Hot answers tagged

5

That "free" wire is actually a bit of a millstone around your neck in your situation The problem with your "free" 4/0 wire and quadruplex (4/0-4/0-4/0?-4) is that it's somewhat too large for the job at hand. You see, devices like breakers, switches, and panels can't accept arbitrarily large wires for simple reasons of physical space, ...


4

You don’t want one row of panels to place the next row in shade. You need to make a balanced choice about panel spacing... too close and you lose useful solar energy... too far and you have too much darn lawn to mow...


4

This is something the inverter's most likely doing, not your wiring Grid-tie solar inverters are designed to feed power into an operating electric grid, and thus need a grid AC source to synchronize to. If you deny them that grid source, they will refuse to invert. This is to prevent the inverter from trying to power up a dead grid, which poses hazards to ...


3

In stark contrast to some statements seen here, in parts of Europe it is a big trend even for non-electricians to put 1 or 2 photovoltaic modules to the balcony or elsewhere with an on- grid converter. Those are plug- and-play- systems which are easy to install via a connection to the 230V net. Feed back into the grid is economically useless since the ...


3

This is a 125A panel From the labeling on your panel, in particular the note about field upgrading 100A mains to 125A by replacing the main breaker and the meter-to-main-breaker wire jumpers, we can tell that this panel has 125A busbars in it, since UL wouldn't have permitted the manufacturer to provide such an upgrade as an option otherwise. The fact that ...


3

It is not that the compressor motor is inductive, but that, at startup, it draws far more current than while running. This is a characteristic of most electric motors, but is exacerbated that until it is pinning, having a large moment of inertia, the compressor is pushing against the "spring" of uncompressed vapor. The locked rotor current draw might be five ...


3

It's easier to teach a violinist the bongoes than the other way 'round. You should be shopping for an A/C unit with "soft start". This is one of the reasons for these units to exist - ability to start off inverters, generators etc. They use an inverter drive to run the compressor motor. They are also able to run the motor at different speeds to suit ...


2

Pumping heat from the greenhouse into the room could be a feasible thing to do. Recall that the amount of heat transferred from one thing to another is proportional to the difference in temperature between the things. You've got four transfers in the proposed system (greenhouse air -> radiator -> water -> radiator -> indoor air) -- it might be a ...


2

The easy part A Great Big Switch is simplicity itself. You need any Siemens subpanel of 12 spaces or more, and the ECSBPK01 interlock ($25) and two 2-pole breakers. A 60A from your main panel and a whatever-A from your off-grid source. You leave 2 rows empty for style points, then below that you fit the breakers for the circuits you wish to be capable of ...


2

Would it be accurate to re-state the option 3 differently: Have a battery-less system that provides power to our house when the power goes out, but only at all times when the sun is shining, and sells excess to the grid? Probably the biggest reason why your solar installer can't do #1 and #3, ie have panels that sell to the grid normally, and work islanded ...


2

What that listing says is this panel is made with wire jumpers between the meter pan and the main breaker. If the wire is 1 AWG, the panel is rated 100A. If 1/0, then 125A. Either way, that wire which is what differentiates the two ratings, is in series with the main breaker, so protected by the main breaker. Therefore it is out of scope for the 120% solar ...


2

PCs, especially cheap PCs, have pretty big power supplies. The "850 watt" power supply actually draws over 1200 watts. It sounds like your PC is simply too much for the system. It may be necessary to downsize the PC, maybe get rid of performance video cards, get a smaller power supply, etc. One of the "micro-PCs or a Mac Mini would be a ...


2

You're not only mixing different models. You're also mixing new and used batteries. This means, as a pack, you will get the performance of the worst battery. When it gives up the ghost, you will be left with 1 battery that still has some useful life, and you will be tempted to pair it with a new battery. Don't. At that point replace with all new. Keep in ...


2

Can you - yes. Is it a good idea - no. A 150AH @ C10 and 150AH @ C20 battery are not the same "size" because one is rated at the 10-hour discharge rate and the other is rated at the 20 hour discharge rate. Since you have not specified some other chemistry, I'm assuming both are lead-acid 12V batteries, as the majority of 12V batteries are. If by &...


