guess who bought a power jack inverter

[oztules]

It will run the house, inc the dishwasher, probably not useful to run the stove because of huge drain on the batteries for short stints......, but would, and will run the aircon if it is the modern inverter style.... but not all at once without mods, and bigger transformers.... but your panels are to small for air con for any period, thats where a big panel, and grid tie helps a lot too.

Hopefully they now have the idle current under control, and you will need to change nothing there.... hope...
If you have trouble with the chargers for some reason triggering OV, then thats stoppable too.


.............Oztules

[mab]

Hello Oztules,

I'd like to add my thanks to that of others for posting your powerjack experiments here - I've just acquired an 8000LF 24v 230v 50hz, and am quite happy so far. You should be charging PJ a commission  - I wouldn't've dared buy one of these if it hadn't been for your posts.

just in case you're wondering: it has 2 transformers with a fan squeezed between them and little ferrite torroids on the leads to the transformers, and has a no-load draw ~ 1A. Having read some of the earlier posts I thought I'd take the lid off and check what I'd got.

Ideally I would like a lower idle draw so I was thinking of ordering one of those E core pairs that you linked for Steve3 (I'm in the UK too), but wondered if it would gain me much as I guess from what you've said in earlier posts it still needs to supply magnetisation current to two transformers?

I have a plan to possibly use a grid-tie inverter to connect distant pv or windmill - in which case I should install the Ecore anyway do you think?

Thanks again

mab

[phri]

I bought the 10000WLF 48v version of the powerjack, it has 2 5000W transformers. Idle current is 0.7 A. Fuses are 15A for incomming and 20A for load; thus max around 3600W for continuous load, much smaller then I expected. Is there anything I can do to upgrade this as transformers should be big enough and I understand that electronics should be able to handle this too?

Wiring inside looks thin for specs; 40000W piek looks unlikely, also transferr relay is only 30A. This is a bit of a worry as I want to hardwire it as an UPS for a fish life support system; pumps/blowers/compressor around 2 kW together. Can I bypass the unit automatically when on standby? 
Also as far as I know standard sockets as on the unit shouldn't be used for currents above 10A, thus these are serious undersized too.

[oztules]

Mab, looks like you are already at the 25w mark, so not a lot to get from there.... I'd probably leave well enough alone for now..
They seem to have enough uhenries so you should be able to run the grid tie as is.

Phri,
20a will get you closer to 4800 watts.
40 kw is doable for short bursts, as the fets can handle 600 amp surge x 6 or 3600 amps@48v... or near 180000 watts... don't bet the house on it though.

2kw should be a walk in the park for it, as the 10kw unit should have the oversize heat sinks in it. I use that power card with a 15kw control card and home brew transformer, and have never seen it struggle running all sorts of things full time.

Sockets for 10a are 2400 watts a piece, and you say the drain should be only 2kw, so you should be good to go.... the 30 amp input relay is over 6000w... you are nowhere near this as yet.... but not sure I would feel cool using that kind of power in that relay....


My concern is the ups part of this. I have not had a good experience with these units in the unattended ups role, maybe it is just my luck, but that is the only concern I have for these units now.... having to turn off the units before the charging occurs, and turning it off before releasing the shore power.... it may be that my units did not have the programming to do this securely, but the instructions clearly stated to turn it off first.... and I  blew it up when I didn't turn it off before disconnecting the shore power.

So if yours specifically has the ups function in the advert, check with the seller what if any precautions need to be followed.... I may be completely wrong too, but thats my experience. No problem changing over from inverter to shore power, but blown up from shore power charging to inverter mode.... but not always.... maybe 1 in 10 times before the bang.

This is what you bought it for, so quizz them.. They are generally pretty good with back up. I think they have become more responsive and less defensive now that a few sites are giving them credit for their LF range, and they do seem to be trying to improve it ...... the HF range can rot on the shelf in my books though.


bypass of the unit on standby is simple .

Luck with it.


......oztules

[mab]

cheers Oz, - that saves me the cost of the E-core.
m

[phri]

I tried to get some info from the manufacturer on the UPS function and they seems to ignore me.

I tested the UPS function probably 20 times; with load, without load, with inductive load and it all still works.

The 10 Kw lf inverter doesn't have a static bypass build in meaning; inverter off or malfunction no power even when the mains are fine. Thus very risky to run essential services through the unit.
I intend to wire the unit with a relay (contactor) which switches the load from mains to UPS output, when mains go off line. This also avoids heavy loads going through the ups unit when mains are on-line. Thus break before make contacts and no delay. My main loads are inductive as they are motors from pumps, thus they will still rotate when switching which will lower surge current. Any advice/comment on this configuration?

