Can I charge a Motorcycle Battery with a Car Charger?

Many BPZ customers are proud owners of both motorcycles and cars. They are often curious as to what tools they can use for the maintenance of both their car and motorcycles batteries.

One common question is whether they can use a battery charger designed for cars to charge the battery of a motorcycle.

For the benefit of such customers and anyone with this particular question, we will try to highlight some important points to consider when thinking about charging a motorcycle battery using a car charger.

In theory, it is suggested that one must never use a car charger, which is designed for larger automotive batteries, to charge a smaller motorcycle battery. The reason being that it can easily overcharge the battery and cause a host of problems. These include overheating of the battery, boiling of the electrolyte which produces harmful fumes, and, in extreme cases, the explosion of the battery itself.

However, that being said, if one finds themselves in a situation where you need to charge a motorcycle battery using a car charger, there are some guidelines you can follow to perform the process with relative safety.

The first thing to note is, as a general rule of thumb, a motorcycle battery should always be charged using a charging current which is less than one-tenth of the battery's rating in Ah. For example, if the motorcycle battery rating is 20 Ah then it should not be charged using a current of more than 2 Amps. If the car charger provides a current higher than that then it is a serious risk for the battery.

A CTEK intelligent charger in the 5 Amp model can charge as little a battery as 2 Amps, so this is a good choice if you have both cars and bikes.

In general, even with a higher amp rating charger, you can use it to charge a motorcycle battery by performing a few additional steps.

Attach loads in parallel to the battery in order to divide the current. These loads can be light bulbs, such as even the headlight being left on, and should draw enough current to ensure that the current flowing through the battery is within the safe range.

This is not ideal, and should only be done in extreme circumstances

The best thing to do it to rather source an appropriate charger that is the correct tool for the job.

If not you can also call BPZ and we can send out a technical team who will be able to assist you to get your bike back into working order.