How Do You Know When to Change a Generator Battery?

Most people find it hard to determine when to change their generator batteries. This is because the conditions of the battery may limit the amount of time that a battery lasts.

However, when all conditions are okay, most battery brands will need to be changed every 24 to 36 months, that is, every two to three years.

Unfortunately, most people extend the use of the battery until the generator cannot start. This is quite dangerous and any mains power problems are likely to cause you to stay in darkness, as the generator will not start.

Sometimes the battery will need to be changed before said periods or within these timelines. I will share other signs that your generator battery needs changing.

You Have Trouble Starting Your Generator

A dead battery is one of the reasons why your generator may fail to start. However, you need to eliminate other issues so that you are sure that the battery is the culprit.

Some other issues that may cause the generator not to start include when there is no gas in the tank, low oil in the crankcase, when the choke is not closed, if the air filter is dirty, or the spark plug is dirty or malfunctioning.

If you have checked the generator for all these issues and it still does not start, your battery may be the cause of its failure to start.

The Battery has a Low Charge

The generator charges the battery when it is running. Therefore, there is no need to take your battery to a service center for charging.

The battery cells deteriorate over time and can no longer store as much power as required. This may cause the generator to have problems when starting, often causing you to try starting several times.

Most of the generator battery brands are maintenance-free. Therefore, you do not have access to the cells, and you can add some electrolytes if it gets weak.

You can use a voltmeter to check the voltage against the set maximum. If the battery is weak, take the generator to a qualified technician to determine if the problem is the battery or the charging system is not working right.

The Voltage Reads Right, but the Battery Does Not Power the Ignition

Sometimes the battery terminals read the right voltages as indicated in the owner’s manual. However, the battery does not power the ignition system.

This shows that the generator charging system is working correctly, but one or a few cells are dead or not working correctly. Such a battery requires replacement.


It is good that you physically inspect your generator and battery for problems. If you notice corrosion or leakage around the connections, it means that you need to take action regarding the battery.

Corrosion may prevent the battery from charging or discharging properly. Most of the corrosion can be addressed by cleaning the terminals with a wire brush.

However, if the battery is utterly damaged or does not improve performance after cleaning, you may need to change it.

If you live in an area that experiences extreme temperatures, it is important that you have the generator batteries checked regularly for functionality.

Very high or freezing temperatures are likely to cause the cells to malfunction and shorten their lifespan.

Since most batteries are maintenance-free, there is not much you can do to extend their life other than replacing them.

Most generator batteries are resilient and will run for the entire period of two to three years without failure. However, it is good to inspect them as regularly as you do with the generator.

However, do not change the battery until you are sure that none of the other components is causing the problem.

When replacing the battery, ensure that the new battery has the same rating as the old one, especially if it is not the same brand.

It is best that you have the purchase decision and the battery change done by a qualified technician so that they can ensure that the terminals are clipped correctly as required. They will also check if the generator is charging the battery as it runs.


A conventional generator battery should be replaced every two to three years. Do not wait until the battery is dead to replace it.

Other issues can point to a dead battery. Here are some of them.

  1. You have difficulties starting the generator, but all other components are working right.
  2. There is corrosion and leakage on the terminals of the battery, and cleaning them does not improve the situation.
  3. The battery has a low charge, yet the generator charger is working right.
  4. The terminals read the right voltage, yet the battery is not able to power the ignition system.

Have a qualified technician check all these signs and do the actual replacement so that it is done right.