[oztules]

The original design of these things had very lossy transformers, with lots of leakage... consequently they did not present as a dead short on start up. Mine is particularly tight, and on start up will nearly always blow 30 amp mains fuses in an instant, just to start them up for testing the windings etc. The can use up to 60 times their normal running currents in this configuration.

This probably has got a lot to do with mine not being able to recover from battery charging to inverter mode... the transformer is just too stiff to drive instantly at full tilt, and destroys the fets in a heart beat... and that s no mean feat. 15kw and beyond won't do it, so it must be huge surge at start up if it hits full tilt first up.

The power jack transformers are  better/tighter coupled  than the original E-I units in the power stars etc..., and  may not present as sever a load as mine do on change over, this may explain why I cannot get the thing to stop blowing up if I don't switch off when finished charging... I need ( very badly) the soft start it does.

Motors and inductive loads seem  not to effect these things, they will just run over the back emf of the motors and tell em  what they should be doing....

Your cross over relay will be fine. I can cross from grid to off grid with a 100 amp cross over switch  (DPST) Even at 5kw or more, it seems to take it in it's stride..... does not seem to care what is running at the time.... water pumps, hair driers, bread makers, jugs, whatever.... I don't have to think what is running... it just does it without a sound or hiccup.


.....oztules

[phri]

Anybody tried the newer units with standard lower idle current as source for a grid connected solar inverter?

What is best; using a mppt charger direct from solar cells to batteries, subsequently feed the powerjack or; use a cheap grid connected inverter (2.5 kW) connected to the powerjack and load. Cost will be close mppt charger vs solar inverter.     

[oztules]

I haven't tried those ones personally.. but they should be the same ( all the electronics are, and the filters perform the work the  same as the e cores )

The other question...... Depends on your loads and how they line up with the solar day.

I think the combination of the battery direct and grid tie is the best of both worlds. If your day loads are of some consequence, then the grid tie is the best, as it gives you a very potent daytime inverter.... if the suns out, you get your 2.5kw continuous from the gird tie direct to your loads, and this means you can drive very hefty loads for long periods in the daytime if you so chose.... ie you get the kws of the grid tie and the kws of the inverter, plus the massive surge of the inverter..... bit like running a generator on the expensive brands for extending the power out of the inverter.

I use this function every day for driving the hot water, washing machine etc etc... It means if there is at least a bit of sun, or brightish cloud, the power for the hot water unit is easily supplied from the grid tie, as well as some for charging. The direct battery charging from the "normal arrays" takes care of the batteries 60-80 amps@50-60 volts..... but my system is usually 90% charged and hot water charged ( 4kwh?) by 9.30-10.30am most days at this time of year.... but I have heaps of solar panel... it is the cheapest thing around now days. Recently got 10kw for 5000 dollars....power to burn even when it rains all day.

At this time of year, once the hot water is done, I can run a 1.5kw mono cp1600water pump and pump water all day for the grass areas needing it. The batteries  and inverter do not see these as the grid tie drives them without bothering the inverter with that load.... can run it all day for free.... thats worthwhile.... and still some extra for the batts or other loads as they turn up.

Most days there is at the very least least 30kwh of power not used. If very overcast ( 8/8 all day and double cloud layers), I would need most of this to fill the bank and hot water .... but that s very rare.

So, if you have plenty of panels, then Off-grid tie to them, it is probably more efficient as you can use the power direct..... and if in Aust, a decent grid tie is only 50-100 dollars for 2kw or so ( I bought 10 1.5kw units for $400 and another 12x  1.5kw units for less than 1000 dollars)..... much cheaper than a multi kw mppt direct unit.

i have so much power, I don't bother to mppt my direct charging panels.... as I use low voltage panels ( 60 cells per "24v" panel @ 8amps + ), so a mppt would be marginal  anyway.... and the controller costs virtually nothing to make for a 80-90amp 60v unit.... rather buy more panels than throw money at electronics or tracking arrays..... now days with 50c/watt panels CEC approved, trackers and fancy controllers are a useless impediment to a rock solid system.... something else to go wrong, and less surface area available on a cloudy day... you can't beat surface area when the chips are down..... and when it's sunny .... anything works anyway.

Be aware, you still need to have some way to shut the grid tie down when the batts are over voltage. I don't think the power jack likes voltage much over 62v. ( 48v system)
My experience is that you home  grid voltage will rise as the batteries get fully charged ( within 10%), and so the voltage will rise to 252v or there abouts, and the grid tie will stop anyway....

I have a cut out built in the inverter box that shuts power down to the grid tie if battery voltage exceeds 59v anyway... as well as. Generally, the over voltage grid will shut it off, but sometimes, the battery voltage will turn it off first.... depends on loads , and inputs and SOC of the battery bank... ie if your banging in 100 amps or so, the voltage may rise above 59v, but the grid volts will still be low as the grid tiw is being used for the batteries, not for driving the grid voltage higher.... then the battery voltage cut off works first.



