Standby Batteries
Battery use can be divided into two categories: cyclical use and standby use. Cyclical use is when a battery is being used as a power source on a regular basis and is being discharged and recharged. In cyclical applications, up to 1,000 charge/discharge cycles can be expected depending on the depth of discharge. Standby batteries are meant to be used as an emergency power source when the main power source has failed. Standby batteries are connected to a trickle charger that will keep the battery fully charged and ready for use. Standby batteries are designed to have a lifespan of up to five years.
Long life batteries are considered a hybrid of deep cycle and high rate batteries with the added benefit of enhanced floating life. Deep cycle batteries provide continuous power output over long periods of time and can withstand repeated charge/discharge cycles at 80% DOD. High rate batteries deliver high power for short periods of time at 50% DOD with a 14-16 year life.
Depth of Discharge (DOD): This is the percentage of the battery that has been discharged relative to the battery capacity. When a battery is discharged entirely or past the maximum recommended DOD, the battery life will be shortened.
It is very common to see industrial control panels that have a UPS or Uninterruptible Power Supply. This UPS allows for continuous power to be supplied to the control panel in the event of a utility power failure.This protection is provided with the help of batteries. When power is lost, the UPS will switch power automatically from utility power over to battery power.
- How much time does a system need to run in the event of a power failure? In most cases, battery backup systems are designed to run for no more than just a few hours. This is typically more than enough time for power to be restored and to prevent losing valuable data in the system. However, there are cases where more time is required depending on the scenario. For instance, a remote site that relies on solar power needs to be able to supply power for multiple days depending on the weather. If it's cloudy, and in the wintertime, the sunlight will be very limited and the power that is generated will most likely not be enough to energize the hardware needed for that particular site. In this case, a larger battery backup system will be needed so that the site can continue to run through these types of weather events.
- What critical hardware needs to be backed up? Once the hardware that needs to be backed up has been selected, it is important to determine how much current each of those pieces of hardware will draw. Most batteries are rated for a specific amount of AMP hours. So if a battery is designed to last for 10 AMP hours, that means it can supply one amp for 10 hours or another way to look at it is it can supply 10 amps for one hour. Once the current draw is known for all of the hardware, the size of the battery can be determined.