The Charger LED is Stuck Flashing Red and Green
The Charger LED is Stuck Flashing Red and Green (LiFePO4)
Situation
The lithium (LiFePO4) batteries do not have enough power to move the cart.
Common Cause
Lithium (LiFePO4) batteries contain a protection circuit that protects the battery against damage from full depletion, as well as overcharging and other things that could damage the batteries.
This scenario is common, especially in carts that haven't been charged for a prolonged period or have been completely drained. In such cases, a standard lithium golf cart charger is unable to initiate the charging process due to the batteries being "asleep."
How to Confirm
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Check Voltage: Use a multimeter to check the voltage over the entire battery pack.
- If your pack voltage is testing below 2.0V per cell, the battery is likely in sleep mode or damaged.
- BMS Reset: If the battery has a built-in BMS, try resetting it according to the manufacturer's instructions.
How To Fix
Option 1: Jump Start with a Fully Charged Battery
- Get a fully charged lithium battery of the same voltage
- Connect the positive and negative terminals of the good battery to the matching terminals of the dead battery using jumper cables.
- Let the batteries stay connected for 1–5 minutes.
- Disconnect the cables, then plug your smart charger into the depleted battery to begin charging.
Option 2: Use a Regulated Power Supply or Manual Charger
- Use a DC power supply or manual charger set to the battery’s rated voltage (e.g., 12V) and a low current (1–2 amps).
- Connect the power source to the battery for a few minutes.
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Once the voltage reaches a safe level, switch to your smart charger to continue charging normally.
⚠️ Always monitor closely—manual chargers won’t shut off automatically.
The following video walks through some ways to wake up a battery that is in sleep mode.
Equipment Used / Where To Buy
After the batteries have more than 2.5V per cell, does the FORM Charge charger start a charge cycle?
The Charger LED is Stuck Flashing Red and Green (Lead-Acid)
Situation
The batteries have enough charge to move the cart.
Common Cause
The most common culprit is a weak or bad cable connection between the receptacle and the battery pack.
The wire from the receptacle to the batteries is often a small gauge wire similar to a cheap speaker wire. Over time, the end connected to the batteries often frays or corrodes, making it difficult to reattach or easily dislodged when replacing batteries or cleaning battery terminals.
How to Confirm
- Set Multimeter: Set your multimeter to DC Voltage at 200VDC
- Read Receptacle Voltage: Take a voltage reading at the front side of your receptacle where you would insert your charger plug.