Powerstar W7 Inverter modification

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Re: Powerstar W7 Inverter modification

Postby markhead » Fri Jan 24, 2014 5:03 pm

---usual story---jack of all trades---master of none. Main role of inverter is to generates 240vac- pure sine wave if they say so but check that anyway esp. at high power to see how honest that is under max load stated. Battery life should never go below 12volt and essential to have an accurate controller designed to do this job that does this properly- so caveat emptor applies to anything that says it does everything and if it speaks several languages too its probably got a personality disorder to go with its other dysfunctions yet to be discovered
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Re: Powerstar W7 Inverter modification

Postby oztules » Fri Jan 24, 2014 6:35 pm

My only thought is that you will need to be running this unit whilst charging from limited solar in your caravan....

I assume ( don't know how they are doing it) you will still have to run the overhead for the inverter ( idle currents) ie turned on whilst charging.

If you are going to be running it anyway during the daytime, then this is not a problem... but if it would otherwise be turned off or you wanted to turn it off whilst your out and about sight seeing, it may swing your thoughts on to another different charging technique... ie a dedicated mppt charger perhaps.


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Re: Powerstar W7 Inverter modification

Postby astro_optics » Sun Jan 26, 2014 12:27 am

Hi beaujewel!

I almost by accident... ended up buying a 24V 5000W LF PowerJack with the built in solar charge controller.
I opened it up to have a look and to do the ferrite mod. The mod worked fine, it's idling on about 20W. But the Charge controller is a waste of time and space. It's a plastic little thing wrapped in tape and wedged on the side of the heatsink, so it obstructs cooling... you'll probably notice that the seller will somewhat give a reduced peak rating of 3x instead of usual x4 as for this model, so the 5000W is rated peak 15,000W. I believe that the reason is that it obstruct cooling so the unit is more prone to overheating. The charge controller is connected directly to the battery terminals (from memory), so it's not connected to the inverters logic and works independently.
I tried using two standard 190W panels in parallel, did not like it very much as they have OC of 45.3V which is above what the controller can handle (40V). It was raising to voltage a bit high and shutting of the inverter... Didn't check but I suspect that the Charge Controller kept going and overcharging the batteries (will have to check that again to make sure I'm right)...
***From the advert***
1000W solar panel off grid inverter
RATED CAPACITY: 40A (1000W SOLAR PANEL) <<< Doubt it
LOAD VOLTAGE : 24V
NO LOAD VOLTAGE: 36-40V

One of the sellers was claiming a while back that it's a MPPT CC, but it was not mentioned in my advert....

I didn't waste time so I disconnected the panels from it, it does waste a small about of power when not in use!

Anyway, I'll play with it a bit more, but I'm pretty sure that's I'll rip it out and not use it in the final setup.

Cheers!
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Re: Powerstar W7 Inverter modification

Postby oztules » Sun Jan 26, 2014 7:30 am

Hi astro,
Nice to hear someone who has tried it.

"I tried using two standard 190W panels in parallel, did not like it very much as they have OC of 45.3V which is above what the controller can handle (40V). It was raising to voltage a bit high and shutting of the inverter..."

I have about 4kw of solar on the bank that uses my powerjack for driving the entire house loads.
I built a small charge controller that handles about 170 amps for the 24v unit.

It works fine until it gets up to near float voltage, then I have a problem similar to you. It pulses the power via PWM, but stopping and starting the available current that high, obviously leads to very high current pulses. I had assumed that the battery bank would squelch these spikes, but if the inverter is not under much load, and the sun is shining, and the bank is nearly full, this train of pulses are of full solar potential for very short bursts. I had assumed the bank would smooth these out as i said, and the 40000uf caps ... but the micro reads them in, and decides that we are over voltage.... even though the battery meter says otherwise. The voltage that it measures is not averaged perhaps, and if it stumbles on a pulse when it scans for the voltage, it can return an error code.

So the ripple is causing problems at low drain, and high solar when the bank is nearly charged.

I may try a higher frequency and a decent choke to see if it can stop the ripple from messing with the inverter's safety regime.... or place an averaging circuit where it measures the voltage from.

I have now bought a 48v version, and it suffers the same overvoltage condition under the same conditions as the 24v one.

Looks like a small redesign of the controller is imminent...... just waiting for some hexfets ( 4110) to arrive so I can push the 48v one up over the 150 amp mark......

Or maybe not.....

I like to give the batteries pulses as I think ( my opinion only) they have benefit (re sulphation)
so I might explore the voltage measuring circuit instead of changing the controller... decisions, decisions

Has your powerjack performed well for you, and driven everything you have thrown at it?... mine certainly has.

Markhead,
I can say that the sine wave still looks excellent at at least 3kw. I struggle to find consistent loads higher than that to take steady measurements from.... but from the looks thus far, it appears to stay the same until saturation of the transformer core perhaps..... have not gotten any where near that yet apparently.



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Re: Powerstar W7 Inverter modification

Postby beaujewel » Tue Jan 28, 2014 9:49 am

Looks like the plain jane version is the go then.
In looking for a mppt reg ive come across a lot of options. I would like to source all my gear from one vendor and it seems that lowenergydevelopments on the bay have a decent range and price.
The reg Im looking at is this one,

http://www.ebay.com.au/itm/330983004903 ... 1423.l2649

In combination with 3 100ah batteries,

2 of these panels,
http://www.ebay.com.au/itm/221331994834 ... 1423.l2649

Look ok?

