diy solar

diy solar

An Enphase Ensemble Installation

So will you get PTO before the battery?
Yes. In fact I already have permission to operate and the system has been generating power since 1/27. Fortunately the net-metering agreement was painless (although as you probably read above the installation had its moment of sparkly excitement).

Does it need another inspection to plug in the battery?
Yes, but where I live you need a building permit for everything. I can understand it too in this case. While it's a very simple add on (Just the battery and switch), in my case the additional wires will run over the rooftop. So, the county is going to want to make sure the wire gauge is sufficient for the current, roof-heat (requires elevated conduit <sigh>), and of course be suitable for my HVHZ.

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First Bill....

Got my first power bill with the solar system activated...no where on the bill does it show the number of kWh generated and pushed onto the grid. Although since a part of the month was on the old meter that might change next month (the How to read your net-meter bill web page the co-op has says it should be there). Fortunately I'd been recording these so knew how much had been generated.

The fields on the bill were the same as previous months, plus 3 new entries that are credits in green.
  • Daily System Access Charge - line maintenance fee
  • Power Cost - the value of the power using the rate at which the co-op purchased it.
  • Equity Charge - Co-op rate per kWh
  • Energy Charge - Co-op rate per kWh > 1000 kWh
  • Power Credit
  • Equity Credit
  • Energy Credit
  • Taxes
Florida law mandates you get the same rate they charge you, but there's a big of ambiguity and it's hard to say what is and isn't included. When I plugged my numbers into their credit prices it all worked out pretty close. There should be some winter months where I generate more than I use, it'll be interesting to see if it's enough to carry forward.

Cycle the Battery?
The big question I had when looking at this is whether or not it would make sense to use the battery at night and export less power during the day. Since they track the consumed and generated (rather than net), once I go over 1000 kWh consumed I get hit with a higher rate and using the battery might help to reduce that. But it looks like the rates are such that I'd have to go way over for the $ difference to be that significant. I'll watch and if I'm wrong post on it. Just for my local co-op of course, your utility may be completely different (and probably is).
 
First Bill....

Got my first power bill with the solar system activated...no where on the bill does it show the number of kWh generated and pushed onto the grid. Although since a part of the month was on the old meter that might change next month (the How to read your net-meter bill web page the co-op has says it should be there). Fortunately I'd been recording these so knew how much had been generated.

The fields on the bill were the same as previous months, plus 3 new entries that are credits in green.
  • Daily System Access Charge - line maintenance fee
  • Power Cost - the value of the power using the rate at which the co-op purchased it.
  • Equity Charge - Co-op rate per kWh
  • Energy Charge - Co-op rate per kWh > 1000 kWh
  • Power Credit
  • Equity Credit
  • Energy Credit
  • Taxes
Florida law mandates you get the same rate they charge you, but there's a big of ambiguity and it's hard to say what is and isn't included. When I plugged my numbers into their credit prices it all worked out pretty close. There should be some winter months where I generate more than I use, it'll be interesting to see if it's enough to carry forward.

Cycle the Battery?
The big question I had when looking at this is whether or not it would make sense to use the battery at night and export less power during the day. Since they track the consumed and generated (rather than net), once I go over 1000 kWh consumed I get hit with a higher rate and using the battery might help to reduce that. But it looks like the rates are such that I'd have to go way over for the $ difference to be that significant. I'll watch and if I'm wrong post on it. Just for my local co-op of course, your utility may be completely different (and probably is).

I did a DIY Enphase iq7+ system. I got my first true up bill a few months ago. I am over producing but I have to pay for .031 per day for grid connection and I have taxes of about .03 per kw when I use power from the grid (not netted against production). I was forced to go to time of use. I just received a $54 credit for over producing and got .05066 per Kw on the amount I overproduced 1.1MWh. You get paid about the same as the super off peak rate for the excess. I think the battery is really cool but it is easier to change your usage patterns I think.
 
First Bill....

Got my first power bill with the solar system activated...no where on the bill does it show the number of kWh generated and pushed onto the grid. Although since a part of the month was on the old meter that might change next month (the How to read your net-meter bill web page the co-op has says it should be there). Fortunately I'd been recording these so knew how much had been generated.

