How to Choose the Right Inverter for Your Solar Energy System

With fossil fuels becoming increasingly scarce and utility bills becoming exceedingly expensive, more and more people are considering solar energy. Although solar energy systems are a significant investment, you can make your money back quickly by saving on energy bills, applying for tax credits, and selling energy back to the grid. However, it can be confusing when attempting to set up a solar energy system. Inverter.com is here to tell you more about solar inverters and how to choose the right one for your needs.

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Why Are Solar Inverters Important?

The solar power process starts with sunshine. Photovoltaic cells in solar panels harness the energy from the sunlight, creating an electrical charge. The charge produced is a direct current or DC energy. However, DC is not suitable for use in your home. A solar inverter converts (or inverts) the DC energy into alternating current (AC), a form of energy that is safe and useable by your home appliances and electronics.

Aside from converting electricity to a practical form, solar inverters also help to flatten abnormal spikes or dips in your current and protect your sensitive appliances from damage. Solar inverters help to maximize the energy produced by your system by determining the ideal voltage for your modules to function at their best. Inverters that record production and consumption are a great way to monitor your power usage as well.

The Main Types of Solar Inverters

There are several different types of solar inverters. Here are the four main types available on Inverter.com.

On-grid inverters or grid-tied inverters are solar inverters that connect directly to the utility grid. They convert DC into AC directly to allow users to power their appliances. Users can also send surplus energy to the grid.

Off-grid inverters or stand-alone inverters are designed to work with batteries. They are capable of powering residences or commercial projects by converting DC from the solar panels into AC in storage batteries.

Micro inverters are small inverters attached to individual solar panels. Instead of having a central inverter on a solar array, the DC to AC energy conversion occurs at the panel level.

Hybrid inverters or multi-mode inverters combine the features of on-grid and off-grid inverters. They can draw and convert energy from both the solar array and the battery system.

How to Choose the Right Inverter

1. Choose Your System

Do you want the independence of an off-grid system or prefer to have the security of an on-grid system? If the power grid in your area is unreliable, a hybrid inverter may be better suited to your needs. The hybrid inverters available on Inverter.com can automatically switch between off-grid and on-grid modes to achieve the best energy outcomes. If you plan to have several modules that experience different levels of shading, micro inverters may be the best option to maximize power output.

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2. Compare the Efficiencies

Conversion efficiency determines how much current is lost when DC is turned into AC. Small inefficiencies can add up over time to cost you a fair sum in electricity loss. Thus, you should aim for an efficiency of 96% or higher. The maximum efficiency of an inverter could be as high as 98.6% in some on-grid models with MPPT efficiency of up to 99.5%. MPPT stands for maximum power point tracking and it is the process of optimizing the match between system components to maximize energy extraction.

3. Check Key Parameters

Many features determine how well your solar inverter works. Some of these critical parameters are rated output voltage, output power, and overload capacity. The single-phase voltage level for most countries is between 220V and 240V. However, in the US, the standard voltage level is 120V for most everyday electronics and 240V for appliances such as washing machines and ovens. Your output voltage should be in the safe operating range for your electronics.

4. Look for Quality Construction

Since solar inverters are often installed outdoors, invest in models made of quality materials that can withstand the elements. For instance, the micro inverters on Inverter.com are designed to be waterproof. They avoid deterioration by preventing rainwater from pooling on the inverter surface. Your inverter should also feature an efficient cooling system to prevent overheating due to continued operation or strong sunlight. Look for units with a good working temperature and humidity range.

5. Consider Additional Features

Solar inverters can come with additional features or accessories that add value to your solar energy system. For example, certain hybrid inverters have built-in timers that can switch your inverters on during the day and off during the night. Inverters can come with digital LCD panels that display detailed operational information or be fitted with Wi-Fi data collector devices that enable you to monitor and track your energy data.

Most solar inverters have a minimum warranty of 12 months. That said, it is best to do your research to find the right system for your needs before purchasing your inverter. Inverter.com specializes in reliable power inverter products with competitive prices. If you need professional recommendations on how to set up your solar energy system, visit Inverter.com for the latest in solar technology and expert advice.