Sorry for the hijack :)
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Re: Powerstar W7 Inverter modification

Postby oztules » Sun Feb 02, 2014 10:38 pm

Important note:

As mentioned in a previous post I have the 48v version now as well.

Be warned, they use the generic board and just reload the software for 48v..... what they failed to also do is upgrade the small 100uf filter capacitor on the lv control board.

They still use a 50v 100uf for the prefilter..... and this does not bode well for the charging of your batteries...... I was equalising using the onboard charger... and at 60v, there was a bang.......

Yes thats when I found out the cap was only 50v... and it was splattered everywhere.

It shorted when it blew, and killed the in line diode, and blew the tracks off the bottom power board that feeds the upper control card.

It only required replacing the cap with a 100v 100uf, the diode, and rebuilding the tracks on the lower board that feed the control card from the battery input..... but what stupidity.

They have a very good platform that they try hard to degrade.... very sloppy.

The power star W7 board has 100v cap in the same holes... thats why I figure powerjack just reprogram the same boards for all of the range... a great idea if they used 100v cap!

That said it now works fine again...... even runs the 225 amp mig welder at full tilt, but does not like it when the wire sticks..

Still very happy with the unit, just disappointed with their attention to detail..... but thats why they are so cheap I guess.

The 24v units do not have this failing... but the 48v units should have this cap changed if your a 48v person.



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Re: Powerstar W7 Inverter modification

Postby Graham_West_Wyalong » Tue Feb 04, 2014 6:15 am

Hello chaps, I am keen to understand a little more on the current recommended mods to the powerstar w7 inverters.

My first question however is one of clarification.... The mods using an ecore as described recently by mr oztules, I presume this only works with the new powerjack lf inverters, I.e. Will not work with the old original powerstar inverters that have the massive arc welder square transformers in them?

My current system is configured thus...

I am completely grid free....
I have two types of battery in my bank, (second hand) a large array of flooded lead acids and a smaller array of SLAs.
I have two 6kva powerstar w7s of the old type... One the very old type has one second hunting, his runs not he flooded battery array. The second inverter is a slightly more modern powerstar w7 still of the old style but with a thirty second hunt mode to effectively reduce the economy mode to some incredibly small load, this is running on the sealed lead acid array.....

Naturally I am extremely happy with the grunt capability of these and the stability and toughness.... However I am really suffering from the massive overhead both in he on state without load, and the extra overhead when drawing low currents...

I find they run the kitchen perfectly and the workshop, no worries... Welder, plasma cutter etc.. BUT....
My wife likes to have the air conditioner running all night, I have insisted that although the air con has low running power, it is the overhead that loads e batteries... A battle to be lost by me.. All you married guys will know what I mean.

So REALISTICALLY, would you recommend I buy the 8kw lf and put one of the toroids in each of the powerstars that I have or would I be better off buying the 8kw and making the mod and running the entire house from the large array and use one of the old powerstars for the sheds etc and keep the other as an emergency backup for when/if one of the others dies?

Sorry for the laborious questions and long message, but I have been fighting with this issue for some time...

Also I am guessing that the charging side of these inverters is not worth the plastic it is made with and I should continue to struggle on with the two GSL 60amp MPPTs and the two 60amp PWMs I am using?

I keenly await comments, suggestions, considerations...

Kindest regards..

Graham
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Re: Powerstar W7 Inverter modification

Postby oztules » Tue Feb 04, 2014 6:44 am

Graham,
As you already have two inverters, it makes sense to buy the ecore ferrite, and do the mod on those transformers.

My friend Bruce was supposed to run this test for us.... but has yet to do so.

My suspicion is that you will get enough relief to make you pretty happy.

Should that fail the test, then yes a power jack 8000 lf will do the trick, we know the mod works on that. Don't split the transformers, just use it on the house, and the intermitant usage on the shed by the power stars.

I too have found the power star to be very tough, and it is the same boards in the power jack essentially, I have only found 1 change thus far.... to the worst in the 48v units from the looks of it.. but only the 50v prefilter cap as I have found. ( power star uses 100v)

The chargers in them work well, but at about half their advertised currents... ie 60 amps not 120 amps... which is more realistic and sensible.


So get the ecore with the 3 1/2 turns on it, and try it out on the power star. you will need to make one for the power jack anyway, if you must head in that direction...... so nothing to lose.

If I can get motivated, I will dig up the power star trannies and do the test for curiosity sake anyway I think... then I will know.

"A battle to be lost by me.. All you married guys will know what I mean.".... yes I MUST run the 60" telly all night... no matter what... I don't understand the reason, but I do obey the commands.


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Re: Powerstar W7 Inverter modification

Postby brucedownunder » Tue Feb 04, 2014 6:59 am

Hello again ,John (oztules), and Graham.

I've ordered the "E" core from China ,and am waiting to do the mod ,sorry John , for my slackness. But be assured ,you and the crew will be first to know my results.

For the last 3 months , I've been running a "Sola" UPS of som 1200 watts capacity,they say!!. It's been running on my 48v battery bank flawlessly during every day, and a few times at night --so, it's OK .

Hoping that the "E" core arrives this week and I'll report back --Thanks to you all.

Bruce.
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Re: Powerstar W7 Inverter modification

Postby Warpspeed » Tue Feb 04, 2014 7:58 am

What model Sola UPS is that ?
When I worked at Sola (and designed all the electronics for a new UPS model for them) all the Sola UPS's at that time used ferroresonant transformers, driven directly with a 50Hz square wave.
If yours is like that, the high frequency choke modification is not going to do anything.
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