Troubleshooting Guide > Vehicle Only Runs When Battery Charger is Plugged Into the Vehicle

Vehicle Only Runs When Battery Charger is Plugged Into the Vehicle

Overview

If the vehicle only runs when the battery charger is plugged into the wall and the vehicle that points toward:

• A battery pack that has been over-discharged and is at a Voltage level that is under the controller's low Voltage cutoff level and that does not allow the battery charger to recharge the battery pack.
• An old, worn out, or faulty battery pack whose Voltage drops under a zero percent state of charge while under load.
• An issue with the fuse, circuit breaker, wiring, connectors, or other parts that are located between the battery pack and controller.

Determine The Battery Pack's History

Determine how long has the battery pack has been left in an uncharged state for. If left uncharged for under 6 months you may be able to successfully recharge the battery pack. However if left uncharged for over 6 months then it is often the case that the battery pack has self-discharged down to a Voltage level where it is not be recharged again and needs to be replaced. Also if the power switch was left on for more than a few days that can also discharge the battery pack down to a Voltage level where it is not be recharged again and needs to be replaced. If you know that the power switch was left on for more than a few days, or that the battery pack has been sitting for a long time without being recharged then the battery pack may have become over-discharged and may need to be replaced.

Try Deep Charging The Battery Pack for 48 to 72 Hours

Sometimes lead-acid battery packs need a deep charge to equalize the cells and help the battery pack regain capacity. Try charging the battery pack for 48 to 72 hours and then see if that helps. It is a good practice to perform a deep charge a couple of times a year or whenever a significant loss of battery capacity is noticed.

Test The Battery Charger Port

(No Tools Needed) If the battery charger is plugged into the wall, unplug it. Plug the battery charger into the battery charger port on the vehicle and look for an illuminated indicator light on the battery charger. If an indicator light on the battery charger illuminates then the wiring and wiring connectors going to the charger port are good and the charger port itself is good. Not all battery chargers have an indicator light that will illuminate when the charger is only plugged into the vehicle, so if the light does not illuminate then a secondary Voltage test with a multimeter should be performed as described below.

(Tool Needed: Multimeter) If you have a multimeter the battery charger port's Voltage can be tested. The Voltage level present at the charging port should be the same as at the battery pack. If the charger port has male terminals then great care needs to be taken to avoid short circuiting the terminals to each other or to the charger port's housing if it is metal.

Test The Battery Charger

(Tool Needed: Multimeter) After testing the charger port and confirming that it has Voltage then the battery charger can be tested. If the charger port has no Voltage then that issue will need to be fixed before testing the battery charger. To test the battery charger to confirm that it is recharging the battery or battery pack, first test the Voltage of the battery or battery pack to confirm that it is below a 100% state of charge and that it needs to be recharged. We have a Battery State of Charge Chart to help with determining if the battery or battery pack needs to be recharged. Once it has been determined that the battery or battery pack needs to be recharged, plug the battery charger into the vehicle's charger port, and then plug the battery charger into the wall. Next test the Voltage of the battery pack with a digital multimeter to see if its Voltage is slowly climbing. The multimeter should be set to a DC Voltage range that allows reading the tenths or hundreds of a Volt of the battery or battery pack. If the battery or battery pack's Voltage slowly climbs to a higher number then that indicates that the battery charger is recharging the battery or battery pack. Continue to charge the battery or battery pack until the light on the charger indicates that it is fully charged, then test the battery or battery pack Voltage to see if it is at a 100% state of charge as specified in our Battery State of Charge Chart. If the charger is not charging the battery or battery pack up to a 100% state of charge then the charger is faulty.

Test The Battery Pack On A Scooter That Runs

Visit our Battery Pack Load Testing Guide.

Test The Battery Pack On A Scooter That Does Not Run

(Tool Needed: Load Tester) If the scooter is not running, a load test can be performed on its batteries by removing the battery pack from the scooter and taking the individual batteries out. The individual batteries can then be tested with a automotive battery load tester. Most entry level automotive battery load testers place a 100 Amp load on the battery which is too high so an adjustable carbon pile battery load tester is required and should be adjusted to place a 30 Amp load on the batteries.

Test The Voltage Of The Battery Pack

(Tool Needed: Multimeter) If you have a multimeter the battery packs Voltage can be tested to determine its condition. A good battery packs Voltage will be above its rated Voltage level even if it has been fully discharged and allows to sit a few minutes, or if it has been in storage. If a battery packs Voltage does not bounce back to above its rated Voltage level within a few minutes after being discharged that points towards a defective or worn-out battery pack. When a battery pack has been fully charged and its Voltage is below its rated Voltage level that also points towards a defective or worn-out battery pack. Good scooter battery packs will bounce back to above their rated Voltage level within a few minutes after the scooter has been driven.