Car Battery Trickle Chargers – What Are They? How Do They Work?

September 13, 2020

A trickle charger is an incredibly useful tool to have in your garage or in a storage facility for recreational vehicles or to take with you on long journeys into the wilderness. But exactly what is a trickle charger? It’s essentially a tool for maintaining a battery that keeps vehicle batteries at their optimum charge for extended periods of time. It’s also a vital part of battery maintenance if you have vehicles that stand idle for an extended period of time.

All batteries, including vehicle batteries, will lose their charge over time. It’s a natural progression. However, batteries in cars and other vehicles are designed to recharge while the vehicle is in use. This is why the car you drive on a very regular basis keeps its charge for longer than a car that is only used on weekends or even less frequently. It is important to note that even if you drive your car every day for the required length of time to fully recharge the battery each time, it will still slowly start to degrade over time. No battery lasts forever.

How a trickle charger works

We’ve already said that a trickle charger maintains a battery in a vehicle that isn’t used that often. But what exactly does it do? This type of charger works by replenishing the charge of a battery at about the same rate that it would lose its charge when standing unused. The charger works at very low amperage and slowly raises the charge level to full. They are specifically designed to work over a long period of time and be left in operation on a battery for days, weeks or even months at a time. How long you can leave the charger attached to your battery will depend on the type of trickle charger that you get, but all are meant for long-term use.

These chargers are very safe to use and can be left connected to a battery for an extended period of time without the risk of overcharging the battery. Overcharging is dangerous because it can actually damage the battery by heating it up too much, causing a change to the chemicals inside the battery or even disfiguring the conductors and casing. The low amperage on a trickle charger means that the battery doesn’t heat up very much during the charging process, which means there isn’t likely to be a build-up of gases coming from the acid within the battery. These gases are not safe to breathe in and can be flammable.

When and how to use a trickle charger

So why would you need a trickle charger? Think about the vehicles you have at your home or in storage. You could have a special car that is just for weekends or holidays. Perhaps you have a boat or a jet ski that lives by the water and waits for you to come and play every summer. Motorbikes, quad bikes, scooters and mopeds are often not used as primary methods of transport – especially in the rainier months. What do all of these have in common? They all have a battery to get the vehicle going and that battery will definitely run flat without use.

The problem that plenty of people face is that when they want to use the vehicle, the battery is often dead. You can get a high amperage charger to give the battery a quick boost to get things going, but you risk overcharging quite easily. This method also means that you have to wait a while before you can use your vehicle or that you have to make sure you plan ahead. Another downside to this is that the constant see-saw of going flat and quickly getting charged can shorten the lifespan of the battery.

This is where a trickle charger comes into play. It can be left connected to the battery (either while it is still attached to the vehicle or after you’ve taken the battery out) and ensure that the battery stays at a healthy state of charge. If you’re talking about a vehicle that lives in your garage at your home, you can easily keep it connected all week and have your holiday roadster or weekend campervan ready whenever you want to getaway. If you’re looking at your vehicles that live by a holiday home or in a storage unit that you don’t visit regularly, then simply take the battery out and bring it home with you. The battery can live connected to the trickle charger and then get taken out with you when it’s time for an adventure in the vehicle it powers.

How long does it take to charge a car battery with a trickle charger?

A trickle charger is exactly what it implies – it trickles the flow in to ensure the battery receives charge without damage. A trickle charger usually runs at around 2 amps and it cane take a 12 volt or 48 amp battery at least 24 hours to charge to a point where it’s usable. This also depends on the condition of the battery prior to the charge.

A trickle charger is often referred to as a maintainer. Its primary function is to maintain a battery and ensure it doesn’t run out of charge. It’ll charge a battery up over a long period of time and automatically turn off once a battery is fully charged. A battery might not keep that charge if its condition is poor.

You’ll often find car battery trickle chargers in mechanic workshops. They’re often used to help maintain a car battery while the car is being worked on. A car wouldn’t be started while it’s being worked on and a trickle charger would be used to help ensure that once the work is done, the car battery can still turn the car on.

How to connect a trickle charger to a car battery?

Position your vehicle

Make sure you part your car in a location where there is enough space for the car and trickle charger. Don’t market near anything flammable or where the charger and car are overly exposed to natural elements like rain, wind and snow.

Once you’ve placed your car, it cannot be moved while the car battery trickle charger is connected.

Set your power specifications in the trickle charger

Generally, most trickle chargers can automatically pick up the charge that is required to go into the battery, if not, please refer to your battery and set the charger accordingly on the trickle charger itself. You need to set the volts and amps correctly according to what the battery needs.

Ensure battery is ready for charging

After you’ve set up the trickle charger and ensured that your car is a solid location where it’s not exposed to bad natural elements, you need to ensure nothing flammable is around too.

You need to ensure that the car is off and the key is out of the ignition before you start charging.

Locate a suitable ground location

You’re going to need a good ground location for your trickle charger to attach to. A large bolt that is connected the engine block or chassis is a good example. Alternatively see if you can connect it to the frame that doesn’t have excessive dirt and grime on it. Don’t use the negative terminal on the battery or you could start a fire.

Attach cables

Once you’ve grounded the trickle charger, ensure that the red alligator clip is available and can reach the positive terminal on the battery. Don’t let the two alligator clips ever touch as you’ll cause sparks to fly and potentially shock and/or injury yourself.

Turn on Charger

After connecting the cables, refer to your battery’s manual to know the proper settings for the charger. Now, plug n your charger and switch it on.

After connecting the two cables – positive and ground – you need to switch the trickle charger on. If you have any issues please refer to your chargers manual for instructions.

Check Display

Many of the better and newer chargers have displays that show you how much charge your battery has, how long it’s been charged for and the various details of the charging happening like volts and amps. Keep the charger connected until the battery charging is complete.

How to choose the best trickle charger

You might think that all trickle chargers are created equal, but there are several different options you can actually choose between. The most basic trickle charger simply is a low-amperage option that slowly increases the charge level in the battery. These do include the risk of overcharging a battery, however, it will take a long time to get to that stage. Additionally, any damage from overcharging will be minimal as the charger won’t allow the chemicals to get too hot due to the low amperage. It is best to know the level of charge of your battery before you start charging though, and to monitor that throughout the process so that you know when to disconnect the charger. Overcharging, even at a low rate, is always dangerous.

Then you get options that have a few more bells and whistles. They tend to be more expensive, and prices can range depending on which extra features your trickle charger has. The most common feature is a built-in monitor that detects the level of charge in the battery for the entire time it is connected. This often comes with an automatic shut-off that stops the charger from operating once the battery reaches its full capacity. These are your entry-level smart trickle chargers.

The next level is a fully smart trickle charger. This type will come with a monitor and the automatic shut-off function, plus the ability to continue monitoring the level of charge once it has shut off and turned itself back on once the battery level has dropped to a specified charge capacity. For example, the charger will ensure the battery reaches 100% and then stop charging. It will then monitor the battery levels and switch the charge function back on once the battery drops to below 80%. The cycle will continue until you disconnect the charger from the battery. While this kind of charger might be a bit pricier, it does give you peace of mind that your battery is being properly looked after while you’re not using the vehicle. You’ll also know that your vehicle is ready to go as soon as you want to use it.

Now that you know the answer to what is a trickle charger, isn’t it time to get one for your vehicle batteries? Check out our buyer’s guide, complete with our reviews for the best trickle chargers available in 2020. You’ll never have to wait for your vehicle to charge again.

James Olive