How long to trickle charge a lawnmower battery?

Lawnmowers are useful machines that keep your lawn beautiful. You can use them most of the year until the winter start, and the grass stops growing. During the winter, it will be stored until spring starts, and the grass needs to be cut again. To keep your machine in good condition, it needs to be winterized. One of the parts that need proper care is the battery. Without some precautions, it will deteriorate over time. Most gas-powered and all-electric mowers have batteries. A good method to keep the batteries in optimal condition is to use a trickle charger with maintainer functionality. But you may wonder how long it might take to charge a battery using a trickle charger? The duration varies from battery capacity to the type of battery. This blog post will include all the relevant details, information, and precautions using a trickle charger to charge your lawnmower battery.

How long to trickle charge a lawnmower battery?

The exact time is difficult to give. In most cases, it can take half a day to several days. It greatly depends on the trickle charger, the size of the battery, the battery type, and how much energy was in the battery. In general, a trickle charger uses a low current to charge the battery and will take longer than normal chargers. Some trickle chargers also include a maintainer functionality. That means that you can keep the battery connected for a long time, and the charger takes care that the battery stays fully charged.

The lawnmower batteries, like all other batteries, discharge over time. This is due to the battery’s internal resistance. Trickle charge means to charge the battery at a rate just above the rate it is losing charge. That is the reason why it takes longer than normal chargers, that use a much higher current. In this blog post, we explain the different factors that influence charging time.

● 1: Dependence on the battery type:

The type of battery plays an important role in the charging process. To find out your lawnmower battery type, we first have to locate it. Probably you know the location already. For a riding lawnmower, you can find it under the seat or in the hood close to the engine. Push mowers will have a small battery present along the mower’s deck. The battery size varies. The battery may be a liquid lead cell type or dry type. If you can’t locate it, use your operator’s manual to show your battery’s exact location.

Next, identify the battery type. Trickle charging a mower’s battery depends on the type. Most commonly, lead-acid batteries take more time of up to 2 full days to charge fully. Dry batteries charge much more quickly, starting from half a day.

Most modern battery-powered lawnmowers use a 12V battery. Though, some old models are equipped with a 6V battery. It is suggested to check the battery’s voltage along with its amperage. Match it with the charger’s voltage. When charging a mower battery, voltage is directly related to the charging duration. When a 12-volt battery takes up to 2 days to completely charge, the 6-volt battery will roughly take half of that.

● 2: Dependence on the capacity of the battery:

Another important factor is the battery capacity. The larger the battery, the longer it will take. The size of the battery should be noted on the outside. In general, a larger battery will also have a bigger capacity. If you have that has a 20Ahr capacity and charge it with a trickle charger that uses a current of 2A, it will take at least 10-12 hours when it is fully empty. If the capacity is 40Ahr, it will take at least double that time.

● 3: Dependence on the amperage of the charger:

You can find trickle chargers that use different charging currents. Some common amperages are 1.25 A, 1.5 A, and 3A. The smaller the charging current, the longer it will take to charge. A 3 amperes charger will take around a single day for a 12-volt battery. A 1.5 amperes charger will take roughly twice as long. Fast chargers use a much higher charging current to charge a battery quickly.

Using a trickle charger with a maintainer functionality will ensure that the battery stays fully charged. As soon as the battery loses some of its charge, the trickle charger kicks in and ads the lost charge. They keep the battery’s current circulating so that the cells don’t die out. This prevents issues like sulfation and corrosion in cells.

Note: If you are going to store the battery using a maintainer, store it in a well-ventilated location with a normal temperature. Check the charger if it is working properly once every few weeks.

● 4: Chargers have different charging modes

Modern chargers are complex devices. They constantly measure the state of the battery and change the charging current and method accordingly. They have a display that shows what they are doing and a user interface to select the charging method. Some have an automatic mode that checks the type of battery and chooses the best charging method.

Some chargers have a jumpstart function that can bring dead mower batteries back to life. Many of them have programmed shutoff settings. When they detect that your battery has reached the maximum charge limit, they will automatically turn the charging off. If the charger does not have an automatic shutoff mode, you need to make sure that you disable the charger when the battery is fully charged. Overcharging can harm the battery.

