cost of central inverter vs enphase
rollandelliott
Solar Expert Posts: 834 ✭✭
I've read a few threads that say enphase is about the same cost as a central inverter, but when I do the math enphase is about twice as much.
Sma 5000 inverter is about $2500 or 50 cents a watt
enphase m215 is about $180 or 0.83 per watt
BUT the stupid cabling system is very very expensive $700 to $800 for a 5kw system increasing the cost by about $0.15/watt
for a total of $0.98/watt.
I have a large open space with no shading issues and know how to do the dc wiring, and can't think of any reasons to pay twice as much for the enphase.
It is easier to wire and it does have a much better warranty of 25 years.
anyone know how long sma inverters really last? I guess if they only last half as long it is a wash and both systems cost the same.
Sma 5000 inverter is about $2500 or 50 cents a watt
enphase m215 is about $180 or 0.83 per watt
BUT the stupid cabling system is very very expensive $700 to $800 for a 5kw system increasing the cost by about $0.15/watt
for a total of $0.98/watt.
I have a large open space with no shading issues and know how to do the dc wiring, and can't think of any reasons to pay twice as much for the enphase.
It is easier to wire and it does have a much better warranty of 25 years.
anyone know how long sma inverters really last? I guess if they only last half as long it is a wash and both systems cost the same.
Comments
-
Re: cost of central inverter vs enphase
each will do as they deem fit for them, but i believe the enphase is great for small installs. when getting to big installs the main central inverter imo should be used. the enphase inverters could even help with allowing oneself to fill the entire roof with pvs after the set strings with their finite numbers in series for the central inverter are done. it is often encountered that there may be room for say 2, 3, or 4 more pvs for example, but it may not fit for the string arrangements or voltage/power limitations being hit on the main inverter. these few enphased (forgive my butchering the language) pvs would fill in the gaps on the roof allowing for more collection. having a roof fully filling in will not be cheap either, but nothing really is is it?:roll: in any case, i'm just saying imo that if going by costs on large systems i agree with the central inverter, but the enphase can fill in the needs for small time installs and as better roof utilization in some cases by taking up the slack the central inverter can't. -
Re: cost of central inverter vs enphase
This question seems awfully familiar. Got search?
The short version: the microinverter advantage is when there are shading issues and you can't get all the panels in the same amount of sun all the time. The cost difference is often shifted by the difference in what you get charged to install: some installers find the microinverters easier because they "don't have to deal with" the DC side which they're not familiar with. Others will not be daunted by a high Voltage array and so there's potentially less actual wiring involved with the central inverter.
Like so many other things about solar power, it's highly site-specific. :roll: -
Re: cost of central inverter vs enphase
yes I did search, but the cost analysis was not discussed much
basically here are the warranty facts
sma has a 10 year warranty
they claim on the phone their inverteres will last 25 years most likely, but no guarantee
you can buy an extended warranty for $1500 which is about 50% 0f the cost of the unit for another ten years.
enphase has a 25 year warranty
obvioulsy if you get the central inverter and it only lasts 10 years the enphase is CHEAPER.
also obvious is if the central inverter lasts 25 years it is the better economical choice.
is there any data /guesstimate as to which is the better buy? or do I need to invets in my crystal ball fund? -
Re: cost of central inverter vs enphase
Get out your crystal ball.
The Enphase units haven't been around long enough to prove their original 15 year warranty, much less 25. The SMA's have lasted 10 years+. But the future? If you can predict that for anything, please tell me the next winning numbers in the 6/49 lottery.
Enphase, I think, is counting on the "long end" of component life coupled with a bit of extra price to cover failures. Every company does this to one level or another. One I worked for used to sell two similar units, one with a fancy label and long warranty. The difference was the extra price buying "insurance" against failure over longer time.
And 25 years from now what sort of inverter technology will we have? If the past is anything to judge by it should be significantly improved over what we have today.
Trying to factor longevity into the price/performance formula is a nightmare. -
Re: cost of central inverter vs enphase
Enphase has been in the field not even 3 years, they could claim a 200 year warranty and it would mean exactly what their 25 year warranty will means, the value of ink on a piece of paper or pixels on a screen.
