Last question.. Solar manual says that the AC output max is 50A from batteries
Then another 62.5A of AC Power with PV.
Is that second AC power max combined from both AC coupled and DC coupled panels?
Should I assume that in a grid down situation with Solar, and Battery available I can only have 50A+62.5A of power available to run my home?
112.5A? Max for the Solark?
Or are there scenarios where you could start with AC coupled power input, then add battery power as input, then if grid goes down for some extended period and you wanted more power available in home and your AC coupled was maxed out, you could hook up DC solar directly to the Sol-ark 15K.
Can someone help me understand how the input and output power varies as a function of AC coupled, DC coupled and Battery power available, all three or just some combination.
I understand that for AC coupled solar, when batteries are full and grid is down it shuts down the panels until some amount of battery is used up, then turns them back on to re-charge them. It cannot gracefully power them down as it does with DC connected panels.
View attachment 102449
This is another instance where Sol-Ark's documentation could use some work.
Also, could you let us know where you got that spec sheet, and the name of the PDF? Because the info you show is different from the one currently on Sol-Ark's Web site
here, which shows 15 kW output from PV on grid and 12 kW from batteries off grid. What the "PV" line doesn't say is that this number is for
DC coupled PV that gets
inverted to AC. Also, it doesn't say anything about the
total output of the inverter being 15 kW. So, the
max (inverted) output you're going to get from
any combination of DC coupled PV and batteries is 15 kW. And if you divide that by 240 V, you get 62.5 A. Another note: in order to produce that 15 kW of inverted
output, you can connect an actual rated
19.2 kW of (DC coupled) PV panels
input to the (three) MPPTs (6500 W per MPPT). Anything above that limit gets "clipped". Now, you can hook up another (max) 19.2 kW of
AC coupled PV panels (let's just say through the gen input for this example), and the "inverter module" circuitry (to coin a phrase) will
add that 19.2 kW AC power to the 15kW AC that was the output of the actual DC-to-AC HF transformerless "inverter" to give a total output of the "inverter module" of
34.2 kW. Divide 19.2 kW by 240 V, and you get 80 A. So the (max) total
output of simultaneous AC & DC coupled
input to the Sol-Ark 15K is 34.2 kW and (this is the part I'm not exactly sure of) 142.5 A (62.5 from inverted DC and 80 A from added AC coupled PV). All of the above numbers except for the 142.5 A are directly from Sol-Ark documentation and/or Sol-Ark Support. Oh, and remember: technically, Amperage is
current, not
power. Power is measured in Watts.
"Or are there scenarios where you could start with AC coupled power input, then add battery power as input, then if grid goes down for some extended period and you wanted more power available in home and your AC coupled was maxed out, you could hook up DC solar directly to the Sol-ark 15K."
Absolutely. Just remember each of the max values I gave above. So, let's say your house uses
lots of power. Let's assume that on an average day, your AC coupled panels - cranking out an actual 19.2 kW because you oversized the panels to produce the max that the MIs (MicroInverters) could handle - just barely covers your actual average daytime loads. If you add batteries, they have to be charged somehow, so in the "power hungry" case I just described, they would have to be charged by the grid (or charged by the panels while the grid handled the loads). In a more frugal case, say the 19.2 kW from AC coupled panels more than handles your daytime loads. Any extra will first go to charge the batteries, and if/when they get full, it will sell to the grid (if set up in the Sol-Ark configuration to do so). But back to the first (power hungry) use case. If the AC coupled panels barely cover your daytime loads (either because your house actually uses all of the max 19.2 kW max of the Sol-Ark 15K, or your AC coupled array is < 19.2 kW, but it still just barely covers daytime loads), then you can still add up to another 15 kW (inverted)
output of DC coupled PV panels (and use up to 19.2 kW of rated PV panel
input to produce that 15 kW
output) so that the AC coupled panels handle the daytime loads and the DC coupled panels charge the batteries (which were hopefully sized big enough to last you from sundown to sunup - and then some). By default, the AC coupled panels will satisfy the loads first. If there is any excess, then it goes to charge the batteries, then sell-to-grid. By default, the DC coupled panels will charge the battery first. If there is any excess, then it gets inverted to satisfy loads, then grid.
"I understand that for AC coupled solar, when batteries are full and grid is down it shuts down the panels until some amount of battery is used up, then turns them back on to re-charge them."
You forgot an important point. It should be "I understand that for AC coupled solar, when batteries are full
and the loads are satisfied, if the grid is down, then it shuts down the panels until some amount of battery is used up
or more load is applied, then turns them back on to re-charge the batteries
and/or satisfy the loads." I believe I am remembering correctly that I was told that the Sol-Ark 15K is "smart" enough that it will use AC coupled panels to satisfy a (AC) load before inverting DC from batteries to satisfy it.
I hope this helps clarify things further.
P.S.: Before making any final design/purchase decisions, make sure you verify all of your assumptions (including any info supplied by me) with a Sol-Ark rep (preferably in writing).
