Solar Panels

[garygid]

There is DC wiring IN the PV panel and to the input of the "built-in" micro-inverter. There is no High-Voltage EXTERNAL DC wiring.

HOWEVER, there is the EXTERNAL "safety" ground that is usually required of all PV installations, connecting all the frames and rails to the "earth-rod" at the service panel.

Also, there is the 2-wire "high" voltage (240v RMS, about 340v peak) AC buss wires that groups of inverters "connect" to. Compare to the High-Voltage DC of around 350 volts. Not much different. Also, the AC currents are often greater than the "string" DC currents would have been.

Normal (DC string) PV panels almost always have two mating "plugs-on-pigtails" so they are also "Plug-and-Play" with the adjacent panels, with no inteconnect "wiring" required.

THEN, since the maximum number of "connected" micro-inverters is often limited to less than "all" the panels, they also have to be wired in "strings", with multiple AC pairs coming together into some sort of "isolator/combiner" thingy. (I do not know what they do.)

If one micro-inverter goes out, must the entire panel be replaced (I suspect not)?
Or, can the "built-in" micro-inverter be removed and replaced (hopefully)?

In most cases, accessing ("fixing") one panel in the middle of an array requires disconnecting and removing at least several other panels.

 

[mitch672]

Gary, up to 10 Honeywell panels per 120V 20A circuit, if you are going to have multiple panels, Honeywell is recommending you use 2 strings, 1 on each leg of the 240 service to keep it balanced. So you can use up to 20 panels (which would be a 4.5KW system with these panels)

The panels are plugged into a connector that is installed
on the 3 wire IDC cable recommended by Honeywell, so if a panel/inverter fails an individual panel can be removed. Of course you would throw the disconnect switch on the monitoring /display interface when servicing the system to remove the panel

Max current for each panel is 1.8AMPS at 120VAC, 18 AMPS for the "string"

You can read all of the specs and even download the installation instructions on the link I posted




Here is the link on the monitor

http://www.honeywellsolarpower.com/products/solarmonitor

 

[LEAFfan]

Gary, up to 10 Honeywell panels per 120V 20A circuit, if you are going to have multiple panels, Honeywell is recommending you use 2 strings, 1 on each leg of the 240 service to keep it balanced. So you can use up to 20 panels (which would be a 4.5KW system with these panels)

The panels are plugged into a connector that is installed
on the 3 wire IDC cable recommended by Honeywell, so if a panel/inverter fails an individual panel can be removed. Of course you would throw the disconnect switch on the monitoring /display interface when servicing the system to remove the panel

Max current for each panel is 1.8AMPS at 120VAC, 18 AMPS for the "string"

You can read all of the specs and even download the installation instructions on the link I posted




Here is the link on the monitor

http://www.honeywellsolarpower.com/products/solarmonitor

20 / 240W panels make it a 4.8KW system and the micro inverters can be removed for replacement (have a 15 yr. warranty). The panels have a 25 yr. warranty. I've heard central inverters only have a ten year warranty?

 

[mitch672]

Leafan, that's DC watts, the AC # works out to 216 watts (1.8AMPs * 120V = 216 watts)

 

[AndyH]

Yes, AndyH, the only difference here is, the microinverters are PART of the panel, in the case of Honeywell. It is not a seperate component, and is integrated into the panel during manufacturing. So, there is no DC wiring to deal with, at all.

http://www.honeywellsolarpower.com/products/12345

I understand what you're saying, Mitch - I promise. Yes - the inverter is fastened to the back of the panel when the panel is going thru final assembly. No problem! This can be a good thing - DC runs are very short (limited to the cell interconnect straps inside the panel and the very short wire from the cell straps to the input of the micro inverter. It appeared folks were feeling that someone had magically invented a solar cell that made AC - maybe my mistake?

I'd much rather have the inverter separate from the panel just as I prefer the DVD player to be separate from the TV. A baseball takes out a panel with a separate inverter and I only buy a panel. The reverse for an electrical fault. Lightning happens.

Edit...It's good that micro-inverters can be detached from a panel - that minimizes my 'baseball' scenario. And my view likely won't apply to the majority, as when something breaks they'll call their installer and tell them that 'number 12' is off-line. I've assembled a small roof-top array by bolting panels to a rack - none of the new-tech mounting clips. But even still - the thought of un-installing a path thru an array to remove a panel with a failed inverter doesn't do much for me. If I don't have shading issues or a split array (some on South, some on west roof, for example), I really like a single central inverter if for no other reason than ease of maintenance down the road. The panels should have a MTBF longer than an inverter - why essentially put a 5-15 year device inside a 20-25 year device where there's enough chance of needing to lift panels to fix something?

How It's Made - Solar Panels
[youtube]http://www.youtube.com/watch?v=qYeynLy6pj8[/youtube]

Micro-Inverters VS. Central Inverters
http://www.renewableenergyworld.com...-vs-central-inverters-is-there-a-clear-winner

Hompower Magazine Inverter Overview
http://homepower.com/view/?file=HP134_pg88_Freitas

 

[AndyH]

I've heard central inverters only have a ten year warranty?

Some are 5 year basic with extensions available. The longest I found in a quick search was 15 years.

