Replace inverter? Need advice

[bcroe]

I talked to one installer recently who discouraged me from getting a larger inverter if my plan is to add panels to my roof and have them feed into the new larger capacity inverter. He thought that because my panels were older, it would be challenging to find panels that were compatible with the existing ones. Rather, he said if I want to install more panels, he recommended doing it with microinverters on a separate array and having that feed into the bus. Is he right?

Here's his quote:

It's perfectly ok to have 2 circuits feeding into the main so long as the mains rated bussing can handle the extra Amps feeding into it. We have done many system increases using micro inverter and a older string inverters.

I was mostly thinking about the larger inverter down the road.... perhaps 10-15 years down the road when I need to get new panels. But I suppose most things will be micro-inverter at that point. Am I thinking too far down the road?

I wouldn't guess what technology and regulations will be in a decade or so. But with proper fusing
you can always add a string having the same V max power to an existing one. Bruce Roe

[egizzi]

One Hopefully Last Question

I would use both MPPT circuits, dividing your panels into groups of similar (or no) shading, for
best performance. In addition, there likely will be a lighter load on both sections, instead of a
heavy load on one MPPT section (hastening its demise) and none on the other. Rearranging
for additional strings later shouldn't be a big deal. Bruce Roe

I talked to one installer recently who discouraged me from getting a larger inverter if my plan is to add panels to my roof and have them feed into the new larger capacity inverter. He thought that because my panels were older, it would be challenging to find panels that were compatible with the existing ones. Rather, he said if I want to install more panels, he recommended doing it with microinverters on a separate array and having that feed into the bus. Is he right?

Here's his quote:

It's perfectly ok to have 2 circuits feeding into the main so long as the mains rated bussing can handle the extra Amps feeding into it. We have done many system increases using micro inverter and a older string inverters.

I was mostly thinking about the larger inverter down the road.... perhaps 10-15 years down the road when I need to get new panels. But I suppose most things will be micro-inverter at that point. Am I thinking too far down the road?

[bcroe]

I'm getting the panels rewired and a new inverter.
Here's what the installer wrote to me:

put all of your existing modules on one of the MPPT circuits (each circuit
can accept 2 strings of modules) and leave the other one open for later. This way
you can use whatever modules you would like on the 2nd MPPT circuit.

I would use both MPPT circuits, dividing your panels into groups of similar (or no) shading, for
best performance. In addition, there likely will be a lighter load on both sections, instead of a
heavy load on one MPPT section (hastening its demise) and none on the other. Rearranging
for additional strings later shouldn't be a big deal. Bruce Roe

[egizzi]

decision time

I'm getting the panels rewired and a new inverter. Deciding between the SMA TL 3000 or TL 4000. Is there any downside to having a larger than current panel output inverter? At some point eventually I'll need new panels though I suspect it will be a while. Here's what the installer wrote to me:

As for up sizing your inverter that is not a problem and a good Idea if
you think this is something you are going to do. The SMA TL inverters
have two maximum power point tracking inputs so what we could do is put
all of your existing modules on one of the MPPT circuits (each circuit
can accept 2 strings of modules) and leave the other one open for later.
This way you can use whatever modules you would like on the 2nd MPPT
circuit. All you have to decide is how much more power you wantyour
inverter to be able to accommodate? The total install including the SMA
TL 4000 would run roughly $4,800 and the SMA TL 5000 would run about
roughly $5,300

The cost increase for the TL 4000 is only $250 more than the TL 3000.

[egizzi]

Why is it working sometimes and not others?

So I just sent an email to the repair guy to start working on a rewiring estimate.

I go out to my inverter and it is humming along at 2 pm in the afternoon generating 3kw.

So my question is.... why would the inverter work only in the afternoon? It clearly has sun exposure in the late morning and it is totally silent. Is this a panel problem or an inverter problem?

When the repair guy came, he came in the late morning and here's what he wrote:

I was able to get voltage from the 3 strings(215v each). I wasn't able to get any amp reading from the inverter so I think it's dead.

Thoughts?

[egizzi]

Thanks for the suggestion

Green Solar Electric:

Thanks for the offer.

If I price it out for the repair....worst case..... it's going to cost me close to $1250 for the repair:

$500 for your repair
$400 for inverter removal and reinstallation
$150 to ship it though I'm unclear if you pay for this both ways, one way, or neither way
taxes

And only a 90 day warranty

This is looking more and more like the need to do the rewiring and getting a brand new transformerless inverter with a 700 year warranty

[greensolarelectric]

sharp jh3500 sun vista inverter repair

Hi I have parts for these sharp sunvista inverters and I can probably repair it. Contact me if your interested. If you have already replaced this inverter and still have the old one I would by it from you for parts.

Thanks,
green solar electric

I have a 9 year old 3.3kw system on my roof installed by Borrego. The panels are 48 cell kyocera panels.

