The power of the lithium battery is too low, which means that the capacity of the lithium battery is insufficient. Replace it with a larger lithium battery.
The reasons for low lithium battery current include: generator V-belt slippage; poor contact of the charging circuit; poor contact between the brush and the collector ring; armature winding short circuit; open circuit or partial short circuit of the stator winding; the voltage regulator is not working properly, etc.
Generally speaking, when the battery is close to a fully charged state, it is normal for the charging current to be too low.
But if the battery does not have enough power and the charging current is too low, it means the charging system is defective. The reasons may be generator faults: the belt slips. You have tocheck the tightness. of the belt, or painting the belt with “belt grease” will suffice; individual diodes are disconnected; one phase of the stator winding is poorly connected or open or the brushes are excessively worn or the slip ring is oily, resulting in poor contact; between the brushes and the slip ring.