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

[plamen]

Hello from Germany,
I would like to place a 8000W LF power jack inverter on a boat (12V).
I worry about what I have found here concerning the idle current.
Having only basic low-voltage experience, I would not be able to make the changes myself.
Unless, someone has a description how to do it FOR DUMMYS (like me).
Or sell me a ready assembled torroid (or whatever it is...)
And, last but not least, does the unit look like it would withstand salty air for long time?

Thanks for your help in advance,
Plamen

[oztules]

The new ones seem to have the small torroid rings in place now, so thats done.

Sea air is what I have here on the island I live on.... but it is still not a boat.

That said, they are aluminum case, but they do have fan cooling if your going to push it.

So it would require opening up and spraying your favorite waterproofing spray ( conformal coating) for electrical gadgetry in your part of the world ( CRC  or equivalent as a rudimentary  beginning ).

If well sprayed or treated, it should make the distance... this includes terminals, and exposed metal anywhere.

Without conformal coating of some sort, they would not last too long if the fan runs for any extended period, and corrosion everywhere will become apparent.

HF pure sine units are now so cheap from china, it may be worth using a new one of them each season. Corrosion will get them  too if not protected from the damp salty air, although I have seen a lot of electronics last a long time on some boats, but if spray is a possibility... not so much... every boat is different.
The cray boats  and trawlers over here are packed with electronics now days, and the gear seems to last surprisingly well on the bigger boats.

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

[plamen]

Thank you so much for helping me....
I got the user manual .pdf, and it say's the following :
"keep the inverter off when battery is charging..."
Is this true, or only a poor translation?
I would have many 12V DC power sources on the boat : engine alternator, solar, wind, shore power charger, gasoline DC generator.
Does it mean, when the battery bank is under charging from one of these sources, I may not run the inverter?
I wonder, how the inverter will determine if the battery bank is just being charged or not?
And how this will influence the inverter?

Greetings from cold Germany...
Plamen
   

[plamen]

here what the user manual says :

[oztules]

They have run amok with their translation.

The inverter can run over a wide range of voltage, and does not care if it is under charging conditions or not. Mine runs from well below 48v to over 62v range.

The only caution for me is be aware to shut down the inverter when changing from inverter charger to inverter mode.... ie if you are using gen set to drive 240v into the inverter so it will charge 12v battery@70 amps or whatever, remember to turn it off BEFORE disconnecting the 240v source ( motor generator or grid or shore power)

If you just shut down the source, I have found a risk that as it instantly changes to inverter function ( changes frequency from your AC source to the on board 50hz), it can push a new pulse into the transformer that may be out of phase with the magnetics of the core. The torroids are very electrically stiff, and can deliver massive current surge in this circumstance..... they need to reprogram for a soft start with the torroids..... I think it is programmed for the W7 EI transformers, which are very leaky and soft. The fets can bully them, but not the torroids with any reliability.

Mine is on charge all day from solar, and runs all day... so I don't understand what the excerpt you showed means really... would render the unit virtually useless .
Example, I saw 100 amps going into the battery today, and no bother to the inverter... nor should there be.... and there would be switching ripple with that input too, as well as some reverse grid tie backwards through the inverter.

"I wonder, how the inverter will determine if the battery bank is just being charged or not?
And how this will influence the inverter?"

It would know the input voltage was over 12.7v.. so must be charging..... it won't care.... but the nett result is that it is easier for it to sustain the load, as the input voltage being higher than 12v, will allow shorter pulses for the same output voltage, so it will be much easier for it to stop voltage sag, or saturating the transformer with long DC pulses trying to push the voltage up from a lower start point. ( providing voltage and frequency and waveform remain the same you won't saturate a transformer by loading it up or even overloading it... but clipping can I think.)


.........oztules

[plamen]

thanks again...

So do you think this application mode will be OK for my boat :
(I think the manual is calling this the “UPS function”)

1. shore AC power will be permanent connected to the inverter 230V AC input.
If shore power present, the inverter will pass it through to the AC appliances, without using the battery.
Question : will the inverter try to  charge the battery when AC input present??
When no shore AC power present, the inverter will produce 230V from the battery.
2. the inverter will be permanent running in inverter mode / “power save on”
(Not sure about, maybe “power save off” is the better choice ?)
3. The battery will be charged by multiple parallel connected sources (solar, wind, engine alternator etc.) regardless of shore power and inverter status or operation mode
4. When I am not on board, the inverter will be switched off.

Do I overlook something?
Best regards
Plamen