Power Jack grid tie inverters

rama

Hi there,
I've been hearing a lot about these Power Jack grid tie inverters that are sold on eBay. It's really strange to me to see their so-called "grid tied" is defined by simply plugging a typical AC power cord into your household AC socket, and somehow this will feed electricity back to the grid??

I did some research on eBay and saw that these GT inverters are not UL certified either... not to mention they are quite cheap, so I have doubts whether it'll even work. Any thoughts?

Here are some examples-
http://cgi.ebay.com/NEW-300-WATT-GRID-TIE-INVERTER-14-28VDC-110-VAC-/220745392045?pt=LH_DefaultDomain_0&hash=item3365735fad
http://cgi.ebay.com/350W-Grid-Tie-Inverter-Solar-Panel-14V-28V-DC-CA-/280656205465?pt=LH_DefaultDomain_2&hash=item415869d699
http://cgi.ebay.com/600W-GRID-TIE-INVERTER-12V-DC-110V-AC-INVERTER-600W-/250801401322?pt=LH_DefaultDomain_0&hash=item3a64edadea

Thanks,
-Rama

niel

Re: Power Jack grid tie inverters

until the federal government for this country, or any other country for that matter, makes it illegal for these inverters to be sold then they are free to sell to an unsuspecting public that it is illegal for them to use them as they are meant to be used. to sum this up is that it is not illegal to sell or own such inverters, but to use it as it is intended is. that is because they can bypass safety factors and other safety parameters that can make these gt inverters dangerous to use by simply plugging them into the wall.

BB.

Re: Power Jack grid tie inverters

Oh... They can work. They may even work well...

Just not safe per code.

-Bill

dgsloan

Re: Power Jack grid tie inverters

You will find that in the end they are not as cheap as you think. By the time you buy all the connectors and remote breakers and spare parts etc you will find that it is actually much cheaper to buy an enphase converter (for comparison only) - If you really want to plug it in = even though it is not safe - take an enphase and plug it into a dryer or stove outlet - I have heard of this being done to test out the electronics until a proper underground cable was installed. The other problem with the Power Jack is that they fail quite regularily. If you search on the internet you will find lots of different fixes (failures) and even eBay sites that sell parts for them. Their rating is way over specified - a 300watt inverter will only handle 175watts continuous.

oil pan 4

Re: Power Jack grid tie inverters

Saying they work well is giving them way too much credit.
They like to over heat and shut down. They are noisy.
In factory configuration a 300w unit might be able to run at 100 watts for extended time with out problem.
There are not really any saftys on them.
To make them use able you have to install a much larger fan, a breaker or fuse on the high voltage side, a push button power isolation relay and an over volt disconnect to get you started.
Unless you have a collection of these items just sitting around, you might want to go with the higher end inverters.

SteveK

Re: Power Jack grid tie inverters

Yep they work but not very well. A side by side with the SUN-500g model of these gorilla GTI's and a set of Enphase's show 20% production gain from the Enphases. This is using the best of the breed (SUN) and not Power Jack too. PJ is the worst of them.

We used a pair of Sun's for about a month last year. They do work but not very well. Had a hard time leaving the home in fear of fire. The Sun's will put out 72% efficiency but the power factor is pretty low ~ .7 until they are well loaded.

Still have the pair, never wil use them again.

oil pan 4

Re: Power Jack grid tie inverters

That is why to put them out side, away from your house.

solar_dave

Re: Power Jack grid tie inverters

oil pan 4 wrote: »

That is why to put them out side, away from your house.

In the garbage can!

russ

Re: Power Jack grid tie inverters

Ask the neighbor - maybe he will let you install them in his garage. Might not be too happy if it burns down but then---

silvertop

Re: Power Jack grid tie inverters

I dinked with a Power Jack, but to be honest when I have excess power ,Ill just run my inverter for my refrig. I dont think I would leave the house with the Power jack running for fear of fire....

SteveK

Re: Power Jack grid tie inverters

Heh, I like it.

So, talk the neighbors into letting me install them in the garbage pail in their garage then? Well, it beats the pants off of selling them to some unsuspecting ebayer and wondering if I burned their house down. This way I'll know for sure if I did.....

XRinger

Re: Power Jack grid tie inverters

The outside shell seems to be constructed much like the 12v automotive type
inverters that have been around for many years. It's 95% enclosed in aluminum.
Not like the PJs are made out of pine wood, soaked in fuel oil..

What's going to burn with any large amount of fire??
1200w PJ GTI


I've heard the FETs burn out and you might get a blown fuse,
but these PJs look like they are made like a lot of other inverters..

2.5kw (5kw peak) Stackable 48vdc - 120vac inverter.

