System details:

Inverter: Solis-S6-EH1P5K-L-PLUS

Battery: Dyness powerbox G2 10kw

Off grid setup, charging from a generator in the gen port.

No pv

I've installed the system myself (qualified electrician & electrical engineer) and it has been working perfect for the last month. I'm using it for a building site so the generator doesn't have to run consistent for small loads (work lights, charging power tools etc)

Had the generator running and I was using a 2.5kw tool for a few minutes. Power turned off so thought it might be a trip switch.

Checked the board, everything is OK. Checked the inverter and it's giving out about a BMS fault between the inverter & battery.

If checked the connections, powered it off (including the battery shut off) for 15 mins but no difference.

The battery is readying 52.8v so it should be about 80% charged.

Can't get support on a Sunday... Any suggestions on where to start? Or how to figure out if it's the inverter or battery that's at fault

Since California is legalizing plug-in solar systems, they also have a limit of 1.2 kilowatts per building.

How do they keep track of how many kilowatts of plug in solar a person has?

Would you go fined if you had more than 1.2?

or is that more of a safety thing because 1.2 KW is just below the limit of the 15a nema outlets and wires.

but let's say you had multiple systems plugged into different circuits in the house?

Does it make sense to try to install the traditional solar system if you can get plug in solar now?

I am looking to replace my gas generator with a power station and am considering the Anker Solix C2000 among others. It has a single solar input with an 800W max with limits of:

• @ 11V-28V limit to 8.2A
• @ 28V-90V limit to 17A

C2000 User guide - FAQ #2

I am wanting to avoid 2 Anker foldable solar panels at $700 x 2. So I am looking at other brands like this two pack of 320W Renogy panels. I am assuming that most panels sold in pairs list the specs per panel. So, if I run them in parallel as required the voltage stays the same but the amperage doubles. In this example the amperage would be 17.84. Other brands I have looked at vary widely.

Is this safe for the power station? Do I risk any damage? How far over can you safely go?

Hi All,

I'm looking for the cheapest option, even if it's not "safe"/to code in a "Grid Gone" situation. I do mean gone not down. Desperate, Donner party vibes. A thought experiment.

I believe the gold standard is an EGP 6000XP/12000xp with two+ 5kwh batteries in AC coupling mode starting at $2800-$3500+ price range.

I have an Anker C2000 2kwh, Wen 3000 running watts inverter generator, and experience and confidence with residential wiring. My solar array is APSystems DS3-L with 17kw of panels so ac coupled from the micro inverter to my load panel.

My understanding is that if I were to close/remove my main breaker and start running a generator my panels may sense a grid and back feed the generator and kill it. Even if I plugged in an uncharged C2000 it would only pull 1800watts and anything my panels produce over that could fry anything connected with over current. This is all because there's nothing to modulate frequency and tell the panels to step down/stop production (I.e. ac coupled inverter)

I think the cheapest option for me would be to purchase a bulk of MC4 cable ends and a backup DC coupling inverter. Then re-terminate the romex cabling with MC4 and put the other end into the inverter. This would mean I'd just need to stock a crimp tool, ferrules, a bunch of MC4 terminators, some batteries, and a DC coupling inverter.

I'd have to research how to configure the strings in series/parallel to not overload 80% of the amperage of the (hopefully) 12ga romex.

Is this a feasible SHTF plan? Is there something in the sub $1000 or sub $2000 range that I can stock? I already have proper PV wiring to hook my Anker C2000 up to my panels directly in a mild emergency but I would love to have a plan to use my whole array in an apocalypse situation.

Thanks for anyone participating in this thought experiment. I'm hopeful with mass adoption of ac coupled balcony solar that some better, affordable options for ac coupled battery systems come out in the next few years.

We’re currently designing a somewhat unusual residential solar project and I’d like to hear from installers/electricians who have dealt with something similar.

The property has a 3-phase grid connection.

Planned system:

• Around 6–8 kW of PV
• Around 15–20 kWh battery storage
• Maximum load we expect the inverter to supply is around 8 kW

The important part is that we do not need grid export.

The idea is basically a backup/off-grid style system:

When the grid is available, the house can use grid power and the batteries/solar system normally. If the grid fails, we want the inverter + batteries + PV to supply the necessary loads.

Because we don't need export, using a full 3-phase hybrid inverter seems unnecessarily expensive. We have access to much more cost-effective single-phase off-grid inverters, but the building itself has a 3-phase supply.

We don't yet have the exact L1/L2/L3 load distribution, but the total backup load should stay below approximately 8 kW.

So my main question is:

How do you normally integrate a single-phase off-grid inverter into an installation that has a 3-phase grid connection?

