inverters

Have a look at these...They are 48V, but if you already need to include batteries you can easily reconfigure to run 48V.

http://www.energymatters.com.au/sma-sunny-island-5000watt-48volt-100amp-inverter-charger-p-415.html

Regards,
Sapper

Miik999 asked: "but where can I get a grid tied inverter of about 5kw/6kw output that can run from a 24v or a 48v battery bank?"

REPLY

Told you before. Unless you tell us where you are located; it is hard to recommend a manufacturer close to you. My personal preference is Victron because I know it can be provided anywhere in Europe much of Africa and also in Asia and Australia and New Zealand. But Victron is based in Holland in northern Europe. the product is manufactured in India. For bulk shipments we had skid loads air shipped direct from India. When I need only one or two at a time we order through some place moer local. SO WHERE IN THE WORLD ARE YOU??

If you can get on the net look for Victronenergy.com and select the language of your choice and then look for sales distribution. Victron inverters ( like several other brands) can be paralleled to give more power. Up to 15 kW single phase and 45kW 3 phase.

I use the 12V and 24V versions mostly because this is the system voltage my clients ask for. But Victron does have 48V systems that are specificaly intended for grid tie designs. Almost any inverter system can be used. The one big difference between Grid tie lies in the fact a Grid Tie system detects presence of Grid voltage and frequency. Protective relaying will disconnect the inveter from the grid tie point when the system gets islanded. However most Grid tie systems can also be used in stand alone mode. Stand alone designs can often be made to run as Grid tie with the addition of external protecive isolation and transfer switching. It is not a clearcut either or situation.

I suggested before that you modify your search parameters if you are unable to locate any sources in your geogfraphical locality. Evidently your keyword list is too restrictive. I hesitate to recommend North American products even if they can be converted to 230v applications only because I think the number of sales reps wil be les abundant than other moer local brands.

Outback does list a Madrid sales center. Mastervolt has sales outlets al over the world.

Milk999,

As Elnav has said it would be a lot easiler if we knew where you were.

However, the link I provided was for a distributor (Aussie based) that will ship for you.

This could be expensive so chase down the suppliers distributors closer to where you are. SMA are global so there should to be a distributor close to you.

Just looked at your profile...Duh...SMA is based in Denmark.

See : http://www2.sma.de/index.php?id=20 and don't limit yourself to that one model they have a good range and several documented configurations.

Regards,
Sapper

Elnav I am in Ireland. Its on my avator.

here

Tinker65 askeded: Why such a low voltage system?

I can't speak for Miik999 but this is a very relevant question for many other people.

Simple answer is cost and safety. Despite your accurate statement about expensive cabling , this is nevertheless true.

The non technical potential user sees 12V as being common, readily available, and with lots of additional products from the automotive, RV and marine applications to choose from. These users lack the experience of building systems and do not realize the implications. Most electrical codes set 50V as a maximum limit for extra low potential catagory. The shock hazard in extra low voltage is not considered a big risk. Above 50V the risk factor greatly increases.

What this means is exemption from much of the onerous and costly compliance associated with system voltages above 50 V. For example you do not need enclosures around every junction box and splice point. You can use non certified and non approved box enclosures and cheaper automotive wires. Consumers perceive 12V batteries as being low cost. They fail to recognize that the low cost is associated with lower quality compared to industrial types. To the average consumer, 12V is the familiar but 24V or 48V is strange and exotic so they tend to shy away from it. Many DIY hobbyists also tend to see 12V systems as something they can build by recycling automotive products like Car alternators start batteries etc.

Consumers as oposed to industrial users seldom calculate system life cycle costs. They only look at the initial purchase price.

Many consumers are not familiar with the technical concept of losses due to wire resistance, sometimes referred to as I squared R losss. Doubling the system voltage while keeping the wires the same results in one quarter the losses because of the squared factor applied to the current. When you double the voltage you cut the current in half. Although this was known back in WW2 and applied to aircraft wiring it never really became recognized by the consumer public.

Logically a 120V or even 240V DC system makes technical sense but the cost of compliance in a home installation is considerable. Staying below the magic 50V limit does result in lower cost system construction. Because battery production tended to focus on 6V and 12V units the cost of these remains affordable. Naturally systems tend to exploit the ready availability and lower cost of 12V so you get a lot of people thinking 12V when in fact any multiple of 6V is still good. Only very recently have people become aware of the avilability of 2V cells. 2V is of course the natural voltage of a single cell lead acid battery. Until we develop some other chemistry technology; 2V becomes the bedrock upon which we will continue to base our electrical DC storage systems.

How many do you want to buy this converter?

All the grid tied inverters that I can locate need a min of 110v dc input.(Some 240V dc). Can their input voltage be changed by any means.

what does the sentence mean? do you need input from 24 to 240dc?

or a series of inverter which has 24, 48 ... 240vdc input respectively?

CN Power, the question means ; I am looking for an inverter that will run with 24v or 48v DC input and give out around 10 kw single ph and can be grid tied.

ok, but I hvnt seen so higher power one unit. ours only form 500w to 2000w, (50hz, 60 or 400hz) occassionally 3kw. this 10kw may connect parallel serveral together.