For more information, please visit grid connected inverter.

I'm getting started in the planning of a ground mount solar system for my place. I've done design of off grid before but this is a bit different and is my first personal project. Most of the resource seem to want to sell me something so hard to tell what to trust and I've got slightly different needs than most discission I've seen.

I'm looking to do grid tie, total system of probably 5-10 kw, but can go to 20kw, final size will be driven by finances. I'm in the use with 120/240 split phase.

I'm not wanting microinverters as much limits and connection fees are based on total inverter nameplate so it seems to make better money sense to have a few string inverters run with max panels.

I'm not really interested in batteries, ability to use batteries might be nice if it extends my production by saving some peek sun, but I don't see it working out from a cost benefit perspective, at least up front. I don't need backup as my grid is very reliable and I do have a portable generator if I need it, also batteries have extra permitting where I am.

this will be ground mount so need something weather resistant but most of the ul listed units seem to be.

And obviously I'd need something I can actually buy...while I'm 100% legal to do this work it doesn't mean people will sell to me...like the local supply houses ...

thanks

My property is a old farm site. The main panel is a a power pole with a yard light. From there I have a series of subs at various buildings or near former buildings. All of my loads are at my home or shop, the location that works for solars is at a former building 400 ft away from where there are actually loads. I do have some loads at the old building site but small loads like a trickle charger. trenching new lines just is too expensive to make sense.

A bit of a weird setup but I'd want to feed at the sub and then feed back to the main. From my reading of code as long as the breaker from the sub to the main is secured and labeled it is compliant.

Ah ok, yeah you've definitely thought this through.

Couple of weird ideas, which sort of point at there being a fundamental tradeoff between whether you put the inverter 400ft away, and have more MPPTs for more flexibility, vs putting the inverter 0ft away from where you want to backfeed and have easier access to the advanced inverter features.

• If you can get away with a single MPPT, you can send DC string from the "former building" (which presumably has no loads) by repurposing the AC run. It has to be a single MPPT since you don't have enough wires in 4-wire service to do two strings. This allows you to put the inverter next to the place you were originally going to backfeed. You don't need to retrench but you will need to place subpanel with terminal blocks.
  • Note: some equipment can be configured to let you lock two MPPTs together, so that the voltage point is locked but the power is distributed across the transistors from the two MPPTs.
  • There may be some pitfalls with the cable type you're using underground not being approved for solar. I'm not 100% familiar with the code here.
  • You would get lower loss by sending the solar at 450VDC than the inverter output at 240VDC
• Some equipment allows you to use a remote transfer switch to grid form. However, if you put the inverter 400ft away from the transfer switch, you'll still have to run control cable.
• Another issue with 400ft distance is that you will have a tough time adding zero export CTs, etc. Because all that will have to go 400ft. Even with digital communications CTs 400 ft is quite a distance, and you'll have to either trench for twisted pair or go against installation guide and use wireless adapters for RS485. 400 ft is long for the cheap wireless.
• One way to try to get the best of both worlds is to install a grid tie inverter 400ft away to start with. And if you want advanced features later, install a hybrid AC couple-capable inverter 0ft away. This way you can sort of have the best of both worlds - as many MPPT/different DC layout you want 400 ft away, while having an easy time using some fancier inverter features via the hybrid. At present this requires a more expensive inverter (hybrids with this capability are $$$, but I fully expect the prices to go down), and AC coupling is less mature in DIY space than DC coupling (but AC coupling I believe is very well understood in utility scale & at some of the inverter companies like SMA so it's arguably a "us DIYers are temporarily under-educated problem").

You don't necessarily need to use a hold-down on the inverter feed, since grid tie inverters are interactive (IE turn themselves off in a fault). Within 5-10 seconds after an unsecured breaker flies off the busbar, the AC will turn off. If you use hold-down and terminal covers then this 5-10 second window of frying yourself goes away. However, hold-down and terminal covers are not available for all breakers sizes.

I don't think you'll have a huge problem finding someone to sell you stuff. Only thing I can think of off-hand that's not "virtually walk into a store and buy it" is if you want, say, dcbel or other early access hardware. Which nobody on this forum uses.