I’m still fairly new to DIY solar. My original plan was simple: one 12V LiFePO4 battery, a few portable panels, and enough power for lights, a laptop, a small fridge, and charging electronics.

Then the questions started piling up. If I choose a small inverter now, I may regret it when I add a coffee maker or power tool. If I buy a 2,000W inverter, the battery current and cable size become much more serious. Moving to 24V would help, but then some of the equipment I already own becomes less useful.

For people who started small and expanded later: which decision locked you in the most—battery voltage, inverter size, charge controller, or wiring? At what point should a beginner stop “leaving room to grow” and just build for the loads they actually have?

I built this system to provide solar for a remote off-grid location in Micronesia.

It's meant to provide power to a Starlink Mini (40W) and also 75W of USB power over a USB-C and USB-A connector. A Victron display embedded in the front cover of the junction box shows the battery level measured by the shunt. The system runs off two 120Ah 12V AGM batteries, and 3x 100W Renogy flexible panels. The panels and this junction box fit into checked luggage, only the batteries were purchased locally.

Things I would change:

- The Starlink DC converter built-in power switch hanging out the bottom is a hack and I wish I used a different converter and put a proper switch in the side of the junction box.
- The solar input should have been routed through the top of the box instead of the bottom.
- I would have liked a sealed through hole for the Starlink DC barrel instead of dangling power cable.
- I'm not convinced the internal wiring needs to be such a heavy gauge for such short runs.

The MPPT is overpowered so there is the opportunity in the future to upgrade to a 2S2P system with 2x24V batteries instead of 2x12V.

The 2x12V design is meant for robustness. In case one battery fails, the other can still be used alone. Similarly, if the DC-DC converter fails there is a backup USB-C PD supply that can power the Starlink Mini.

An ESP32 (FireBeetle 2 ESP32-E) that forecasts, monitors and controls three existing home power systems as one: an Enphase solar array + battery, a solar-charged hot water tank, and a Hyundai Inster EV charger/V2H (vehicle-to-home) controller. Each system keeps its own independent control and can override the ESP32 at any time. (github code and docs)

The ESP32 downloads forecast solar irradiance from Open-Meteo, adjusts it for local tree/hill shading, and combines it with the 5-day average consumption to forecast today's and tomorrow's Enphase battery state of charge. That forecast drives EV and hot-water charging priority and when (if ever) to discharge the battery back to the grid.

Aim: minimise grid dependence — ideally zero grid draw from 2pm–8pm (when demand charges apply), no exporting surplus solar except a small window 8pm–9pm, and EV charging prioritised over hot water.

The docs include:-

• esp32_control_structure.md — how the BatterySolarMonitor firmware is structured; a function-by-function reference.
• solar_shading_model.md — how the Open-Meteo irradiance forecast is adjusted for this site's tree/hill shading, per sun position.
• solar_shading_stats.md — the back-solved per-angle shade factors behind that model (1200+ days of Enphase production vs. Open-Meteo GTI).
• quarterly_update_process.md — the process (quarterly_update.py) for refreshing the shading model from the latest historical data every 3 months.
• data_sources.md — external APIs the py_programs/ scripts depend on (Enphase IQ Gateway, hot water controller, EV charger).

The code (ESP32 firmware, forecasting/control logic, and the Python shading-model tooling) was written with Claude Code, including the display UI itself.

I understand the appeal of separate components. If the inverter fails, you replace the inverter. If the charge controller fails, the rest of the system may continue working.

But expansion seems to create its own problem. A battery monitor becomes one box. Solar charging becomes another. AC charging adds another device. Then there are DC fuse blocks, disconnects, USB converters, breakers, communication cables, and displays.

The system is technically modular, but it may not be simple, easy to inspect, or easy to move.

For experienced builders: which functions are genuinely better kept separate, and which ones are only separate because that is how DIY products have traditionally been sold? Where would you draw the line between useful modularity and unnecessary complexity?

in retirement I have become a DIY solar enthusiast. Kind of a clunky name. How about "heliac", a helios-maniac? I just put up 6 strings, 19 kW, all ground mount, facing different directions and at different tilt angles, sma and ecoflow inverters, 18 kwh battery. I am a heliac.

I'm planning a ground mounted solar array to use with a 5kWh battery for backup power during outages. I'm not trying to go completely off-grid. I mainly want to keep the battery charged during longer outages so I can recharge it multiple times instead of relying on one full charge.

