Powerstar W7 Inverter modification

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Re: Powerstar W7 Inverter modification

Postby WALL-E » Tue Feb 07, 2012 6:48 pm

Photos of the Powerstar W7 inverter 48V 6000W
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Re: Powerstar W7 Inverter modification

Postby WALL-E » Tue Feb 07, 2012 6:50 pm

Photos of the Powerstar W7 inverter 48v 6000W
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Re: Powerstar W7 Inverter modification

Postby WALL-E » Tue Feb 07, 2012 6:52 pm

Photos of the Powerstar W7 inverter 48v 6000W
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Re: Powerstar W7 Inverter modification

Postby WALL-E » Tue Feb 07, 2012 6:53 pm

Photos of the Powerstar W7 inverter 48v 6000W
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Re: Powerstar W7 Inverter modification

Postby WALL-E » Tue Feb 07, 2012 6:58 pm

The Powerstar W7 inverter 48v 6000W heating my shed at a constant 223W 24/7
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The Powerstar W7 inverter 48v 6000W heating my shed at a constant 223W 24/7
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Re: Powerstar W7 Inverter modification

Postby Andrew_electrix » Mon Feb 13, 2012 12:26 am

HI Walle ,
Great photo's they show the stock unit off nicely...!
Looks like you got a great rig happening in your shed!!

Sorry i havn't replied, i havn't even had time to scratch myself this week...
Unfortunately i don't have endless amounts of time to post on the EM forum like some (Gordon, Karl ect)

THis weekend my wifes uncle came down from west wyalong (unexpectedly) and collected the modified power star W7 inverter and also a 8kVA generator that i'd brought to use for charging the battery through the inverter when PV contribution is low.
Previously they have been using a deltec 48V 1kVA UPS which has been suprisingly not died given the accidental overloads it's had to endure.
I'm crossing all my fingers and toes that it's going to be reliable, having done my homework as carefully as possible.
But i can't do any more checks on it unfortunately...

You should be able to use a 5kVA transformer, the main issue is the current rating of the primary side filter inductors...
The 110uH parts that i use have a combined current rating of 120A and resistance of 1.75mili Ohms, 3.6kVA at 30VAC on the primary side, which is conservative for the 3kVA rating of the transformer.
To mange 5kVA you are going to need to pass 167A and the voltage drop and i^2R losses go up with the current.
You could go for 4x 220uH 50A inductors, with two in parallel on each winding for a combined resistance of 2.45 mili Ohms, this would drop 0.4V and disipate 68W at full power which should be fine.

Also you'd want to have a CRO to see what's going on with the waveform coming out of the inverter, otherwise you are guessing really, as to what's happening.

How does that 7seg LED voltage/current/power meter perform,does it log the kWh??
Or is that why you have the disc meters??
I was looking at them on Ebay for about $100...

Where abouts do you live mate??
I'm in Adelaide, SA

regards
Andrew
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Re: Powerstar W7 Inverter modification

Postby jackatwo » Tue Feb 21, 2012 4:20 pm

I thank you for a very interesting input of information,
I am a importer of the Power Star 7, 48volt X 6KW to 18KW,
I have found that these inverters need more work technically and electrically, they vibrate badly from half power mode with a hair dryer or blow dryer.
I have informed the manufacture of this problem but there seems to be a problem, I think, with there sales people as the information does not get back to there technical area. but I am still trying.

Both of you testing this machine has given me a lot more doubt on it, even though we have been testing it for the last 2 years with full power of a battery bank of 2400amp/h = 48/12volt X 200A/H gel batteries in 48volt banks, these are hooked up to a hybrid wind generator and solar panels now running a factory with no problems apart from what I have mentioned

If I was to find a better manufacture of 6kw or bigger inverters I would bring them in , specially if the price was reasonable. but at this time these inverters are at a reasonable price. $1800.00 is a bit steep in price.
my prices fluctuate with the USD and at this time are around $1300.00
the latest inverters are upgraded now from what you have got, I do not know what they have done to upgrade them

I see that Andrew-electrix has used PS7 hooked up to grid connect ???
correct me if I am wrong is that inverter Australian Compliant?? just because it has a CE mark does not make it compliant.
there should be a importer or manufacture number on the machine to identify where it was approved from?
I think the number starts with a N-303**. at least a C tick to it

The reason I am asking is that I am trying to get these Australian Compliant and they do need more work done to improve them.
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Re: Powerstar W7 Inverter modification

Postby Andrew_electrix » Wed Feb 22, 2012 12:48 am

Hi all,
Just a another update and response to some of the comments...