Chargers are getting more complex features:

  • Multiple mode settings, like fast charge, slow charge, and float mode
  • Built-in charging and discharging timer
  • Variable amp rates

Many combine charging functions to improve the process. For example, if the total charging takes some 40 hours. It will constitute a 2-3 hours’ fast charge start, 30+ hours of slow charging, and finally, a float charge. And when the battery is full, it will start the maintaining mode.

● 5: Dependence on the charger specifications

The time it takes to trickle charge a lawnmower battery also depends on the charger’s internal electronics. Some more complex chargers have improved charging functionality that can charge faster than simpler models:

  • Orion motor tech automatic lead-acid battery: A very good charger for lawnmower batteries. It takes care of overcharging and reverse polarity. It can charge a 12-volt battery in around 35 to 40 hours.
  • Black decker BM3B fully automatic battery charger: This is another good charger that charges and maintains a lawnmower 12 Volt battery. It can do the job in around 30 to 35 hours.
  • Battery tender plus smart charger: One of the better chargers on the market. Rated at 1.25 and 1.5 amperes. It can charge an empty battery in around 30 hours. One of the safest and most reliable products.

Additional tips:

We combined some tips for charging your lawnmower battery:

  1. Damaged battery: If your battery has been damaged and has signs of it like cracks in battery casing, swollen or bulging battery, or broken battery terminals posts, you should always replace it.
  2. Test for a damaged battery: Most of the lawnmowers are equipped with a rechargeable battery, so keep it charging for an additional hour and retest if your DMM reveals a reading of less than the battery’s voltage. It is a test to check a damaged battery.
  3. Lead-acid batteries water level: For some lead-acid batteries, check that the water level should be filled to the optimum level. If the water level is too low, it can slowly damage the battery. Fill it accurately and test the mower battery again.

Frequently asked questions:

1. What keeps the lawnmower battery charged during mowing?

The lawnmower alternator takes care of this. It delivers voltage to the mower while the engine is running and also recharges the mower battery. When the mower engine runs at its peak, the voltage regulator drives the proper voltage from the alternator to the battery to keep the battery constantly charged.

2. My charger does not charge my battery

If your battery is dead, a modern charger will not charge it. It will give an error or turns itself off. Most modern chargers will not charge if they do not detect a certain minimum amount of energy. To make the battery charge again, you need to precharge it. This can be done with an older simple charger, or you can use another battery to charge it a little bit. See step 2 for more information on this.

3. Why should you use a trickle charge with maintainer functionality?

Trickle charging a battery is a process where you keep the battery fully charged. When you store a battery, it will lose some of its charge over time. A modern charger with a trickle charger and maintainer functionality will measure the energy that the battery is losing and keep the battery fully charged and in an optimal state.

4. Do I need to disconnect the battery before charging

No. There is no need to disconnect the battery before charging. You can connect the charger and leave the battery cables connected. If the battery is really dead, would we advise you to disconnect it and charge it separately.

5. How do I know if my lawnmower battery is bad?

If, after starting your lawnmower, you feel the clicking and the beating sound by your engine. The most probable cause is the weak or dead battery. Inspect it further if your find irregularities like cracks and leaks on the battery. It will have gone bad. Also, test its voltage capacity with a multimeter to be sure about your finding. An engine that takes time to start is a good indication of a poor battery.

6. Is trickle charging bad for batteries?

Leaving a battery attached to a trickle charger for a long time can lead to overcharging, initiating impairment to the battery. This is the case when trickle charging with an electrical source or some other battery. However, special maintainer chargers offer a programmed function to switch to a float-mode once the battery is fully charged.

Final remarks:

Trickle charging is a phenomenon that one can use to extend and preserve a lawnmower’s battery life. It keeps the battery’s charge from draining away. You can use either trickle charge it once or use the trickle charger method followed by the maintainer functionality. In any case, it is important to know how long to trickle charge. When the charger does not have an automatic shutoff system, it needs to be disabled when the battery is full. Overcharging may destroy the batter’s cells. In this article, we have explained the dependence of trickle charging duration on different components to help you understand the whole process better.

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