How to Charge a Scooter Battery without a Charger

Last Updated
How to Charge a Scooter Battery without a Charger


Scooters are widely considered one of the most economical forms of transportation available. And these scooters use the power from the battery to start the engine. That is why the battery is widely considered the most important part of the scooter after the engine.

One of the most important things to remember is to ensure that the scooter’s battery is fully charged. This can be done either with regular usage or, when necessary, with the designated charger provided with the battery.

However, in absence of a charger, you can still charge the battery. This article will explain how to charge a scooter battery without a charger

Charging a Scooter Battery

Many of us don’t realise that scooter batteries can be charged manually. This can be accomplished using a Variable Power Supply. This is a simple power supply which charges with an adjustable voltage feature, whilst limiting the current flow. Variable power supplies can be purchased online or at any specialist electrical store.

However, charging a scooter battery with a power supply is not without risk, and it is important that the battery is not left unattended. This is because once the battery is fully charged the process will not terminate automatically. This could result in overheating which can ultimately damage the battery’s internal cells, or, in rare cases, cause an explosion.

As there are different types of batteries, including lead-acid, lithium-ion and the NiCd or NiMH, we will take a look at each one.

Lead Acid Scooter Batteries

Before charging a lead acid scooter battery, it is essential to calculate the exact voltage, determined by the number of cells in the battery. All you need to do is to connect the battery to the adjustable power supply. Then, set the desired voltage and current limit, which you need to charge the battery.

To give an example, the nominal voltage of lead-acid is 2 volts per cell. So, for a 12-Volt lead-acid battery containing six cells, you are required to set the voltage to 12V (6 x 2V).

In addition to this, it is essential to select the charge current in accordance with the battery size. For the standard lead-acid battery, the current must be adjusted between 10 and 30 percent of the rated capacity.

For example, a standard 10Ah battery at 30 percent charges at about 3-Amps, however, the percentage can be lower. Similarly, an 80Amps starter battery normally requires a current charge at 8A.

As mentioned earlier, charging scooter batteries using a variable power supply is a risky operation and you must not leave the charging operation unattended. It is recommended that you monitor the battery temperature along with voltage and current flow during the charging process.

Always charge the battery at room temperature in a ventilated room. Once the battery is fully charged and current has dropped to the 3 percent of the rated Ah, disconnect the charger.

As the power supply can also reverse sulfation, it is recommended that you set the voltage slightly higher than the required level. The battery may draw little current at the beginning but as the sulfation layer dissolves current flow will increase gradually.

Charging Lithium-ion Scooter Battery

Similar to a lead acid battery, the lithium-ion batteries can also be charged with a power supply. However, charging the lithium-ion battery may require extra measures.

Before charging, always ensure the full charge voltage first which is commonly 4.20V/cell. Set the current and voltage accordingly. In addition to this, it is highly recommended to check and monitor that none of the cells connected in series exceeds this voltage.

When the charge reaches the 4.20V/cell voltage and the current drops to 3 percent of the rated current, your battery is charged. Simply disconnect the battery from the power supply once it is fully charged.

Charging NiCd & NiMH Scooter Battery

Before you start using a power supply to charge nickel-based batteries, you must be aware of the challenges and precautions that you’ll be facing. One of the biggest challenges is that full-charge detection is rooted in a voltage signature that varies with the applied charge current.

While charging the NiCd and NiMH with an adjustable power supply, always use the temperature rise on a 0.3–1C rapid charge as an indication of full charge. While charging the battery at low current, always estimate the level of remaining charge and calculate the charge time. A standard empty 2Ah NiMH battery will charge in about 3 hours at 750–1,000mA.

Battery drain issue is quite common. It can be avoided by keeping the battery regularly charged as most lead-acid batteries would drain out if left unused for a long duration. For a battery to be fully charged it should read between 13.7 – 13.9 volts on the voltmeter. Anything below 12 volts indicates a completely depleted battery.

How to Charge a Scooter Battery without a Charger – Build Your own Battery Charger

If you do not have a designated charger to charge the batteries, you can make a portable home battery charger using the following equipment:

  • Deionized water or Electrolyte
  • Electric cables for positive and negative connection
  • Voltmeter and Hydrometer to monitor the charge
  • Gloves and goggles for hands and eyes safety
  • Dry and cool place

To start charging the batteries, the most important thing you need to do is to wear protective gloves and goggles for safety. This applies to any work you do with batteries. After that, remove the battery from the scooter and clean it thoroughly. Place the battery on a clear and dry surface and remove the chamber caps.

The next step is to fill the chambers with electrolyte or deionized water. Pour the water slowly to avoid any bubbles. Connect the charger cables to the positive and negative terminals and simply turn the power on. Check the charge with a voltmeter. Once the battery is fully charged, turn the power off. Finally put the caps back on the chambers.

Always ensure that the battery is set back in the previous alignment. To assist with this, we recommend taking a picture of the battery in situ, so you remember how it goes. Fix back into the scooter and clip the terminals to the battery in the right order.

For more information about battery chargers, click here

Steve Brown


Steve is a gadget enthusiast who's always been intrigued by batteries. The founder and editor of Battery Chargers Info, he's assembled a group of like-minded experts to cover every facet of portable power His aim is to help you learn more about your favorite gadgets and their batteries so you can maximize both their performance and their life. Follow him on Twitter: @batterycharge1

Learn to Revive almost any Battery from Home!

If you are sick and tired of paying exorbitant fees to replace your batteries, this secret method to recondition almost any battery can save you BAGS of MONEY. Click this ad NOW to find out how!

Click Here
How to Recondition Batteries at Home