high powered system).

Were you thinking of fitting 1x230a/h and 2x75ah leisure batteries to your touring caravan?
It's up to you of course but have you considered the effect that the weight of these batteries could have on the stability of the caravan when it's being towed?
Will there be any payload left for you to use when all of these batteries are fitted?
Wouldn't it be less expensive simply to choose sites with ehu?

 

[RogerL]

Well after much searching and allot of reviews and info i've just paid £507 delivered for this 3000w

I'm currently stopping on a lovely quiet CL with 16A EHU for £7/night, increasing next year to all of £8 - so how much to you actually save by choosing sites without EHU.
If you add the £507 cost of the inverter, the cost of how many batteries? and the cost of gas for heating & cooking, just how many decades will it take to break even, let alone save any money ?

 

[ProfJohnL]

Whilst I too think Obladeo's approach to caravanning is somewhat unique and perhaps some of his choices are in my mind misguided and will bring some quite unique challenges, I don't think its fair for us to criticise his life style or choice of sites, but it is right to point out any issues we may foresee from his choices of equipment or methods, and to offer the benefit of our experiences and expertise if he asks for it.

I seem to recall in another thread he has stated that much of his caravanning is the result of his pass times which precludes fully services caravan sites.

 

[Gozza]

I seem to recall in another thread he has stated that much of his caravanning is the result of his pass times which precludes fully services caravan sites.

Yes, in another thread he has said that as part of his hobby he stays a lot in places with no facilities, where EHU isn't an option: I can't help thinking that for the price of his inverter (not to mention ongoing battery costs etc) he could've got a pretty good generator, but it may be they're not allowed on the sites he uses.
For similar reasons we sometimes have to stay in no-EHU-sites, personally I just say that for those weekends, anything that won't run off the battery we have to do without, but as the Prof said it isn't for us to criticise another person's choices.

 

[oBladeo]

This is all because of my paintballing hobby and staying on MOD sites that do not have electric.

I will also be buying a decent suitcase generator but didn't want to be running the generator all the time. I also wanted a setup that i didn't have to keep fiddling with. With the inverter the 12v and 230v sockets will be live be it running off 12v or generator 230v. This means that i do not need to buy a 12v microwave or a 12v tv. Plus by using the inverter if i have issues with e.g. hair dryers and kettle at the same time (high power for a short periods) i can just switch to the 12v and it won't trip out if I’m staying on a caravan sites.

I always like to design and build things that are more powerful than needed. This is to ensure nothing will be under strain at any point.

 

[Dustydog]

Although I am a dog and only did physics A level 40 something years ago I do recall that energy of whatever sort was never free.
Can someone tell me how long SWMBO could use her 2000 watt hair dryer before our 110ah leisure battery gives up if I used an inverter?

 

[ProfJohnL]

Dusty,

Basic electrical formulas suggest that to produce 2000W from a 12V source would need 2000W/12V = 166A.

That suggests that a 110Ah battery would be fully depleated in about 35 to 40 Minutes.

To run the hair dry you would of course need a 2000W 12Vdc to 230Vac inverter, which will also use a little power of its own.

BUT, There are a number limiting factors that might reduce that time further.

Caravan battery chargers will only charge a battery to between 85 to 90% of its full capacity. So at best your 110Ah battery will only have about 95 to 100Ah.

As batteries age, their capacity is also reduced.

Also leisure batteries do have a limited maximum current draw so you would need to check the batteries specification to see if its is capable of supplying 166A.

Further, Most inverters have a battery protection system so if the batteries terminal voltage fall below a threshold it turns off. Its quite possible the battery may still have 20 to 30Ah charge remaining, but is unavailable to the inverter.

So all in all you may get 20 Minutes from a caravan charged battery.

Alternatives:-
Only use sites with EHU, Get a 2kW generator,
Send the OH to the toilet block where a 13A 230V supply is available,
Tell her you love the bad hair day wild look!