I'm NOT talking about using three single-phase inverters in parallel to create a 3-phase system. I'm specifically interested in using one single-phase inverter.

Would you:

• move all essential/backup loads onto one phase?
• create a separate backup subpanel supplied by the inverter?
• reorganize the existing loads between phases?
• use some other transfer/changeover configuration?

And what happens if the property has actual 3-phase loads rather than just single-phase loads distributed across L1/L2/L3?

I'd especially appreciate hearing from anyone who has actually installed a system like this. I'm interested in real-world practices, limitations and things we should be careful about.

This is r/SolarDIY’s step-by-step planning guide. It takes you from first numbers to a buildable plan: measure loads, find sun hours, choose system type, size the array and batteries, pick an inverter, design strings, and handle wiring, safety, permits, and commissioning. It covers grid-tied, hybrid, and off-grid systems.

TL;DR

Plan in this order: Loads → Sun Hours → System Type → Array Size → Battery (if any) → Inverter → Strings → BOS and Permits → Commissioning. 

1) First Things First: Know Your Loads and Your goal

This part feels like homework, but I promise it's the most crucial step. You can't design a system if you don't know what you're powering. Grab a year's worth of power bills. We need to find your average daily kWh usage: just divide the annual total by 365.

Pull 12 months of bills.

• Avg kWh/day = (Annual kWh) / 365
• Note peak days and big hitters like HVAC, well pump, EV, shop tools.

Pick a goal:

• Grid-tied: lowest cost per kWh, no outage backup
• Hybrid: grid plus battery backup for critical loads
• Off-grid: full independence, design for worst-case winter

Tip: Trim waste first with LEDs and efficient appliances. Every kWh you do not use is a panel you do not buy.

Do not forget idle draws. Inverters and DC-DC devices consume standby watts. Include them in your daily Wh.

Example Appliance Load List:

Heads-up: The numbers below are a real-world example from a single home and should be used as a reference for the process only. Do not copy these values for your own plan. Your appliances may have different energy needs. Always do your own due diligence.

• Heat Pump (240V): ~15 kWh/day
• EV Charger (240V): ~20 kWh/day (for a typical daily commute)
• Home Workshop (240V): ~20 kWh/day (representing heavy use)
• Swimming Pool (240V): ~18 kWh/day (with pump and heater)
• Electric Stove (240V): ~7 kWh/day
• Heat Pump Water Heater (240V): ~3 kWh/day, plus ~2 kWh per additional person
• Washer & Heat Pump Dryer (240V): ~3 kWh/day
• Well Pump (240V): ~2 kWh/day
• Emergency Medical Equipment (120V): ~2 kWh/day
• Refrigerator (120V): ~2 kWh/day
• Upright Freezer (120V): ~2 kWh/day
• Dishwasher (120V): ~1 kWh/day (using eco mode)
• Miscellaneous Loads (120V): ~1 kWh/day (for lights, TV, computers, etc.)
• Microwave (120V): ~0.5 kWh/day
• Air Fryer (120V): ~0.5 kWh/day

2) Sun Hours and Site Reality Check

Before you even think about panel models or battery brands, you need to become a student of the sun and your own property. 

The key number you're looking for is:

Peak Sun Hours (PSH). This isn't just the number of hours the sun is in the sky. Think of it as the total solar energy delivered to your roof, concentrated into hours of 'perfect' sun. Five PSH could mean five hours of brilliant, direct sun, or a longer, hazy day with the same total energy.

Your best friend for this task is a free online tool called NREL PVWatts. Just plug in your address, and it will give you an estimate of the solar resources available to you, month by month.

Now, take a walk around your property and be brutally honest. That beautiful oak tree your grandfather planted? In the world of solar, it's a potential villain.

Shade is the enemy of production. Even partial shading on a simple string of panels can drastically reduce its output. If you have unavoidable shade, you'll want to seriously consider microinverters or optimizers, which let each panel work independently. Also, look at your roof. A south-facing roof is the gold standard in the northern hemisphere , but east or west-facing roofs are perfectly fine (you might just need an extra panel or two to hit your goals).

Quick Checklist:

• Check shade. If it is unavoidable, consider microinverters or optimizers.
• Roof orientation: south is best. East or west works with a few more watts.
• Flat or ground mount: pick a sensible tilt and keep airflow under modules.

Small roofs, vans, cabins: Measure your rectangles and pre-fit panel footprints. Mixing formats can squeeze out extra watts.

For resource and PSH data, see NREL NSRDB.

