Author Topic: guess who bought a power jack inverter  (Read 121881 times)

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Offline oztules

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guess who bought a power jack inverter
« on: January 12, 2014, 06:52:26 pm »
 Yes it's all true.
In a moment of weakness I decided to buy a power jack inverter to play with.... and it looks like this.
2807-0

It looks like this inside... warranty blown right there......

2808-1

2809-2

2810-3



Well there it is.
This one is a 24v unit ( my mistake ), but it can do what it says. I can run loads of 6kw or more without problems.... I had the electric stove on, the hot water on and then the water jug..... and it turned off after a minute or so.... can't complain really, the stove was 3200w the hot water some 2500w, and the jug another 2500w... so all up it tried to do over 8000w... I don't now if it was batt under voltage, or power overload... one or the other, because over 8000w is over 300 amps, and I think I had voltage drop in the line... surprise suprise.
The 200 amp meters were way past their stops, and it will never again have to try this, but i could not get it to trip any other way.

So it was impressive to say the least. It also started the 3 phase converter, which is a 3 ph 10hp induction motor running in delta@240v from single phase...... so it can start darn big inductive loads too..

About this time I was becoming rather impressed, as i didn't think it had the  ticker for this kind of abuse, so it seemed I needed to take a more serious look at this thing.

I had bought it because it was darn cheap, with free shipping to this island.... and as it weighs over 60lbs or 32kg, it is not so easy to get stuff that heavy sent here... so I bought it as a back up.

I was becoming of the view that this wasn't a toy like the ones I had heard and seen on the web earlier.... so decided to do some more testing.


Well it wasn't all tea and bikkies I'm afraid.

The engineers have not addressed the idle current other than a sleep mode at 25 watts.... but an awake mode of no power draw costs a whopping 8 amps..... yes you read that right .... 8 amps at idle.

Now as a cheap back up this is acceptable.... but as a house driving unit.. it is not good news to burn up over 5kwh a day and do nothing.

So it was time to try a few things we have learnt from the other unit I have ( the power star thing).

It already has two whopping torroids ( worth buying just for them ), so it was not going to be addressed like the power star was.

So I wound this:

2811-4

This solved the problem.... now idle currents were down in the sub 1 amp range.... in fact now it could be alive all the time, and waste less than 20 watts..... less than their sleep mode...... so 3 and a half turns around a 65mm e core made the thing very very acceptable as a front line unit..... who'd have thought.... a power jack as a front line unit.

Well it's true, it has been running the house... including the electric hot water for the last few weeks. The only thing on grid is the stove.... so usage from the grid was about 1kwh per day, and the house was running at about 11-13 kwh/day.

There was one other thing of interest here.

I have panels running at 300 volts and more intp grid tie inverters into the batteries via the inverter.... ie the grid ties run on the output of the inverter. When the house loads are greater than the grid ties can manage, the inverter takes up the slack, when the grid ties put out more than the house can use, the extra is fed back through the inverters output, and back through the sitching fets and transformers into the batteries.

I have seen in excess of 170 amps being back fed into the batteries via this method. The drawback is you need a big dump load on the batteries, or a cut out system to sequentially turn off the grid ties to keep the batteries from over charge.

If this is allowed to go, then the power jack will turn off when the batteries exceed 32v... which is the final safety in all of this.....THIS DOES NOT INVOLVE THE GRID for those folks wondering..... this is strictly off grid antics.

It is interesting to note, that without the e core filter in series with the primaries of the transformers, it would not grid tie to the grid inverters... but rather, blow all the overloaders in the ac line to the inverters.

With the filter in place, it was perfectly happy to be the grid, and sync the grid ties to it's output, and reverse flow the power to the batteries.... but not without the carrier filter.

So the big filter did two things, made the inverter a classy unit, and allowed it to back feed grid tie inverter inputs into it's outputs.

To say that I am impressed is an understatement. It appears bullet proof, and the spare parts ARE available.

Thats the clincher for me, in fact after I chased them up, they have even put the spares on ebay... about 170 dollars for the entire innards of the machine... ie power board, and control board, battery selector board, and driver board for the display..... just add transformers and a box, and you have built your own..

Before you rush out and do just that...... it is heaps cheaper to just buy theirs, as the cost of those torroids over here are over 1500 dollars alone, cheaper in the UK, don't know about USA. The transformers are over 25 lbs each....

