Solar simulator
Watch a day of solar reach the battery
Point the panels, pick the day and the sky, and see what your array delivers hour by hour. It starts in Charleston on the longest day of the year. Drag the scene to look around.
Jun 21 · Charleston, SC
1:00 pm
sun 80° up, SSE
Into the battery
4.6kW
of 5.4 kW installed
Panels face S
Roof, size and more ↓This day
34.0kWh
full sun
Peak output
4.6kW
from 12 panels
Turned away
0.0kWh
nothing lost to the input limit
A typical year
7,850kWh
Charleston-area weather
Battery system
Each one accepts a different amount of solar.
Solar panels
5.4 kW total
Size of each panel
Number of panels
12 × 450 W
Within what the DELTA Pro Ultra can take in.
Sky
Cloud settings are round-number illustrations, not a forecast.
Where the panels are
Which way the panels face
S · 180°
Roof pitch
27°
Drag the compass for fine steps. Roof panels face wherever that side of the roof does, so the house turns with them.
Panels on
This direction, over a year
100% of the best
About as good as it gets here. The best is due south at 33°.
Day of the year
Jun 21
Location
Your location is used in your browser to place the sun. It isn’t sent anywhere.
Your setup is saved on this device, so it's here when you come back.
12 × 450 W (5.4 kW) facing S on a DELTA Pro Ultra
Panels wire straight into the battery's solar input, so there is no grid export or interconnection to arrange. The battery side is what the analyzer sizes.
NRG Sense may earn a commission when you buy panels through a link to a partner retailer, at no extra cost to you. How this works →
From here to panels on a rack
Four steps, in this order
- Step 1Size the arraySet the direction, the tilt and the panel count, and see what reaches the battery hour by hour.Use the simulator →
- Step 2Pick panels that fitA solar input has a voltage window and an amp limit. They decide which panels work and how many go in a string.Read the input specs →
- Step 3Order and receive themPanels come by freight on a pallet. What to order, and what to do if one arrives broken.Pallets, freight and claims →
- Step 4Have it wiredMounting and the DC run back to the battery are work for an electrician. Know how the pieces connect before you call one.How it connects →
The limit that matters
Every battery has a ceiling on solar
Panels on these systems plug into the battery's own solar input, and that input has a maximum. Go over it and nothing breaks: on a bright afternoon the system takes what it can and the rest is turned away. The chart above shows that as an orange band. A somewhat oversized array is often still the right call, because it delivers more in winter and under cloud, when you are nowhere near the limit.
EcoFlow
DELTA Pro Ultra
5.6kW
about 12 panels at 450 W
EcoFlow
DELTA Pro Ultra X
10kW
about 22 panels at 450 W
EcoFlow
TITAN 5000 Plus
8kW
about 18 panels at 450 W
Anker
SOLIX E10
9kW
about 20 panels at 450 W
Kinds of panel
What each type means for a battery
Each solar input on the EcoFlow DELTA Pro Ultra and Ultra X takes in up to 15 A. That one number sorts most panels on the market into ones that fit well and ones that leave output unused. Other systems publish their own limit, and the same sorting applies.
Standard, 400 to 450 W
about 14 AThe common residential size. Its current sits just under a 15 A input, so nothing is left unused. The simple choice for most strings.
Bifacial
front rating plus rear gainGlass on both sides, so the back collects light bounced off the ground. The gain shows up on a ground mount over a light surface and is close to nothing flat against a roof. It arrives as extra current, so check it against the amp limit.
Large format, 550 W and up
often 17 to 18 AAn input limited to 15 A takes in 15 A, and the rest of what the panel could deliver goes unused. The bigger panel can be the worse buy.
Older and surplus, 300 to 350 W
about 10 AOften sold at a lower price per watt. They need more panels, more rack and more space for the same output. Check what warranty comes with them.
The brand on the label matters less than the numbers on the datasheet. I run ZnShine and Silfab panels; what made them work is that each string fits its input. How to check a panel against an input →
What I run
A 6.38 kW ground mount, four strings
My own array in Charleston feeds two EcoFlow inverters. Every string is one panel model facing one direction, with a southeast string for the morning and a west string for the afternoon on each inverter.
