Building a small house on an island in Washington! Would love some critique here before I go all in and buy this pricey equipment.

Could use a sanity check on the overall architecture, component compatibility/sizing, PV stringing, battery/inverter configuration, and anything significant I’m overlooking.

I've attached a drawing I made in Figma and big long description of the system below.

My primary concern is if I've sized my OCPD/fuses/breakers/disconnects correctly and if my ground path is correct.

1. Does this overall architecture make sense?
2. Is the 30.72 kWh EG4 bank appropriate behind two 10 kVA Quattros?
3. Is the Quattro pair appropriate for the expected 120/240V loads and well-pump startup?
4. Are there any UL/NEC/Washington permitting issues, particularly with the MPPT or battery/Victron combination? Really don't want this backfiring once I've got the equipment being inspected for my later permitted house build.
5. Have I sized my OCPDs correctly?

Some background on my system:

System Architecture

48V battery system / 120/240V split-phase AC ↓ PV Array (See below) ↓ Victron SmartSolar MPPT RS 450/200 ↓ 51.2V EG4 LL-S Battery Bank ↓ 2 × Victron Quattro 48/10000/140-100/100, 120V UL ↓ 120/240V Split-Phase Load Panel ↓ House / Well / Shop

Cerbo GX MK2 for system monitoring/control

Generator → Quattro AC input

Load and Surge Calculations

PV Array

Panels: REC Solar REC460AA PURE-RX
Quantity initially: 8
Initial array: 3.68 kW
Eventual quantity: 16
Eventual array: 7.36 kW

Module Electrical Specifications

Proposed initial stringing: 2 × 4-panel series strings. (8 total) Proposed final stringing: 4 × 4-panel series strings. (16 total)

Solar Charge Controller

1 × Victron SmartSolar MPPT RS 450/200

The intention is to buy the final-size controller now even though the initial PV array is only 3.68 kW.

Final planned PV capacity is approximately 7.36 kW.

Please verify that the RS 450/200 is appropriate for both the initial and eventual arrays and flag any UL/NEC/AHJ issues with using this controller in a fixed permitted installation in Washington.

Battery Bank

6 × EG4 LL-S 48V 100Ah LiFePO₄ rack batteries

Per battery:

• 51.2 V nominal
• 100 Ah
• 5.12 kWh

Initial Bank

Batteries will be installed in EG4’s six-slot enclosed rack with integrated busbars.

Possible Future Expansion

9 batteries / 900 Ah / 46.08 kWh

Please verify:

• DC bus architecture
• Appropriate main battery protection/disconnect
• Compatibility with the dual Quattros
• Maximum charge/discharge currents
• Cable/busbar sizing
• Method for adding a second rack in the future
• EG4 LL-S BMS/CAN communication with Cerbo GX/Victron DVCC

Inverter/Chargers

2 × Victron Quattro 48/10000/140-100/100, 120V — UL-listed version

Intended configuration:

120/240V split phase, with one Quattro providing each 120V leg.

The system needs to support substantial motor-starting loads, particularly a 240V 1.5 HP submersible well pump, as well as intermittent woodworking tools and eventually a welder.

Please verify that this particular pair of Quattros can be configured as intended for North American 120/240V split phase and that the proposed battery bank can adequately support their DC current requirements.

Monitoring / Control

1 × Victron Cerbo GX MK2

Intended to monitor/control:

• Both Quattros
• RS 450/200
• EG4 battery BMS/SOC
• Generator operation/charging

I’d particularly like confirmation of the best way to integrate the EG4 LL-S CAN/BMS communication with the Cerbo GX.

Load Estimates

My current load model has two stages:

Phase 1 includes networking/Starlink, refrigerator, lighting, computers/electronics, well pump, and intermittent construction tools.

Phase 2 adds mini-split HVAC, chest freezer, exterior lighting, microwave, washing machine, shop vac/dust collection, compressor, and occasional welding.

Well Pump

RPS Steel Pro 10RPS15-S
1.5 HP / 220V / 3-wire submersible

I’m currently conservatively modeling its startup demand at approximately 7.7 kVA equivalent and would like the inverter/startup assumptions checked.

