How can I disconnect from utility in event of power grid melt down?

Re: How can I disconnect from utility in event of power grid melt down?

It can be done,, but it is very expensive. Special inverters,, plus a very expensive battery bank (that will sit idle 99.9 % of the time. Your money is generally much better spend buying a good back up generator. (Unless your particular grid connection is really unreliable).

Question is, how many times in the last say 10 years has your grid gone down,, and for how long? How much are you prepared to pay to have the lights on during those times?

Tony

PS Welcome to the forum. There are some very smart folks here who are all too willing to help,,, folks that forgotten more about PV than most of us will ever know.

PPS. the short answer on how to bypass the grid for dummies is,, don't.

T

Re: How can I disconnect from utility in event of power grid melt down?

as to a grid meltdown you are talking a long term outage that you want to prepare for. the generator will work as long as you have gas, but those gas stations will not be pumping gas as they won't have power either so once your supply is done so is the generator power.

what i think could be done is a backups type arrangement so you have some key critical things being power by a sine wave inverter and batteries. the problem here is once the power is gone the countdown on the batteries has started and you don't want to deplete them farther than 50%. what you might do is tap your pv system at a suitable point to feed a high voltage mppt controller that goes to the batteries. this will not power your whole house or the few critical circuits 24/7 either, but may prevent food spoilage if power usage is spaced out. add to that a generator and you could survive fairly well for some time.

for those that would yell about efficiency, the backups would still be maintained by the solar as long as the sun shines. when it doesn't shine the excess that went to the grid is now starting to be used, but it most likely won't take much back from the grid as the float charges would be fairly small.

there are a few high voltage mppt controllers out there, but the only one that is in line as far as costs go is the classic. the inverter on most gt systems can get fed in the area of 300v to 500v from pvs and the classic 250 can go to 250v. this would mean a tap at the point where the pvs total voc is less than 250v would suit fine (for classic 250 model), but be sure the outputted current won't be exceeding the controller's cutoff current after downconverting as it would then be wasted power. the tap can go lower in voltage and if low enough it could fit into another category of classic controller and would gain a tad of current output capability.

this can get complicated to implement, but would be doable if no certification violations would be breached in doing it. one would have to leave the tap disconnected as long as the grid is active and when an outage is present a break in the gt inverter connection might be advisable too as power may come back on in the meantime.

Re: How can I disconnect from utility in event of power grid melt down?

I have to agree with the Generator. I bought one 15 years ago after a couple day power outage. I installed a backfeed Breaker a 240V outside waterproof receptacle. I left the generator in the box and never started it for 9 years. Then we had a Ice storm that took down the Power lines. I got out my untested Generator out, filled it with gas and it started on the first pull. I cut the main breaker and plugged up my adapter cord and plugged the generator in and after qualifying the voltage, I energized the backfeed breaker and had all the power I needed. I had enough Gas in my cars and trucks Plus 10 gal in cans to keep it going for 5 days. I didn't run it 24/7 and never planned to, I'd run it for about a hour every 2-3 hours.

When I de-engerized it, I drained the tank, lines, took the carb apart and removed all the gas completely , blew it all out with air. Pulled the plug and put a teaspoon oil in the cylinder and turned it over changed the oil and re-filled it.


Total cost= $500 at the most in 15 years for a 5000w no-name with a B&S engine and the receptacle and cord.

Re: How can I disconnect from utility in event of power grid melt down?

Bill. I think with the gasoline now having alchohol in it I wouldn,t want to keep the gas over 3 or 4 months. Tell you why. My brother has his johnsereds chainsaw burn a piston. He traded it in on a new one and it burned a piston within a couple months. The company did replace the piston and cylynder ubder warranty but is blameing the gasoline for the meltdowns. I have a jonsereds chainsar that I used the gas left over from winter wood cutting in my huskvarna weed eater. It melted down too and the dealer blamed it on the gas. There are lots of sawmills in my area and there is a gas station about 10 miles from me that sells gas that he claims is alchohol free. A lot of the chainsaw users get thier gasoline there. Most high quality chainsaws run around 12,000 to 14,000 rpm. Don,t know if that is the reason the reason for the meltdowns. My huskvarna weed eater runs high rpm too. Maybe the little honda generators can take the low quality gas as they probably run lower RPm. :Dsolarvic:D

Re: How can I disconnect from utility in event of power grid melt down?