2

A much simpler solution: Build your pergola with rafters that are aligned in the most aesthetically pleasing manner to you (this is a personal preference and none of us can answer that for you). Then, once it's built, plant some leafy vines at the base of each post, or in pots near the top and train the vines to cover the roof. As the vines grow, they'll ...


2

Given you say the shed/house cable was completely disconnected from the input, and is being used the other way around, then there's something else going on. You have not fully disconnected the link wire, and it is still connected to other wall jacks with load on them? Your inverter is simply too small and the cable's length is causing too many losses. But ...


2

I gather the service panel is full, otherwise you'd just backfeed a 2-pole breaker there. The junction box would have to be absolutely enormous because of the wire bending rules for such large feeder. So how about killing 2 birds with 1 stone? You might as well use a load center there instead of the junction box; not least, it comes with all the lugs you ...


2

There's no magic here. Plenty of engineering, though. Yes, the inverter output needs to be greater than your peak load. Not only that, your battery bank size needs to be adequate that the peak load is not exceeding the battery bank charge drawdown rate. Hint, yours is not - you're contemplating drawing over 100 amps at 24 volts off a 200AH battery, or C/2 - ...


1

I don't have any experience to answer this directly but this might help you work it out yourself. There is a sundial simulator which is open source, you can view it at https://tvf.github.io/sundial/ and it allows you to upload your own "sundial" model and choose any location and date you like. The upload format it understands is .obj, this should ...


1

Your problem #1: UL/CSA/ETL certification exists for rather good reasons The primary problem with what you've picked out so far for gear is that basically none of it is correctly listed to the applicable UL specifications (UL 1703 for solar panels, UL 1741 for charge controllers and inverters, and UL 1973 for non-lead-acid type stationary service batteries). ...


1

PCs, especially cheap PCs, have pretty big power supplies. The "850 watt" power supply actually draws over 1200 watts. It sounds like your PC is simply too much for the system. It may be necessary to downsize the PC, maybe get rid of performance video cards, get a smaller power supply, etc. One of the "micro-PCs or a Mac Mini would be a great ...


1

If you have utility-provided electric service now, then you probably want to use a GRID-TIED inverter and generally fewer are better than more unless you go the "micro-inverter" route. For example I have a system with 50 330W panels and one Fronius Primo 15KW inverter. It's sized to provide 100% of my average usage but there are scenarios that ...


1

Well, there's optimal, and there's working with what you have. Optimal is large capacity batteries in series. Really optimal is connecting that to a charge controller that actually looks at each cell voltage individually and can adjust - those tend to be rather high-end "boat" systems in my experience, and probably unaffordable for the African bush,...


1

Motor startup surge is going to be the biggest issue. You will probably need a 2000W inverter for this. The motor will surely be 240V. Pump motors are run at the highest practicable voltage to reduce voltage drop. A motor is typically at the bottom of a potentially deep well, and so the run from house to wellhead, then down the well itself can be 600 feet ...


1

If you have not yet bought the pump, you may want to reconsider. If you buy a 3 phase pump, you can use a VFD to power it. Use a VFD that will accept a DC input directly, then you don't need the inverter (it IS an inverter). That will avoid the starting current surge of the motor, because VFD controls that. The down sides: Your DC voltage for a 230V pump ...


1

"Romex" is a brand name, not a type. But generally people mean NM-B when they say that. They meant you can't run "Romex" outdoors in conduit. It's technically possible to run indoor Romex (NM-B) in conduit, though the conduit tends to be bulky for the size due to the oval shape of the wire. It's treated as a round wire of the larger dimension. They ...


1

What you can do is run your Romex as planned to a junction box on the inside wall and run conduit from the junction box through the wall to your combiner box. Splice your 10/2 Romex to #10 AWG THHN single conductors with wire nuts and run the THHN in the conduit to your combiner box. That should keep everyone happy.


1

In most cases, take it on a trip to the recycling center, or trade it in to be recycled when you buy the replacement. Lead acid batteries are a consumable item in solar service, and more so if the solar service is poorly managed such that they are not brought to full charge, or are over-discharged on a regular basis. They are a finicky and fickle part of the ...


1

I doubt sealer from the outside will be any sort of long-term fix. Either the joint has come apart or one of the pieces has split. Either way you'll need to take it apart, replace any broken parts and reassemble the parts with proper solvent.


Only top voted, non community-wiki answers of a minimum length are eligible