3) Choose Your System Type

• Grid-tied: simple, no batteries. Utility permission and net-metering or net-billing rules matter. For example, California shifted to avoided-cost crediting under CPUC Net Billing
• Hybrid: battery plus hybrid inverter for backup and time-of-use shifting. Put critical loads on a backup subpanel
• Off-grid: batteries plus often a generator for long gray spells. More margin, more math, more satisfaction

Days of autonomy, practical view: Cover overnight and plan to recharge during the day. Local weather and load shape beat fixed three-day rules.

4) Array Sizing

Ready for a little math? Don't worry, it's simple. To get a rough idea of your array size, use this formula:

Array size formula

• Peak Sun Hours (PSH): This is the magic number you get from PVWatts for your location. It's not just how many hours the sun is up; it's the equivalent hours of perfect, peak sun.
• Efficiency Loss (η): No system is 100% efficient. Expect to lose some power to wiring, heat, and converting from DC to AC. A good starting guess is ~0.80 for a simple grid-tied system and ~0.70 if you have batteries
• Convert watts to panel count. Example: 5,200 W ÷ 400 W ≈ 13 modules

Validate with PVWatts and check monthly outputs before you spend.

Production sniff test, real world: about 10 kW in sunny SoCal often nets about 50 kWh per day, roughly five effective sun-hours after losses. PVWatts will confirm what is reasonable for your ZIP.

5) Battery Sizing (if Hybrid or Off-Grid)

If you're building a hybrid or off-grid system, your battery bank is your energy savings account.

Pick Days of Autonomy (DOA), Depth of Discharge (DoD), and assume round-trip efficiency around 92 to 95 percent for LiFePO₄.

Battery Size Formula

Let's break that down:

• Daily kWh Usage: You already figured this out in step one. It's how much energy you need to pull from your 'account' each day.
• Days of Autonomy (DOA): This is the big one. Ask yourself: 'How many dark, cloudy, or stormy days in a row do I want my system to survive without any help from the sun or a generator?' For a critical backup system, one day might be enough. For a true off-grid cabin in a snowy climate, you might plan for three or more.
• Depth of Discharge (DoD): You never want to drain your batteries completely. Modern Lithium Iron Phosphate (LiFePO₄) batteries are comfortable being discharged to 80% or even 90% regularly, which is one reason they're so popular. Older lead-acid batteries prefer shallower cycles, often around 50%.
• Efficiency: There are small losses when charging and discharging a battery. For LiFePO₄, a round-trip efficiency of 92-95% is a safe bet.

Answering these questions will tell you exactly how many kilowatt-hours of storage you need to buy.

Quick Take:

• LiFePO₄: deeper cycles, long life, higher upfront
• Lead-acid: cheaper upfront, shallower cycles, more maintenance

6) Inverter Selection

The inverter is the brain of your entire operation. Its main job is to take the DC power produced by your solar panels and stored in your batteries and convert it into the standard AC power that your appliances use. Picking the right one is about matching its capabilities to your needs.

First, you need to size it for your loads. Look at two numbers:

1. Continuous Power: This is the workhorse rating. It should be at least 25% higher than the total wattage of all the appliances you expect to run at the same time.
2. Surge Power: This is the inverter's momentary muscle. Big appliances with motors( like a well pump, refrigerator, or air conditioner) need a huge kick of energy to get started. Your inverter's surge rating must be high enough to handle this, often two to three times the motor's running watts.

Next, match the inverter to your system type. For a simple grid-tied system with no shade, a string inverter is the most cost-effective. 

If you have a complex roof or shading issues, microinverters or optimizers are a better choice because they manage each panel individually. For any system with batteries, you'll need a

hybrid or off-grid inverter-charger. These are smarter, more powerful units that can manage power from the grid, the sun, and the batteries all at once. When building a modern battery-based system, it's wise to choose components designed for a 48-volt battery bank, as this is the emerging standard.

Quick Take:

• Continuous: at least 1.25 times expected simultaneous load
• Surge: two to three times for motors such as well pumps and compressors
• Grid-tie: string inverter for lower dollars per watt, microinverters or optimizers for shade tolerance and module-level data plus easier rapid shutdown
• Hybrid or off-grid: battery-capable inverter or inverter-charger. Match battery voltage. Modern builds favor 48 V
• Compare MPPT count, PV input limits, transfer time, generator support, and battery communications such as CAN or RS485

Heads-up: some inverters are re-badged under multiple brands. A living wiki map, brand to OEM, helps compare firmware, support, and warranty.

7) String Design

This is where you move from big-picture planning to the nitty-gritty details, and it's critical to get it right. Think of your inverter as having a very specific diet. You have to feed it the right voltage, or it will get sick (or just plain refuse to work).