I think this one got up to about 72F when tested with a 1500w space heater.

All of four Chinese inverters I've looked at, (I have 2 more smaller 12v units)
all seem to have fuses on the DC input and AC output.

I've seen boards in PCs and PC power supplies go bad, but I've never
actually seen any make smoke and flames for more than a few seconds..

solar_dave

Re: Power Jack grid tie inverters

I don't think it was an issue with the unit burning but using a plug in to existing 15 AMP house circuit and overloading the line between the PJ and the circuit break in the panel.

SteveK

Re: Power Jack grid tie inverters

solar_dave wrote: »

I don't think it was an issue with the unit burning but using a plug in to existing 15 AMP house circuit and overloading the line between the PJ and the circuit break in the panel.

That and, insurance problems, no UL, illegal to use, being charged for what you produce just to name a few.

I'd go on a limb and say that anyone installing them in their home is being a tad bit "shady" and underground about things. You know...like that rush that came from smoking in the boysroom in high school. That's how I felt anyways....

XRinger

Re: Power Jack grid tie inverters

solar_dave wrote: »

I don't think it was an issue with the unit burning but using a plug in to existing 15 AMP house circuit and overloading the line between the PJ and the circuit break in the panel.

Humm, I guess if you exceeded the rating and the safety margin of your home's branch circuit.
15a * 120v = 1800w.. I guess mine is okay, since it's 1200w max. :roll:

I saw a Youtube of a guy (I think in Europe) using a bunch of PJs.
He had one connected to each of his panels. Maybe 15 or 20 panels.?.
He was getting pretty good results out of his system.
I'll bet he didn't have them all plugged into the same branch circuit.

The reason I got this 1200w PJ was to see if I could connect it to
a PWM or pure-sine-wave inverter and get it to sync up and work.
Wanted to see if it could be done. I was also wondering if it would
be possible to use the 1200w PJ with my gasoline generator.

If the PJ & 500w-800w of PV contributed power to the load connected
to the generator, perhaps the PV could help save gasoline during a long power failure..?.
Maybe the PJ would allow the generator to run at idle,
while the PV fed the basic house 300-600w load.?.

XRinger

Re: Power Jack grid tie inverters

SteveK wrote: »

That and, insurance problems, no UL, illegal to use, being charged for what you produce just to name a few.

I'd go on a limb and say that anyone installing them in their home is being a tad bit "shady" and underground about things. You know...like that rush that came from smoking in the boysroom in high school. That's how I felt anyways....

I think that a lot of the guys who buy PJs are hackers or Hams etc..
It's just another toy. I would not use one because of the insurance issue.
But, I will play around with mine outdoors.. (someday).
Maybe like this.. http://youtu.be/ESvL-Nc-pRk

SteveK

Re: Power Jack grid tie inverters

Xringer I've recently begun remodeling our 60 year old and have pulled the covers off the outlets in several rooms. What I found in there was more belly button lint and dust that appeared to be a great tinder box. Upon further inspection I found that the wire nut juntions (untaped) contained so much oxidation it was hard to tell if it would even conduct.

I looked into this and found this was a source of ignition in many house fires. I would imagine that the increased resistance at that point would create heat and sparks that Bear Grylls would be proud of.

This in an otherwise fully code-compliant home.

XRinger

Re: Power Jack grid tie inverters

SteveK wrote: »

Xringer I've recently begun remodeling our 60 year old and have pulled the covers off the outlets in several rooms. What I found in there was more belly button lint and dust that appeared to be a great tinder box. Upon further inspection I found that the wire nut junctions (untaped) contained so much oxidation it was hard to tell if it would even conduct.

I looked into this and found this was a source of ignition in many house fires. I would imagine that the increased resistance at that point would create heat and sparks that Bear Grylls would be proud of.

This in an otherwise fully code-compliant home.

My home was assembled in 1956, so I've replaced all the ungrounded outlets over the years.
And we had the service upgraded and added a breaker box (glass fuses gone! :grr )

The existing wiring still looks good. No squirrels have been at it yet..
All the runs seem to be end-to-end without any patches.
They used the outlet screws to daisy-chain to the next connection.
I don't know if they used any wire nuts. I've added some over the years.

Here in Woburn, the inspectors allows requesting homeowners to do their own work,
if it's not too complicated. (like changing the cable from the meter etc).
So far, all my work has passed inspection.

The cables in the attic are exposed to a lot of heat during the summer.
That's a bit worrisome. And now, they are buried deep under FG insulation.
I just hope the rodents don't dig them up and find them tasty..
I have fire sensors up there. I hope they never get used..

BB.

Re: Power Jack grid tie inverters

And then there where the aluminum wired homes and buildings of the late 60's and early 70's...