I know of no electronic product ever sold that could be stuck in a daily 50C temperature cycle and work so it will meet a 25 year warranty, your talking that better than 95% would perform that long, heck, I don't know of any electronic product, even if put into a closet that 25 years latter would have 95% work even if never powered, you have lots of interesting things that happen to semiconductors chemically over time, same with the capacitors and the integrated components (dsp or micro ) flash isn't designed for that type of life span.
Time will tell ... -
Re: cost of central inverter vs enphaserollandelliott wrote: »
obvioulsy if you get the central inverter and it only lasts 10 years the enphase is CHEAPER.
Yes... well, assuming Enphase is successful enough to meat their warranty. (And unless string inverters drop in price in the future and become cheap enough to replace.)
It needs to be assumed that a string inverter will need to be replaced at least once during the 20-30 year life of a solar system. It may need to be replaced twice, and possibly more than that (albeit probably under warranty) if you are unlucky.
As for micro-inverters, no doubt there will also be a point at which they start failing one-at-a-time in turn. There is a tradeoff here: When one micro-inverter fails the rest keep producing and it is less urgent to replace it to avoid lost energy harvest. But it is more of a pain in the ass to replace them. (The trade-off is a little different depending on whether you are the customer or the guy who has to service the system.)
At this point, I'm not convinced that micro-inverters offer any advantage if you don't have shading issues. But I agree with Cariboocoot about the crystal ball. -
Re: cost of central inverter vs enphaserollandelliott wrote: »I've read a few threads that say enphase is about the same cost as a central inverter, but when I do the math enphase is about twice as much.
Sma 5000 inverter is about $2500 or 50 cents a watt
enphase m215 is about $180 or 0.83 per watt
BUT the stupid cabling system is very very expensive $700 to $800 for a 5kw system increasing the cost by about $0.15/watt
for a total of $0.98/watt..
A complete install includes more than just the inverters. Check out the prices for DC disconnects (not needed with Enphase), DC breakers and breaker box (Not needed for Enphase), DC wiring and combiner boxes (Not needed for Enphase), etc.
Once you price out the entire installed price, Enphase is not that much more expensive. -
Re: cost of central inverter vs enphase
I've done the numbers in my head and don't see how
80.58 Midnight Solar MNPV3 Combiner Box
10.80 Touch Safe Fuse Holder
75.48 PV OUTPUT - MC4 MALE & FEMALE 30FT
100 to 300 for dc wires.
maybe $300 to $400 tops of stuff which would still make central inverters cheaper. -
Re: cost of central inverter vs enphase
The quote I recently received for an added install here to support a second Volt added $0.25 a watt on for enphase @ a cost of $4.75 a watt installed. -
Re: cost of central inverter vs enphase
This is not a solar product, but my parent's purchased a RCA stereo console in the mid 1970s. It's a piece of furniture with hand-made components, and is hand-wired with solder globs everywhere. Believe it or not, it still works, has acceptable sound, and the 8 trk player still has stereo separation. It might need a new stylus for the record player. It's used once a week to catch our local farm report.Solar Guppy wrote: »Enphase has been in the field not even 3 years, they could claim a 200 year warranty and it would mean exactly what their 25 year warranty will means, the value of ink on a piece of paper or pixels on a screen.
I know of no electronic product ever sold that could be stuck in a daily 50C temperature cycle and work so it will meet a 25 year warranty, your talking that better than 95% would perform that long, heck, I don't know of any electronic product, even if put into a closet that 25 years latter would have 95% work even if never powered, you have lots of interesting things that happen to semiconductors chemically over time, same with the capacitors and the integrated components (dsp or micro ) flash isn't designed for that type of life span.
Time will tell ... -
Re: cost of central inverter vs enphase
i can guarantee that the stereo is not working like it did when new as those parts have degraded. lesser usages may help to a point, but the electronics in an inverter placed underneath a pv is under extreme stress from the temps. even the circuit boards themselves can fail with expansion and contractions of temperature extremes so that stereo still working is not a good comparison. -
Re: cost of central inverter vs enphase
Yeah, that's why I used the term 'acceptable'. If it sounded lousy, we'd never turn it on again.i can guarantee that the stereo is not working like it did when new as those parts have degraded. lesser usages may help to a point, but the electronics in an inverter placed underneath a pv is under extreme stress from the temps. even the circuit boards themselves can fail with expansion and contractions of temperature extremes so that stereo still working is not a good comparison. -
Re: cost of central inverter vs enphase
Has this stereo ever seen 50 deg C. ever in its life? Are you going to bet your business it will keep working for many more years? Stick it in an oven and see how long it keeps working. I bet it dies the first time it sees 50 deg C (122 deg F)
Not a valid comparison. -
Re: cost of central inverter vs enphase
Where did this personal attack come from?