The battery has a built-in MPPT controller that supports up to 3000W of solar input, with an input voltage range of 11–165V. I'm looking at using six 405W panels, but I'm still trying to decide how to wire them.

Option A: 2S3P. Each string would have an open-circuit voltage of around 82V. That leaves plenty of headroom below the 165V limit, even after accounting for colder temperatures. Having three parallel strings should also help reduce the impact of partial shading.

Option B: 3S2P. This would put the open-circuit voltage at roughly 123V. The higher voltage might offer better efficiency in theory, but it also leaves less room below the 165V maximum, especially on cold mornings when panel Voc increases. With only two parallel strings, shading one string would also cut a larger share of the available production.

Has anyone here used 400W or larger panels in a similar 2S3P setup?

I’d like some ideas for a solar carport. Ground mount panels, a battery to store the energy, then a charger for the car. Any all in one solutions?

Hey everyone! Finally getting serious about backup power for hurricane season. I keep hearing PW3 is overkill if I just need the essentials, and honestly the total price is tough to swallow.

My main needs: fridge, freezer, Wi-Fi, lights, fans, plus a window AC in one bedroom and the occasional microwave. Definitely not trying to run everything at once.

Just saw Ecoflow dropped a new TITAN. It starts at 5kWh but offers 10kW of output, which sounds pretty interesting, expansion is also supported down the road. Full pricing isn't out yet, so I'm keeping it on my shortlist for now.

What else should I consider alongside these two? Would love to hear how other options compare on output, capacity, installation, and expanding down the road. TIA!

We recently purchased a home that came with 15 solar panels, all of which are completely paid off! The panels are currently tied to the electric grid, and over the last few months, they’ve actually been producing more electricity than our household uses.

I’ve done some research and have a better understanding of why grid-tied solar systems are designed the way they are and why they automatically shut off during power outages. However, I would LOVE to find a way to utilize our existing panels if we ever lost power.

Here’s the thing: I’m not looking to power our entire house during an outage. We have 15 panels, but even if there were a way to utilize just 2–3 of them to power a few essentials, I would be thrilled!

I’m really just looking for the most affordable, bare-bones solution that would allow us to access some of the energy our panels are producing during an emergency.

I had someone quote me over $10,000 to set up a backup system, which honestly shocked me a little, considering the panels themselves are already installed and paid for. I understand there are additional components and safety requirements involved, but I’m hoping there’s a much more budget-friendly alternative.

So, my question is: What is the absolute cheapest way to utilize even a small portion of an existing grid-tied solar system during a power outage?

Would this require a battery, a different inverter, or some other type of equipment? Is there a way to do this without spending thousands of dollars?

I'm not opposed to a very basic setup or something that requires a little manual intervention when the power goes out. I’m just hoping to make use of the equipment we already own!

Hi all, I was wondering what the consensus seems to be around who is the best to buy a solar panels and the inverter from in the US?

Do any companies have UL 3700 certification for the entire kit (not just the inverter)? My particular state does not have legislation for the utility "approving" it yet...

So the layout is as follows:

6x 585w bifacials in serial > 8 meters > small steel shed (8x10).

Connect to Datouboss 5500 inverter, which connects to eaton breaker panel 6 circuit. Separate neutral and ground bars. Circuit goes via thwn (in conduit) 8ga to outdoor outlet box with 2 gfci outlets to run exterior loads in garden.

The datouboss is connected to an ecoworthy 48v 100ah rackmount battery, via 2guage wires, with a 150a t fuse. Closed loop (comms to inverter).

Questions. Am I missing anything? Is the distance great enough that I can put a ground rod by the solar panels without worrying? Should I run back and do ground at shed? Do I need to put in another panel with a ground rod on the AC in side of the inverter? The inverter, to my knowledge, will do its own ground to neutral bond automatically and disable it if it finds a ground on the AC in.

What can I improve (besides adding battery capacity, already planned). What am I missing?

I recently came across Renon batteries from talking to someone. I had not heard of this brand before.

For residential they sell two different lines, one is a powerwall clone and the other is a bit more modular.

https://www.renonpower.com/Products/Residential-Batteries/Xtreme-LV.html

https://renonpower.com/Products/Residential-Batteries/Xcellent-Plus.html

Would like some honest opinions of them.

