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