Micro-inverters vs a single inverter

[ButchDeal]

SolarEdge optimizers, which has about the same failure points as micro inverters.

Keep it simple, period.

The solarEdge optimizer has far fewer parts in it than a micro.

[silversaver]

I'm talking about possible failure points, not necessary parts count.

[J.P.M.]

The solarEdge optimizer has far fewer parts in it than a micro.

But, seems to me anyway, just as many points of possible failure ?

I suppose I could make a case for fewer contained parts/unit making statistics for MTBF look better, but I don't know if/where such #'s exist and if from mfg.'s, not sure they'd be meaningful or to be trusted.

[ButchDeal]

every part on the board has a MTBF as well as the connections on the board etc. The micros have caps in them, and the optimizers doesn't. It only has ceramic parts in fact which have a much longer MTBF, as well as far fewer parts.

[DaveDE2]

From what I've seen, Enphase has replaced all caps with ceramics as well. Solaredge does indeed have fewer parts in roof top electronics (Tigo has even fewer).

[ButchDeal]

Maybe less caps on the s series but the OP is considering M215s

[jflorey2]

The solarEdge optimizer has far fewer parts in it than a micro.

But far more parts than a traditional string inverter.
Optimizers (and microinverters) are great when people have shading issues to deal with. When they don't, that's extra functionality that they don't need. (And extra complexity and cost.)

[ButchDeal]

not really true on the "Extra Cost part at all" When you have to meet rapid shut down with a string inverter you are adding a very complex and expensive system just to shut down each string, with communications etc.

[DaveDE2]

rmk9785e:
Seems like you are confused about the three possible options. Let me clarify:

1. Micro inverters: Microinverters are placed on your roof under each panel and convert the DC output from each panel to AC directly. All of your panels would do this and combine their outputs and tie directly into your AC feed from the power company. You could theoretically add panels later without affecting anything (to a limit). Easy, no brainer installation (sort of)

2. Optimizers: This is a Solaredge (and Tigo) solution similar to micro inverters, One each placed under each solar panel - only they convert the DC output from the panel to an intermediate DC level ~350v and then feed into a DC-AC converter (looks like a string inverter) located in your house or garage or wherever. The output of this inverter then feeds the power company. Less parts on the hot roof than the microinverter solution. Easy, no brainer installation (sort of). Many installers like Solaredge (and Enphase) because they can install on almost any roof top

The advantage with these two approaches is that if shading ever falls on one or more panels, the other panels still output full power. If shading isn't an issue than no advantage unless panels are facing different directions.

3. String inverter. String inverters have the advantage of simplicity, no electronics on the roof and just one (or more) DC-AC inverters in your garage, house etc. If shading is not an issue, string inverters can easily compete with micros or optimizers. String inverters are generally more serviceable, less expensive and more reliable than options 1 and 2, even if rapid shutdown is required.

[ButchDeal]

It is our experience that string inverters are more costly with Two or three rapid shutdown kits per-inverter plus all the additional install time, etc.

[silversaver]

That might be true because each string/strings needs a rapid shutdown, but the cost might be not be much more since rapid shutdown acts like a combiner on rooftop. Not many resident solar need more than one rapid shutdown unless they got roof/ground mount at same time.

[DaveDE2]

Real world experience shows that only one rapid shutdown box per inverter is needed since each box can handle up to four strings. Each box from SMA is $300, a lot less than the price of optimizers.