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expand the relevant charging voltage
no-load voltage of the charger – for three-stage charger for float voltage is the voltage, usually to a single cell 13.5v-13.8v (typically the battery have indicated, can also be found according to the manual), then for the 36v it is: 40.5v-41.4v, compared to the 48v: 54v-55.2v.
Therefore, considering the error of your multimeter, 53.6v 55.6v appears are considered normal and, after all, has been transferred charge phase and light, so its value is required so it is not very harsh.
charge voltage
Charger – This voltage is called the turn lamp voltage, typically a single battery 14.4v-15.0v (marked with a general secondary battery, may be isolated according to the manual), then for 36v is: 43.2v-45.0v, 48v, compared to: 57.6v-60.0v.
The actual charging end voltage charger – for sealed batteries, its value should be the best to 2.4v per cell, corresponding to 36v so as 43.2V, the correspondence of 57.6v 48v.
But in fact the reason for an appropriate increase in this value is out of the charging time and “full” to consider, which is 36v is 44.4-44.8v, as 59.2v-59.7v 48v, but so easy resulting in water loss and shorten battery life, both advantages and disadvantages. It is not easy to figure out, just know that here is how to determine the value of voltage on it.