PV Microinverters vs Tigo Power Maximizers

Vic99

I've had 2 companies give me an estimate on grid-tied photovoltaics for my roof. I want about 125% current electricity capacity because in 4-5 years when a car dies I want replace it with a plug-in electric to charge off of my house. To get 125ish % would get 327 watt panels (Sun Power, I think).

Both outfits told me I'm at 80% for sun. I had one tree cut down and a few branches trimmed. Roof faces almost dead south. Most of paneled area would be at 28 degree pitch.

Company A said get a central inverter and Tigo Power maximizers
http://www.tigoenergy.com/data_sheets/MM_ES_datasheet.pdf.

However, Company B told me to beware of the maximizers because the generation of maximizers that are out now is being discontinued in favor of a newer generation. This run would only have been out for less than a year and the new one will come online within a year, I think. Co B said their engineer thought it was a decent product from a technical standpoint on paper, but that short run caveat makes him a bit wary.

Co B said get micro inverters instead.

My understanding is that the microinverters are not compatible with 327 Watt panels, so I would have to go with 240 W panels. This will get me to about 95% of my current usage.

If I just kept adding panels to surpass 100%, I would start hitting roof area that is shaded with much more frequency. I already had a tree taken down and had a few others trimmed. I don't want to do much more because it would change the character of my yard. Plus, some of the shading trees are across the street in the neighbors property and realistically I can't do anything about that. Despite all that, I still get a lot of sun for 12 of the 19 panels. The other 7 would be decent, but adding another row of panels down would probably not be worth it due to the shade. I'll try to include a graphic below. A week after the photo was taken, I had a new roof put on my house.

I am also not sure if tigo power maximizer (PM) product would be as efficient as a microinverter (MI).

If MIs are on 20 panels and 1 is shaded to 10% efficiency, then I understand that 19 panels would be operating at ~100% (I know temp may reduce that, but let's call it 100% for this discussion) and one would be only at 10%.

However, with a PM on each of 20 panels all running to a central inverter, if 19 are full sun and one is shaded to 10%, would I get 19 panels at 100% and 1 at 10%? Does that 1 shaded panel hurt all others because a central inverter is involved? Co A seemed to think it would, but not a lot. When I tried to get a ballpark %, I couldn't get a concrete # . . . . to be fair, I don't think the rep was trying to be evasive, I think he really didn't know because there are too many variables.

Anyone have any experience with either? Don't want disappointment due to shading knocking down productivity because lots of panels are tied together.

BB.

Re: PV Microinverters vs Tigo Power Maximizers

I don't know--Because of the different angles and the "dormer" shading a couple panels morning/evening time, I probably would tend towards the Micro Inverters...

However, I really do not know anything about the Tigo units--If they can make the array perform "correctly" with shaded/partially shaded panels, may be an interesting option.

Normally, any shading really kills panel output, and if you have a series string of panels (central inverter type), then it can kill overall performance too (especially if you have two or more parallel strings with unequal shading). It is not usual to see 50% power loss with even "minimal" amount of shading on two paralleled arrays and one GT inverter.

I think I may be learning a lot from this thread.

-Bill

stephendv

Re: PV Microinverters vs Tigo Power Maximizers

If you need the most W per area, then hybrid panels like the Sanyo HITs should be top of the list IMO. Some of their models are compatible with microinverters. Can't comment on Tigo, not heard of them before.

rollandelliott

Re: PV Microinverters vs Tigo Power Maximizers

i asked about the tigo units around a year ago, no one knew much about them then either.

the new enecsys micro inverters are less expensive than enphase and the wiring seems easier as well I would go with those over enphase

or the new westinghouse panels
http://www.westinghousesolar.com/index.php/do-it-yourself/18-diy-resources which I believe use enecsys micro inverters.

I would not go with Tigo, just because I hate being a guinnea pig and last time I checked on pricing the tigo + central inverter combination was more expensive than micro inverters, but that was a while ago, price may have decreased.

as far as products being discontinued, who cares, I'm betting the solar panels you get will not be made in 2 years, the micro inverter or central invert you get will not be made in 3 years and the only major components that won't be discontinued over 5 years is the racking system. The only thing constant is change......

mike95490

Re: PV Microinverters vs Tigo Power Maximizers

If you don't need them, (unavoidable shade) don't get them. Use a plain string inverter. Maybe go hybrid, one string for the sunny area. Micro inverters for the problematic areas.

I think the tigos are best reserved for an "oops" repair of an install that has a couple shady panels.