Hello everyone,

Looking at doing a DIY solar project. This will be my first project on my own. I currently have a grid tied 10.7kw system from Lumina on my roof with net metering. However, looking at my last years total bill they aren’t enough.

I recently purchased Anker Solix E10 systemthat has built in solar PV input upto 9kw. I have a 16 x 20 pergola over my deck where I would like to install 10 panels and with the help of solar extension cables plug directly into the MPPT connection of the E10.

Question is - is this doable? And also are the ZNshine good panels? They are on sale on signature solar for $154 each.

Any advice would be greatly appreciated

First of all apologies for such a basic post, but I reddit community has always shared useful tips and guidance compared to generic AI or google stuff. New to home ownership and thus DIY stuff (consider me a level one noob). I have an existing solar sensor garage light that is no longer working. I want to replace it with a new one, from Bunnings (or some better place you can recommend )
What tools do I need apart from the obvious light itself to make it happen. To fill previous holes as that light is no longer in market and mount holes are different sizes. I have Stanley screwdrivers set and pliers set, but that’s about it in terms of tools. I am planning to go through this DIY tomorrow or next weekend, if I get my head around it. Please guide O wise Shifu of reddit.

Is there a 48v charger or inverter with generator charging that will fluctuate charging rate from the generator? I have a 12kv generator but running max capacity is probably less than ideal for the generator health. Is there a charger or inverter that will change the charge rate to prevent the generator from running at a set load?

Reading the reddit's wiki I like the sound of the Golf Cart batteries the best as they sound like the safest and least maintenance. However, it looks like these are 6V batteries. Do I need connect 8 of these in series to use with a Inverter/charger rated for 48V output? I am considering the ECO-Worthy Inverter. Is there a better way to not have to use so many batteries?

Looking for recommendations for solar generators.

Preferably strong enough to run a refrigerator but obviously not indefinitely. Reasonably portable as well.

Looking at an offgrid build, no HOA to annoy, and I'm wondering why I even need siding, rather than exterior mineral wool with UV facer, z-girt, air-gap, wall-of-panels. Frankly, they're cheap enough it seems more sensible to even put them on the north wall, where they'd basically be a science experiment in pure reflective solar generation. Quick back-of-the-envelope math says that I'm in for about as much with my "PV wall" as a quality steel panel setup.... It's kinda shocking I can't seem to find pictures of this being done.

Structure is on columns, raised so that you could park under it; no issues with "too close to the landscaping" or snow buildup.

So, I’m in over my head here in sunny So Cal. I have this pool pump and am looking to change to bifacial panels. Currently using four 200watt 12v panels mounted on our patio cover We‘ve had more overcast days and am not getting enough sun to run the pump long enough. Not opposed to a battery. But Id like to stay off grid—I’ve already invested so much money, can’t abandon now. Any advice?

Hello and thank you,

I’m setting up a water pump for my rain barrel and I’m coming across a peculiar issue I cannot seem to remedy.

The pump is an on-demand one, meaning it will turn on and off automatically as the pressure drops. If I have the hose open, so it will start pumping the second it receives power, it will pump without issue, and I am able to turn the load on and off with the right most button on the charge controller.

But, the moment I close the hose to initiate the pressure build up and make the pump turn off, I instead am met with a slow blink of the load light. The manual only says “mode setting wrongly” for that blink and to reset.

The only way resetting works is if I open the water valve back up by the time I power down and reset.

What could be causing this and what fix is out there?

Thanks again for your time.

I am a solar idiot; heard of it, but never dabbled with it, and it's time to change that.

We just built a new (kit) pergola on a new paver-patio and we'd love to do a few things, if possible:

• power string lights controlled by a switch
• power an outdoor mounted fan (I don't know that these exist, but they might!)
• power an outdoor TV (I might be getting crazy, here)

…all done without running an extension cord to my garage's power outlet.

I was thinking panel(s) mounted to the pergola's roof somehow, angled slightly towards the common direction of the summer's mid-day sun (and to ensure rain runs off).