About the only practical repair method I have seen is the Alumiconn connector... Basically a small bus bar setup to connect both aluminum and copper wiring together (hopefully) safely.

They probably are even better than wire nuts for copper to copper connections--but there is only one size and they are not cheap.

-Bill

SteveK

Re: Power Jack grid tie inverters

Seems once you start digging it is to no end. Every outlet box has a length of wire added to extend from a mass of wires in a wire nut. Everything is highly daisy chained for lack of a better term. The only way to connect the outlet itself is to add a single conductor in order to keep the other circuits complete.

So when I looked at this I couldn't help but think fire hazard. By adding the ChiTie inverter I felt it to be even more dangerous unless you ran a direct line from the breaker panel dedicated to it. Just the opposite intention of the unit itself. They claim plug and play, I see it as plug and possibly pay for it in loss of property. Or hire an electrician in many cases to provide for it.

XRinger

Re: Power Jack grid tie inverters

I'm running my PC and a few other loads off an inverter (MSW) right now,



I'm trying to do it as safely as possible. Just about everything is UL
approved parts and should be to code.. (or close )..

That little black box on the left side of the pic is a TED transmitter.
It's UL listed, but it's little power supply is likely more of a risk
than anything else I've got hanging off my wiring..

solar_dave

Re: Power Jack grid tie inverters

I think this has been covered pretty extensively before. if you place six 5 amp load on a #14 gauge line which is electrical code for 15 amps it is possible the breaker in the power panel will not trip if a plug in Inverter rated at 15 amps is added at the end of the line. This is way over the capacity of a 15 amp line, yet the 15 amp breaker in the panel will not trip because the source of power is from 2 locations, 15 amps from the breaker and 15 amps from the inverter. The aggregate power sources are well over the line rating.

This is certainly a huge fire risk on the 14 gauge wire, and I can't see how any of these plug in inverters would pass UL listings.

XRinger

Re: Power Jack grid tie inverters

solar_dave wrote: »

I think this has been covered pretty extensively before. if you place six 5 amp load on a #14 gauge line which is electrical code for 15 amps it is possible the breaker in the power panel will not trip if a plug in Inverter rated at 15 amps is added at the end of the line. This is way over the capacity of a 15 amp line, yet the 15 amp breaker in the panel will not trip because the source of power is from 2 locations, 15 amps from the breaker and 15 amps from the inverter. The aggregate power sources are well over the line rating.

This is certainly a huge fire risk on the 14 gauge wire, and I can't see how any of these plug in inverters would pass UL listings.

Wouldn't that 3.6kw (30A) load (six 5A loads) trip the 15A breaker the second the clouds showed up?

I can see the danger you are pointing out. I can imagine there are people
out there, that would plug in a dozen 300w PJs on extension cords,
and then start adding waffle irons.

You are right, there is no way this type of device is ever going to be deemed safe.


A smarter design would be an island inverter that didn't put anything on the grid,
but could switch the load back to the grid. (when it got dark out).
A bit like the UPS Power Backup units people use on their PCs, but with solar PV charging the batteries.


Have to make it look cute.. And smaller than this thing! :roll:
Or this one.. http://i46.photobucket.com/albums/f147/Xringer/Solar/z203.jpg

TheBackRoads

Re: Power Jack grid tie inverters

This guy likes his Power Jacks!


http://www.youtube.com/watch?v=t3Yi5tohQfU&NR=1

hehehe

JP

solar_dave

Re: Power Jack grid tie inverters

scary, he doesn't show the AC side of all that. Hope he doesn't live next to me!

XRinger

Re: Power Jack grid tie inverters

He's in the UK..

http://www.youtube.com/user/1R7E7B

TheBackRoads

Re: Power Jack grid tie inverters

I should have known from the music in the videos



TBR

XRinger

Re: Power Jack grid tie inverters

TheBackRoads wrote: »

I should have known from the music in the videos



TBR

More PJs.. Check out this music..

http://youtu.be/f2BTNJQNUnk

Name that country!

solar_dave

Re: Power Jack grid tie inverters

one big plug strip????? oh so scary! 1.4Kw into that plug strip has to be not up to even the local code, but who knows about those overseas folks.

XRinger

Re: Power Jack grid tie inverters

I'm thinking that's a pretty large strip, so it might actually be rated for higher power, then our USA strips are rated for (1800w?).

The switching and monitoring work isn't bad. I'll bet these guys are running
a dedicated 220ac line into their home's breaker panels..
A line with no load outlets on it.

stephendv

Re: Power Jack grid tie inverters

Most multi-plug strips are 13A, so at 230V that's 2990W.