The fields on the bill were the same as previous months, plus 3 new entries that are credits in green.
  • Daily System Access Charge - line maintenance fee
  • Power Cost - the value of the power using the rate at which the co-op purchased it.
  • Equity Charge - Co-op rate per kWh
  • Energy Charge - Co-op rate per kWh > 1000 kWh
  • Power Credit
  • Equity Credit
  • Energy Credit
  • Taxes
Florida law mandates you get the same rate they charge you, but there's a big of ambiguity and it's hard to say what is and isn't included. When I plugged my numbers into their credit prices it all worked out pretty close. There should be some winter months where I generate more than I use, it'll be interesting to see if it's enough to carry forward.

Cycle the Battery?
The big question I had when looking at this is whether or not it would make sense to use the battery at night and export less power during the day. Since they track the consumed and generated (rather than net), once I go over 1000 kWh consumed I get hit with a higher rate and using the battery might help to reduce that. But it looks like the rates are such that I'd have to go way over for the $ difference to be that significant. I'll watch and if I'm wrong post on it. Just for my local co-op of course, your utility may be completely different (and probably is).
They have installed a separate meter for consumed and generated? The 1000 kw consumed is for what period of time.
 
They have installed a separate meter for consumed and generated?
No, the netmeter reports the power I export to them and the power I import from them as two separate values. One meter, 3 readings (the 3rd is dnn, but don't know what that is, see What is the "dnn" reading?). See Using RF to read ITRON utility meters and
The 1000 kw consumed is for what period of time
That's not consumed, that's generated, and since the system went active on 1/27 (see post #11)
 
Made a first pass at some monitoring software that reads the two power readings from the Itron RF netmeter and the Enphase total watts produced. By looking at the delta I can tell how much power the house consumed. I'll post it up in another thread I've started on monitoring software some time this morning.
 
Got an unexpected alert from the software today! It's somewhere between an actual problem and a false alarm. As the sun drops in the west there is a small roof obstruction that casts a long shadow over one of the panels on the eastern array. Not like I'm going to remove the obstruction, so I'll probably just alter the time that particular test runs so I don't have long shadows tripping it. Still, cool to see it working as intended!
 
Got an email from my installer regarding the Encharge battery. Basically Enphase is complying with the CA public health order to remain-at-home for 3/17 to 4/7 (or later) to help curb the spread of COVID-19; so the launch is being postponed for an indefinite period. Sounds like a good move all in all.
 
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Roof Prep

You probably noticed in the earlier photos that the roof is white. It's Henry's tropi-cool white silicone roof coating. The roof has been in the sun for a while in this photo and is obviously quite cool. I've been up there a lot, and it's always cool to the touch. The downside is it is very slippery when wet. In typical local style, it also took forever to get done, which helped push the deployment into 2020.

I wanted to put a new coating on before the panels went up as I didn't want to have to take them down in 10 years just to re-coat the roof (has a limited lifetime warranty so hopefully will last 30 years). I always thought it would be a good combination with bifacial panels, but those need to be elevated a bit off the roof and in my hurricane wind high velocity projectile zone that just wasn't in the cards.

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I picked this coating from the CCRC data looking for a "cool roof". Henry 988 has the same CCRC stats as 887 (I think one is the homeowner version and the other a contractor):

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AFAIK, this is the best there is for a DIYer to keep a roof cool, and that'll reduce the AC bill so you'd consume less power.
When I put it on my roof I even got a state rebate for an energy credit!

As you probably also noticed in the earlier photos, having a cool roof did not allow me to skip the elevated roof conduit nor the lower gauge because the NEC rules only use highest ambient temperature, not roof temperature. It's amusing that the elevated conduit temperature is hotter than the roof temperature.
 
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Sam Vs. Reality
I've been using SAM to model my system as it takes into account local weather patterns and many other economic factors. It's a great tool for answering what-if questions. While SAM isn't that good for estimation of power on a day-to-day basis, I'm wondering how good it is over a month or a year on my east/west roof-flush mounted arrays. So let's find out....

SAMActualAccuracy
Jan776.Installed
Feb890918.755% (spooky, the soiling loss is set at 5%)
Mar120913068%
Apr134913158%
May14041317-6%
Jun1270.751227-3%
Jul1299.11198-8%
Aug1247.2113568%
Sept1043.61998-5%
Oct1005.44875-13%
Nov769.033724.7-5%
Dec734.15773.16%
Total to date12221.312008.6-1.7%
 
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Got a credit on my February bill! Probably won't see that again until Winter rolls around again, but it was nice to see!

