Enphase M250 Specs for off-grid, tips and tricks and results

[inetdog]

... Most people with grid power do not need to go Off-grid capable immediately, it's better to get your feet wet and pay off phases 1-3.

Pay off phases 1-3 so that you can afford to pay more for off grid energy than for grid energy for the life of the system?
Most people (all but a very few) with grid power have no reason to go off grid at current power and battery prices.

[SunEagle]

No, using microinverters makes the system more complicated, and more prone to failure. The grid can be faked for any grid-tie inverter equally well, and the rest of the islanded system will look the same. It is much easier to balance the generation with the demand when it is managed through a single point (MPPT controller) than when it is distributed and communication with each device needs to occur. Please see ButchDeal's comments in this thread. With some re-programming it might be possible to make microinverters support islanding at least as well as SolarEdge does, but as they exist right now, they are probably the worst choice for building a hybrid system.

Ok. My mistake and lack of knowledge of a hybrid inverter system.

I would never consider or support installing hardware to "fake" a grid tie so the micro inverters would work in "island mode". I just thought if you install a legal micro inverter "grid tie" system and then choose to expand you could then add a charging system.

My thoughts were that while a micro inverter system is more expensive and has a higher chance of point failure then a string inverter it would be easy to just add the DC charging hybrid hardware, as opposed with the need to first remove the existing string inverter with a new hybrid string inverter.

[solarddy]

testing testing can you hear me in the back?

Expensive to go off-grid with Micro's, true. String better for residential grid tie, False. The sun not coming out for weeks? Maybe in northern latitudes. However if below/south of Dallas Tx., @ 25' x 40' squared there is enough power to run over 7KW of micro-inverters, which can have all additional non-used A.C. power dumped to a 240VAC or direct from panel PWM or MPPT battery charge controller. True (SolarEagle), Cloudy conditions cut power by a large margin, True. MPPT charge controllers help this a bit (by 30% online sources), so do large capacitors on the D.C. output side of a solar panel, (40VDC caps "surge 50VDC", coupled "parallel" to the panel output for micros on standard 300 watt solar panel + to positive, - to negative like paralleling batteries) the caps turn on the micros under very limited trickle lighting adding about 300+Kwh/mo more under test conditions from only 5. Micro-inverters help with that by adding many separate points of small scale D.C. to A.C. inversion. A single point of capacitors on a 500-1000VDC bus would be cost prohibitive to say the least.

Maybe you should look into micros boosted with trickle-charged caps, they get full of this thing called voltage, then the micros turn on, then the caps discharge based upon load demand, a lot slower than I thought they would have. I think most of you are ok people, just misinformed on what is best, (electro-spun carbon nano-tube mats vs. Batteries of any type) I'm here to help you understand more complex solar systems that are less limited than you might be used to.

Gas backup... hmmm I just sold my gas generator 6.5KW that I've owned for over 5 years and never turned on for emergency power once. I'd say it loses to micro-inverter phase lock grid tied solar which keeps my Air Conditioner, refrigerator, computer and all other electrical things running all day, every day. (without batteries) Phase 4 will bring a battery bank as my system grows to include emergency off-grid.

When Enphase (or some Chinese company) adds the islanding switch- all bets are off, micro-inverters rule. A completely parallel micro-power grid is much better than a SPOF, and when the micro-inverter manufacturers do it, all others will become obsolete overnight. They would need to site reference to parallel capable grid-tie/offgrid inverters such as the Magnasine for IEEE approval in a US courtroom, using the required cut-off Disconnect switch that cuts off the grid in case of utility grid failure, but allows for remote islanding by user manual request by them pushing the islanding button. I've seen plenty of RV's that have an anti-grid-tie switch installed on Youtube when using Inverter power from batteries remotely and not wanting to back-feed the grid with MSW inverters that are not compatible with IEEE grid-tie standards.

Micro-inverter arrays are snap together, like super simple, anyone who can snap together legos could do it, quit lying saying they are more complex.. if 2 more snap together connections x # of micros is too difficult... I wonder about people that post such things.

Sam Keninson once said: "I know the cure for hunger in Africa, move the people out of the Desert where there is no food, to where the food is." I agree. So if you are having trouble making your solar system work, I suggest moving to where the sun shines to an amount that makes your solar system actually worth owning, because every day the sun comes out, somewhere. I did. you can too.

[lkruper]

Expensive to go off-grid with Micro's, true. String better for residential grid tie, False. The sun not coming out for weeks? Maybe in northern latitudes. However if below/south of Dallas Tx., @ 25' x 40' squared there is enough power ...

Sam Keninson once said: "I know the cure for hunger in Africa, move the people out of the Desert where there is no food, to where the food is." I agree. So if you are having trouble making your solar system work, I suggest moving to where the sun shines to an amount that makes your solar system actually worth owning, because every day the sun comes out, somewhere. I did. you can too.

So then, you are of the opinion that in most of the United States and all of Canada there is a problem with weather interrupting solar gain for extended periods?

