The Quick Diagnosis If your scissor lift batteries won't hold a charge but the charger seems to be running, the charger's DC output has likely failed. A multimeter test showing 0V DC or a voltage below 26V on a 24V system confirms the charger is bad and needs to be replaced. The likely culprit is an internal failure of the control board or rectifier.
Symptoms & Identification
If you're reading this, you've probably seen one of these classic signs of a failed or failing charger:
- Machine is dead after charging all night: The battery gauge may show full, but the lift dies minutes after being unplugged.
- Charger flashes error lights: Many Delta-Q or Schauer chargers use a Red-Green-Red flash pattern to signal an internal fault.
- Loud humming from the charger, but no charge: This means the AC side is getting power, but the DC output has failed.
- A "rotten egg" smell near the batteries: The charger is overcharging and boiling the electrolyte, a dangerous condition.
Tools Required
- A quality Digital Multimeter (rated for AC/DC voltage and amperage)
- Insulated hand tools (wrenches, screwdrivers)
- Safety Glasses
- Class 0 Insulated Gloves
Safety Warning
High-amperage DC systems can create a violent arc flash if shorted, causing severe burns and vaporizing tools. Always disconnect the main negative terminal from the battery pack before you begin any work. Batteries release explosive hydrogen gas during charging; work in a well-ventilated area and avoid creating any sparks.
The Technical Guide (Step-by-Step)
Follow these steps in order to diagnose a faulty scissor lift charger. Skipping steps is how you miss the obvious and waste time.
1. Test the AC Input Voltage
Before blaming the charger, confirm it’s getting power from the wall.
- Set your multimeter dial to AC Voltage (V~). Use the 200V setting for a standard 120V outlet.
- Insert the probes into the wall outlet. You must see a reading between 110V and 125V AC.
- If the outlet is good, plug the charger's AC cord in.
- If the charger has no lights or signs of life, the AC power cord itself may be faulty.
A solid 110V-125V AC into the charger is non-negotiable. If you don't have it, fix the supply power first.
2. Test the DC Output Voltage
This is the critical test. It tells you if the charger's internal components (transformer, rectifier, control board) are working.
- Reconnect the main negative battery terminal if you disconnected it for safety checks. The charger must be connected to the battery pack to produce an output voltage.
- Set your multimeter dial to DC Voltage (V⎓). The 200V DC setting is appropriate for 24V or 48V systems.
- Carefully connect the red (positive) probe of your multimeter to the charger's main positive output terminal or lead.
- Connect the black (negative) probe to the charger's main negative output terminal or lead.
- Read the voltage on the display. For a 24V battery system on a machine like a Dingli or LGMG, you should see a voltage between 26.0V and 29.0V DC. This confirms the charger is in its "bulk charge" phase and is working correctly.
A reading of 0V DC or a voltage stuck below 25V indicates a failed charger that must be replaced.
3. Test the DC Output Amperage (Optional, with Clamp Meter)
Voltage tells you if the charger can work; amperage tells you if it is working right now.
- Set your clamp meter to DC Amps (A⎓).
- Clamp the meter's jaws around only one of the main DC output cables (either positive or negative). Clamping both will give a zero reading.
- On a discharged battery pack, the amperage should be close to the charger's rating (e.g., a 25A charger should read close to 25A). As the batteries charge, this number will drop.
A reading of 0A with correct voltage points to a failed current regulation circuit in the charger or a bad connection in the output plug.
The Part You Need
For most Chinese lifts from brands like Sinoboom, Dingli, and LGMG, the charger is a standard unit from a manufacturer like Delta-Q or Schauer. You do not need a dealer-branded part. A Delta-Q QuiQ 912-2400 is a common 24V charger that fits many models, provided it has the correct charging profile for your batteries (Flooded vs. AGM). These universal-style chargers fit multiple brands.
China Lift Supply stocks these OEM-compatible chargers in the US, programmed and ready for same-day shipping to eliminate the 6-week dealer lead time.
Can't wait 6 weeks for this part? We have it on the shelf in Kansas. Check the price and availability here: scissor lift battery chargers.