I seem to recall that premium gas has no methanol in it's formulation. I use it in any small engines, chainsaws, trimmers etc. My Husqvarna chainsaw manual calls for it's use, some others don't (Echo).

Ralph

Re: How can I disconnect from utility in event of power grid melt down?

I recommend a small battery backed system to complement your GT solar system. SMA has the Sunny Island system that can keep your GT inverter running but is maybe $7,500 installed. My solution is the Xantrex PowerHub 1800 system ($2000 incl. batteries and CC) that can keep your critical loads (fridge, lights, computer) alive during an outage. Connect it to your GT array either with a high-voltage charge controller ($1000) or rewire the array so that during an outage you can flip a switch and reroute a lower voltage to a regular charge controller to the PowerHub and keep it going indefinitely.

Re: How can I disconnect from utility in event of power grid melt down?

I also have a 6K system installed, and was thinking of this.
Going to check on a few panels and another inverter to back feed my current inveter and make it think the utility is up if the utility goes down.
From what my installer told me this will work and be up to code.
Now I do have a generator interface at my meter that allows me to run my generator without exporting any power to the grid.
Not unusual to have minor outages here and week or longer outages can happen.

Re: How can I disconnect from utility in event of power grid melt down?

erne wrote: »

if you go to the airport and by aviation gas you wont have the problem of alcohol and it will store for 6 years without any additives. (cost more though)

Or you can get a diesel generator.
This fall I finished off a barrel of diesel I had filled and left sitting since 2006. My truck ran great off that pre-ULSD fuel.

Re: How can I disconnect from utility in event of power grid melt down?

techntrek said:
"You try to run leaded fuel in an engine designed for unleaded fuel and eventually you'll have problems with the valves." I believe this is not accurate. The reverse is true, and was a problem when unleaded fuels were first introduced. It was determined that the lead deposits had been acting like a dry lubricant on the valve seats, and without the lead in the gasoline, the valve seats showed excess wear, requiring redesign with harder seat materials. (Remember that graphite, a form of lead, is used as a lock lubricant.) Engines designed for unleaded fuel should not have valve problems when operated with leaded fuel.

Lead deposits will not "fry" a catalytic converter like the overheating due to a misfiring spark plug that will allow unburned fuel and air to enter the catalyst. However, lead will deposit in the converter and deactivate it, making it useless, but not due to overheating. As techntrek said, lead is certainly bad for the environment.

It is used in Avgas to achieve very high octane numbers; 100 octane is the standard high-octane aviation gasoline, while high-octane automotive fuels are typically around 93 ((R+M)/2). Since those engines do not have catalysts, there is not catalyst damage. Vapor lock has to do with the volatility (vapor pressure) of the gasoline and the fuel system design, and I don't think that there is any relationship to lead additives.

The lead could make deposits on the piston and head faster than unleaded fuels, but this would be a very long-term issue. To keep lead out of the environment, it seems like a better idea to use fuel stabilizers and occasionally refresh the gasoline by using it in a car, but NOT if it has lead in it since that would ruin the catalyst.

Re: How can I disconnect from utility in event of power grid melt down?

Lee Dodge wrote: »

It was determined that the lead deposits had been acting like a dry lubricant on the valve seats, and without the lead in the gasoline, the valve seats showed excess wear, requiring redesign with harder seat materials. (Remember that graphite, a form of lead, is used as a lock lubricant.)

Graphite is NOT lead, it is a form of carbon. Perhaps the confusion comes from the so-called 'lead pencils' which may be graphite but certainly are NOT lead.
--vtMaps

Re: How can I disconnect from utility in event of power grid melt down?

I have run 100LL AVGAS in my car plenty of times.
It still runs fine.

My car does not have a catalytic converter.