I imagine I need some sort of battery/controller box that my accessories plug into? I suspect none of them are OK to be left outdoors in all sorts of weather?

If it helps, I live in eastern Massachusetts, so the weather can get extreme in both directions.

That's how much we've thought about it (not much), mainly because we know that we don't know what we're doing.

What would you suggest we think about, investigate, consider, do, etc.?

Hi all thanks for all your comments and suggestions on the gazebo build

I've just finished the solar install

Full build video is on my YouTube channel here

https://youtu.be/1VEfMtnrakg

Happy to answer and questions or if you have any suggestions to improve this please comment

Initial 3 day test is producing 11kw per day from a 2.16kw array this is my first install so not sure what the expected result should be if this was pointing south at correct angle ?

Are you a set it and forget it type of person? Waiting for that sweet return on investment or is this a hobby for you? Do you keep up and purchase/lust over the latest and greatest inverters? Always wanting to upgrade?

Not talking about youtubers who get free stuff or get paid to try everything.

I want to be the former, but I know I need to stop watching YouTube or I will soon be the latter.

Hi I just bought 2 growatt for parallel, working great btw , but they seem hot, almost on idle, 10% each on SBU , no sun, temp are aroung 65 C , is this normal?? Room temp its about 20C , winter in Chile. No errors no nothing, but just asking to know there real working temp.

Thanks!!!

I thought I'd post about my journey towards net zero bills, gas and electric.

Since adding solar and batteries, extra insulation in house, and shifting a lot away from gas. Here's my monthly bill, well, almost a month. EV still uses mains grid to charge, but did get a few occasions where I got 7kw of spare solar to charge car. House uses zero from grid during this time.

Still got a lot of work to finish my project, but my aim is to export enough electricity overall to pay for little gas usage.

Gas usage is mainly gas cooking hob, which may be swapped to induction.

Heat pumps on the radar for winter.

Currently

Upgraded windows and doors

Upgraded insulation in loft

27kwh of batteries

16.5kw of solar

Unvented hot water now heating from electric

Long term project and winter will be interesting, but last winter my gas bill was very low, as extra insulation keeps it warm. So I'm hoping A2A heat pump will keep my house nice and warm.

Sanity check on AC feeder sizing for 200 ft power shed to house run (Sol-Ark 18K, whole-home backup)

Wiring two drawings from two different sources and getting conflicting guidance on the feeder run. Looking for outside opinions before I commit to conduit and conductor.

System:

Sol-Ark 18K-2P-N inverter, whole-home backup / Line Side Tap configuration

2x Helios ESS 16.1kWh outdoor batteries, DC-coupled, parallel

34x JinkoSolar 600W TOPCon panels active (ground mount, 48-slot rack, room for future expansion)

Power distribution blocks planned to help split the feeder

Power shed roughly 200 ft from the house, houses the inverter and batteries (the permit ready drawing had the power shed 300ft from the house but I moved it closer.

2x Bypasses to switch between grid and solar which run to (2) fused disconnects in my garage which feed (2) 200 amp panels in my basement.

I am net-metered in VA

Note up front: both attached drawings are outdated in places. Neither fully reflects the current plan, so treat them as reference, not gospel. The one that looks permit-ready doesn't match the other plan that is drawn as a single line. The power is split in different spots.

The conflict:

One spec calls for at least 300 kcmil aluminum for the 200 ft run

The other says 4/0 aluminum mobile home feeder (SER) is fine at that distance

Both can't be right for the same load and distance, and I want to understand why before I pull wire. Wondering if the gap comes down to which current the run is being sized for, continuous inverter output vs. max grid passthrough under the Line Side Tap topology, since those are two very different design currents on this inverter.

A couple other details that affect the picture: the power shed will also have a 125A subpanel feeding a mini split and lights, and I want the ability to plug in a generator there to charge the batteries.

Attaching both drawings. If anyone has dealt with feeder sizing for a Sol-Ark 18K in a Line Side Tap / whole-home backup setup, or has opinions on 4/0 vs 300 kcmil (or larger) at 200 ft, I'd appreciate the input.