Perhaps you should move to a country where the sun never stops shining and address your comments to them

[ButchDeal]

Gas backup... hmmm I just sold my gas generator 6.5KW that I've owned for over 5 years and never turned on for emergency power once. I'd say it loses to micro-inverter phase lock grid tied solar which keeps my Air Conditioner, refrigerator, computer and all other electrical things running all day, every day. (without batteries) Phase 4 will bring a battery bank as my system grows to include emergency off-grid.

Micro-inverter arrays are snap together, like super simple, anyone who can snap together legos could do it, quit lying saying they are more complex.. if 2 more snap together connections x # of micros is too difficult...

Sam Keninson once said: "I know the cure for hunger in Africa, move the people out of the Desert where there is no food, to where the food is." I agree. So if you are having trouble making your solar system work, I suggest moving to where the sun shines to an amount that makes your solar system actually worth owning, because every day the sun comes out, somewhere. I did. you can too.

So you only have a grid tie micro system with no battery and are comparing it to an off grid system with battery and generator...
yes grid tie micros are pretty easy though not as simple as legos, BUT have absolutely no backup capability.

What everyone here (including you) is talking about is a system that you can use RIGHT NOW off grid called AC coupling. It uses a second inverter (like you keep mentioning Magnasine) and batteries to allow ANY (yes including micros) GRID Tie system to work off grid. This is a pretty complex install and the batteries and dual inverter system has a lot of configuration and sizing to get right.

Further you suggestion that everyone move to the desert so they can have more sun and not have to worry about cloudy days in temperate climates in the US seems at best ridiculous. A suggestion of Dallas TX seems just as ludicrous , a quick search of pvoutput shows this site just north of Dallas showing clear weather issues on 10/22- 10/25 http://pvoutput.org/list.jsp?p=0&id=...=29366&v=3&s=1 .

[solarddy]

So you only have a grid tie micro system with no battery and are comparing it to an off grid system with battery and generator...
yes grid tie micros are pretty easy though not as simple as legos, BUT have absolutely no backup capability.

What everyone here (including you) is talking about is a system that you can use RIGHT NOW off grid called AC coupling. It uses a second inverter (like you keep mentioning Magnasine) and batteries to allow ANY (yes including micros) GRID Tie system to work off grid. This is a pretty complex install and the batteries and dual inverter system has a lot of configuration and sizing to get right.

Further you suggestion that everyone move to the desert so they can have more sun and not have to worry about cloudy days in temperate climates in the US seems at best ridiculous. A suggestion of Dallas TX seems just as ludicrous , a quick search of pvoutput shows this site just north of Dallas showing clear weather issues on 10/22- 10/25 http://pvoutput.org/list.jsp?p=0&id=...=29366&v=3&s=1 .

Bad press? I wouldn't put too much stock in that article, I spent years in that area, it is so bright you gotta wear shades! South of that line I have been to most USA places, and they are full of sunlight, every day. It may be time to just get serious and move your solar to somewhere it will work. The sun is so hot and so every-day bright the grass is all dead by the end of spring.

mmmm stackable magnasines that would be nice, maybe a $10K PACE loan? 16KW cap sounds about right and with 4 parallel inverters with batteries for the nighttime I think it will last a while too. My favorite battery is: Telcomm batteries! I bet you thought I was gonna say Walmart! http://www.northstarbattery.com/batt...opzv/index.php ooo they are expensive but with a 20 year lifespan and up to 3000Ah wow.

[lkruper]

Bad press? I wouldn't put too much stock in that article, I spent years in that area, it is so bright you gotta wear shades! South of that line I have been to most USA places, and they are full of sunlight, every day. It may be time to just get serious and move your solar to somewhere it will work. The sun is so hot and so every-day bright the grass is all dead by the end of spring.

mmmm stackable magnasines that would be nice, maybe a $10K PACE loan? 16KW cap sounds about right and with 4 parallel inverters with batteries for the nighttime I think it will last a while too. My favorite battery is: Telcomm batteries! I bet you thought I was gonna say Walmart! http://www.northstarbattery.com/batt...opzv/index.php ooo they are expensive but with a 20 year lifespan and up to 3000Ah wow.

That's a great idea. Everybody north of Dallas should move below that line. Perhaps we can swap all that land in the US with Mexico.

[ButchDeal]

Bad press? I wouldn't put too much stock in that article, I spent years in that area, it is so bright you gotta wear shades! South of that line I have been to most USA places, and they are full of sunlight, every day. It may be time to just get serious and move your solar to somewhere it will work. The sun is so hot and so every-day bright the grass is all dead by the end of spring.

mmmm stackable magnasines that would be nice, maybe a $10K PACE loan? 16KW cap sounds about right and with 4 parallel inverters with batteries for the nighttime I think it will last a while too. My favorite battery is: Telcomm batteries! I bet you thought I was gonna say Walmart! http://www.northstarbattery.com/batt...opzv/index.php ooo they are expensive but with a 20 year lifespan and up to 3000Ah wow.

