A logging machine in British Columbia equipped with a 24V electrical system exhibits symptoms of dim lights and slow cranking. A technician measures 12.2V at one battery and 11.8V at the other battery, with both batteries wired in series. What is the most likely cause of the issue?

Question: A logging machine in British Columbia equipped with a 24V electrical system exhibits symptoms of dim lights and slow cranking. A technician measures 12.2V at one battery and 11.8V at the other battery, with both batteries wired in series. What is the most likely cause of the issue?

Answer options: ✅ One or both batteries are failing or significantly discharged.

• The alternator is overcharging the batteries.
• A short circuit in one of the machine's 12V accessories.
• The engine glow plugs are drawing excessive current.

Correct answer: One or both batteries are failing or significantly discharged.

Explanation: In a 24V series system, each 12V battery should be close to 12.6V when fully charged. Readings of 12.2V and 11.8V indicate undercharged or failing batteries, which would result in insufficient overall voltage (approximately 24V under load instead of a healthy 25.2V+) for proper operation of lights and starting.