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Practical guide · Charging and winter storage

How to Charge and Store a Motorcycle Battery for Winter

Motorcycle batteries rarely die of old age: they die because they are left discharged. Here’s how to charge yours properly, how often to do it and what to do to get it through the winter without losing capacity.

By Redacción de Satkit Updated Published on 6 min read 3 sources cited

OUTDO UTX7L-BS, YTX7L-BS motorcycle battery shown from the front with both terminals
Photo: Satkit (satkit.ie) · Original

In short

  • A smart motorcycle battery charger, rated at 3 A maximum; the ideal current is capacity in Ah divided by 10.
  • Before storage, charge it to 100 %; then leave a battery maintainer connected or disconnect the negative terminal.
  • Without a maintainer, check it every month: if it drops below 12.4 V, charge it. Charge it every 3 months regardless.
  • A cool place is better than a warm one; a discharged battery can freeze.

Most motorcycle batteries that are replaced aren’t worn out: they’ve been left discharged for too long. Below a certain voltage, lead-acid batteries sulphate and permanently lose capacity. With a good charger and a few simple habits, your battery can last for many more seasons.

Which charger to use

  • A smart motorcycle battery charger: it charges at a controlled current, then switches to float or maintenance mode. It’s the only type that can be left connected to an AGM battery for an extended period.
  • 3 A maximum. High-current car chargers heat up and damage small batteries.
  • With reverse-polarity protection and spark prevention, so you can connect the clamps safely.
  • A recovery mode is useful for very flat batteries.
  • For a lithium battery, use a charger with a lithium profile; never use one with a desulphation mode.

Basic, uncontrolled trickle chargers must not be left connected for weeks: they keep supplying current and overcharge the battery. Overcharging an AGM battery causes it to lose electrolyte that cannot be replaced.

A permanent charging lead

A fused lead with a quick connector, attached to the terminals and easy to reach under the seat, lets you connect the charger without removing anything. Many battery maintainers come with one.

What charge current should I use?

The rule is simple: capacity in Ah divided by 10. A 12 Ah battery should be charged at around 1.2 A; a 6 Ah battery at 0.6 A. Never charge a motorcycle battery at more than 3 A. A smart charger adjusts the current automatically, but its output should not be much higher than that figure.

How long does it take to charge? It depends on how flat the battery is. As a guide, Yuasa estimates that it takes around 8 hours to charge a YTX14 from 50 % to 100 % at 1 A.

Step by step

  1. If possible, remove the battery or at least disconnect the negative terminal from the motorcycle.
  2. Connect the red clamp to the positive terminal and the black clamp to the negative terminal.
  3. Plug in the charger and select motorcycle battery or AGM mode (or lithium mode, if it’s a lithium battery).
  4. If the battery gets hot, stop: let it cool for a few hours before continuing.
  5. When charging is complete, switch off the charger before removing the clamps: charging produces hydrogen, which can be ignited by a spark.
  6. Let the battery rest for an hour, then check the voltage: a charged AGM battery reads 12.8–13.0 V.

Safety

Keep flames, sparks and cigarettes away from a battery while it is charging, and charge it in a well-ventilated place. Wear safety glasses and gloves. If acid splashes into your eyes, rinse them with water for several minutes and seek medical attention.

If it discharges on its own

If the battery goes flat within a few days, look for the cause before replacing it:

  • Short journeys. On trips of less than 25–30 km, the motorcycle does not have time to replace the charge used to start it.
  • Parasitic drain. Alarms, GPS trackers, clocks and control units use some power even when the motorcycle is switched off. At 7 mA, a battery takes around 60 days to drop to half charge; at 30 mA, it takes just 14 days.
  • Charging system. With the engine running at 3000–4000 rpm, the voltage across the terminals should be between 13.0 and 14.5 V. If it stays at the resting voltage, the regulator/rectifier or alternator is faulty.

Leaving a battery on a concrete floor does not discharge it: that’s a myth from the days of old battery cases.

Storing your motorcycle over winter

  1. Charge the battery to 100 % before putting the motorcycle away.
  2. Choose one of two options:
    • leave a smart battery maintainer connected all winter (pulse mode keeps the battery almost fully charged), or
    • disconnect the negative terminal or remove the battery and store it in a cool, dry place.
  3. Without a maintainer, check the voltage every month. If it drops below 12.4 V, charge it. Charge it every 3 months even if it has not dropped below that level.
  4. Before your first ride, check it again and charge it if needed.

Cold and hot weather

  • Heat speeds up discharge. At 10 °C, the battery loses around 0.1 V a month, and the loss doubles for every extra 10 °C. An AGM battery at 0 °C retains most of its charge for months; at 40 °C, it can lose half its charge in four months.
  • Cold does not damage a charged battery, but it can damage a discharged one: the electrolyte in a flat battery freezes at around 0 °C, causing the case to crack or the plates to bend. So, if your garage is unheated, the battery needs to be charged.
  • Lithium batteries should be stored in a cool place, with the motorcycle’s power consumption kept in mind.

Frequently asked questions

Can I leave the charger connected all winter?

If it’s a smart charger with a maintenance phase, yes: it can be left connected to an AGM battery indefinitely. An uncontrolled trickle charger should not be left connected, as it will overcharge the battery.

Which charger should I use for my motorcycle battery?

Use a smart charger for motorcycle batteries, rated at 3 A maximum, with an AGM mode if your battery is AGM. For a lithium battery, use a charger with a lithium profile.

What current should I use to charge a motorcycle battery?

One tenth of its capacity: charge a 10 Ah battery at 1 A. Never use more than 3 A.

How often should I charge the battery if I don’t use the motorcycle?

Check the voltage every month and charge the battery if it drops below 12.4 V. Even if it stays above that level, charge it at least every 3 months. A conventional flooded battery discharges sooner, so check it more often.

Satkit battery

OUTDO UTX7L-BS, YTX7L-BS motorcycle battery shown from the front with both terminals

OUTDO UTX7L-BS

12 V, 7 Ah battery with 75 A CCA, replacing the YTX7L-BS. Supplied factory-activated and charged, ready to fit. Positive terminal on the right.

Where to buyfrom €20.28

Prices incl. VAT checked on 7 October 2026; they may change.

OUTDO UTX9-BS, YTX9-BS motorcycle battery shown from the front with both terminals

OUTDO UTX9-BS

12 V, 9 Ah battery with 135 A cold cranking amps, a replacement for the YTX9-BS. Factory-activated and charged, ready to fit. Positive terminal on the left.

Where to buyfrom €24.35

Prices incl. VAT checked on 7 October 2026; they may change.

Sources

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