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Electrical/Electronic equipment => Wind, Solar and Hydro => Topic started by: cujet on April 19, 2012, 05:13:11 PM

Title: El-cheapo grid tie inverter?
Post by: cujet on April 19, 2012, 05:13:11 PM
Has anybody purchased an imported 1200W grid tie inverter.

I have a number of solar panels that I'd like to hook to my house and "extract" the energy from. In other words, it seems silly to have them not doing anything useful on a normal day.

The latest generation of Chinese or imported 120V grid tie inverters are cheap enough to be tempting (at around $250 street price) One brand I see is "power jack"

Title: Re: El-cheapo grid tie inverter?
Post by: bschwartz on April 19, 2012, 09:35:14 PM
before going with my outback system, I did try one of the cheap 300w units.  Not UL listed, but it did work.  Just hook up the panels, and plug it in.  I was able to watch my meter turn backwards.  Important note, I have an old spinny meter.  I can't imaging any electric company being OK with these, but who is really gonna check?
Title: Re: El-cheapo grid tie inverter?
Post by: mike90045 on April 20, 2012, 08:11:23 AM
I'd watch the efficiency of the thing, I've heard of the cheap imports, cranking out 50-70% of the input.  If the critter heats up a lot, it's going to die soon.   The quality Enphase inverters are in the +96% ballpark.
Title: Re: El-cheapo grid tie inverter?
Post by: LowGear on April 20, 2012, 02:10:19 PM
A couple of things to keep in mind.

1.)  It only takes one chicken livered insurance adjuster to ruin your whole day.  UL tested?  Listed?  See 3.

2.)  Enphase is a great modular approach.  SMA's answer is going to be out pretty soon as well.

3.)  Remember, if it isn't permitted you'll probably be pulling it out when you move.

Has anyone heard of window screens that are also PV cells / panels?

Casey

Title: Re: El-cheapo grid tie inverter?
Post by: cognos on April 21, 2012, 09:11:08 AM
A recent occurrence hammered home the UL/CSA.Insurance issue for me locally. Canad, that is. Your situation may be markedly different.

Nothing to do with inverters, though.

A good friend of mine is an insurance broker.

Two weeks ago, a mutual friend of ours had a serious house fire. Cause currently undetermined, started in the basement/workshop/rec room area.
Lives outside of town, nobody home, fire was pretty well established before anyone noticed and called it in.
Lots of damage, first floor caved into the basement, structurally damaged to the point that it was likely to be written off.

House was only ten years old or so, well-known local builder, all permits completed and on file. Had premium insurance. No problem, right?  

Wrong...

A few years ago, the couple had decided to upgrade their kitchen appliances, and had gone to the US (we're only about 60 miles from Buffalo, cross-border shopping for major appliances is quite common here) and purchased a built-in gas cooktop for a new kitchen island, along with fridge and dishwasher. Much less expensive than the ones they were looking at locally. "Imported" the stuff in the back of their truck. Non-certified stuff is not supposed to be imported, but it happens all the time.
Installed it themselves, even had it hooked up by a licensed contractor who tagged the gas line properly...

Insurance company's investigator had one look at that cooktop in the remains of the house, and cancelled the replacement value policy. Not certified for use in Canada. Small print in the policy allows this in the case of non-certified major appliances. Most gas appliances for sale in the US aren't, apparently. Even though it "most likely" had nothing to do with the fire.
Couple will only get something like $15,000 for some content coverage. This on a house that will easily cost $300,000 to replace.
There is an appeal process, which is in progress, so they may end up with something. But what a pain while it works out...

Made me go check my permits at the registry office... and have a look for the CSA stickers on my gas appliances...

Everybody thinks insurance is to pay you when something bad happens. In a tight economy, their business models switch to determining new and more creative ways to not pay you...
Title: Re: El-cheapo grid tie inverter?
Post by: LowGear on April 21, 2012, 01:01:26 PM
QuoteEverybody thinks insurance is to pay you when something bad happens. In a tight economy, their business models switch to determining new and more creative ways to not pay you...

This has been the business model of insurance companies since before Loyds of London became a household phrase.  If you don't understand the way the system works then you probably don't visit Hawaii for Christmas being transported by your private Jet.

