Backup generator is an optional component in the off grid solar system. However, if you are looking for full energy independence, then it is a must. Keep in mind that solar energy cannot be guaranteed in all days. Even on those days without sunshine or if there is no ample sunshine, you still need to generate energy so as to power the appliances. And in such cases, backup generators can come to your aid providing you with full energy independence. They are the practical secondary source of power in case of no sunlight or low sunlight conditions.
Types of Backup Generators
There can be different types of backup generators available in the market. It is a point to be worth noted that not all of them are compatible with the off grid solar systems. There are mainly two types of backup generators suitable for the off grid solar systems. They are: conventional generators and inverter generators.
Conventional generators are relatively cheap backup generators which are easy to maintain. They are also readily available. They are used in places where portable energy is required. They are a bit noisy and also the energy provided is fluctuating.
Inverter generators are more suited for integration with home systems as they are advanced in their function. They provide reliable energy. They are quieter in operation. They are more fuel efficient. They are expensive. They can also have shorter run times due to smaller fuel tanks.
Factors based on which a backup generator is selected
Most of the off grid solar systems comes paired with a generator which acts as a backup planning case the system is not capable of producing the enough energy so as to meet with the required needs. Look for reliable and durable models which are cost effective. The system used should be compatible with your solar system or else can make the output power not suitable for the connected appliances thereby having adverse consequences. Below mentioned are some of the factors based on which the backup generator is selected for your offgrid solar system.
Sizing considerations of the generator
The size of the backup generator is selected based on the function for which it is intended. It should be capable of charging the batteries while powering the loads as and when needed. And for achieving this, it is essential that the output of the generator be about double the size of the continuous output of the inverter. So a 8000 Watt generator may be needed to be paired with a 4000 Watt inverter. And only then will you be able to power both the loads as well as the battery bank.
The generator fuel used should be efficient and cost effective. The most common fuel used in the backup generator can be diesel, propane, or natural gas. Diesel powered generators are found to be more fuel efficient with longer lasting power when compared to the other alternatives. However, the cost factor associated with diesel backup systems is about double. So propane or natural gas is considered as the most common choice of fuel
Engine Speed of the generator
Based on the engine design and the type of the alternator used, the generator can operate at engine speeds of either 1800 RPM or 3600 RPM. If you consider the aspect of fuel efficiency, then 1800 RPM generator speed is found to be superior over 3600 RPM engine speed. However, the 1800 RPM generators are also found to be costlier. On the other hand, the 3600 RPM generators are on the cheaper side. But the efficiency that they offer is inferior when compared to the 1800 RPM generators.
2-wire start capability
When pairing the off grid backup generators with your solar power systems, it is better to use 2-wire start capability which can elicit a better response from the automatic generator start (AGS) functionality. Suppose if your batteries need a boost charge either because of less solar energy for your solar modules thereby lacking sufficient charge, or in case you have been running some large loads, then the auto-start kit works with the AGS (Auto Generator Start) module in the Inverter/Charger. It seemlessly fires up the backup generator and run it until a pre-set voltage is reached in the battery bank. Once the required level is reached, it is then shut off until required again.
The backup generator should offer good warranty period so that they are more reliable for the price which we invest. Now the scenario is such that most of the backup generators do not have the warranty covering off grid or prime power applications. It will be good if you check into the warranty information with good care and make sure that the warranty covers the off grid applications.
Best Brands of Generator Backup for Solar System
Generac claims to be number one selling home backup generator. The Generac backup generators are preferred by 7 out of the 10 homeowners. They have both standalone and completely offgrid backup generators. They offer automatic protection to your home. Running on natural gas or liquid propane as fuel, they can be installed outdoor where the system sits just like the central air conditioning unit. They deliver power to the home electrical system or the essential required items, acting as a secondary source of power when in low sunlight or no sunlight conditions. Generac also offers 24×7 support for its customers. So you can be peaceful without any worries. There is also sufficient warranty period. Based on the home back up power needs, the Generac tool will recommend the custom model suiting your need.
Kohler claims to build the best backup generators in the world. The backup generators undergo many quality tests which results in the best of the products. The commercial grade engine in the system is built to last for years. They provide fast and reliable power to your home systems when in need. They offer LPG and Natural gas backup generators. The models are also backed with premium warranty. They mostly offer completely offgrid systems with good capacity fuel tanks. Based on your home and power needs, the home generator selector will give the best models to suit your necessity.
Ryobi Backup Generators
Ryobi offers portable generators working on gasoline. They offer greater fuel efficiency when compared to other conventional backup generators. The models have added safety features. There is also three year limited warranty.