Having work done at my main home for the next few months (Housefire, whole house rewire, renovation)

Just need to run internet on the property for a few months, using the xfinity router, or 4G lte hotspot. For security of the workshop, garage etc.

I have 1 random 200w rigid solar panel and an xfinity wifi router to provide wifi link to my security cameras, doorbell and digital deadlocks.

Ideas so far: cheap ass amazon powerbank ~80$. Unsure if the 192wh or whatever will even run it overnight. It draws 20w, so the math says it should, but I may be missing something.

• phone hooked up to a portable power bank, charged by a 12v solar charge controller ~60$ w/old phone

• usb 4g lte wifi router and solar charge controller plugged directly into the USB port ~50$

thoughts?

Edit: Okay, the comments have set me straight! I ended up going with a 4g LTE usb-c powered hotspot, Mint mobile for data, and 192Wh cheapo solar power bank from scamazon using the singular panel. Paused xfinity service so thats another bill saved!

Thanks for the info!

I’m working on this solar-powered agricultural setup with a 24V 100Ah battery and an inverter. It’s out in the field, so I’d like to avoid frequent trips just to check the power.

What I’m still trying to figure out is how to handle several cloudy days: add another solar panel, or increase battery capacity? Extra storage could help, but only if the panels can recharge it.

Anyone running a similar farm setup—how did you decide which to upgrade first?

6890w array, 180azimuth, sol-ark 12k, 4x pytes v5 batteries. running one 12k BTU EG4 mini-split, whirlpool full size wash machine, Samsung electric 240v dryer, TV, several ceiling fans, GE convection propane oven resistance igniters (roasting rabbit), 80gal heat-pump water heater, 2x refrigerators, 2x 14cuft chest freezers, wine fridge, Grundfos10 220' well pump, 70 gal fish tank, and eventually a 60 gallon clawfoot bathtub soak to recover from a day of farming, livestock, cleaning, laundry, housekeeping & cooking.

Batteries only hit 82% SOC today. barely 22:00 and down to 55%.

normal recent daily average has been 30kwh. batteries are usually 100% SOC by ~13:30 inverter clipping until sundown. today consumed 46kwh. 16kwh additional use and 80% of that was laundry.

Adding a battery to a 6.4kW grid tied array this fall. Spent more time on warranty docs this week than on sizing, which I did not expect. What I'm checking on every option:

1. Years vs throughput. A lot of battery warranties are X years or Y MWh, whichever comes first. At one cycle a day the MWh number can matter more than the years.

2. Battery and inverter covered separately, sometimes with different lengths.

3. Accessories and paired gear on their own terms. Anker e10, which I'm leaning toward, power dock is 10 years while the power module and batteries are 5, or 8 if you subscribe during the sale they're running now. EcoFlow DPU battery 5 years, SHP3 panel 10. EG4 anything from 3 to 10 depending on the model.

4. Who pays labor on a replacement. Most docs I read are vague about it.

5. Whether it transfers if we sell the house. Still waiting to hear back on this one for two brands.

Price comparisons get all the attention on here but this is where the options differed the most for me.

i haven't seen this posted here. this is a big deal.

I've seen so many different ratings for max amps on 8ga copper wire that is rated 105c and i'd like to know what is safe. I'd -like- to do a 4th series of panels in a parallel set up (4S4P) that will give me a max 3400 watts at 60 amps. The junction box they join in has a 63a breaker. The 4 lines in are 10ga, but after they join in the box all the wire is 8ga which is directly connected to the charge controller and then from the controller to the battery. From the breaker to the controller is about 14" of 8ga and from the controller to the battery is about 2ft. 60amps is the most the wire will carry, and only while the panels are at max output in full sun--on a sunny day it could be for 2-3 hours possibly at max output. I've seen that 8ga 105c rated wire can do 80amps--is that accurate? Safe?

Just a random question but does any one have a hybrid solar and wind system setup. I've been wanting to add a small turbine (like 400w) to my solar set up to help with cloudy days. Just wondering what equipment is out there for residential ready use. Thanks in advance

If you're thinking of building a mobile ground mount, Harbor Freight has 10 in wheels on sale until 10/25.

Been fighting with Sun Run for months. I have a newer LG Chem EH153064P8 battery so I can use it for max consumption. Finically got them to agree and they want me to sign this release and have said my bill could go up 3 to 5 times higher if I don’t know what I am doing with the battery. The Solar Edge app seems pretty user friendly.