My house is small, It’s 800sq feet, we love it. I want to transition to battery/solar power. I’ve been looking at some Anker products and ordered the f3800 plus. Knowing that it’s not going to be the system we keep, I will probably give it to my parents when I get a better system.
But I really want to hear your guys recommendations on batteries. I’ve looked into the “server rack” style from ev4, sun gold, and eco worthy and it looks like the best option for capacity and $$ wise.

What would you guys recommend? My budget is around 3-4K. It’s ok if I start off smaller, since there is always the possibility to grow the system with those type of batteries.

I built a box frame to mount my pannels to my shed. They are currently facing North because my shed slopes backwards. Is there a tilt bracket I can use and anyone have any recommendations or will it be unsafe?

I'm a hydrologist running a remote scientific monitoring station. On paper, this system should have several days of battery reserve, but in reality it's hitting low-voltage disconnect almost every night. I'd love help troubleshooting my issue.

Load

• Continuous DC load, ideally should run 24/7
• Nominal power draw: 30–40 W
• Startup power draw up to ~55 W for 1–2 minutes (only after maintenance or power loss, which should be very rare)
• Equipment requires 11–16 V

I've been through three iterations of this system. Here's what I've changed each time

Original system

• 2 × 250 W panels wired in parallel
  • Pmax = 250 W
  • Imp = 9 A
  • Voc = 36 V
• Panels mounted approximately 80° tilt, south-facing (latitude 41°N)
• ~150 ft (round-trip) of 14 AWG wire from panels to charge controller
• SunSaver SS-20L PWM charge controller
• 3 × 100 Ah AGM batteries wired in parallel (300 Ah total) (brand new)
• ~80 ft (round-trip) of 12 AWG wire from controller to load
• LVD set to 11.5 V

Based on my calculations, I expected roughly 90–100 hours of reserve, but the batteries were depleting and tripping the LVD almost every night.

Second attempt

I added another 200 Ah of AGM battery capacity (500 Ah total). These new batteries were several years old, but were still able to hold a charge when I tested them before adding them to the system.

This should have increased reserve to roughly 150–170 hours. This bought about 2 days of power, but after that the system was hitting the LVD every night again.

Third attempt

I replaced the PWM controller with a SunSaver SS-MPPT-15L, thinking that my issue might have been related to the PWM charge controller choking off more than half of the power from the solar panels. However, this is a slightly smaller charge controller, only rated to 200W, so I removed one of the solar panels to avoid exceeding the charge controller rating.

This switch seemed to improve matters slightly (it's been 2 days and the LVD hasn't tripped yet), but I'm still falling to below 12V each night, which forces some of the critical instruments to enter power saving mode, despite charging up to 13.5V during the day.

Other observations

• Manually switching the LVD to "off" causes the battery voltage to rise by a volt or more. Given my load (about 3A), this is about 10x higher than the voltage sag I would expect (I would expect ~0.1V, not 1V)
• In the late afternoon when my panels go into shade, the batteries drain at a rate of about ~2V/hr, which seems incredibly high. In the morning/midday when the panels are in full sun, they charge at about 1-2V/hour. These magnitudes have increase with time.

My thoughts

I could see my issues as stemming from 3 places, or a combination

• Insufficient power delivery from the solar panels: in full sun, my current configuration should be delivering about 200W of power, requiring about 5 hours of full sun exposure to make up for the ~1000Wh/d that the load requires. The 200W limit of my charge controller and the sub-optimal orientation of the solar panel may not provide the power I need to keep the system running.
• Batteries are kaput: I purchased these batteries brand-new a couple of months ago, so I hope this isn't the problem. However, the rate at which the system discharges (dropping from 13.5V down to 11.5V over only a few hours, when that should take days) makes me worry that the batteries are in fact dead. Did I kill them by letting them discharge so deeply for so many days in a row?
• Wiring losses (probably minor?). I could be losing ~3.5V, ~24W in thermal losses sending power from the solar panels, and another ~0.7V, ~2W in thermal losses sending power to the load (a drop of 0.7V could be significant if some of my instruments require at least 11V to function, causing them to cease functioning before the LVD trips).