Grab your panel's datasheet and your local temperature extremes. You're looking for two golden rules:

The Cold Weather Rule: On the coldest possible morning, the combined open-circuit voltage (Voc) of all panels in a series string must be less than your inverter's maximum DC input voltage. Voltage spikes in the cold, and exceeding the limit can permanently fry your inverter. This is a smoke-releasing, warranty-voiding mistake.

The Hot Weather Rule: On the hottest summer day, the combined maximum power point voltage (Vmp) of your string must be greater than your inverter's minimum MPPT voltage. Voltage sags in the heat. If it drops too low, your inverter will just go to sleep and stop producing power, right when you need it most.

String design checklist:

• Map strings so each MPPT sees similar orientation and IV curves
• Mixed modules: do not mix different panels in the same series string. If necessary, isolate by MPPT
• Partial shade: micros or optimizers often beat plain strings

Microinverter BOM reminder: budget Q-cables, combiner or Envoy, AC disconnect, correctly sized breakers and labels. These are easy to overlook until the last minute.

8) Wiring, Protection and BOS

Welcome to 'Balance of System,' or BOS. This is the industry term for all the essential gear that isn't a panel or an inverter: the wires, fuses, breakers, disconnects, and connectors that safely tie everything together. Getting the BOS right is the difference between a reliable system and a fire hazard

Think of your wires like pipes. If you use a wire that's too small for a long run of panels, you'll lose pressure along the way. That's called voltage drop, and you should aim to keep it below 2-3% to avoid wasting precious power.

The most important part of BOS is overcurrent protection (OCPD). These are your fuses and circuit breakers. Their job is simple: if something goes wrong and the current spikes, they sacrifice themselves by blowing or tripping, which cuts the circuit and protects your expensive inverter and batteries from damage. You need them in several key places, as shown in the system map

Finally, follow the code for safety requirements like grounding and Rapid Shutdown. Most modern rooftop systems are required to have a rapid shutdown function, which de-energizes the panels on the roof with the flip of a switch for firefighter safety. Always label everything clearly. Your future self (and any electrician who works on your system) will thank you.

• Voltage drop: aim at or below 2 to 3 percent on long PV runs, 1 to 2 percent on battery runs
• Overcurrent protection: fuses or breakers at array to combiner, combiner to controller or inverter, and battery to inverter
• Disconnects: DC and AC where required. Label everything
• SPDs: surge protection on array, DC bus, and AC side where appropriate
• Grounding and Rapid Shutdown: follow NEC and your AHJ. Rooftop systems need rapid shutdown

Don’t Forget: main-panel backfeed rules and hold-down kits, conduit size and fill, string fusing, labels, spare glands and strain reliefs, torque specs.

Mini-map, common order:

PV strings → Combiner or Fuses → DC Disconnect → MPPT or Hybrid Inverter → Battery OCPD → Battery → Inverter AC → AC Disconnect → Service or Critical-Loads Panel

9) Permits, Interconnection and Incentives in the U.S.

• Most jurisdictions require permits, even off-grid. Submit plan set, one-line, spec sheets. Pass final inspection before flipping the switch
• Interconnection for grid-tie or hybrid: apply early. Utilities can take time on bi-directional meters
• Net-metering and net-billing rules vary and can change payback in a big way
• See our Tax Credit and Incentives Guide for the 30 percent federal ITC and state programs. For California policy context, seeCPUC Net Energy Metering and Net BillingCPUC Net Energy Metering and Net Billing

Tip: many save by buying a kit, handling permits and interconnection, and hiring labor-only for install.

10) Commissioning Checklist

• Polarity verified and open-circuit string voltages as expected
• Breakers and fuses sized correctly and labels applied
• Inverter app set up: grid profile, CT direction, time
• Battery BMS happy and cold-weather charge limits set
• First sunny day: see if production matches your PVWatts ballpark

Special Variants and Real-World Lessons

A) Cost anatomy for about 9 to 10 kW with microinverters and DIY

Panels roughly 32 percent of cost, microinverters roughly 31 percent. Racking, BOS, permits, equipment rental and small parts make up the rest.

B) Carports and Bifacial

• Design the steel to the module grid so rails or purlins land on factory holes. Hide wiring and optimizers inside purlins for a clean underside
• Cantilever means bigger footers and more permitting time. Some utilities require a visible-blade disconnect by the meter. Multi-inverter builds can need a four-pole unit. Ask early
• Chasing bifacial gains: rear-side output depends on ground albedo, module height, and spacing.

