How to Jump Start a Dead Forklift Battery

A forklift battery can wear down for any number of reasons. The vehicle could have been used too long before being recharged. The truck may have been left parked with its lights on. Even extremely cold weather can sap the charge from a battery.

Forklift batteries are too heavy to remove and replace with a fresh one. So if your forklift loses its charge, rather than towing it back to the garage, another option is so simply jump start it.

Step-by-Step Jump Starting Instructions

Here are steps to jump start a forklift battery using a fully charged booster battery in another truck. Keep in mind that jump starting a forklift battery can be potentially dangerous — both to the vehicle and to yourself — so follow these steps carefully. If you are unsure, call for a tow.

1. Only use a 12-volt negative ground battery to jump start your forklift. (Use a 12-volt battery X 1 for 12-volt models.) If you aren’t sure of your battery’s voltage or if it has a different ground, don’t try to jump start it because you could hurt yourself or damage your forklift’s electrical system, which may not be covered under warranty.

2. Check the fluid level of the dead battery. If it’s low, add distilled water until it reaches the proper level. Put the caps back on before jump starting your battery.

3. Bring the booster battery as close to the dead forklift as possible so that the jumper cables reach. But make sure the trucks aren’t touching each other. Be careful when connecting a booster battery so that it doesn’t spark.

4. Engage the parking brake on both trucks. Both should be in neutral and have their ignition switched off. Turn off all accessories, including the headlamps and leave them off until the battery has been jump started.

Connecting the Jumper Cables

5. Now you want to connect the jumper cable, following this exact sequence:

A. Connect the red jumper cable from the positive (+) terminal on the live battery to the positive (+) terminal of the dead battery. Never connect a positive (+) to a negative (-) or a negative (-) to a positive (+) because  this can damage your alternator. Make sure the clamps aren’t touching any other metal.

B. Connect one end of the black cable to the ground (-) terminal of the forklift with the live battery.

C. Finally, connect  the other end of the black jumper cable to a stationary, solid metal point on the engine of the dead forklift. Make sure you don’t connect it to the negative (-) terminal of the battery! This connection should be a minimum of 18 inches away from the battery. Don’t connect it to pulleys, fans or other moving parts of the motor.

6. Start the engine of the live forklift and run the engine at a moderate speed for a few moments.

7. Start the engine of the dead battery, following your normal starting procedures. It may take a moment for the engine to catch. Once the engine has started, let it idle for at least two minutes before disconnecting the jumper cables using the exact reverse sequence — in other words, remove the black jumper cable from the engine block of the (formerly) dead forklift then remove the other end of the negative (-) lead from the live truck. Then remove both ends of the red jumper cable.

Incidentally, this same sequence works for jump starting a dead car battery!