*****Scroll down to find a calculator tool that will help you determine how long your pellet stove will operate on a battery backup.*****

One of the most common questions people have when considering an automatic battery backup for their pellet stove is, “how long will my pellet stove run on a battery backup?” The answer depends on several factors:

- The condition of the battery
- The size of the battery bank (how many batteries are connected in parallel)
- The A-hr rating of the individual batteries in the bank
- The make and model of your pellet stove
- The pellet stove's average operating input current with a given thermostat setting.

With an average current draw of 1.5A, you can expect your pellet stove battery backup to operate for to 8 hours with a 120 Amp Hour battery, and up to 24 hours with a 360 A-hr expanded battery bank.

### If you want a more accurate calculation of backup operating time during a power outage, you will need the following information:

**A) The size of the battery bank i.e. its total Ampere-Hour (A-hr) capacity**

Ampere-Hour capacity is calculated by adding the A-hr ratings of all of the batteries in the battery bank where the batteries are connected in parallel.

**B)** **The number of batteries in your battery bank **

The batteries in the battery bank must be connected in parallel. this means that all of the negative battery terminals are connected to one another and likewise for all of the positive terminals.

**C) The current draw for the backup in Amps**

Find this input by consulting the pelet stove user manual or other manufacturers' data. The parameter to look for is average input current. Typically, they will cite "input current" and "input current under ignition." The meaningful term is the former one.

**Once (A), (B), and (C) are known, the operating time of the pellet stove battery backup can be calculated by this formula: **

T = (N x AH) / (C x 10)

T = Operating time in hours

N = Number of batteries

AH = A-hr rating of each battery

C = Average current draw in Amps

**Here is an example calculation: **

- The system has 3 batteries (N)
- Each battery is rated 120 A-hr (AH)
- A load that draws 1.75 Amps (C)

T = (3 x 120) / (1.75 x 10) = 20.57

Use the calculator below and input your own information to determine how long your pellet stove will operate on a battery backup. This important information will help protect you and your home in the event of a power outage.