Home Battery Backup - Medium

Product Description

Frankensolar America’s Home battery backup systems are designed to provide backup power to critical loads in a home in the case of a power outage in Canada. Critical loads are typically the following items in your home:

• Fridge & Freezer
• Lighting
• Communication infrastructure
• Furnace Fans and Controls

Most modern heating systems require electricity to operate even if the natural gas or propane supply is not interrupted.

Most residential homes have a low power demand for these critical loads and a 4kWac system supplying the home’s critical load panel is more than sufficient in most cases.

The two smaller Home Backup Systems, Small and Medium, both build on the Schneider Electric’s Conext SW Battery Hybrid Inverter. The inverter has an AC input (120/240V) and an AC output that supplies the critical load panel and all loads connected downstream.

During normal operation when the grid power is available, the internal transfer relay is closed, and all loads are powered directly by the grid. The SW battery hybrid inverter maintains the battery voltage and keeps the batteries fully charged.

When the grid fails the SW battery hybrid inverter detects the loss of AC power on the grid input terminal and immediately opens the transfer relay and initiates the battery operation. This transfer happens very quickly within 16 milliseconds and is therefore nearly instant and will not affect the continuous operation of the connected loads.

Besides the power capabilities, the runtime of the battery is an important aspect to pay attention to. Statistically, most grid power outages do not last very long , therefore you only need a system to last you a few hours, and to keep the aforementioned critical loads running. The following table can give you an idea how long the system could last on battery power in different load scenarios:

Per 5kWh Increment of Nominal Battery Storage (smallest battery size is 10kWh in this kit)

Longer runtimes can be achieved by adding additional battery storage. An 18kWh nominal battery storage system could provide the following runtime: 

If multiple day power backup is required, the best combination is a medium sized battery system that uses a small generator as a multi-day backup energy source. This combination represents the best of both worlds: instant, fully automated silent battery backup at a low upfront cost, and multiday backup capability with sporadic recharging sessions from a small generator. Honda EU generators are very popular solution for these applications.

Battery Options:

In general, two battery chemistries are suitable for battery backup installations in residential homes.

The most common is a Lead Acid AGM battery. AGM is maintenance free, does not need ventilation and has a long floating life.

The higher cost, yet modern chemistry is the Lithium-Ion battery. Lithium is also maintenance free and can be easily installed in homes and has a long-life expectancy as well.

In either case, each technology is not limited by their respective cycle life. Assuming there are 10 backup incidents per year. Over the course of 20 years this might result into just 200 cycles. The AGM battery can easily provide 800 cycles and most Lithium chemistries a few thousand cycles. Therefore cycle life is not the determining factor in a backup system.

We recommend simple systems, that can be installed easily and can be scaled to the individual customers needs. The most common battery selections are the maintenance free Trojan SAGM06-220 (Kit 8) and SAGM06-375 (Kit 9 & 10). For most residential backup applications, this battery type represents the best combination of longevity, maintenance free operation and at an attractive price.