In other news... the Encharge battery and smart switch are now showing on AltE. This note was interesting:
*NOTE: Installers must be certified to buy/sell the Enphase Ensemble system. Only certified systems will be warrantied.
 
I do believe that’s the best price around for the Encharge 10?? Thanks for input. Can’t remember...did you install all this yourself? We’re you your own general contractor? Did you put together your own permit packet?
Thanks
 
I do believe that’s the best price around for the Encharge 10?? Thanks for input. Can’t remember...did you install all this yourself? We’re you your own general contractor? Did you put together your own permit packet?
Thanks
I have a solar company doing it, but it's not delivered yet... Enphase shutdown for a while due to the health crisis and expected to start shipping them in mid April. So, no installation date for me yet.
 
Wow 80lbs for the SmartSwitch nice big transformer.
The way I understand it, the SmartSwitch is a glorified transfer switch, it's only job is to disconnect the house from the grid when it switches to battery.
 
I thought all of these AC tied units cant form the 120 / N hence the need for a neutral forming transformer? and also to help with imbalance. SMA's unit is transformer and switch for the SMA storage.
 
I thought all of these AC tied units cant form the 120 / N hence the need for a neutral forming transformer? and also to help with imbalance.
Yes they are! Guess I shouldn't have left the details inside the "glorified" out. Here's what my setup looks like and a brief description of the parts in case I confused anyone.
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  • IQ7+ - these take the place of the MPPT/inverter in your typical string array. One for each panel so no worry about string shading (except this) and they output 240V AC. These are synchronous to the grid's signal and add to power, by raising their voltage the microinverters can export power to the grid. If the grid goes out, the microinverters shutdown, e.g., no power when the grid is down unless you've a SmartSwitch/Encharge or other AC coupling solution.​
  • IQ Combiner - This allows multiple power wires from the roof to be combined into a single output. Has circuit breakers so could act as the AC disconnect in a traditional string system (I have a stand-alone AC disconnect switch too, not in the diagram). Also holds the Envoy. The Envoy is the "brains/communications" of the PV system and collects data from the microinverter / panels using the powerline protocol. It also uses Zigbee to communicate to Encharge And WiFi to the cloud.​
  • Empower Switch - Technically this is a Microgrid Interconnection Device (MID). In a traditional AC Coupled String array this would be the transfer switch. But it does a whole lot more, including a neutral-forming transformer for split phase 120/240 V backup operation, and a future generator input connection. I suspect, but am not positive, that the Grid Forming "brains" are in here too, but it could be in the Encharge or Envoy.​
  • Encharge Battery - In an AC coupled solution, this would be the LiFePO4 battery, a set of grid forming inverters (IQ8s, see speculation below), and communication package. The AC output is either grid synchronous (e.g., the TOU case) or the main signal source (e.g., the Grid down case), but the SmartSwitch might be the signal source too.​
Speculation
A normal grid forming inverter's job is to stabilize the voltage and frequency. The Encharge is probably neither a voltage source like an off grid inverter, nor a current source like a grid tied inverter. Instead, I suspect they are controlled grid forming sources. For example, in the TOU function, the IQ8 inverters in the Encharge must increase their voltage so power is consumed from the battery before the grid and the brains must manage/balance the voltage/load so as to not export power to the grid.

We can be pretty sure in an off-grid scenario the brains in the SmartSwitch ask the Envoy for the power available from the panels and it monitors the load to the house. If the panels have too much power, it adjusts the frequency and throttles the panel output back to meet the demand. If the frequency is at the max output, then the IQ8s in the Encharge probably act as voltage sources to supply current as needed to keep voltage stable.
 
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Dzl thumbed up a post in the surge protection thread which reminded me to share that it turns out my house already had a whole surge protector on it. Never noticed it... until I had the net meter installed. Meant to mention it earlier, but the foot long sparks when the net meter was installed made me blank it out (forgetfulness, another undocumented danger of electricity ;) ).

My local power company installs them for $95. It sits behind the meter and pushes it out a bit. There are two LEDs that can be viewed through the visible circular window (one is really hard to see on mine) that indicate it's health. Not quite as nice as the Midnight.
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