Project Journals > Oztules
guess who bought a power jack inverter
oztules:
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.
It looks like this inside... warranty blown right there......
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:
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
It is about 10am, and already it is up at 80 amps
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
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 )
All in all...... I love my power jack..... did not expect to ever say that in a million years.
................oztules
oztules:
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
tomw:
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
dang:
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..
oztules:
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
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