I’ve been working on a free project called SolarPro Toolkit for people who are curious about solar but aren’t ready to talk to a salesperson or give out their phone number just to see some estimates.

You don’t need to download or install anything. The whole app runs in your browser through GitHub Pages. There’s no signup or tracking, and the calculations stay on your device.

It can help you:

• Estimate solar payback time, your potential new bill, and long-term savings
• See how long a battery could power your fridge, Wi-Fi, CPAP, and other essentials
• Compare the monthly cost of an EV with your current car
• Estimate home energy usage if you don’t have a bill handy
• Understand which parts of your electric bill solar can and can’t reduce
• Learn how time-of-use rates and NEM 1.0, 2.0, and 3.0 affect the numbers

I tried to keep the assumptions visible and editable. The California-style defaults are included, but you can change the numbers for your own situation. Sometimes the result says solar makes sense, and sometimes it says you’re better off keeping your money. That’s exactly what I wanted from it.

It’s mainly for homeowners doing early research, but it may also be useful for solar consultants who want a transparent way to explain the tradeoffs. Personal use is free. Commercial or consulting use requires a license, and I’m working on a Pro version for industry users.

This is still an estimate, not a quote or financial advice, so always confirm rates and incentives with your utility.

I’d really appreciate any feedback, especially if something is confusing or there’s a feature you’d want before making a solar decision.

Many people view home energy storage only as backup power for blackouts. But modern residential batteries can actively lower monthly electricity costs, depending on your utility plan and setup.

There are three primary ways storage helps you save money:

🔋 **Maximize solar self‑consumption**
Solar panels produce most energy at midday when many households are away. Without storage, excess power is fed back to the grid, often at low feed‑in rates. A battery stores that surplus solar energy for evening and night‑time use, so you rely less on expensive grid power.

⏱️ **Peak shaving & time‑of‑use arbitrage**
If your utility uses time‑of‑use pricing, power costs are higher in peak evening hours and cheaper off‑peak. Smart home ESS charges when rates are low and discharges during expensive peaks, cutting bills without changing your daily habits.

⚡ **Reduce demand charges (high‑consumption households)**
Some utilities add demand charges based on your highest short‑term power draw. Running heavy appliances together spikes this fee. Batteries smooth these short‑term power peaks and bring down demand‑related costs.

Of course, savings are not guaranteed. It heavily depends on local electricity rates, solar setup, battery round‑trip efficiency, cycle life and system sizing. Good LiFePO4 home storage typically needs high round‑trip efficiency and smart energy management to deliver real savings over its lifespan.

Curious to hear from this community:
- Has your home battery actually lowered your monthly electricity bill?
- What kind of utility rate plan are you on?
- What surprised you most about real‑world savings vs marketing claims?

For those who built their own solar setup, what part ended up being harder than you expected?

Planning, wiring, battery sizing, permits, or something completely different?

Curious what you wish you knew before starting.

talk to me like I’m 5. what do I need to get to be able to have water access if we loose power?

static water level is 400ft. id like the option to basically tie it into the house to operate as normal.

I was liking just a hand pump but seems our well is too deep and solar is probably the only option. I’ve talked to rps or whatever company and had a kit built. But now I’m thinking why would we replace our current pump with theirs? is there some way to just wire a solar panel onto the current wires while adding a battery, inverter whatever else I have no idea what it means no matter how much research I do!

Hello all,

This is my first foray into solar, so I ordered some kit from Alibaba just to mess around with and see how it is. Unfortunately, the inverter isn't working properly. It turns on fine and there's even power coming out of the USB ports, but the outlet isn't working. Any ideas?

Thank you!

Hi all - i bought the circuit breaker in the picture (Pjerjzn brand) and was ready to make final connection when I came across a potential polarity issue. The positive leads on my solar panels have male MC4 connectors, but they are pictured here as having female connectors. (And the actual product is consistent with the picture). I’m frozen with fear I’m going to hook my system up backwards and fry something. Am I going crazy or is this circuit breaker wired backwards?

Not sure where to start, they say inverter is good an there is a DC grounded. Any help would be appreciated

I started putting up solar hot water panels. Can anyone suggest a reasonably priced delta t pump controller for them? I have a few inkibird heatimg and cooling controllers I plan to use for testing, but yhy only work at a set tempature, rather than comparing two temperatures.

context first. 9.8 kW on a south facing roof, i am doing the racking and the dc side myself and paying a licensed guy for the grid tie. three quotes on the table, and the spread between cheapest and most expensive was about 11 percent on the panel line alone.

i did the classic thing where you tell yourself you will spend one evening on it and then two weeks disappear.

the three on the shortlist were jinko, trina and one the installer brought up called swiss solar. all three are n-type topcon at this point, so the cell technology itself was not really the differentiator, which surprised me. i went in assuming that would be the whole decision.

what i thought mattered going in was efficiency and watts per panel. what actually mattered once i built the spreadsheet was the annual degradation figure and what the performance warranty guarantees at year 25 and 30.