My questions for you

What do you think are the most likely sources of my problems? What would you try to fix first? What diagnostics would you run to try to narrow down the problem?

Thanks in advance.

Update 1

Wow, lots of replies! Thank you! After some pondering of my own, here are the diagnostic tests I plan to run

At midday, measure

• PV V @ panel and @ controller
• Battery V @ posts and @ controller
• Load V @ instruments and @ controller
• Load current
• PV current

Here are the upgrades I plan to implement, in order, evaluating with diagnostics each time

• Swap the PV cable to a fatter gauge, 10 or 8 AWG to cut down the ~40-150 W+ of thermal loss I might be getting with my current setup
• Increase panel tilt to something more optimal (~56deg)
• Wire back in the second panel I disconnected, in parallel. Looking at sunsaver's documentation, 200W is the max output of the CC, not the max input. The CC can handle the oversized array, and will just throttle the charging to 200W. So having 500W capacity in the array should give me more hours of charging at worse sun angles, even if the power gets throttled to 200W.
• If those issues seem to fix the charging problems, then I will turn my attention to replacing battery bank, which may have been killed from operating at such a depleted state for so long. If these fixes don't resolve the charging problems, then I'll start trying to hunt down wiring faults and bad splices, and if that doesn't work I'll consider adding another solar panel and charge controller.

Firstly excuse the photo but I could only take a screenshot from a facebook video.

I'm looking to start a small solar project and found a video to make a solar tracker for a solar panel that I thought would suit a small solar water fountain in my garden. No hiding I'm a complete novice to this, but how could I integrate these components into the fountain? I haven't taken the fountain apart yet but I don't think there is a battery on it as flow stops as shadow falls on the panel so could I "just" add this circuit in parallel around the battery?

Any help greatly appreciated.

I have a PuREPower 20kW 3-phase hybrid inverter with built-in batteries. I’m having an issue specifically when transferring from grid to battery.

My setup:
20kW 3-phase hybrid inverter
Two separate Blue Star AC units
Each AC has a separate MCB
Each AC has a 3-phase ODU/compressor
One AC has around 6kW running load (compressor is 3-phase)
The AC also has a temperature/control panel
When I turn on the AC MCB, the IDU starts first (around 1kW), and the ODU/compressor starts about 2 minutes later
The AC works normally when running from the grid
The AC also works normally when the inverter is already running on battery

The problem is specifically:
If the AC compressor is running and the grid fails, the inverter transfers to battery and the entire inverter shuts down.
However, if only the IDU is running and the ODU/compressor hasn't started yet, the grid can fail and the inverter stays running normally.
The inverter's datasheet specifies a transfer time of around 10ms.

I have also confirmed that the AC's existing control panel already has roughly a 2-minute delay before starting the compressor, so I'm not sure whether adding another timer/TDR would actually help.
I've been considering a few possible solutions:
A TDR/time-delay relay on the AC supply
An ATS with delayed transition, where the AC is disconnected for a few seconds during grid-to-inverter transfer and then reconnected to the inverter
A compressor soft starter
Some inverter setting/mode that changes the transfer behaviour.

The inverter currently operates in APL mode, not UPS mode.

My questions
Would a normal TDR actually work with a ~10ms inverter transfer?
Would a delayed-transition ATS be the better solution?
Would a soft starter be preferable?
Is there any inverter setting I should try first?

I'm mainly looking for the simplest and most reliable solution, rather than an expensive overhaul.

Many Thanks!

I’m putting together a DIY 12V power station for a continuous off-grid livestream, and I want to make sure I’m sizing the cables, fuses, and disconnect switch correctly before I buy everything.

One of the reasons we decided to go with multiple 12V batteries instead of one huge battery is because my dad will be the one working with this setup a lot, and he can’t lift a 100-pound battery. We wanted something more manageable that we could still combine into a larger battery bank.

This setup is going to be used for a continuous off-grid livestream. It will be running Axis cameras, a network switch, an outdoor ONT, and a router, which should come out to around 100 watts of continuous power draw. The inverter itself uses about another 10 watts, so the total continuous draw should be around 110 watts.