One problem I had was the 24v part... I was set up for 48v..... so I had to do something about it.
I rearranged the battery pack to reflect the new setup... now it was 1500AH @ 24v

Re wired the solar panels for 24v ( left 4kw as 350v for the real grid ties ), and that gave me about 130amps of 35v solar power.

Now I needed a controller.
I sat down and scribbled a circuit of sorts out, and fleshed it out as I designed the board.. and finished up with this

2812-5

It is about 10am, and already it is up at 80 amps

2813-6
I have seen it at 120 amps. The heat sink ( and no those burn marks are form when this heat sink belonged to someone elses 2500w HF pure sine inverter) stays at less than just over skin temp even at high currents. The wave form is very clean, but swithcing at only about 4khz... makes the "layout" simple.

Here is the current going to the batteries after the power jack has used a few up from the incoming 80 odd amps
2814-7

May do an article on that if folks really want to try it.

Here is the wave form of the makeshift "solar controller" ( not the power jack.... that  is pure sine) when it is running at only 40 or so amps after the bulk of the charging is done ( mid morning )
2815-8

All in all...... I love my power jack..... did not expect to ever say that in a million years.


................oztules



Flinders Island...... Australia

Offline oztules

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Re: guess who bought a power jack inverter
« Reply #1 on: January 12, 2014, 09:03:53 pm »
Just an additional comment re power outputs.

This thing will do well in excess of 8000w for short stints.. read seconds...

It will power things in the 5-6000w range for quite some time ( 5-10 mins with current transformer mod) without getting dangerously hot (>60c) The cooling fan is quite large, and very quiet unless your pulling full over 4kw, then it is at max... still quite by most standards.

At 3-4000w it will run for extended run times with the fan keeping things cool, but my batt lead lugs ( and the 200 amp shunt in particular ) get  warm to very warm ( maybe 65c )... the fan seems to keep the unit well under 50-60c

At 2-3000w and less, the unit will keep itself very cool. Should not exceed 50c ( probably 35c) even in hot weather... fan at half speed or less

At 1500w and less, the fan may not bother coming on at all on cool days, the transformer and heat sinks will remain well under 35c if the fan does come on.

So I am very happy to drive it with the full house, and nothing uses massive power for extended periods....mostly the house is idling in the 200-700w range.

This makes it ideal for here, as large start up loads are no problem, ( light flicker for an instant if large induction motor starts up)  microwave, water pumps, 670 ltr freezer 60" telly, and the host of other stuff that seems to be required for the other halves comfort ( double door fridge with ice maker etc).... rarely seem to run all together, and does not matter if they do all run or even start all together.

But don't think your going to run the thing all day at 5000w and above.... you will need some mods for that.... and a much bigger battery bank.

The power and control boards are made outside power jack I suspect, as they are part for part resistor for resistor identical to my power star 6000w inverter..... and that is one tough hombre too.... same rules apply to that, except the fans are smaller, and run all the time.... minor piss off if you live next to them.

In the marine environment here, the power star starts to rust from the salty air here... I expect the blue anodized finish of the power jack to survive longer. For here the boards need protection from the almost 100% humidity and salt loads... so dunking them in grease or drowning them in CRC regularly stops the corrosive problems seen on an island.

Wifes  washing machine is outside ( under cover ) but the air over here corroded the hair thick leads on the micro that was in it in the first 2 months...... after that , I managed to recover it, then drowned it in crc.
We turn it off after every use so there is no "sleep" current in it... then it lasted the next 7 years outside on the back portico..... thats the difference here between inside and outside on an island with electrical ( and anything else really) gear.


............oztules
Flinders Island...... Australia

Offline tomw

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Re: guess who bought a power jack inverter
« Reply #2 on: January 13, 2014, 08:46:15 am »
Oz;

Pretty interesting info.

Good to see you doing testing and improving on a "cheaper" inverter to meet your needs.

Hope all is well out on that spec in the sea where stuff is expensive to get  and one fellow I know of has more fun dealing with that than is probably legal!  ;D

Tom
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Offline dang

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Re: guess who bought a power jack inverter
« Reply #3 on: January 13, 2014, 12:26:10 pm »
Howdy - glad you shared the review with us!