This console has been across several counties, sat in uninsulated stone houses, stored in a crawl space, and been hauled around quite enough with its vacuum tubes. And since it's resistors are hand-wrapped, and its capacitors hand-dipped, with clumpy soldering in no orderly fashion, I am sure it goes through enough stress every time it's turned on.
I was responding to a statement made about longevity of electrical circuits. I didn't know that the circuit police were going to pounce on me for mentioning one grand old stereo.Has this stereo ever seen 50 deg C. ever in its life? Are you going to bet your business it will keep working for many more years? Stick it in an oven and see how long it keeps working. I bet it dies the first time it sees 50 deg C (122 deg F)
Not a valid comparison. -
Re: cost of central inverter vs enphase... I didn't know that the circuit police were going to pounce on me for mentioning one grand old stereo.
<cue dramatic music>
nobody expects the Spanish Inquisition !Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A
solar: http://tinyurl.com/LMR-Solar
gen: http://tinyurl.com/LMR-Lister , -
Re: cost of central inverter vs enphase
How about auto radios? They see large temperature swings. There are thousands of pre 1986 cars still on the road and it's a rarity to see one with a dead radio.
Personally I think Enphase is worth the little extra they cost for one reason: Quiet. I am "allergic" to things that hum, and central inverters hum. It happens that I make my living in my basement. If I had a central inverter ..... I can't even type it.... Suffice it to say I will not, can not, do not, have an inverter humming in my cellar. -
Re: cost of central inverter vs enphase...... Suffice it to say I will not, can not, do not, have an inverter humming in my cellar.
I don't even have a cellar. Most central inverters are in weather proof boxes, and can go anywhere you have a place to hang them. Securely !
And if you are off grid, that hum means you have power. I don't believe anyone suggests you place it in your bedroom or dining room.Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A
solar: http://tinyurl.com/LMR-Solar
gen: http://tinyurl.com/LMR-Lister , -
Re: cost of central inverter vs enphase
As they say in France: Chacun son goût.
Sometimes the selection criteria for equipment includes personal idiosyncrasies which others may consider irrelevant or absurd. We can but point out choices based on technical specifications; beyond that we can't venture. -
Re: cost of central inverter vs enphaseI don't even have a cellar. Most central inverters are in weather proof boxes, and can go anywhere you have a place to hang them. .
Yaaa, I heard that they are waterproof, but I live where it commonly get's colder than a bankers heart. Here in Maine we often see temps well below what the specs of the popular central inverters call for. Sunny boy minus 13F, Fronius only minus 4. So, inside they go. I have only seen a few systems live and in person, but they all had the inverters in the basement.
Enphase, minus 40F. (Which also happens to be minus 40C.) *smile* I haven't seen it get quite that cold, even here.
It is very cool how investing time, love, and money into a solar array is such a personal thing. -
Re: cost of central inverter vs enphaseYaaa, I heard that they are waterproof, but I live where it commonly get's colder than a bankers heart. Here in Maine we often see temps well below what the specs of the popular central inverters call for. Sunny boy minus 13F, Fronius only minus 4. So, inside they go. I have only seen a few systems live and in person, but they all had the inverters in the basement.
Enphase, minus 40F. (Which also happens to be minus 40C.) *smile* I haven't seen it get quite that cold, even here.
It is very cool how investing time, love, and money into a solar array is such a personal thing.
Outback: -40C to 60C (-40F to 140F).
Yes, it does get that cold here. Thankfully not that hot, though! -
Re: cost of central inverter vs enphase
I have an HP 41CV calculator on my desk in front of me that I bought in 1983 or so that still works perfectly. I use it many times a day. I have two of them, actually, though the other one (a 41CX) I obtained used in the early 90's so I don't know when it was made. It works, too. I have lots of electronic musical gizmos that are at least 20 years old and still trucking as well.Solar Guppy wrote: »I don't know of any electronic product, even if put into a closet that 25 years latter would have 95% work even if never powered, you have lots of interesting things that happen to semiconductors chemically over time, same with the capacitors and the integrated components (dsp or micro ) flash isn't designed for that type of life span.