The inverter is a Sharp Sunvista JH-3500. It's a 3.5kw inverter.

The first inverter died right before the 5 year warranty expired. Sharp replaced it through the company Borrego had sold their residential service (I believe it was GroSolar). Now the second one has died a little over 4 years later.

The problem is that Sharp has no record of this second inverter and the solar company that replaced it can't find their paperwork either. Mea culpa that I did not get any paperwork when it was replaced.

I will call Sharp to press them directly about repairing/replacing this inverter for free. If they agree to do that, then that's the obvious choice.

If they refuse, then I have two options:

1) pay for Sharp to repair it
2) switch inverters, and go with a sunny boy inverter with a 10 year warranty

If I switch to a sunny boy inverter, I'm looking at their new ones (the 3800 and the 4000). I'm not sure why the 4000 is less expensive than the 3800. Am I correct that I simply need to get an inverter that exceeds the kw that my panels generate? I would go this route through one of the local solar shops that repair/install solar.

I am totally disappointed that my inverter has died again. When I went through the math to decide about solar, I did not calculate equipment failure. I can't change to micro-inverters because my panels are 48 cell. So I have to have a single grid-tie inverter, and I'm leaning towards the sunny boy just for peace of mind.

-Elio

[bcroe]

Oy. What a headache.

My inverter seemed to come back to partial life and I watched it for a while but it is definitely malfunctioning. It would start generating power late in the day but not during peak sun exposure times.

I paid for a reliable small solar company to come and look at it and tell me what inverter options I have. They confirmed the inverter is malfunctioning. It turns out that the wiring is 3 arrays of 8 panels, which fit the Sharp inverter just fine. But most inverters are not made to accommodate that wiring arrangement now so I have 3 choices:

1) send the sharp inverter back to sharp for repair. I have to call sharp to see if they even still repair these. The solar company will charge me $350 to take it of and put it back on. I have no idea how much the repair will cost

2) find an older inverter that can accommodate the wiring arrangement. Apparently there is a 3.8kw Aurora inverter that would work but I am confused by which model...maybe someone can help. I'm guessing the inverter would cost $1500 (if new) and installation $400, so 2k after taxes

3) rewire my system to a more modern wiring arrangement (2 arrays of 12) and get an sma inverter. 2k for the rewiring and 1.5k for the inverter plus $400 to put the inverter in and we're looking at 4k

I appreciate the post about microinverters and my panels but for 24 panels, it will be too expensive.
Thoughts?

Perhaps you can find an old inverter, which being old may not have a lot of life left. The cost
of repairing your rather dated one could be quite expensive, and probably comes with a quite
short warrantee. The issue of rewiring the panels I would consider a trivial no brainer. My
choice would be go for the latest technology inverter, which no doubt has numerous advantages
over the old, and is immediately available. Running a higher voltage might buy some efficiency.
Bruce Roe

[egizzi]

Latest Update

Oy. What a headache.

My inverter seemed to come back to partial life and I watched it for a while but it is definitely malfunctioning. It would start generating power late in the day but not during peak sun exposure times.

I paid for a reliable small solar company to come and look at it and tell me what inverter options I have. They confirmed the inverter is malfunctioning. It turns out that the wiring is 3 arrays of 8 panels, which fit the Sharp inverter just fine. But most inverters are not made to accommodate that wiring arrangement now so I have 3 choices:

1) send the sharp inverter back to sharp for repair. I have to call sharp to see if they even still repair these. The solar company will charge me $350 to take it of and put it back on. I have no idea how much the repair will cost

2) find an older inverter that can accommodate the wiring arrangement. Apparently there is a 3.8kw Aurora inverter that would work but I am confused by which model...maybe someone can help. I'm guessing the inverter would cost $1500 (if new) and installation $400, so 2k after taxes

3) rewire my system to a more modern wiring arrangement (2 arrays of 12) and get an sma inverter. 2k for the rewiring and 1.5k for the inverter plus $400 to put the inverter in and we're looking at 4k

I appreciate the post about microinverters and my panels but for 24 panels, it will be too expensive.

Thoughts?

[SolarEU]

The panels are 48 cell kyocera panels. I can't change to micro-inverters because my panels are 48 cell.

I guess some micro-inverters work with the Kyocera panels. I saw this "If the MPPT voltage of the solar panel is above 20V, such panels can be used with [delete] micro-inverters. - http://gwl-power.tumblr.com/post/78038251705/

[Mike90250]

.....Having said that, I believe that I put enough qualifications in my post to make it clear that I'm not absolutely sure of anything. In my post, I said "I read somewhere" and a lot of "maybes" and "This is only my guess". Just throwing out some possibilities based on what I read. Whether the info is right or wrong, I don't really know for sure. Just passing along info.......

Actually, it bad rumor, if you do not know. You don't "qualify" unknowns, you simply say unknown.
"having never tried this, maybe you can torque a 4-40, grade 8 bolt to 70 foot pounds "
Don't bury uncertainties in a volume of blather.