Very curious if there is data to chart efficiency for small loads, like the day is done and a couple of PC's are on, some lighting and a fan, yanno spending the evening in IRC  8) with some tunes on in the background while the missus shops Lands End and Amazon?  ???

Also -  the power star thing - chances on Daddying ( :o ) those few of us w/o perfect memory where it was revealed and your insights? Thanks in advance..
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Offline oztules

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Re: guess who bought a power jack inverter
« Reply #4 on: January 13, 2014, 01:44:50 pm »
The power star is here:
http://www.anotherpower.com/board/index.php/topic,780.0.html

The power stars have given very good service over here... but there are only two I know of
Both have done perfect  operations for the last few years for one, and only a year for the other... both flawless.

They are essentially the same thing as the power jack, and i think the control and power boards are interchangable.. less some side show stuff
Here are the replacement boards for the power jack,

http://www.ebay.com.au/itm/repair-parts-main-board-control-board-of-LF-Pure-Sine-Wave-Power-Inverter-/221351354856?pt=AU_Tool_Parts_Accessories&var&hash=item338991a1e8&_uhb=1

I suspect they will fit the power star as well.... certainly the power card will, and with a little loss of flashing lights, the control will work fine too.
The huge difference is the transformers in the power jack are torroids, and the power star are E I construction..... why I bought the power jack in the first place.

Loads:

Once you change the performance by putting in an inductor as described in both stories, the unit will draw about 20 watts of magnetising power... and thats it.

Any load big or small after that will incur only a few percent loss over the load value..... ie if your only drawing 200 watts of real power out of it, it will be probably using about 225, with 500 watts load, then less than 530.

These heavy things are about >90% efficient... so they claim, and my figures would give them a better grade than this..... but the 20 watts will always be there. In th the original configuration, the 200 watts magnetising current will always be there.

With the inductor in the line, the total draw = load + 20watts +about 5-8% of the loads value.

The long and the short is, once you pay  the 20 watts for the magnetising current, the rest is load+ about 5-8%..... not sure if that holds for multi kilowatts above 3 or 4kw...... that said, it does not seem to suffer saturation, so it , may hold true for most of the range.

It has read outs for power, power factor, amps, voltage, hours used, kwh used ( and resettable).... but has no DC measurements on board.

I am rectifying that soon.

It cost me $650 for the inverter and I spent another  $150 for the spare parts kit...... which is a total rebuild kit... start to finish less the torroids and display meter.



...............oztules
Flinders Island...... Australia

Offline brucedownunder

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Re: guess who bought a power jack inverter
« Reply #5 on: January 16, 2014, 11:59:34 pm »
Oztules,   good post mate, as usual ..

  How do you think some 16mm cable would go for that inductor ?.  I've plenty and it's rated at 90c .

  Thanks for the posts.

  bruce

Offline oztules

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Re: guess who bought a power jack inverter
« Reply #6 on: January 17, 2014, 12:15:30 pm »
It comes down to the expected duty cycle and current.

In my case, I expect massive surges, but low duty cycle, so the wire I used in this case was 10mm diameter core ( not cross section ) or about 78mm sq... but this was 24v, so would see 200A - 300A plus currents for very short periods ... and 150 amps for longer periods... maybe 10 mins max, then back to around 10-30 amps most of the time.... average of  500 watts or 12kwh/day for my setup.

So use as big as you can get into the space you have. If you can get two in hand then better. The 16sq mm is a bit light for my taste, but two in hand would get close to what I would care for at 48v.... it's only a few turns I guess.

If you mean 16mm diameter, then if you can get it in and bent... you will have done extremely well..... 10mm diameter core was a stretch for my bending ability.


................oztules


Flinders Island...... Australia

Offline dang

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Re: guess who bought a power jack inverter
« Reply #7 on: January 17, 2014, 02:19:03 pm »
ahh - I see 'power stat' is the brand of the first unit you'd upgraded, I went looking at it as if it were a homegrown toroidal transformer 'feedback loop' logic design you'd proofed and installed (whew!) ... I'm reading you've added a (third?) toroid to swap an E-core out that avoids core losses, and after reading ALL the ebay auction text for 'LF inverters' am seeing that is why some vendors advertise upgrading to their 10,000w model that has all toroids?

Understood about idle losses tracking across usage, still was curious once the bulk-of-system and wiring was injected...

