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How to Charge a Scooter Battery Without a Charger? 

 September 19, 2021

By  Phil Borges

There are more ways than one to charge a scooter battery even if you don’t have a charger in hand. Let’s take a look at some of the easiest options available to you.

How To Charge a Scooter Battery?

You can use a portable car jumper and hook it up to the battery and charge it in just about 20 minutes. You can also use an adjustable power adapter and charge your scooter. It might take a little longer but if you do it right, it works just fine.

But before you pick up your gear and head towards your scooter battery, there are a few things to remember. Depending on the kind of batteries your scooter functions on, there are a few precautions to take so that you don’t end up damaging the battery accidentally. Let’s see how it’s done.

How To Charge Electric Scooter Without Charger?

Charging a scooter battery is possible. There are two easy ways to do it. We will take you through the step-by-step process of charging your scooter battery.

Mobility Scooters

Try a Portable Car Jumper

This is one of the easiest ways to charge a scooter battery. Their large and portable built-in battery comes in very handy when you need a quick jumpstart. Now, the voltage is a lot higher than your scooter needs. So, there’s that to consider. Here’s how you go about it.

Step 1: Connect the battery of your scooter to the jumper. You do this by connecting the electrodes of your battery to the jumper cables. Connect the positive charges first and then the negative.

That means start by connecting the red cable to the positive electrode of your battery and the black cable with the negative. Make sure they are done right and fit properly before proceeding.

Step 2: Turn the jumper on which will start the flow of current into your scooter battery. Keep it steady for about 20 minutes. Now this time frame also depends on the kind of battery you are trying to charge. So, you must check the instruction manual of your scooter.

You must also remember that when the battery starts to feel hot, it is getting overcharged and you must remove the cables. Otherwise, you risk damage or depletion in the battery’s life in the very least. Now, the latest models of some portable chargers actually come with a digital control unit which can manage the amount of current flowing into the battery. See if your unit has one of those and monitor it.

Step 3: Remove the jumper after the right amount of time (which you must have figured out by now). Start by disconnecting the black cable from the negative electrode and then the red one from the positive.

Get a Universal Power Adapter

The second efficient way to charge your scooter batteries without a charger is to use what is called a universal power adapter. This is a device which stores electrical charge for a certain amount of time. And this is how you use it.

  1. 1
    Plug in the power cables into the adapter. Start doing that by connecting the negative port to the black wire and then connect the positive port to the red wire.
  2. 2
    With an adapter you must set the voltage. Typically, setting it at 4.20 volts per cell is recommended. But it is better to go through the instruction manual of your scooter to make sure you are doing this right. It is a key step in the process. If you mess it up, you might end up causing damage to the battery instead of charging it.
  3. 3
    Now measure the capacity of the battery. Let’s say that is 9 amp-hours or 9 Ah. Set the output current from the adjustable energy source (which in this case is your adapter) to 20 percent of that which will be 1.8 A. Once again, this is so that excess charge doesn’t damage the battery.
  4. 4
    Just wait. When the supplied current reaches 3 percent of your battery’s rated capacity (measured in Ah) you will know that the battery is full.
  5. 5Disconnect the adapter and place the battery back in the scooter.
  6. 6
    Check to see if you did it right.

Charge Multiple Batteries

This is not so much a third method as it is the way you should deal with the different batteries that run your scooter. Now, this might feel a bit tricky and technical but it is really not. Let’s see what we’re talking about.

Lead-Acid Batteries

If you are trying to charge a lead-acid battery, you need to start by calculating the voltage. And be as accurate as possible. This can be done by checking the number of cells in each battery.

What you must do is connect them to the power supply and set the voltage and output current to the desired levels. So, if you have a 12-volt battery with six cells and each of them is nominally 2 volts, you need to set the output voltage to 12 volts.

Next is selecting the charge current. For this, check the size of the battery. A standard lead-acid battery requires the current to be between 10-30 percent of its rated capacity. So, if you have a 10 Ah battery and it needs to be set at 30 percent (which is the maximum), you are looking at 3 amps.

When using variable power supply, check the voltage, flow of current and also the temperature of the battery as it is being charged.

You will know that the battery is charged when the current drops to 3 percent of the battery’s rated capacity. And finally, remove the charger.

The process of charging your batteries also leads to reverse sulfation when applicable. This is a process that occurs when the batteries have a layer of lead sulfate crystals on them. That’s not supposed to happen. But when it does, it can cause battery failure.

So, when you start charging your battery again, reverse sulfation might occur. If that is a possibility, you must set the voltage a little higher than what we just mentioned as it takes a little while for the layer of sulfation to dissolve and then the current starts to flow to the cells.

Lithium-Ion Batteries

This is a very popular choice today for most electrical equipment because they produce less heat, save power and are flexible. They are also cheaper than the lead-acid variety and hence found their way into scooters too.

Now, before you start charging these batteries, once again, you must determine the full voltage of each cell in the battery. Usually that is 4.2 volts per cell which means your input voltage and power supply must not be more than that. Charge your batteries and you will know when it is done once the power supply falls to 3 percent of the battery’s rated capacity. At that point, each cell will be charged to 4.2 volts, exactly what you want and you are now good to go.

But the difference between charging a lead-acid battery and its lithium-ion counterpart is this. Make sure that if the cells are connected in series, their maximum voltage is not more than the full charge voltage. 

NiMH and NiCd Batteries

And finally, you have the NiMH and NiCd batteries. You might want to be extra careful with these when you are not using a charger. You can charge them with adjustable power supply but detecting the full charge is a pretty challenging task because it varies with charge current.

While you are charging them, keep checking the levels of remaining charge (this will be an estimate). If you are charging a standard NiMH battery, it might take about three hours. Use a voltmeter to make sure the voltage reading is accurate. Typically, you will see it in the 13.7 to 13.9-volt range. If you are seeing numbers less than 12 volts, you are dealing with a depleted battery.

Razor Scooters

You can use the same power sources mentioned above for razor scooters too. But you will need to remove the battery from a casing in the motor compartment. For that, you will need a battery charger, screwdriver and a power supply cord.

  1. 1
    Remove the outer shell of the razor scooter with a screwdriver.
  2. 2
    The battery will be in between two rods that are holding it in place. Loosen the screws on the rods and remove the battery.
  3. 3
    Unplug the wires connecting the battery terminals to the motor.
  4. 4Connect the battery to an alternating power source like an adapter and charge it.
  5. 5Put the battery back in between the metal rods and connect the wires.

Wrapping Up

Charging your scooter battery without a charger is not a difficult thing. Just make sure that you take the necessary precautions. Remove the battery from the scooter before you hook it up with the power source.

About the author

Hi, I'm Phil Borges.. thanks for reading.. My wife says I can't shut up about batteries so to save my marriage I've started this blog .. where I'd be ranting about batteries! Please leave a comment if you have any questions, I'm happy to help!

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