Its not easy to make in one unit, Im afraid.

btw, what is "grid tied"? I dont know this word. connect directly to accumulator?

CN,

Grid-Tied (or Grid Interactive) systems are where the Inverter parallels with the Utility provided or Mains power Grid in order to export any excess power that is unused on the site of generation back to the grid and\or allow power to be imported if there is insufficient power being generated by the Solar PV or other renewable source.

Regards,
Sapper

Thank you very much, Sapper and bwire .

Now I know it means can link to power grid.

Regards

miik999,

You'll need first a step up DC/DC converter

aims in the us has a new 240 3 phase unit due out in the next few weeks it will not be able to be grid tied but that is ok keep your money as times are a changing

Keep looking! Victron among others have grid tie inverters that meet your spec requirements. In the US Skystream is a wind generator company which has the inverter located inside the wind turbine. The output of this inverter is 230V AC I have been told they can select 50Hz or 60Hz.

Outback, Mangum and Xantrex all offer grid tie inverters. They have European offices so 220V 50Hz models are available.

You did not say in what part of the world you are locate4d. I discovered that Google wil apply a filtering process to product searches basd on the place of origin in order to find local sources. sometimes this contrary to what you really want to do.

I recommend Outback, Their sytems, are 24, and 48 volts and are stackable, and can be configured for single or three phase. Their system, and a couple of others use a volatage regulator, to control the PV; from 24-180V DC; to whatever voltage your battery system is, 12-60V DC. The inverters are 3500W but can be stacked or configured, based on your needs.

Any questions, shoot me an e-mail.

I don't sell this stuff, I just sell the idea that alternative evergy is COOL.

Hope this helps.

The reason why most large inverters do not operate at 24VDC is that the input current would reach at least 450A. This needs large cables and switches. At 120VDC, this current is down to a more manageable 100A. It is easier to connect batteries in series with small wires than using huge cables on parallel banks. But it can be done if it is what you need.

When you are talking about industrial applications like ours starting at 40KW, we use 480VAC and 800VDC. This carries us to about 2MW. The DC currents are between 50A and 2500A. Above this, you are looking at medium voltage in the 2KV and up.

Marcot, it should be mentioned that industrial installations like you mention starting at 40KW are typically maintained by trained staff with extensive knowledge of work place safety. This is very different from the typical residential installation where it is not uncommon for the home owner to have no experienc with DC systems except for working on their car.
I see your location is Montreal. Might you then be talking about Hydro Quebec? This is a very different proposition than a residence or even small factory with a 4 - 8 kw installation. We had 120V DC for our inverter system in a 2MW transformer station. My work partner and I were more concerned working with that than we were working with the 27.6KV AC switch gear DC arcs do not extinguish and DC burns heal a lot slower than comparable AC burns. There is a good reason why 48V DC is the defining limit for extra low voltage systems.

I agree with you 100%. DC voltage becomes dangerous very quickly. This is especially true when DC capacitors are used in inverters. The short circuit current becomes extremely large and explosions are possible. High voltage DC is not for beginners. I am afraid that some people will get injured when electrical cars will be more common. People will do things that they are not supposed to do. Hopefully they will treat the car hood like an electrical paned and stay away. Electric car manufacturers might keep to lower voltage and use very large current to drive the motors for safety reasons.

I work for a provate company. Our inverters / converters are mainly used to make large power supplies for ozone generators and for harmonics filtering in industrial applications.

Miik999 are you still looking? Perhaps you need to change your search parameters to capture more products in the size / type of range you are looking for? Ther are many good brands availabel to serve your need.

Marcot, while you are correct that 450 amps is a sizable amount when the inverter is placed close to th ebatery bank the shot lenght of necessary cable is nut an insurmountable barrier.

I normally work with and design 24V systems, I have not heard of many accidents or mishaps due to the amount of current involved. There are a number of good commercial products available to safely handle the currents required and even more if necessary.

Elnav, you say you design systems. After reading your comment 14 it has made me think again. Could you design a unit that could be attached to an off grid inverter to make it act like an on grid inverter ie; quickly switching off the power going back up the grid when the grid is down plus whatever an on grid inverter does.

Check out Xantrex or Outback Inverters, they both can do what you wish. You can see a nice collection of available manufacturers at http://www.sunwize.com They are in US but much of their stock can be obtained worldwide or by you. Good Luck and do not buy any Chinese Wind Turbines, they have not one single good feature. Keep it Fused !

Guest I don't think so! Look at where the poster lives. Ireland. 230V 50Hz country.

Xantrex and Outback are both designed for 60Hz 120V applications.

Outback does offer a 240V option. They add a heavy transformer on the output of the 120V model. Xantrex has a heavy duty nmodel called th e(Trace) SW4024 that delivers 4000 watts of 120 power. For 240V they connect a second inverte4r in tandem using a special sync harness to give th esplit phase center tapped neutral so common in North America but non existent in any other part of th eworld.

In Ireland ther at wo big names to consider. Victron and Mastervolt. More bang for your buck and if either of these has a problem, service and repair is much more convenient.

I am still waiting for a call back from Outback since I left a telephone request over a week ago asking about their 240V 50Hz models that I was contemplating using on a project. When a company cannot bother to return a phone message in over a week I wonder about their sincerety in serving a market niche.