Casey

Title: Re: El-cheapo grid tie inverter?
Post by: cujet on April 21, 2012, 03:44:11 PM
In my case, nothing will be installed. It's currently 4ea. 170 watt panels in a portable frame. The hookup would simply be an extension cord run to an exterior outlet.

Yes, technically, this is "unusual" because I'm feeding in power to an unused 20A circuit, rather than drawing it out. Not sure the wires know the difference. Certainly, the peak of 720W worth of panels will be down to a much lower number after inverter and wiring losses.

Enphase is many, many times the price. My thoughts were simply that I don't mind spending a small sum of money for a grid tie inverter, to make my panels work daily. Not for "return on investment" or any other such thought.

I have no pressing need for a grid tie system. Just thought it would be neat.
Title: Re: El-cheapo grid tie inverter?
Post by: cujet on April 21, 2012, 03:54:16 PM
Just an FYI,

Insurance is "betting against yourself". I'm not an adrenaline junkie risk taker, but I am a pilot, motorcyclist, mechanic, swimmer, bicyclist. I don't insure everything I own against loss. Yes, my house is covered, and that's for the bank's risk, not mine.

I don't cover my personal aircraft against loss. It's outside an average of 20 days per year, otherwise it's in a very tough hangar. $2700/20=$135 per day outside. That's stupid money. Put another way, in the 5= years I've owned it, I've cut over $16,000 from my expenses. And, in general, I tie it down and cover it when "on the road". Or, ask line service to put it in the hangar if weather comes. Yes, I could "lose it all". I'm betting I won't. And, if it's simply damaged, not destroyed, I'll fix it.

Bottom line, I'm willing to accept certain risks, as long as I clearly understand what they are. Putting 550W through an extension cord to "grid tie" is probably not a huge risk, but I'm willing to learn.
Title: Re: El-cheapo grid tie inverter?
Post by: LowGear on April 21, 2012, 04:40:40 PM
Makes sense to me.  I can' or won't count the dollars I've helped out with the margin insurance enjoy.  I simply haven't your confidence.

I also agree with the extension cable assessment.

Casey
Title: Re: El-cheapo grid tie inverter?
Post by: vdubnut62 on April 21, 2012, 05:28:23 PM
Casey, the NEW DIGITAL electric meter that the Upper Cumberland Electric District just installed on my house is NOT UL listed or approved.
I'm not kidding.
Ron.
Title: Re: El-cheapo grid tie inverter?
Post by: mike90045 on April 21, 2012, 10:45:32 PM
Quote from: vdubnut62 on April 21, 2012, 05:28:23 PM
Casey, the NEW DIGITAL electric meter that the Upper Cumberland Electric District just installed on my house is NOT UL listed or approved.
I'm not kidding.
Ron.

They are in bed with the insurance company !
Title: Re: El-cheapo grid tie inverter?
Post by: LowGear on April 22, 2012, 03:51:55 AM
Hmmmmmmm.  So if my house burns then I can sue the utility for knowingly putting substandard equipment on my house.  Has anyone asked the electrical permit folks if its legal?  OK!  Give them a call when you stop laughing.

Casey
Title: Re: El-cheapo grid tie inverter?
Post by: mike90045 on April 22, 2012, 07:24:23 AM
It's the old "Heads I win, Tails you loose" story. 
Title: Re: El-cheapo grid tie inverter?
Post by: cujet on April 24, 2012, 03:50:20 PM
I've been watching the "power jack" you tube video's.

I'm not sure what to think. One guy is getting rated power, with great efficiency out of one faulty and one good set of PJ inverters.

Some of the other guys have had bad luck. But, the unit I'm looking at is not well represented on YT. It's the newer model, with higher voltage input.

I'm ok with spending $225-250, for a real world 500-600W output. I'm not OK with spending $1300 for a "good one". That's stupid money for such little power.
Title: Re: El-cheapo grid tie inverter?
Post by: LowGear on April 25, 2012, 12:13:33 AM
I think the Enphase are closer to $175 now and are rated at something like 230 watts.  At 44 cents a KWH its going to take around 1600 hours to break even at full rated power.  (230 watts means almost a KW ever 4 hours.  So 400 hours would get you $44 and 4 of those would get you $176.)  And most of us know 50 weeks at 40 hours a week comes up with 2000 hours.

It's getting cheaper every year.