For charging a semi-traction battery, a charger with specific properties is usually recommended. Here are some characteristics to watch for when choosing a charger for a semi-traction battery:

1. Suitable charging current: Make sure that the charger can provide a charging current suitable for the capacity of the semi-traction battery. Refer to the battery specifications to find out the recommended charging current and choose a charger that can deliver it.

2. Battery type: Check if the charger is suitable for the specific type of battery you have. Semi-traction batteries are usually lead-acid batteries, so ensure that the charger is suitable for this type of battery.

3. Charging profile: Some chargers have different charging profiles for different types of batteries. Ensure the charger has a profile that suits semi-traction batteries or can be set to an appropriate charging program.

4. Safety features: It is important that the charger has safety features such as protection against overcharging, short circuit, reverse polarity, and thermal protection. These features ensure a safe and reliable charging process.

5. Quality and reliability: Choose a charger from a reputable brand with good reviews and reliable performance. A quality charger ensures optimal charging and helps extend the battery's lifespan.

It is always advisable to follow the instructions and recommendations of the manufacturer of the semi-traction battery when choosing a charger. They may have specific recommendations that take into account the characteristics of their batteries.