WTFAYTA? What article? I included a live link to an ACTUAL SOLAR INSTALL, with live data you can look at.

All you seem to talk about is fairy tales and magic dust that "might some day exist". Build your off grid battery-less micro PV system, hook it up to pvoutput. We would love to see the results (when you have some).

[J.P.M.]

That's a great idea. Everybody north of Dallas should move below that line. Perhaps we can swap all that land in the US with Mexico.

I once suggested the U.S. buy Baja from Mexico, cover it with PV and use the power to desalinate sea H2O. Results: Drought problems in the SW U.S. become a thing of the past, the desert blooms, and anyplace in the remaining U.S. with lousy winters empties out beaucoup pronto.

[inetdog]

My favorite battery is: Telcomm batteries! I bet you thought I was gonna say Walmart! http://www.northstarbattery.com/batt...opzv/index.php ooo they are expensive but with a 20 year lifespan and up to 3000Ah wow.

That website seems to be down at the moment (or forever?).
But the Google cache shows that these are, as stated, telecom batteries. They are designed primarily for emergency power and so are engineered for long life in float service with minimal maintenance requirements. They can also deliver a very high current for their AH rating.
Sunking has talked about this kind of battery in the past, they are nothing new.
Their cycle life in a a repeated discharge situation is low (1500 cycles would be about 4 years) and their tolerance for spending a long time at a Partial State Of Charge (PSOC) is unknown but probably not good. They do apparently have low self-discharge, so once charged fully they can tolerate being on their own for awhile. Again great for backup service but not for RE.

Have you worked out the cost per kWh of storage? These will be very expensive batteries, I fear.

[SunEagle]

So you only have a grid tie micro system with no battery and are comparing it to an off grid system with battery and generator...
yes grid tie micros are pretty easy though not as simple as legos, BUT have absolutely no backup capability.

What everyone here (including you) is talking about is a system that you can use RIGHT NOW off grid called AC coupling. It uses a second inverter (like you keep mentioning Magnasine) and batteries to allow ANY (yes including micros) GRID Tie system to work off grid. This is a pretty complex install and the batteries and dual inverter system has a lot of configuration and sizing to get right.

Further you suggestion that everyone move to the desert so they can have more sun and not have to worry about cloudy days in temperate climates in the US seems at best ridiculous. A suggestion of Dallas TX seems just as ludicrous , a quick search of pvoutput shows this site just north of Dallas showing clear weather issues on 10/22- 10/25 http://pvoutput.org/list.jsp?p=0&id=...=29366&v=3&s=1 .

Based on what I have found there isn't anywhere on earth that has perfect solar sunshine every day of the year. Even the sunniest (supposed to be Yuma, Arizona) may get > 4000h of annual sunshine but that is still about 91% of the time. So it really doesn't matter where you live except maybe in orbit to expect continuous sunlight for pv to produce.

I understand the attraction that solarddy has for a micro inverter system but without another way to generate or purchase power (batteries, gen set, grid, hydro, wind, etc) when the sun isn't shining I will say your electrical equipment will not run.

[J.P.M.]

Based on what I have found there isn't anywhere on earth that has perfect solar sunshine every day of the year. Even the sunniest (supposed to be Yuma, Arizona) may get > 4000h of annual sunshine but that is still about 91% of the time. So it really doesn't matter where you live except maybe in orbit to expect continuous sunlight for pv to produce.

I understand the attraction that solarddy has for a micro inverter system but without another way to generate or purchase power (batteries, gen set, grid, hydro, wind, etc) when the sun isn't shining I will say your electrical equipment will not run.

As it turns out, and FWIW (maybe), Tucson, MAY edge Yuma out by a nose with a clearness index - common symbol "Kt" = = (Annual global horiz. irrad./Extraterrestrial "horiz."rad, at same loc. above the atmos.) of ~ .653, vs Yuma's ~ .630. More than a few places in NM come close to that # like Las Cruces (.656), or Santa Fe (.652). But that may be separating fly fraas from pepper.

However, looking outside the U.S, places in the Atacama desert in Chile ( ~ 2,500 m above sea level) probably have Kt values exceeding .80 or so. Kind of a harsh climate however. There's a bit more than anecdotal evidence that it's not rained in most places there as long as records have been kept, and the arch. evidence is that it hasn't ever rained in some spots.

Just sayin'.

[ButchDeal]

There's a bit more than anecdotal evidence that it's not rained in most places there as long as records have been kept, and the arch. evidence is that it hasn't ever rained in some spots.

Just sayin'.

We are all interested to see the pvoutput graphs of the solar community you set up there with Solarddy.

[J.P.M.]

We are all interested to see the pvoutput graphs of the solar community you set up there with Solarddy.

Just adding some information for those with perhaps some curiosity. I forgot to add the usual "Take what you want of the above. Scrap the rest." My bad.

[ButchDeal]

Just adding some information for those with perhaps some curiosity. I forgot to add the usual "Take what you want of the above. Scrap the rest." My bad.

you mean you are not planning to move