Lithium battery conversion for old electric tricycles is a cost-effective upgrade method, which can solve the problems of short cruising range, heavy weight, frequent failure, and short service life of original old lead-acid batteries. Most old three-wheel tricycles are originally equipped with lead-acid battery packs. After converting to lithium batteries, the vehicle’s cruising ability, power performance, and battery service life can be significantly improved, and the later maintenance cost is greatly reduced. The conversion process is mature and suitable for most old passenger tricycles and cargo tricycles, with high practicability and economy.

First, confirm the matching specifications before conversion. The core principle of lithium battery modification for old tricycles is that the battery voltage must be consistent with the original vehicle voltage system. If the original old tricycle is a 60V or 72V lead-acid battery system, the matching 60V or 72V lithium battery must be selected, and the voltage cannot be arbitrarily increased or decreased, otherwise it will cause damage to the vehicle controller, motor, and instrument panel. In terms of capacity, users can choose 20Ah, 30Ah, 40Ah and other specifications according to daily use needs. Compared with lead-acid batteries, lithium batteries of the same capacity are 50%–60% lighter, which can reduce the overall weight of the tricycle, reduce motor load, and save power consumption. For old tricycles used for daily passenger transport and short-distance cargo transport, 72V30Ah lithium battery is the most cost-effective modified specification.

The specific conversion steps are simple and suitable for personal operation or professional modification. First, turn off the tricycle power supply, remove the original lead-acid battery pack, clean the battery installation compartment, and check whether the vehicle circuit harness is aging or damaged. If there is circuit aging, replace the harness first to avoid potential safety hazards. Second, install the new lithium battery into the original battery compartment. Most lithium batteries are designed with drop-in size, which can perfectly match the original lead-acid battery installation position without drilling or modifying the vehicle body. Then, connect the positive and negative lines correctly, ensure the wiring interface is firm and insulated, and avoid short circuit caused by loose wiring. Finally, replace the special lithium battery charger. The original lead-acid charger cannot charge the lithium battery, otherwise it will cause over-charging and damage the lithium battery protection board.

There are key safety precautions for lithium battery conversion of old tricycles. First, must choose a regular lithium battery with an integrated protection board, which has over-voltage, under-voltage, over-current, short-circuit and temperature protection functions to ensure safe use. Second, do not pursue high capacity blindly and modify the voltage privately, which will cause the vehicle circuit system to be unable to bear the load and burn out electrical parts. Third, after the conversion is completed, test drive at low speed first, check whether the power output is stable and whether the instrument display is normal, and confirm no abnormality before normal use. In addition, lithium batteries have stricter temperature adaptability. Old tricycles modified with lithium batteries should avoid collision and extrusion during use, and avoid charging in high-temperature and humid environments, so as to extend the service life of the modified lithium battery.