The power star w7 inverter that i have modified has is now installed in West Wyalong NSW, at the off grid house right out in the middle of the bush.
The results so far are great!! From a reliability point of view as it has been providing power 24/7 for the last week without any issues what so ever.

As part of this off grid setup, i brought a 8kVA generator (3000RPM sigle cylinder 15hp OHV honda clone engine) 2nd hand off ebay.
The thought was that this SHOULD be able to charge the 520Ah battery with the powerstar w7 inverter working in charger mode.
The governor spring on the generator was vibrating and resonating which was causing the generator to "hunt" or "wander" around the setpoint and respond poorly to increasing load. After sorting this issue out we tried to use the generator to charge the battery using the powerstar W7.

Unfortunately this did not really work as planned for a couple of reasons and i ran out of time to resolve the problems adequetely:

1. The charger load is imposed too quickly and the generator has trouble tracking the increased load without the frequency dropping too low and causing the powerstar W7 to switch back to inverter mode. This had the rather disturbing side effect of making the generator "jump" around off the ground as the load came off suddenly, potentially damaging the engine's conrod or something else!!

2. The AC current waveform that the inverter draws is DISCONTINEOUS and HIGHLY NONLINEAR. Firstly this cause the generator to throw it's 26A output breaker as the current peaks of the current waveform far exceed it's average value.

3. Secondly the when the generator finally accepted the load, the alternator was overheating as a result of non-linear current waveform causing extra losses in the generating machine.

Unfortunately there arn't really any easy answers to this problem
Ideally they would include:

1. Rerwite the code on the micro controller to ramp the charging load on slower giving the generator time to respond - Eg 10sec rather than approx 3sec.

2. Limting the charging current to a more sensible value as 70A DC or 3000W really is quite full on. Even the 8KVA generator which has no problems delivering the required power into a resistive load just can't manage this difficult load. Halving this to 35A DC would make life alot easier all round.

3. Smooth the incoming AC current waveform with a large filter inductor to help the alternator cope with the load.

The 3 stage charging controller seems to work fine but there is no way to control what is happening other than by the small rotary switch which sets the ABSORB and FLOAT voltages.

Does anyone have access to the FULL circuit diagram for the powerstar W7, i've found part of it here that includes the power output PCB, but NOT the control/microcontroller PCB
http://www.pinnaclewholesalers.com.au/uploads/01%20PowerStar%20Inverter%20Service%20Manual.pdf

Or more importantly the microcontroller firmware or source code??

In answer to your question Jackatwo - NO i was not using the the powerstar W7 to connect to the grid, as it
is a stand alone inverter, it can't be used to connect to the grid in any case.

The inverter could be certified as MEN compliant (as per AS3000 wirng rules) as the neutral can be tied to the earth which is in turn connected to the chassis of the inverter, whether the appropriate paper work and testing has be done by someone(?) to prove this is another story.

Best regards

Andrew
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Re: Powerstar W7 Inverter modification

Postby jackatwo » Thu Feb 23, 2012 9:51 am

Hi Andrew
I will try to get a Diagram for you, have just sent a email to the manufacture.
there are two new types or updates of 48 volt inverters out now that are from the same company.
one for battery preference and the other solar or wind or both preference.
I see that you like to play around testing them.
if your close enough to me I can give you one for testing out, this would be ideal for you as long as I am able to get it back some time.
now you do not get a offer like that every day.
I feel I need to give this manufacture a kick in the butt some times and as I am heading off to see them in October I would like to take some ammo with me.
I am in Melbourne check your message box for my number
I do like these inverters and know they draw a lot of power when recharging the batteries I am using a 500amp fuse on these batteries and it seems to be OK with them, I was going to use a 160 amp fuse but the wind and solar together would blow it.
its great under extreme loads so in general I am happy with it. just do not like the half power when it runs a hair dryer and starts to vibrate
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Re: Powerstar W7 Inverter modification

Postby Bthree » Thu Feb 23, 2012 4:04 pm

We have deard a lot about the 48volt version but ....
has anyone had experience with the Powerstar W7 24volt 3000/9000w version ?
Network = Powercor .. Retailer = Origin .. Installed Christmas 2008
Latronics PV-1200 feed by 8xTrina TSM DC-01 .. 170watt = 1360watts DC in .. 1096watts AC out .. 5+years later 990watts ac out
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