short version of why. efficiency mostly decides how many panels fit on the roof you have. if you are not tight on space it barely touches lifetime output. degradation decides what the array is still making in the back half of its life, and the back half is where the money is, because by then the system is paid off and everything it produces is profit.

so i pulled three numbers off each sheet. first year drop, annual drop after that, and the guaranteed percentage at end of warranty. jinko and trina landed in roughly the same range as each other, which i expected. the swiss one quoted zero first year degradation, 0.35 percent a year after that, and around 88 percent still guaranteed at year 30.

worth saying i am comparing the sheets my installer handed me, not the flagship series off each company website. if you have newer quotes in front of you the numbers may not match mine.

i ran it out over 30 years on 9.8 kW. the compounded difference came to a few thousand kWh. at my tariff that roughly cancels the 11 percent price gap and then a bit more, but only if two things hold. the panels are physically still up there in year 25, and the warranty means something when i actually need it.

the second one is where i keep going in circles. a 30 year performance warranty from a company with a service network in every country is not the same document as a 30 year warranty from a company i had to google. i did ask whether the warranty is insured by a third party rather than just a company promise, and apparently it is, which helps. i have also never had to test one, so who knows.

three things i still do not know and would take input on.

does anyone have real production data off a 10 plus year old array to compare against what the datasheet promised at the time? every number i have been staring at is a manufacturer claim.

is glass glass actually meaningfully better over 25 years, or is that mostly marketing now that everyone has moved to topcon and glass glass anyway?

and honestly, how much of a 0.2 percent per year difference is even measurable at household scale once you account for inverter clipping and year to year weather? i might be optimizing something i will never be able to see.

Has anyone considered such a set up as a base for their panels (assuming a flat surface to begin with?)

The idea being that in the summer my South-facing panels can function great but in the evening the sun is still up but not in their range anymore. So another set of panels could be aimed North-West in the summer to catch the evening sun, but re-oriented in autumn and winter more towards South as the sunset location moves back.

To clarify, I'm not suggesting live-tracking the sun position as it moves during the day (I think that's way too brittle and failure-prone), but some sort of manual winch that you could adjust just a few times a year.

Hello

I am in the process of converting a shed to a home, plan it to eventually power it completely with solar for self sufficiency. Because at the beginning of the process im going to be fully on grid power with a plug in panel to help reduce my electrical usuage. And there are going to be some items like my clothes dryer that will stay on grid. My plan is to have 2 100 amp breaker boxes, 1 which at first is everything but the heavier draw items. so how would everyone wire this system. and i will be getting an electrician involved as the system develops

Hi just received my battery and inverter, on the growatt page 11 on the control screen is the charge part I'm currently only trying arbitrage using night rate energy during the day I til I can get healthy enough to put 4 or 6 465w panels on the roof of my bungalow, the thing is I'm currently using a 13a fused 3 pin plug and heavy duty immersion heater cable to the inverter on page 11 is this the DC amps chatgpt told me to shut off AC charging and lower it to 12a but I think it got it wrong thinking it was 230v amps instead of the DC charging side my rack battery this way is only charging at 644w. Any help would be great as I've had a stroke last November where I had to learn to read and write again and heart failure in January and a clot in my heart the heart failure at least is reversing so hopefully In another few months I should be able to do the panels on my bungalow roof. Appreciate any help

I've been trying to figure out a particular puzzle for a little while now: I occasionally will thermo or vacuum form plastic sheets when 3D printing isn't going to produce the best result. I'm limited in size by the dimensions of the plastic sheet I can consistently heat to the correct forming temperature, and so if the sheet won't fit in the toaster oven I use for crafting or the heat gun isn't sufficient, I can't do it.

For awhile I've been looking for the simplest method of upscaling a heat source that I could use to heat plastic to its forming temperature. I think the largest I would ever need to get would be about 30 inches by 30 inches, and a good target temperature for something like HDPE sheeting would be between 300 and 350 degrees. I know someone who used to demonstrate solar cooker ovens to middle school students, and when I heard them talk about it I thought it was perfect. Unfortunately, even with someone to assist me I've been unable to get any solar oven hot enough to use.

My current solar oven is made from two layers of heavy corrugated cardboard, a box sitting inside it's fitted lid, with heavy duty aluminum foil lining every square inch of the inside of the box. The foil is as smooth as I can make it, but I will admit there are a few wrinkles in the foil by this point. There's a 3/32" thick new piece of clear glass that is not UV treated to cover it. The box itself measures 30 inches wide, 30 inches long, and 6 inches high. I have repeatedly tested it and just cannot get the oven hot enough to use-today the high temperature here was 104F with minimal clouds and high UV index, and I never saw the oven thermometer inside the box even reach 200 degrees after 2 hours in the direct sunlight.

I've tried different sheets of glass, triple sealing different boxes and have used a couple of infrared thermometers to check the sides of the box to see if heat is getting out somewhere, but it doesn't seem to be. Any thoughts here? This seems like it should be working better, but I'm just about out of ideas. Is the oven just too large to get hot enough for what I need?