How Long Does It Take to Charge a Lawn Mower Battery?

In most cases, an electric or riding lawn mower will require some type of battery to power the motor. Whatever type or brand of mower you have, you’re going to have to recharge it at some point. There are two possible reasons why this may happen: either the battery lost charge while sitting during the winter, or it simply became depleted after being used.
Whatever the reason might be, knowing the length of time it takes to charge a lawn mower battery is crucial. There are a number of factors that affect the battery charging time, so I’d like to go into more detail about different battery charging times.
For each battery type, there is no exact charging time, but there are a few general guidelines that you can use to estimate the charging time.
To figure out how long the battery will take to charge, you need to know a few things: its voltage, its amp-hours, and the voltage and amperage of its charger. The charging time varies greatly depending on this information.
You can estimate the charging time for your battery by taking the amp-hours it is rated for and dividing that number by the amps your battery charger supplies.
Listed below is a table showing a few examples of how much time it will take to charge two types of batteries using different types of chargers. However, you should always double-check the manufacturer’s recommendations.
Estimated Charging Times
6 Volt, 4.5Ah Battery
12 Volt, 35Ah Battery
At 2 Amps
2.25 Hours
17.5 Hours
At 6 Amps
45 Minutes
5.8 Hours
At 10 Amps
25 Minutes
3.5 Hours
At 10 Amps
25 Minutes
50 Minutes
Factors affecting lawn mower battery charging time
As I said in the previous section, there are a few important factors to consider when trying to figure out how long it takes to charge a lawn mower battery? Since there are many different kinds of batteries available, and not all lawn mowers use the same battery, you’ll have to consider a couple of things when estimating your own charging time.
The information that you will need to know is: the voltage rating of your battery charger, the voltage of your battery, the amperage of your battery charger, and the amperage of the battery. All of these factors will affect how long it takes to fully charge your battery. Let me explain each factor in more detail.
Battery and Charger Voltage
It is extremely important that you use a charger that is the same voltage as your battery when charging it. Incorrect voltage chargers may damage your battery, or prevent it from being charged.
Many people wonder if it is possible to overcharge a lawn mower battery? In short, yes, it is possible to overcharge a lawn mower battery. If, for example, you are using a 12-volt charger on a 6-volt battery, you have a very higher chance of your battery overheating and breaking down.
There are people who may attempt to charge a 6-volt battery rapidly with a 12-volt charger, but this is not something that you should do. On the other hand, it is important to bear in mind that when a 6-volt charger is used with a 12-volt battery, it will not produce enough charge for the 12-volt battery to work efficiently.
It doesn’t matter how long you leave the charger hooked up in this case because 12-volt batteries are considered completely dead even if the voltage drops as low as 10 volts.
Battery and Charger Amperage
With regards to charging times, the amp-hours your battery is rated for and the amperage your charger delivers are definitely the most important considerations. Batteries of 6 and 12 volts are manufactured in a wide range of amp-hour capacities, and chargers are offered in many different amp outputs.
Unlike voltage, your battery and battery charger don’t need to be the same amperage. It’s generally recommended that your battery charger shouldn’t be more than 20% of your battery’s amp-hours (Ah) rating.
It would therefore be ideal for the users of a 40Ah battery to use a battery charger that has a maximum current rating of 8 amps or less. Choosing a battery charger that doesn’t charge your battery very quickly can actually be good for the health of your battery.
In any case, you don’t want a charger that is too powerful because you could easily destroy the battery even after you’ve used it a number of times.
FAQs About the Time Needed to Charge Lawn Mower Batteries
As we have covered the basic factors that affect battery charging times, and also talked about how you can make an estimation of the time your battery will need to charge, let’s take a look at some examples.
There are many people who wonder not only how long it takes to charge a lawn mower battery, but also how long their batteries will take to charge at different amps. Therefore, I’ll explain the timeframes needed for each charger below.
How long does it take to charge a lawn mower battery at 10 Amps?
Most lawn mower batteries can be charged in about an hour with a 10 amp charger. But, batteries with greater amp-hour ratings will take longer to charge. Using a 10 amp charger will efficiently charge your battery without too much risk of overcharging.
However, it is always a good idea to monitor the voltage of your battery while it is charging, especially if you are not using an automatic or trickle charger.
How long does it take to charge a lawn mower battery at 6 Amps?
As a result, using a charging method such as a 6 amp charger will ensure that it takes nearly double the amount of time to charge your battery when compared to a 10 amp charger. If you have an average lawn mower battery, this means you probably need to recharge it for two hours or so before it is fully charged.
How Long Should I Charge a Lawn Mower Battery at 40 Amps?
Chargers with a capacity of over 20 amps are known as rapid chargers. You will not need much time to recharge your lawn mower battery if you use a 40 amp charger. Charge your battery completely within an hour or less (depending on the amp-hour rating of your battery).
However, it is not advisable to charge your battery as quickly as possible. Fast charging can lead to serious battery damage or explosions if not closely monitored.
How Long Should I Charge a Lawn Mower Battery with a Trickle Charger?
Trickle chargers (also known as battery tenders) are typically rated at 2 amps or less. Chargers of this type are designed to charge batteries very slowly and they pose no risk of overcharging. In some cases, a trickle charger may take nearly 24 hours to fully charge your mower battery.
However, it is worth the wait if you have the time because slowly charging batteries extends their lives. Just make sure that the trickle charger you’re using is set to the same voltage as your battery.