[Volusiano]

Actually that is incorrect
The tl series are not grounded on one side of the DC. (either positive or negative) the array floats.
Please try to refrain from giving technical advise unless you are absolutely sure it is correct.

First of all, thanks for the clarification, Rich. It's always good to have knowledgeable installers on the forum to clarify and correct things.

Having said that, I believe that I put enough qualifications in my post to make it clear that I'm not absolutely sure of anything. In my post, I said "I read somewhere" and a lot of "maybes" and "This is only my guess". Just throwing out some possibilities based on what I read. Whether the info is right or wrong, I don't really know for sure. Just passing along info.

The only technical advise I gave the poster in my post is to check with his installer or SMA technical support to find out why they can't use the TL and must use the HF.

[Naptown]

I read somewhere that the TL needs the panels to be earthed, but the HF doesn't (because the HF has galvanic isolation). It's a safety issue I guess. So maybe your panels were not earthed 11 years ago (code didn't require back then?), so now rather than earthing the panels, which is more troublesome and more expensive, they want to go with the HF to avoid having to earth the panels. The galvanic isolation of the HF will let them not have to earth the panels.

The Sunny Boy design website said the 3KTL was OK for your panels because it probably assumed a new installation with earthed panels.

This is just my guess. It may benefit you to confirm whether this is the real reason they don't want to go with the TL but want the HF instead. You can ask either your installer or call SMA technical support and ask them directly.

I don't know about your system, but my recently installed system last year has a bare ground wire going into the 2 inverters I have. Maybe this is a tell tale sign that my panels are earthed which allows me to use the 4KTL. If you don't see any bare ground wiring going into your current inverter, that may be an indication that your panels are not earthed???

Actually that is incorrect
The tl series are not grounded on one side of the DC. (either positive or negative) the array floats.
Please try to refrain from giving technical advise unless you are absolutely sure it is correct.

[Volusiano]

It's not a major shade problem. But there is a big Oak tree off to the side of the house that does shade. Microinverters were not possible 11 years ago for residential installations. Before my inverter died, my power production was good enough that my initial estimate of a break even point of 11 years was reached.

Here's the update from the solar company I've been emailing about the inverter replacement:

The TL models would technically string up OK. They have dual mppt’s and a much larger input band.

However your solar modules are not compatible with transformer-less inverters.

Our new recommendation, which comes via tech support of SMA suggestions, is the 3000 HFus inverter. Cost of the inverter are $1512 plus tax. Our 350 installation fee would remain. When I went to the sunny boy design site, I entered my exact brand of panels and picked the TL model of inverter and no error was mentioned.

Strings would be 2x12, so we would need to re-wire at the PV system. Additional cost TBD.

This is a little too technical for me, so I'm not sure what to say. The panels are Kyocera 167G, and they are arranged in a 4 x 6 grid which fits nicely on my dormer roof. Wisdom appreciated.

I read somewhere that the TL needs the panels to be earthed, but the HF doesn't (because the HF has galvanic isolation). It's a safety issue I guess. So maybe your panels were not earthed 11 years ago (code didn't require back then?), so now rather than earthing the panels, which is more troublesome and more expensive, they want to go with the HF to avoid having to earth the panels. The galvanic isolation of the HF will let them not have to earth the panels.

The Sunny Boy design website said the 3KTL was OK for your panels because it probably assumed a new installation with earthed panels.

This is just my guess. It may benefit you to confirm whether this is the real reason they don't want to go with the TL but want the HF instead. You can ask either your installer or call SMA technical support and ask them directly.

I don't know about your system, but my recently installed system last year has a bare ground wire going into the 2 inverters I have. Maybe this is a tell tale sign that my panels are earthed which allows me to use the 4KTL. If you don't see any bare ground wiring going into your current inverter, that may be an indication that your panels are not earthed???

[egizzi]

update

It's not a major shade problem. But there is a big Oak tree off to the side of the house that does shade. Microinverters were not possible 11 years ago for residential installations. Before my inverter died, my power production was good enough that my initial estimate of a break even point of 11 years was reached.

Here's the update from the solar company I've been emailing about the inverter replacement:

The TL models would technically string up OK. They have dual mppt’s and a much larger input band.

However your solar modules are not compatible with transformer-less inverters.

Our new recommendation, which comes via tech support of SMA suggestions, is the 3000 HFus inverter. Cost of the inverter are $1512 plus tax. Our 350 installation fee would remain. When I went to the sunny boy design site, I entered my exact brand of panels and picked the TL model of inverter and no error was mentioned.

Strings would be 2x12, so we would need to re-wire at the PV system. Additional cost TBD.

This is a little too technical for me, so I'm not sure what to say. The panels are Kyocera 167G, and they are arranged in a 4 x 6 grid which fits nicely on my dormer roof. Wisdom appreciated.