Time will tell ... -
Re: cost of central inverter vs enphase
I have several of my earliest computers still, like the TRS 80 Model 100 and two Atari 130XE, all of which still work.
http://en.wikipedia.org/wiki/TRS-80_Model_100
http://old-computers.com/MUSEUM/computer.asp?c=214.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is -
Re: cost of central inverter vs enphase
Hey folks, you're kind of wandering off the path here.
Yes, there are antique radios from the 1920's still working. That some electronics will stay functioning for 100+ years is not surprising. Most of those things are used intermittently, not always at full power, and not left out exposed to the elements their whole life. If they were, would you want to guarantee they'll still be working to spec in 25 years time? That's what Enphase is gambling on with their warranty. It's a bit different circumstances. Since component manufacturers don't warranty the individual parts for that long, Solar Guppy is quite right in his doubts about the viability of the microinverters lasting. No doubt some will. Hopefully most of them. Those that will (not may) die are being covered by a bit of the purchase price invested against failure. -
Re: cost of central inverter vs enphase
I submit that Guppy is the one who wandered off the path when he asserted that (paraphrasing) all electronic devices fail after 20+ years irrespective of their treatment due to weird chemical things that happen to semiconductors over time. As an engineer with 20+ years experience in semiconductor design and failure analysis, I contest that claim. No offense intended; his point is well taken in spite of being a bit inaccurate.Cariboocoot wrote: »Hey folks, you're kind of wandering off the path here.
Yes, there are antique radios from the 1920's still working. That some electronics will stay functioning for 100+ years is not surprising. Most of those things are used intermittently, not always at full power, and not left out exposed to the elements their whole life. If they were, would you want to guarantee they'll still be working to spec in 25 years time? That's what Enphase is gambling on with their warranty. It's a bit different circumstances. Since component manufacturers don't warranty the individual parts for that long, Solar Guppy is quite right in his doubts about the viability of the microinverters lasting. No doubt some will. Hopefully most of them. Those that will (not may) die are being covered by a bit of the purchase price invested against failure.
Is Enphase relying on stress testing and projections rather than realtime data to predict how long their products will last in the field? Absolutely, no question. Is there risk associated with that approach? Again, of course there is.
On the other hand, what else is there for them to go on? It's a new product. If they plan to be in business 20 years from now, they have a lot riding on those projections, too. -
Re: cost of central inverter vs enphase
I doubt Solar Guppy meant all in the sense of "every single one" but rather "every type" of device.
His words:I don't know of any electronic product, even if put into a closet that 25 years later would have 95% work even if never powered
Probably time to stop rehashing the warranty value - until the 25 years are up. Then we can count the number of survivors and see how the various companies have fared.
You'll probably have to do it without me, though. :cool: -
Re: cost of central inverter vs enphase
It appears that my few month old replacement (original was out of warranty and working fine) GT inverter just popped the circuit breaker in the main panel and is now complaining of failed 240 VAC input voltage... Oh well--Called the installer and see what happens next.
That 95% running appliances after 25 years in closet is starting to look really good to me. :roll:
-Bill
Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
Categories
- All Categories
- 222 Forum & Website
- 130 Solar Forum News and Announcements
- 1.3K Solar News, Reviews, & Product Announcements
- 191 Solar Information links & sources, event announcements
- 887 Solar Product Reviews & Opinions
- 254 Solar Skeptics, Hype, & Scams Corner
- 22.3K Solar Electric Power, Wind Power & Balance of System
- 3.5K General Solar Power Topics
- 6.7K Solar Beginners Corner
- 1K PV Installers Forum - NEC, Wiring, Installation
- 2K Advanced Solar Electric Technical Forum
- 5.5K Off Grid Solar & Battery Systems
- 424 Caravan, Recreational Vehicle, and Marine Power Systems
- 1.1K Grid Tie and Grid Interactive Systems
- 651 Solar Water Pumping
- 815 Wind Power Generation
- 621 Energy Use & Conservation
- 608 Discussion Forums/Café
- 302 In the Weeds--Member's Choice
- 74 Construction
- 124 New Battery Technologies
- 108 Old Battery Tech Discussions
- 3.8K Solar News - Automatic Feed
- 3.8K Solar Energy News RSS Feed