 

[greenleaf]

I was just reviewing the rate plans from PG&E as well as the SmartDays program:

https://www.pge-smartrate.com/smartrate-details/rates-details/

Summer Pricing Credits and Surcharge
Residential energy charges are calculated by using your previous pricing plan with the following adjustments:

* Summer Pricing Plan customers will receive a credit of $0.02992/kWh for energy usage from June 1 through September 30, with the exception that the credit will not be given for energy usage that occurs from 2 p.m. to 7 p.m. on SmartDays.
* From June 1 through September 30, Summer Pricing Plan participants will receive an extra credit of $0.01/kWh for usage in tiers 3, 4 and 5.
* Summer Pricing Plan participants will be charged a $0.60/kWh surcharge in addition to the regular rate for just five hours (from 2 p.m. to 7 p.m.) on each SmartDay™.

Does anyone with solar panels use this program? My yet-to-be-installed system would generate an excess of electricity between 2pm and 7pm during summer. What is the rate PG&E would pay me during the time SmartDay is active?

 

[cinmar]

Woohoo! We just got our financing in place for a SunPower 4.9 kw system for our garage's roof. I don't have the quote details with me, but I'll post them later. I was just so excited that it's actually going to happen, I had to post. Now, our future LEAF will run on the sun.

 

[Jimmydreams]

Woohoo! We just got our financing in place for a SunPower 4.9 kw system for our garage's roof. I don't have the quote details with me, but I'll post them later. I was just so excited that it's actually going to happen, I had to post. Now, our future LEAF will run on the sun.

Congrats!! Once your system is up and running, you'll be kicking yourself for not doing it earlier!!! :lol:

 

[Gavin]

yeah...and if you have enphase you will be kicking yourself for checking the site every 30 minutes to see what your power production is...gah, I check that site more than this one...

it's like solar OCD...

Gavin

 

[cinmar]

Petition to put solar panels on the White House:
http://www.solaronthewhitehouse.com/

 

[Jimmydreams]

Petition to put solar panels on the White House:
http://www.solaronthewhitehouse.com/

Jimmy Carter put solar panels on the White House. Ronald Reagan took them down. :evil:

 

[cinmar]

Petition to put solar panels on the White House:
http://www.solaronthewhitehouse.com/

Jimmy Carter put solar panels on the White House. Ronald Reagan took them down. :evil:

Yep. The group that's "marching" to the White House soon to ask Obama to install solar is bringing with them some of the original panels removed by Reagan.

 

[Ready2plugin]

They should do it before the tax credit goes away .

 

[evnow]

Jimmy Carter put solar panels on the White House. Ronald Reagan took them down. :evil:

It is unfortunate that environmentally conservative ideas got tied to the political left. Reagan set back the "energy independence" by decades. Infact probably enough to push western civilization to the edge ...

 

[cinmar]

Here's the cost of my SunPower panels to be installed next month in NorCal:

4.9 kW (24 SunPower 230 watt modules)
24.5 kWh/day Performance Guarantee
SPR-5000m inverter
Upgrade 100A panel to 200A, and install sub-panel in garage
All racks and installation

$40,568 Total Cost
- 3,068 CSI Rebate
--------
$ 37,500 Initial Outlay

- 11,250 Federal Tax Credit
---------
$ 26,250 Net System Cost

6.8 year break-even, based on our current PG&E bills.

 

[DaveEV]

4.9 kW (24 SunPower 230 watt modules)
24.5 kWh/day Performance Guarantee

Uh, doesn't 24*230 = 5.5 kW? 4.9 kW must be the PTC rating.

And they are guaranteeing 8942.5 kWh/year on your system? For how many years?

Do you know the orientation of your modules (mounting direction and angle)?

The CSI rebate calculator is only estimating 8269 kWh/year for a system like yours in Sacramento with the panels mounted optimally with no shade.

 

[LEAFfan]

Here's the cost of my SunPower panels to be installed next month in NorCal:

4.9 kW (24 SunPower 230 watt modules)
24.5 kWh/day Performance Guarantee
SPR-5000m inverter
Upgrade 100A panel to 200A, and install sub-panel in garage
All racks and installation

$40,568 Total Cost
- 3,068 CSI Rebate
--------
$ 37,500 Initial Outlay

- 11,250 Federal Tax Credit
---------
$ 26,250 Net System Cost

6.8 year break-even, based on our current PG&E bills.

Wow, that's expensive! We're getting a 4.8 DC/4.5 AC system ( 8,640 Kwh/yr.) with micro-inverters (20/240W panels) for a net cost of $5,400, with a payback of only 5 years. But since the 'rebate' from our utility is taxable, the net cost may be somewhat higher. Still, yours sounds like someone ripped you off, unless that's the best deal you can get in CA.

 

[DaveEV]

Wow, that's expensive! We're getting a 4.8 DC/4.5 AC system ( 8,640 Kwh/yr.) with micro-inverters (20/240W panels) for a net cost of $5,400, with a payback of only 5 years. But since the 'rebate' from our utility is taxable, the net cost may be somewhat higher. Still, yours sounds like someone ripped you off, unless that's the best deal you can get in CA.

SunPower systems are generally expensive as their panels are the most efficient in the industry - around 20% for the module where the average is around 15%. Good if you have limited roof space, but you'll pay for it. So $7.35/watt isn't totally out of range especially given that a service upgrade had to be done (that's worth at least $2k or so), but I'd hope for less given that systems can be had for as low as $5/watt these days before rebates.

It does seem that Arizona is one of the cheaper areas of the country where $6/watt is very common.

Where did you come up with 4.5 kW AC for yours? What panels/inverters are you using specifically?

 

[LEAFer]

IIRC this is an old house that needs a major service upgrade. So naturally that adds to the price. I think cinmar was the one quoted $10k+ by AV Home Assessment ?

Upgrade 100A panel to 200A, and install sub-panel in garage