Those LF inverters have a 20-30% price premium on our US auction site over what the AU site offerings have (had) which kind of ventures into honest pain area price instead of bearable... I'm still interested in a 24V unit soonish so when the times comes..

Thanks again
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Offline oztules

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Re: guess who bought a power jack inverter
« Reply #8 on: January 17, 2014, 04:06:40 pm »
Yes the power star was the test bed for making changes to a cheap pure sine inverter that has proved to be very tough in the field.

It had very sad power drag, so that was fixed.

The power jack shares the same mother board and power board. They finally realised the HF units they made were rubbish.... and used the same boards and better transformers and case and in fact seem to have a very good little unit.... but again, expensive on the power draw at idle.

The ecore seems to solve this, or at least mitigates it to a large degree, and allows grid tie inverter operation using the power jack as the grid.... it won't do this without the ecore.


As they now sell the power and control boards as a spare parts pack, you can just biy that and provide your own transformers and case and ecore.... and have a very cheap inverter.. as much power as you have transformers.. big welding transformers may be the ticket, as there is 12, 24, 48v controllers, and the price seems to be the same for all and any. A decent welder transformer and ecore would probably keep the idle current to a reasonable level.

who knows what you can get up to.


...............oztules
Flinders Island...... Australia

Offline brucedownunder

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Re: guess who bought a power jack inverter
« Reply #9 on: February 25, 2014, 04:09:33 pm »
 
  Hi ,

  This topic on the conversion of the W7 power-star inverter has come a long way ,recently.  Thanks to Oztules,(John) and a few very informed technical team.

  I am converting my W7 , so far hard wiring work ,bending 25mm Sq. hard wiring .

 Just letting those interested in the new developements.

  Bruce.

Offline oztules

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Re: guess who bought a power jack inverter
« Reply #10 on: February 26, 2014, 03:17:08 am »
Bruce, here are the pictures of the conversion, with twin torroid transformer, and put in the inspire box... with a few gauges for battery capacity and Ah and kwh volts ac and dc etc etc and kwh used and power usage  time frames.

Here is the new transformer core with two inspire torroids wrapped up with the twin primaries already.

2903-0

Here is the transformer in the W7 chassis for testing with the powerjack boards.

2904-1


What it looks like installed in the inspire box

2905-2

outside the box:

2906-3

more outside the box

2907-4



................oztules

ps there is more information in these pages here where we discuss the powerjack and inspire and w7 conversions in depth.

The interesting thing is the massive difference that only 13uh of choke makes. It can't just be blocking carrier or harmonics, but Warpspped has a theory in there that may change the way we look at fet switching  perhaps.
http://forums.energymatters.com.au/solar-wind-gear/topic3344-320.html
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Offline MadScientist267

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Re: guess who bought a power jack inverter
« Reply #11 on: March 14, 2014, 12:24:30 am »
 Oz -

Absolutely amazing no doubt, you've got this one cornered rather thoroughly.

I had a thought re the E core inductor that might kill two birds... ?

Litz? Might be able to squeeze a bit more effective cross section in there by both utilizing more of the void around the core as well as reducing skin effect, all while making it relatively easy to wind (in terms of grunt, not necessarily "where was I" factor hehe) if its done strand by strand?

The skin effect I'm not positive on, as I'm of course imagining near nil carrier in the primary of the toroid, and the E is in series, yada. But sure would allow the "easier" winding and "heavier" wire no doubt.

Just food for thought ;)

Steve
Wanted: Schrödinger's cat, dead and alive.

Offline eliafino

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Re: guess who bought a power jack inverter
« Reply #12 on: April 18, 2014, 09:06:51 am »
Hi, thanks for this topic!!!

If I buy an inverter power jack 10kW/40kW 48V, how do I reduce the power consumption at idle?

Best regards,
Elia

Offline oztules

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Re: guess who bought a power jack inverter
« Reply #13 on: April 18, 2014, 12:58:44 pm »
The simple addition of a 18uh choke will do the trick.
No other change required for idle current reduction.

2975-0

Simple as that.


......oztules
Flinders Island...... Australia

Offline eliafino

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Re: guess who bought a power jack inverter
« Reply #14 on: April 18, 2014, 01:24:25 pm »
Wow, very simple...

Thank you very much!

P.s. It also works for the power star w7?