Flat maximum energy production

[scrambler]

That is a major oversight in the part of the installer indeed
And the fact that they tried to BS you on top of it is more like a black eye...

Glad you got it sorted out.

[J.P.M.]

That is a major oversight in the part of the installer indeed
And the fat that they tried to BS you on top of it is more like a black eye...

Glad you got it sorted out.

Built in clipping. What a concept.

[oregon_phil]

SOLVED: I finally got the SolaX company to respond directly. These units have dual string MPPTs. Each string has a maximum capacity of 3.5 kW. My installer has wired 5 kW to one string only in each unit.

The only solution is to split the panels so there is 5 panels per string (2.5 kW) and run 2 more twin core DC cables. Down the side of my 3 story house with no access now that the scaffolding my neighbour let me put on his driveway has long since gone. The ducting is 1 inch (25mm) so no room to get 4 sets of 4mm DC pairs plus a 6mm earth.

The installer is going to have a big cost to fix this. Not my problem and ready to sue if they don't step up.

I bet the installer has quite a few installations with maxed out MPPT inputs since they originally thought it was normal.

I have reviewed the Solax X1 boost "manual" in detail and cannot find anything about having MPPT input power limitations of 3.5kW. Solax manuals and technical support documents are very below par. Compare Solax documents to SMA, Fronius or Solar Edge.

Some possible solutions you can discuss with Other installers.

1) My SMA 7.7 -40 inverter supports parallel inputs on strings A and B. My original design had two strings of 9 panels panels each paralleled on the roof in a junction box (4 wires to 2 wires) , then split back out in my garage (2 wires to 4 wires) to inputs A and B. In my case this was 420Vdc max and 20amps max in two wires coming down from the roof, split back out to inputs A & B each 10mps max. Upon booting up, the inverter figures out that inputs A and B are paralleled and configures inputs A and B as one MPPT. The SMA 5.0 has three MPPT inputs and can parallel MPPT inputs A and B.

2) or you could look at a Fronius Primo and bring the + wire from the array input Fronius DC + input 1 and put a jumper between DC + input 1 and DC + input 2. Array - wire goes to Fronius DC - input 1; no jumper required. Then set MPP tracker 2 to off during start up.

Both of these potential solutions would not require you to pull additional wires from your roof. SMA and Fronius documentation is extensive. It would be up to your new installers knowledge base to ensure the solution selected would work with all of the equipment. I also believe you would have to change the export meter too, but I would do that anyway since Solax would have to remove all their less than perfect equipment.

This also assumed your original installer used the correct wire and wire sizes.

Like I said, I have an SMA -40 and it is built like a tank. I like it so much, I went ahead and bought a replacement to sit on the shelf. Lead times are out of this world right now. If you want first hand knowledge on Fronius, bruce can give you feedback.

[smbunn]

Neither my installer nor SolaX are responding to any emails. I pointed out that this 3.5kW limit is not documented. Expect there will be a lot of finger pointing and shouting. Just as long as I get my system fixed.

[J.P.M.]

Neither my installer nor SolaX are responding to any emails. I pointed out that this 3.5kW limit is not documented. Expect therw will be a lot of finger pointing and shouting. Just as long as I get my system fixed.

If you are not proactive and persistent, don't hold your breath waiting for a response.

[scrambler]

If you are not proactive and persistent, don't hold your breath waiting for a response.

My experience too, these people don't care once they sold you the goods ...

[J.P.M.]

My experience too, these people don't care once they sold you the goods ...

+1. The bigger they are, the less they'll respond.

But a pitch for and another advantage and logic of using established, local, quality vendors: They are usually much better at service after a sale.

[smbunn]

Just wanted to wrap this up. SolaX issued me new firmware and remote installed it. This immediately increased production to the full 5kW on both invertors. They said bi-wiring was still required but this could just be from the DC isolator to the invertor and did not need to be all the way to the solar cells. My installer turned up and bi-wired the units (no apology or even any comment on the fact they had screwed up) but hey, they did turn up and it was free. I regularly got the full 10kW in summer (actually 9.96 kW) so maybe I should sue for my missing 40 watts

A good outcome but I am absolutely sure if I wasn't a data nerd and an engineer monitoring this closely it would have been capped at 3.4kW per unit for the entire life of the units.

[scrambler]

That is what I hate about the solar industry. Most of them expect their customer to know nothing and care for nothing.
When you actually monitor things and point out the problems, they act offended and annoyed....

[J.P.M.]

That is what I hate about the solar industry. Most of them expect their customer to know nothing and care for nothing.
When you actually monitor things and point out the problems, they ask offended and annoyed....

Same for many folks in just about any trade.
This is probably, among other social faux pas, a politically incorrect statement: Time is still money and listening to what's often ignorance from many folks is a waste of both. The expectation of customers knowing nothing has a high probability of being correct.
As an example, look at some of the stuff that shows up around here.