guess who bought a power jack inverter

[ClockmanFrance]

And.....

[augustus]

Hi Oztules and otw
I am in the process of starting a paypal dispute over this, I have several sellers spec of this model powerjack that say that the 8000w inverter does indeed have two transformers and that the seller has issued an obscured warranty number, so Ill see what happens!
regards
Augustus
ps does anyone have an official powerjack photo showing the two trannies?

 

Hi all, my problem has been fixed by the seller who sent me a replacement two transformer inverter, i paid the $ difference without having to return the single trannie one!
Perhaps they will re-do their specs to point out the differences!
Augustus

[oztules]

Good outcome!.... now you have three transformers you can use as per OTW has done.

[off the wall]

three transformers you can use

Yes

I wrote to him yesterday a summary possibly helpful to others

As it is, a 8000LF unit will give 2kw happily all day, 3kw for 20 minutes at a time and towards 4kw for a short period. WIth the extra transformer this will then be 4.5kW for 20 minutes or so and 6kW for a short period.

One simply wires the low voltage side of the transformer in parallel with the low voltage side of the other transformers of the two transformer unit, and one then puts one side of the high voltage transformer connected to the neutral side of the inverter output and then you measure the voltage between the Live of the inverter and the other side of the extra transformer. If this voltage is over 400V, then it's out of phase so reverse the wires. Do so and check it again. It might not be the same. Mine, from memory was around 15volts less. So I wound, from memory, 17 turns of 2.5mm wire around the transformer, and then you have to measure whether the voltage is added or subtracted and you want it to add. Adjust the added turns until the voltage of the extra transformer is equalised with that of the inverter, and then you can simply wire it permanently and have the facility of the extra capacity. I wired in the thermostatic switch monitoring the transformer temperature retaining the fan. From memory I think I incorporated in addition the top control board, applying the power supply DC to the board using the fan output on that connected retaining the second existing fan.

There are probably more details in my posts above

Best wishes

OTW

[augustus]

And many thaks for all your help and that easy to follow description OTW
Augusts

[augustus]

Good outcome!.... now you have three transformers you can use as per OTW has done.

Hi oztules, ill give otws 3 trannie mod a go, when i have a cosenting adult engineer doen on holidays next week!
Although it sounds really simple i don't see myself needing that much power even long term as our house was buitlt from the start to be off grid and modern technologies have made it even easier, we run a 24v 160litre fridge freezer so no losses through the inverter and the new 32'' telly dvd uses 39-42 watts, lpg and solar heating etc etc.
We only have 600amps of 2v cells at 24volts, but it seems to be more than enough, even in winter.

[off the wall]

Well in that case . . . you're better off actually using the one with just one transformer! If you put in the choke as suggested you'll have the very minimum of power loss and a very efficient system.

Best wishes

OTW

[augustus]

Thanks OTW
We'll mount the double trannie inverter, but I'll put my recently Aquired E choke on the single one first and measure the outcome.
regards
Augustus

[off the wall]

For your use, depending on losses permissable, your smaller inverter may wall be better. Even with the choke, the more transformers, the more the losses.

In England we have had record rain - and that means a corresponding lack of sun. I've had my offgrid system only performing at 50% for three of the last four months and not at all in the last month. Now the days are getting longer I'm putting it back on 50% again. I use a time switch to switch over the house circuits to the battery bank system and at the moment alternate the hours in daylight and draw in the evenings continuously, but such darkness is the hazard of solar systems

Best wishes

OTW

[augustus]

Hi OTW I'm a few degrees further south than Oztules, so at the moment we are getting useful sun till about 8pm.
I'm in the middle of trying to replace the slew bearing in my Hyacinth wind generator with a double bearing setup that will hopefully stop the premature wear and oscillation of, and noise and vibration from the blades in high winds.
It is only 300 watts but it looks nice and does top up the batteries at night.
I hope to have it back up before winter hits.

[toxsickcity]

Got my Powerjack, LF 3000

It is fairly good, used it overnight seems to worked fine.

today, a fairly hot day I am having a issue of the system shutdown and buzzzzzz constant noise (a buzzer.. not an electrical buzz hahaha)

so i guess 1 of 2 things,

overvoltage or overheat

I have just set voltage to equalise at 15v and not shutting down.. must be undercoating
I have also noticed shutdown was at 14.6-14.7v max seems low?

anyways
I have a small switch on the rear and it makes fan stay on,

I have just switched the fan on and after close to an hour I turned it off  after running fine for an hour..

EDIT: OK, It just turned off again!.. and I forced the fan on again and it has fairly warm air coming out, wouldn't call it hot!!
maybe they have a overtemp. set too low?!
My load is minimal.. like 200-300w

OK, so what can I do to solve this if I dont want the fan running 24/7
I can buy a small relay thermo switch on ebay for a few $$ and wire it up myself.. will be messy and adding of a small circuit.., I would rather fix it internally

can I fix this by changing anything inside? say a resistor?

[Offgriddin]

Hi Oztules and others
Hope you don't mind me adding to your thread as this seems to be the best collection of powerjack officianados on the web. I am in the interesting position of having two identical PJ 8000w LFs each with a single transformer. Each are good for about 2000w continuous, but I really need to run at up to 3000w at times and thermal shutdown kicks in on the single unit. The two options I can see to increase the continuous output is:

1. Take the transformer out of one and put it in the other, this does look like a bit of work, and I'm not 100% on the procedure, even after reading your post above OTW, unless people know of a concise writeup somewhere? The other thing is its gonna be a very tight fit, and probably not going to take the second fan in the middle.

2. Run the inverters in parallel. As per this guys vid

This looks like it could be pure genius or fiery ball of fail. Could the PJs be connected like this, and if so where to make the connections?
Any informed opinions out there on this?

Thanks in advance
Chris

[oztules]

Depends how long you need the 3kw for.... however...
That video will be useless for these things... there is no intermediate stage to couple up.

So your back to just adding the second transformer.
It should/will fit... maybe the fan too.. dont remember the fan in the units with two transformers.
Simply parallel both the inputs and outputs of the transformers together... thats it. Try to use the fan as well.
They must be in phase... so use the wires carefully..... ie duplicate the original in every way.

If you hook it up with the wires reversed for some reason, it may not be pretty... depends on if the current is seen by the computer at start up.

So you can rewire three of the four wires from the tranny.. 48v ones first, and one 240v one next... then turn on with the fourth wire unconnected.

When running it should have the 240v on both transformer windings..... there should be no voltage between the hanging wire and the place you expect to place it.....




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

[Offgriddin]

Thanks oztules for the expertise and quick reply. So just to confirm parallel the wiring, but leave one of the 240v wires disconnected, does it matter which one, red or black? I guess not or you would have said.

And I take it leaving the 4th wire disconnected is just to confirm its wired correctly, in phase and working. And once confirmed shut down and connect the 4th wire, and power the inverter back up?

There seems enough lead on the wires to place the second transformer where it needs to go, so paralleling should be straightforward-ish. Gone are the days of buying a two transformer unit for $650 off ebay, two different sellers, two dodgy units...

[Offgriddin]

Urgh they've made the cases smaller so two trannies won't fit easily now....