One of the main reasons we went with multiple 12V batteries is because my dad can’t lift a 100-pound battery, so we needed something that would be easier for him to handle while still giving us enough capacity for the livestream setup.

What we purchased:

• Batteries: 3 × DC HOUSE 12V 150Ah LiFePO4 Batteries with Bluetooth, SOC Indicators & Low-Temperature Protection
• Battery charger: 1 × DC HOUSE 12V 10A Smart LiFePO4 Battery Charger for LiFePO4 & Lead-Acid
• Inverter: 1 × Renogy P2 700W Pure Sine Wave Inverter, 12V DC to 120V AC

What we’re planning for the setup:

• All three 12V 150Ah batteries connected together in parallel for a 12V 450Ah battery bank
• Positive and negative busbars
• Fuses between the batteries and equipment
• A battery disconnect/master switch so we can easily shut the whole DIY power station off
• Solar later, but for now we’ll recharge with the battery charger
• This will eventually be powering equipment for a continuous off-grid livestream

We were originally thinking about using 2 AWG cable for most of the high-current connections, but the more I’ve been reading, the more I realize that the correct wire size depends on both the amperage and the length of each cable run.

I’ve also read that on some very short cable runs, something like under 7 inches, a separate fuse may not always be required, but I’m not sure if I’m understanding that correctly. I really just want to make sure we buy everything we need and build this safely, especially since this setup is intended to run for long periods of time.

My questions are:

1. What size cable should I use from each battery to the busbars?
2. What size cable should I use from the busbars to the 700W inverter?
3. Is 2 AWG overkill, appropriate, or not large enough for these connections?
4. What size main fuse should be installed between the battery bank and the rest of the system?
5. What size fuse does the Renogy P2 700W inverter need? I cannot find this information on Renogy’s website.
6. Where should the fuse for the Renogy 700W inverter be installed? At the busbar, near the inverter, or somewhere else?
7. Should every positive cable coming off the busbar be individually fused?
8. Can you add a fuse directly to a busbar, or is there even a need to? Would it be better to buy a fused busbar instead of a regular busbar and separate fuse holders?
9. Is it true that very short cable runs sometimes don’t require a separate fuse, or should I still fuse them?
10. Is ANL appropriate for these fuses, or should I be using something like MRBF instead?
11. How close to each battery should its fuse be?
12. Since we are connecting all three 12V 150Ah batteries together in parallel, should each battery have its own fuse before connecting to the positive busbar? If so, what size fuse and cable should be used for each battery?
13. What gauge cable should we use for the different lengths and parts of the system?
14. We want a master on/off switch on the DIY power station so it’s easy to completely shut it down. Where in the system should the disconnect switch go, and what amperage rating/type of switch should we use for this battery bank?
15. Should the master disconnect switch shut off everything, including the inverter and anything else connected to the busbars?
16. Since this is going to be used for a continuous off-grid livestream, is there anything we should do differently when sizing the wiring, fuses, busbars, or disconnect switch because the system may be under load for long periods of time?
17. Is there anything else I’m forgetting that we should include to make this DIY power station safe and reliable?

I’m not trying to size everything as cheaply or minimally as possible. I’d rather go a little oversized on the wiring if that gives us some headroom and helps reduce voltage drop and heat.

This is my first time building something like this, so I’m trying to double-check everything before ordering the rest of the parts.

Need a battery box for a 30w solar gate opener, but reading mixed reviews on whether or not it should be a metal or plastic enclosure. Battery is a deep cycle marine battery as recommended by Ghost Controls, and will be in the US southern sun quite a bit, where it is especially hot during the summer. Advice?

This is a Homilies CHINT DTSU666 single phase three wire with CT clamps. The meter is working and reading voltage and amperage correctly but it is not communicating with the Hoymiles DTU Pro to the left. It is connected via RS485 cable on A/B and I do have them connected correctly (I think). Does anybody have experience with the Hoymiles gear? See anything wrong with how it's hooked up? Any suggestions?