Handy Links

• Production calculator: NREL PVWatts
• Solar resource and PSH: NREL NSRDB
• Policy, California example: CPUC Net Energy Metering and Net Billing
• U.S. incentives: DSIRE
• Tax Credit and Incentives Guide: Link to wiki

You now have a clear path from first numbers to a buildable plan. Start with loads and sun hours, choose your system type, then size the array, batteries, and inverter. Finish with strings, wiring, and the paperwork that makes inspectors comfortable.

Pecron

Any opinions on this set up

PECRON Solar Generator E3600LFP 3072Wh/3600W with 300W Solar Panel
5x3600W AC Outlets Portable Power Station, Expanded to 18.43kWh, LiFePO4 Battery Backup for Home Use, RV, Camping, CPAP

For what?! For starter kit : a basic back-up for refrigerator, chest freezer, charging.

Hello,

I'm in a state (New Mexico) that has yet to pass legislation allowing balcony solar installs. I'm considering doing it anyways before a bill gets passed, and keeping it discrete as our electrical utility still does manual readings. We get so much sun that it feels like a no-brainer, and I'm concerned pricing will go up in the next 6 months due to global shipping challenges. Is there anything glaring that I'm missing in doing something like this?

I'm the homeowner, and would probably upgrade from my old 100A panel to a 200A service before connecting anything. My home wiring is original from 1960's and doesn't even have a ground, but the outlet I'd connect this to would be new romex. I was hoping to do a couple 400W panels, an Ecoflow Stream inverter, and add in a rack mount LiFePO battery down the line. Am I a fool for jumping the gun on something like this?

Are there any engineering firms that specialize just in solar permitting? Specifically I want to build my own ground mount system from 6x6 timber and I will still need to get permitted by the city for for that I'll need a PE (Professional Engineer) stamp. I've got an over-engineered design, I just need to work to get the stamp.

Previously I did a self-installed rooftop array in which I bought the kit from the solar wholesaler and they had their contracted engineer do the plans and permitted for the city. That's what I need again for this ground mount array.

I’ve been looking at hybrid inverter for my heat pumps but I’m really not sure which ones to get. I am looking to install a 240v inverter outside next to my heat pump and charge my battery when time of use is cheaper. I don’t need a high power one (3kwh?) because I have 6 heat pumps and possibly install one inverter on each heat pump, one at a time. Thank you 🙏

Ive re-terminated various cables before, but never solar. I actually thought MC4 was the standard, but it seems some of the Aiko panels use their proprietary connector.

Am I going to run into any issues with just... cutting them off and re-terminating the wires to something I can use?

I have a bit of a conundrum. I've installed a 13.5 kW system on my roof, and the contractor I had arranged to connect it from the roof space to the installed inverter has disappeared. Or well, I think he was lying that he could do it, then will not answer my calls. And I have had a hell of a time finding someone to do the connection. So now I am casting the net wider.

I've found that solar experts are only interested in doing the whole system, and doing the physical install of the panels myself saved me somewhere in the region of $20k.

Has anyone got an electrican who knows these systems well that does this part of the solar install? I cannot find anyone in Pittsburgh. The system is fully installed, permitted, and with a interconnection agreement. Just literally need the connect.

I'd be prepared to fly someone here from continental US and put them in a hotel for the duration of the work if required.

Anyhelp would be much appreciated.

Additional information: 30 Canadian Solar panesls with Tigo optimizers, and sol-ark inverter. System was designed by an engineer (not me) and stamped.

So... I have two 4kw systems, each with a xantrex gt-3. One panel got smashed by a baseball (?) in a storm, and it took me ages to realize nobody was willing to replace old panels. Eventually I did it myself, after learning how to do it safely. The new panel is a used one of same make and model, and tested well with my cheap chinese panel tester. Full voltage being delivered to the inverter. But... inverter says "insufficient solar". :-(

I could theoretically narrow down the problem by swapping the inputs on the inverters temporarily to see if the problem moves with the inputs, but I'm not sure that's a great idea. (It'd mean making a hack extension for the DC lines.)

Each has two strings in parallel, and the bad unit gradually failed over months after the baseball incident, fwiw.

Thoughts?

How frowned upon is my idea...

I can get nicely priced plug in solar units (1000W panels, 800W inverters, so within the new UK spec), but it'll basically only just cover my daily usage as I work from home.

So I'd like a second of the same kit. And then I'd like to install a battery, so any excess goes to that and I take the excess back from the battery in the evening.

The plug in solar units explicitly state they must not be connected to a battery - which is fine. I'll connect to the AC.

I don't intend on registering the plug in solar units as I don't want to sell back to the grid. I will probably utilise 100% of the energy every day.

Am I "allowed" to do this? Two plug in solar products, plus battery, no professional install except for the mounting of the solar units.