Ultra X, input 1
6 × Silfab 330 W
1.98kW
facing west
Ultra X, input 2
3 × ZnShine 440 W
1.32kW
facing southeast
DELTA Pro Ultra, high-voltage
4 × ZnShine 440 W
1.76kW
facing southeast
DELTA Pro Ultra, low-voltage
3 × ZnShine 440 W
1.32kW
facing west
Where to buy
Retailers that sell panels for these systems
Panels ship by freight, and a full pallet is 30 or more panels, which is more than one battery takes. Choose the panel from your input specs first, then buy the count your strings need.
A1 SolarStore →
Partner · we earn a commission$0.34 to $0.49 a watt
More than 100 panel models, priced per panel and shipped by freight. Delivery orders started at 10 panels on the listing I checked.
Good for: Comparing brands and price per watt in one place.
Signature Solar →
No commission$0.36 to $0.41 a watt
Where I ordered panels for my own array. Full pallets, and part pallets from 10 panels, shipped by freight.
Good for: Ten panels or more at a low price per watt.
Outbound Power →
Partner · we earn a commission$0.44 a watt by the pallet of 32, $1.14 in a two-pack
Authorized EcoFlow and Anker dealer. Brand-name rigid panels two at a time (Anker, EcoFlow), and full pallets (SunGold Power).
Good for: Fewer than ten panels, or one order with the battery.
Prices are what each site listed for 385 to 450 W panels on November 13, 2026, before freight and tax. They change often, so check the current price before you order.
Before the truck arrives, read what to do on delivery day. One of my panels arrived damaged, and the ten minutes with the driver are what got it refunded.
How to read it
What the numbers mean
- Into the battery is the power arriving right now, after wiring and heat losses and after the input limit.
- This day is the energy for the day you picked under the sky you picked.
- Turned away is what the array made that the system could not accept.
- A typical year blends clear and cloudy days using Charleston's measured average sun hours, the same figure the analyzer uses.
What it leaves out
Where a real site differs
- Shade. Trees, chimneys and neighbors are not modeled, and shade on one panel can pull down a whole string.
- Your wiring. How the panels are strung has to stay inside the system's voltage window. An electrician works that out for your layout.
- Weather on the day. The sky settings are round-number illustrations. The yearly figure is an average, so any single week can land well above or below it.
Frequently asked questions
How much solar can a home battery take?+
It depends on the system. Each one has a maximum solar input: 5.6 kW on the EcoFlow DELTA Pro Ultra, 10 kW on the EcoFlow DELTA Pro Ultra X, 8 kW on the EcoFlow TITAN 5000 Plus, 9 kW on the Anker SOLIX E10. An array larger than that still works. It delivers more on dull days and in winter, and on bright days the system takes its maximum and the rest is turned away.
Which direction should solar panels face?+
In the northern hemisphere, due south produces the most over a year. East-facing panels produce more in the morning and west-facing panels more in the late afternoon, each giving up roughly 15% of the yearly total at a typical tilt. North-facing panels lose far more. The simulator shows the difference for any direction on any day.
What tilt is best for solar panels?+
A tilt close to your latitude gives the most over a year, about 30 degrees near Charleston. Flatter panels do better in summer when the sun is high, and steeper panels do better in winter when it is low. Within about ten degrees of the ideal the yearly difference is small.
How much less do solar panels make on a cloudy day?+
A lot less under full overcast, because cloud removes the direct beam and leaves only scattered light. As a rule of thumb, a partly cloudy day delivers around two thirds of a clear day and a fully overcast one around a quarter. The sky settings in the simulator use those round figures; they are an illustration, not a forecast.
What kind of solar panel works best with a home battery?+
One whose current fits the battery’s solar input. On the EcoFlow DELTA Pro Ultra and Ultra X, each input takes in up to 15 A. A standard 400 to 450 W residential panel runs near 14 A and fits. Large-format panels of 550 W and up are often rated 17 or 18 A, and the input leaves the difference unused. Bifacial panels add current from the rear side on a ground mount, so check that against the limit too.
Where can I buy solar panels for a home battery?+
From online retailers, in anything from a two-pack to a full pallet, shipped by freight. A full pallet is 30 or more panels, which is more than one battery takes, and some retailers set a minimum such as 10 panels for a freight order. Choose the panel from your battery’s input specs first, then order the count your strings need.
Does this work for grid-tied solar?+
No. It models panels wired directly into a battery system’s solar input, with nothing exported to the grid. Grid-tied solar is sized and paid for differently, through your utility’s interconnection and credit rules.
How much solar can a home battery actually use?
The input limit, system by system.
How solar works with a home battery
And how it differs from grid-tied.
Size the battery side
Backup time, savings and cost from your own power bill.