When any panel gets shaded, it's output will drop. Microinverters / Tigos will NOT prevent this, but will keep one shaded panel from shutting down the whole array.

I dislike the idea of power electronics being baked on the roof. Even if the warranty is good in 4 years, it does not cover labor, generally.

Vic99

Re: PV Microinverters vs Tigo Power Maximizers

Thanks for the replies.

What are the advantages and disadvantages of the hybrid panels?

Why use a central inverter for some and micro for others . . . . why not just go all micro? Cost? Complexity?

Anyone have any experience with 300+ watt panels and their associated equipment? I really want to go bigger than I need now for that car.

stephendv

Re: PV Microinverters vs Tigo Power Maximizers

Vic99 wrote: »

What are the advantages and disadvantages of the hybrid panels?

They're the most efficient panels available. I.e. they produce the most energy for a given area. They also tend to do better than poli/mono in high temperatures and low light conditions. Disadvantage is the price!

Vic99 wrote: »

Anyone have any experience with 300+ watt panels and their associated equipment? I really want to go bigger than I need now for that car.

Are you really saving that much space by using the 300+ W panels? Surely you could simply fit more smaller panels in the more common 200-250W range?

vtgoingsolar

Re: PV Microinverters vs Tigo Power Maximizers

I have solaredge power optimizers (to do the mppt) and their central inverter in the basement to do the inverting. Had it for a little over a year. I have it on 240W panels. I know enphase's max out at 225 output (they may take a 260W or something input but their max output it 225).. I have a co-worker in NY state that has enphase microinverters on 245 W panels and his power curve during the day comes up to peak sooner due to the 245W panels. .but then clips at 225x# of panels. Since temperature causes reduced output.. in the summer.. the 245W max will drop anyway so the clipping effect may be less pronounced.. I am not sure what the max output of the solaredge powerboxes are but I've never clipped until I get to my 5000W inverter max (I have 4320W worth of panels so only get above that in optimal..cold sun conditions in april for example)

I dig their solaredge portal (can look at panel by panel like enphase).. and I use a TED monitor to push both consumption and generation up to pvoutput.org that works really well.

I am a happy optimizer customer.. and I have 0 shade ever.. so really.. may not have needed it but peace of mind knowing I can diagnose a problem with one panel quickly and not lose any of the other panels.. is worth something to me.. Plus.. in winter. .when some have snow on them and some not.. due to drifts on the roof, I can get some power vs zilch in a string setup.

dtstein

Re: PV Microinverters vs Tigo Power Maximizers

I'd like to point out another parallel module wiring/ distributed MPPT option, and that is what I chose - the Eiq vBoost. They have a 250w and 350w unit and I think they just came out with a 600w unit meant for combining two panels. I am attaching a picture of my roof. Not only do you get individual panel monitoring, but you also get Pi, Pi, Ii, Io, Vi, Vo and temperature. You can see data for any individual panel as well as the array as a whole. My back roof is severely shaded to east and west, but clear to the south. I reached my 80% insolation only by doing the parallel design. I doubt a series string array would have bested 30-50%. I am one very happy customer. The DC-DC converters boost from 40v to 330v, and I linked it to a GTI inverter (Fronius). Per my production meter and the Eiq monitoring, it looks like I'm losing about 10% overall in conversion losses from PV through inverter. Attachment not found.. I've had the system operational since April. We'll see with the winter how it performs, as I expect shading may be better or worse due to the low sun angle, but relatively diffuse shading caused by branches at a distance. Of note, I'm told that Tigo no longer offers the parallel design dc-dc modules, but still offers the serial dc-dc maximizers.

new2solar

Re: PV Microinverters vs Tigo Power Maximizers

Hi Guys
I just thought I'd relay my experience with Tigo. I installed a fixed ground mount system a year and a half ago in Ontario. My installers used two string 5kw inverters on an array of 52 225w panels. I installed the Tigo system myself primarily for the monitoring. During the first year, I noticed my inverters would momentarily cut out several times a day, during sunny periods, and was worse when it was cooler. I would have not noticed it was happening anywhere near as often as it was without the monitoring system. I notified the inverter manufacturer, who knew about the issue on certain installations. (I think it became an issue with the inverters because of the Ontario Government's feed in tarriff policy of capping the inverter capacity at 10kw, but not limiting the array size) The inverter manufacturer shipped me a loaner inverter, and repaired mine one at a time...Great customer service on their part!! The system is now working properly. I believe repairing this one glitch will easily pay for the Tigo system system over the life of my 20 year feed-in-tarriff contract as we are paid 80.2 cents per kwh.